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Ptyctodontida

Admin — Fri, 15 Sep 2006 21:12:16 GMT

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{{Taxobox
| color = pink
| name = Ptyctodontida
| fossil_range = Early/Mid [[Silurian]] - Late [[Devonian]]
| status = {{StatusFossil}}
| regnum = [[Animal]]ia
| phylum = [[Chordate|Chordata]]
| subphylum = [[Vertebrate|Vertebrata]]
| infraphylum = [[Gnathostomata]]
| classis = [[Placodermi]]
| classis_authority = McCoy, 1848
| ordo = [[Ptyctodontida]] [[extinction|†]]<br />
| subdivision_ranks = [[Family (biology)|Familie]]s
| subdivision =

}}

The Ptyctodontids were a group of primitive, unarmoured placoderms. Their armor was reduced to small plates around the face and neck.

[[Category:Prehistoric fish]]
[[Category:Placoderms]]
{{fish-stub}}

Bothriolepis

Admin — Sat, 09 Sep 2006 05:28:22 GMT

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Pseudopetalithchyida

Admin — Sat, 09 Sep 2006 05:27:43 GMT

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Gemuendina stuertzi

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<div style="float:right;">
<table border="1" cellspacing="0" cellpadding="2">
<tr><th bgcolor="#CCCCCC">'''[[Placodermi]]'''</th></tr>
<tr><td>
*[[Domain]]: [[Eukarya]]
*[[Kingdom]]: [[Animalia]]
*[[Phylum]]: [[Chordata]]
*[[Subphylum]]: [[Vertebrata]]
*[[Infraphylum]]: [[Gnathostomata]]
*[[Class]]: '''[[Placodermi]]'''
</td></tr>
<tr><td>
'''Order:'''
*[[Rhenanida]] [[extinction|†]]<br />
</td></tr>
<tr><td>
'''Family:'''
*[[Asterosteidae]]
<tr><td>
'''Genus:'''
*'''''Gemuendina'''''
</td></tr>
<tr><td>
'''Species:'''
*'''''G. stuertzi'''''
</td></tr>
<tr><td>
Fossil_range:
Early [[Devonian]]
</td></tr>
</table>
</div>

'''''Gemuendina stuertzi''''' was an early [[placoderm]] of the order [[Rhenanida]], of the seas of Early [[Devonian]] Germany. ''Gemuendina'' resembled a scaly ray with a pair of staring eyes, a pug-nose, and an upturned mouth. This leads virtually all artists who reconstruct it to give the creature a quizzical, almost shocked expression.

Unlike most other placoderms, such as the [[Antiarcha| Antiarchs]], or the [[Arthrodira| Arthrodires]], ''Gemuendina'' and its three other known relatives had armor made up of a mosaic of unfused bony plates. Also unlike other placoderms, it did not have the characteristic tooth plates of placoderms. Instead, it had star-shaped tubercle scales that allowed it to pick out [[shellfish]] and [[echinoderms]] out of the sediment, and crush them.

==References==
Paleos Rhenanida [http://www.palaeos.com/Vertebrates/Units/Unit060/060.100.html#Rhenanida]

[[Category:Prehistoric fish]]
[[Category:Fish]]
[[Category:Placoderms]]

Stensioella heintzi

Admin — Sat, 09 Sep 2006 05:26:26 GMT

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Stensioellida

Admin — Sat, 09 Sep 2006 05:25:41 GMT

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#REDIRECT [[Stensioella heintzi]]

Rhenanida

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Phyllolepida

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Petalichthyida

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Arthrodira

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Antiarchi

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Placodermi

Admin — Sat, 09 Sep 2006 05:22:41 GMT

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<div style="float:right;">
<table border="1" cellspacing="0" cellpadding="2">
<tr><th bgcolor="#CCCCCC">'''Placodermi'''</th></tr>
<tr><td>
*[[Domain]]: [[Eukarya]]
*[[Kingdom]]: [[Animalia]]
*[[Phylum]]: [[Chordata]]
*[[Subphylum]]: [[Vertebrata]]
*[[Infraphylum]]: [[Gnathostomata]]
*[[Class]]: '''Placodermi'''
</td></tr>
<tr><td>
'''Orders:'''
*[[Antiarchi]] [[extinction|†]]<br />
*[[Arthrodira]] †<br />
*[[Petalichthyida]] †<br />
*[[Phyllolepida]] †<br />
*[[Ptyctodontida]] †<br />
*[[Rhenanida]] †<br />
*[[Acanthothoraci]] †<br />
*?[[Stensioellida]] †<br />
*?[[Pseudopetalithchyida]] †
</td></tr>
<tr><td>
Fossil_range:
Early [[Silurian]] - Late [[Devonian]]
</td></tr>
</table>
</div>

The [[Class]] '''Placodermi''' is composed of a group of armoured [[prehistoric fish]]es known from [[fossil]]s dating from the late [[Silurian]] to the end of the [[Devonian]] Period. Their [[head]] and [[thorax]] were covered by articulated armoured plates and the rest of the body was scaled or naked. Placoderms were one of the first [[jaw]]ed [[fish]], their jaws likely evolving from the first of their [[gill]] arches. Starting with the the studies of Dr Erik Stensio, and supported by uncrushed fossils that preserve their 3-dimensional structures from the Gogo Reef formation in Australia, it is presumed that sharks share a common ancestry with placoderms.

The first identifiable placoderms evolved in the late [[Silurian]]; they disappeared in the [[Late Devonian extinction]]s. The first appearance of late [[Silurian]] placoderm fossils, in [[China]], show the fishes already differentiated into [[Antiarchi|Antiarchs]] and [[Arthrodira|Arthrodires]], along with the other, more primitive groups; apparently Placoderm diversity originated long before the Devonian, somewhere in the middle Silurian, though earlier fossils of basal Placodermi, have yet to be discovered in these particular strata.

Many placoderms, particularly the [[Rhenanida]], [[Petalichthyida]], [[Phyllolepida]], and [[Antiarchi]], were bottom-dwellers. As such, to paraphrase from what was said in Paleos, Placodermi has been popularly misinterpreted as being a tribe of bottom-feeding snails and garbage trucks, nevermind that the placoderms were the dominant vertebrate group during the Devonian. One must remember that the vast majority of placoderms were predators, many of which lived at or near the bottom. Many, primarily the [[Arthrodira]] were mid- to upperwater dwellers, and were active predators. The largest known arthrodire, ''[[Dunkleosteus telleri]]'', was an 8 to 11 meter long predator and was presumed to have a nearly worldwide distribution, as its remains have been found in Europe, North America and Morocco. Other, smaller arthrodires, such as ''[[Fallacosteus]]'' and ''[[Rolfosteus]]'' of Gogo, had streamlined, bullet-shaped head armor, strongly crediting the idea that many, if not most, arthrodires were active swimmers, rather than passive ambush-hunters whose armor practically anchored them to the seafloor.

It was originally thought that the placoderms went extinct due to competition from the first bony fish, as well as the early sharks, due to a combination of the supposed inherent superiority of the bony fish and sharks, as well as the presumed sluggishness of the placoderms themselves. Since then, though, as more accurate summaries of prehistoric organisms have been developed, it is now presumed that the last placoderms died out one by one as each of their ecological communities suffered due to the environmental catastrophes during the Devonian/Carboniferous extinction event.

The earliest studies of placoderms were published by [[Louis Agassiz]], in his five volumes on fossil fishes, 1833 – 1843. In those days, the placoderms were thought to be shelled jawless fish akin to ostracoderms. Some naturalists even suggested that they were shelled invertebrates, or even turtle-like vertebrates. The work of Dr. [[Erik Stensio]], at the [[Swedish Museum of Natural History]], Stockholm, from the late 1920s established the details of placoderm anatomy, and identified them as true jawed fishes related to [[shark]]s. He took fossil specimens with well-preserved skulls, and ground them away, one-tenth of a millimeter at a time. Between each grinding, he made an imprint in wax. Once the specimens had been completely ground away (and ironically, completely destroyed as a result), he made enlarged, three-dimensional models of the skulls in order to examine the anatomical details more thoroughly. Many other placoderm specialists suspected that Stensio was trying to shoehorn placoderms into a relationship with [[shark]]s, but with more [[fossil]] specimens found, especially the exceptionally well-preserved fossils from the Gogo Reef formation in Australia, Stensio's theory of sharks and placoderms as sister groups is accepted as fact.

== See also ==
*''[[Gemuendina stuertzi]]''
*''[[Bothriolepis]]''
==External links==
*[http://hoopermuseum.earthsci.carleton.ca/placoderms/first.html Annetta Markussen-Brown, "Devonian Armoured Fish" 2000]
*[http://www.ucmp.berkeley.edu/vertebrates/basalfish/placodermi.html Introduction to the Placodermi Extinct armored fishes with jaws]
*[http://www.btinternet.com/~vendian/FOSSILWEB/paleozoic_fish.htm PALAEOZOIC FOSSILS UK]
*[http://www.toyen.uio.no/palmus/galleri/montre/english/m_panserhai_e.htm Placoderms]
*[http://www.palaeos.com/Vertebrates/Units/Unit060/060.000.html Placodermi: Overview]
*[http://www.amonline.net.au/archive.cfm?id=1137]

[[Category:Prehistoric fish]]
[[Category:Fish]]
[[Category:Placoderms]]

Petalocrinus

Admin — Sat, 09 Sep 2006 05:22:02 GMT

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'''''Petalocrinus''''' was a [[genus]] of [[crinoids]] from the [[Silurian]]. They are extremely distinctive from most, if not all other crinoids, in that their arms were modified into relatively large, wedge-shaped plates that gave their owners a decidedly flower-like appearance. All though the genus did not live out the Silurian, it was quite successful, with at least 15 species found in the United States, China, and Sweden (primarily from Gotland).

''P. mirabilis'' is the type species, with specimens found in Iowa, British Columbia, and Yunnan province in China.

== Links ==

Reconstruction of ''P. mirabilis'' [http://www.deviantart.com/deviation/33783990/]

List of species [http://crinoid.gsajournals.org/crinoidmod/indexii?genus=PETALOCRINUS]

[[Category:Prehistoric invertebrates]]

Eotitanops

Admin — Sat, 09 Sep 2006 05:20:36 GMT

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Main Page

Admin — Sat, 26 Aug 2006 20:29:48 GMT

Admin: Reverted edit of 67.33.130.38, changed back to last version by Bmeyers

Welcome to PaleosWiki!

Here, we intend to create a catalogue of prehistoric organisms!

[http://web.archive.org/web/*sa_/http://www.palaeos.com/ Internet Archive] of Palaeos.com

== Life ==

This section is the heart of Palaeos. We have to begin this section somewhere, and so this is also the Beginning of [[Life]]. If time permits, we will one day add sections on the definition of "life" and the ways it may have begun. However, that kind of systematic treatment is not exactly what this site is all about (see, infra, the Purpose of Life). So instead, we'll get right to business.

=== Bacteria ===

Bacterial phylogenetics and systematics are areas that are fraught with controversy, confusion and very little concordance. To attempt to fit some sort of analysis of them within the confines of a single web-page, and without years of study to give oneself authority, would be the height of folly. With that in mind, feel free to read on, as we strive to raise ourselves to greater heights than ever before. If any of the arguments presented seem somewhat circular and self-contradictory, they probably are. You have been warned.

=== Eukarya ===

Organisms in which the genetic material is contained within a nuclear membrane are known as Eukaryotes, the name means "true kernel". This domain includes all multicellular forms of life: Plants, Fungi, and Animals. However, in this section, we will deal only with the group classically called "Protista," single-celled Eukarya. In fact, the line is a bit vague. By convention, slime molds are treated as "protists" while sponges and Cnidaria (or at least most of them, as we will see) are treated as Metazoa. Similar uncertainty marks the borderlands of the plants and fungi.

=== Fungi ===

The Fungi are the great saprophytes, the master recyclers. They are the black rot, the dry rot, and the white rot, the colorful fate of last week's lasagna left too long in the 'fridge, and the great, grey walls of stinking mould that can destroy whole buildings. But, they are also the baker's yeast and the brewer's yeast. They are the difference between grape juice and Chateauneuf du Pape. They are the portobellos and the morels and the cloud ears and the truffles. In fact, the French could not be half so obnoxious about their cuisine were it not for the Fungi. But, then again, perhaps they could [1].

=== Plants ===

Beginning in the Archean era, Cyanobacteria evolved photosynthesis, which enabled them to use sunlight to draw carbon dioxide from the atmosphere and convert it to oxygen, water and glucose (a simple carbohydrate). These could be considered the first simple "plants" Plants therefore might be seen as any organism that is able to use sunlight, carbon dioxide, and water, to manufacture its own food, that is, as a special class of autotroph. However, that's far too broad. It would include all kinds of things like diatoms, chromists, and photosynthetic bacteria which have nothing to do with plants in a phylogenetic sense. They are, to be sure, all within the subject matter of a General Botany class. All of these groups share some essential biochemistry. However, what they don't share is a common ancestor to the exclusion of all other organisms. This similarity arises from (a) convergent evolution and (b) the exchange of plastids.

=== Invertebrates ===

=== Chordates ===

== [[Time]] ==

Geologists and Paleontologists measure the age of the Earth and the history of life in ages of millions and even billions of years. The entire history of humankind is but a blink of an eye next to the vastness of geological time. For this reason a special sort of "calendar" or "almanac" is required; one that measures not days, weeks, months or years, but millions and tens of millions of years. This is the Geological Time-Scale

=== [[Hadean]] ===

The name Hadean was coined by geologist Preston Cloud for the pre-Isuan sequence whose record may not be preserved on Earth but is better known from Moon rocks. Consequently, the time sequence and stratigraphy of the Hadean are largely based on lunar events. For example the Nectarian Era is defined by reference to the formation of the Nectaris Basin (southwestern Nearside). The Hadean has no place in the ICS system followed in the rest of Palaeos. The ICS lumps everything earlier than 3600 Mya into the Eoarchean Era of the Archean Eon.

=== Archean ===

Rocks of the Lower Archean (in geology time is often referred to vertically, because younger rocks are deposited above older ones) are rare, and include the oldest known terrestrial rocks, from 3.8 to 4.2 billion years ago. Most of the oldest rocks are so altered through subsequent metamorphic processes it is difficult to know under what conditions they were formed. The situation is rather brighter with the more numerous rocks of the Younger ("Upper") Archean, from 3 to 2.5 or 2.6 billion years ago. These are mostly volcanic in nature, consisting of pillow-like structures identical to those of present-day lavas which have formed underwater. The implication is that at this time the entire Earth was covered by ocean. Perhaps the bulk of the continental masses, formed through volcanic outpourings, had yet to appear from beneath the waves.

=== Proterozoic ===

Beginning in the Archean era, Cyanobacteria evolved photosynthesis, which enabled them to use sunlight to draw carbon dioxide from the atmosphere and convert it to oxygen, water and glucose (a simple carbohydrate). These could be considered the first simple "plants" Plants therefore might be seen as any organism that is able to use sunlight, carbon dioxide, and water, to manufacture its own food, that is, as a special class of autotroph. However, that's far too broad. It would include all kinds of things like diatoms, chromists, and photosynthetic bacteria which have nothing to do with plants in a phylogenetic sense. They are, to be sure, all within the subject matter of a General Botany class. All of these groups share some essential biochemistry. However, what they don't share is a common ancestor to the exclusion of all other organisms. This similarity arises from (a) convergent evolution and (b) the exchange of plastids.

=== Paleozoic ===

The early Paleozoic saw the continents clustered around the equator, with Gondwanaland (representing the bulk of old Rodinia) slowly drifting south to the poles, and Siberia, Laurentia and Baltica converging in the tropics. There was a large ocean between Laurentia and Eastern Gondwanaland.

=== Mesozoic ===
=== Cenozoic ===

== Science and Literature ==
=== Evolution ===
=== Geochronology ===
=== Systematics ===
=== The Earth ===
=== Ecology ===
=== Books ===

Talk:Chlorobionta

Admin — Sat, 19 Aug 2006 19:21:39 GMT

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This page is approaching (or has already exceeded) the 32K limit that some browsers can display. It needs to be cut up into separate pages.
:Why don't we slice it up into separate pages, per section?--[[User:Admin|Stanton]] 23:46, 18 August 2006 (EDT)

I've taken the liberty to cut this page up into separate pages... Anything else we need to do?--[[User:Admin|Stanton]] 15:21, 19 August 2006 (EDT)

Embryophyta

Admin — Sat, 19 Aug 2006 19:18:27 GMT

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=== Bryophyta ===

Bryophyte Life Cycle If the mosses had not survived into the present, we would be forced to invent them as just the sort of intermediate we might expect between essentially aquatic algae and fully terrestrial plants. Mosses do have differentiated stems. Although these are generally only a few millimeters tall, they are still designed to provide mechanical support against gravity without help from water -- the first such structure in any kingdom. Bryophytes also have leaves. These are typically one cell thick and lack veins, although they may have a central thickening for support. Mosses also have rhizomes. These may have some function in extracting soil nutrients, although their primary function seems to be mechanical attachment to the substrate. Thus they are not true roots, but do approach that condition.

The bottom line is that, structurally, mosses really differ from rhyniophytes in only one aspect: mosses lack specialized vascular tissues. That alone is sufficient to explain the lack of big leaves, long stems, and true roots. This whole complex of characters is thus probably primitive. The other distinctive character of mosses is that the plant we normally observe is the haploid, gametophyte stage. But this character is shared with liverworts (basal embryophytes) and so is also probably plesiomorphic.

Curiously, in hornworts (also basal embryophytes) the sporophyte generation is dominant. In addition, it turns out that the leaves of moss probably evolved independently from the leaves of higher plants. So the relationships of the mosses and basal embryophytes are still uncertain. What really does seem to set mosses apart is their unique form of leaf. What really seems to unite mosses with higher plants is (a) the presence of stomata to control water loss and (b) meristem (apical growth) in the sporophyte generation. See, Friedman et al. (2004). Phylogenetically, we treat Bryophyta as Moss > Quercus.

=== Rhyniophtya ===

HorneophytonSee Rhyniophyta. That section covers the basal rhyniophytes, such as Horneophyton, which were the first real land plants. These probably evolved in the Ludlow and formed the stem group for all other land plants. Consequently, they are paraphyletic. Rather than abandoning this name and its rich history, we use it to mean all land plants. Our working phylogenetic definition is definition is Quercus > moss.

This group is characterized by the ability to reproduce without open water. Anatomically, in all rhyniophytes, the (diploid) sporophyte generation is dominant, and the sporophyte is branched. For this reason, the taxon is often referred to as the Polysporangiophytes. In addition, the archegonium develops inside the body of the plant, rather than being superficial as in mosses and most basal embryophytes. Kenrick & Crane (1997).

Horneophyton and a few other basal forms lack tracheids. That is, they are avascular plants. However, almost all other rhyniophytes have some development of specialized vascular tissues. The most basal tracheid type, present in most stem rhyniophytes, appears to be the S-type tracheid.

=== Lycophytina ===

The Lycophytina includes the lycopods, zosterophylls, and related forms, including (probably) a number of plants often treated as basal rhyniophytes, such as Baragwanathia. Kenrick & Crane (1997). Since they are a complex group and are treated extensively elsewhere, we will defer discussion to a revision of the existing materials.
Euphyllophytina

The clade that unites oak trees and ferns is Euphyllophytina = Quercus + Equisetum. The two complementary stem clades are Moniliformopsida and Spermatophytata. Euphyllophytines are characterized (Kenrick & Crane, 1997) by monopodial or pseudomonopodial branching, helical arrangement of branches, small, pinnule-like vegetative branches, the branch apex is recurved or coiled, paired sporangia which split open along one side through a single slit, and radially-alligned xylem in the larger axes. Only early euphyllophytines have P-type tracheids. Kenrick & Crane identified this clade based entirely on morphological characters. However, Euphytophytina has also been recovered, with essentially the same structure, using ssu rDNA. Duff & Nickrent (1999).

=== Moniliformopses ===

Psilotum nudumThe Moniliformopses are the horsetails and ferns, including the Psilotidae (whisk ferns). They are closely related to the seed plants. Pryer et al. (2001). So, for example, they exhibit apical growth (meristem) in both sporophyte and gametophyte generations. They have well-developed roots megaphyllous leaves and the vascular system needed to make use of both. However, both may have been evolved independently of higher plants. Friedman et al. (2004). In addition, Moniliformopses lack a complete vascular cambium, and growth of xylem is restricted to lobes of the primary xylem strand.

Since this is a new clade -- discovered, for all practical purposes, by Preyer's group, we have little to say about Moniliformopses as a taxon, and defer discussion to a fuller consideration of its three component parts. The Psilotidae are the most basal, followed by the horsetails, then the remainder of the ferns.

We apply a crown group defiition to Moniliformopses: Equisetum + ferns.

=== Spermatophytata ===

PsilophytonThe clade that unites oaks and lycopsids is Euphyllophytina. The two complementary stem clades are Lycopsida and Spermatophytata = Quercus > Lepidodendron. A second way to look at Spermatophytata is as the stem group leading to angiosperms. It includes Trimerophyta and the progymnosperms, in fact everything up to and including the seed plants (Spermatopsida). However, we will only be concerned with the more basal forms for now. A third way of considering Spermatophytata is as the seed plants. However, this applies only to living forms. The basal Trimerophyta and their immediate descendants (assuming Trimerophyta is paraphyletic) lacked seeds, true leaves, or even, perhaps, roots. It is quite likely that virtually all the important land plant adaptations were independently developed in the moniliformopsid and spermatophytate lineages.

What seems to have set Spermatophytata apart quite early is not, in fact, the development of seeds, but the evolution of a full vascular cambium which permitted secondary growth. Early plants with apical growth were able to use that trait to grow taller and (a) get more sunlight (b) shade their competition and (c) have a better shot at spore dispersal. However, supporting a long stalk is much easier with a wider central column. Less derived groups either had no way to do this, or developed lateral lobes of the apical meristem. The latter worked, but required the tree to grow wide before it grew tall. The evolution of a complete vascular cambium permitted the tree to grow just wide enough to suit its height -- growing continuously wider as it grew tall.

The evolution of seeds follwed this innovation. Seeds are embryonic sporophytes, held in a sort of metabolic stasis and provided with enough food to get started once their growth has been re-stared by exposure to suitable growing conditions. Well adapted seeds combined sexual reproduction with spore-like wide dispersal and so made the alternation of generations obsolete. However, early seeds, which might lack these refinements, probably evolved on tall trees which gave any sort of propagule a head start in dispersal.

The Spermatophytata are the stem group for our next major division, the Spermatopsida.

[[Chlorobionta|Back to Chlorobionta]]

Chlorobionta

Admin — Sat, 19 Aug 2006 19:17:40 GMT

Admin: /* Embryophyta */

Chlorobionta

Admin — Sat, 19 Aug 2006 19:16:49 GMT

Admin: /* The Diversity of Plants */

The Diversity of Plants

Admin — Sat, 19 Aug 2006 19:15:59 GMT

Admin:

== The Diversity of Plants ==

We will cover the higher taxa of lower plants in two blocks: Chlorobionta and Embryophyta. The prasinophytes (basalmost chlorobionts), chlorophytes and charophytes are essentially algae, which normally impinge on our consciousness just long enough to apply a little wasabi and shoyu. Arigato, and next I'll have ni unagi, kudasai. Don't try that with an embryophyte. There's a differnce between sushi and soba. Embryophytes are mostly land plants, and it was the ability of plants to live on land that allowed all the other branches of life to live on land as well. In fact, only the plants can really be said to have adapted to land. With few exceptions, the rest of life simply adapted to plants.

=== Chlorobionta ===

Halosphaera viridisThe general characteristics of the green plants are touched on above. The purpose of this section is to introduce the prasinophytes. These are a paraphyletic group of green algae which radiate from the base of the Chlorobionta. Most are photosynthetic flagellates. In addition, the prasinophytes are the only mixotropic plants, i.e., they obtain food both by photosynthesis and phagotrophy. This is, presumably, how they obtained chloroplasts in the first place.

The phycomate prasinophytes (those with large, thick-walled floating stages, or "phycomata") have received special attention because of their extremely long fossil record. Phycomata are known as acritarchs well into Proterozoic time. One genus (Tasmanites) dates back to 600 Mya. Javaux et al. (2004) have turned up an entire menagerie of forms from the Mesoproterozoic, and even beyond (at least 1500 Mya), which are almost certainly eukaryotic and could well be prasinophytes, or somewhat stemward of the plants. They cannot be too distantly related, as the presence of thick organic walls, with extreme resistance to degradation, seems to be a trait of the plant-chromist lineage. One of these in particular, Leiosphaeridia crassa, from the c. 1460 Mya Roper Fm. of northern Australia, is being investigated as a possible green alga. Interestingly, in Recent or merely Paleozoic forms, these relatively large, thick-walled morphs are associated with moderately anoxic conditions and nutrient exhaustion during algal blooms.

=== Chlorophyta ===

UlvaWithin the Chlorobionta are two large clades making up the "green algae." The green algae, as currently conceived, have no formal taxonomic name. We will define the group as Quercus + Chlamydomonas. The corresponding stem clades are Chlorophyta (Chlamydomonas > Quercus) and Charophyta (Quercus > Chlamydomonas). "Chlorophyta" is also the old name for all green algae, so this is perhaps unnecessarily confusing. Tough luck. The ambiguity is now so embedded in the literature that there's nothing anyone can do about it.

The Chlorophyta have largely been delineated by molecular techniques, so it is a bit difficult to describe their characters. We know of two possible synapomorphies of the Chlorophyta. First, chlorophyte sexual forms bear paired apical flagellae usually separated by 180�, but sometimes at the same end. Second, they retain the nuclear envelope during mitosis. Indeed, chlorophytes seem to be distinguished by a variety of bizarre variations on the usually pedestrian theme of mitosis; however those variations are not entirely consistent within the group.

Like the land plant lineage, they tend to form large aggregates, with some tissue differentiation (primarily holdfasts and reproductive structures). They are very often found in terrestrial and fresh water environments, with a distinct preference for very cold environments, such as under snow cover, or even within Antarctic ice. Various species are important in forming symbiotic relationships with fungi, i.e., lichens. As with all green algae, chlorophytes tend to have a double cell wall -- an inner wall of cellulose and an outer gelatinous wall of protein, particularly pectin, known in higher plants as a marker for parenchyma. Starch stored in pyrenoids, located inside the chloroplasts.

=== Charophyta (= Streptophyta) ===

KlebsormidiumThe Charophyta are the other lineage of green algae, the group which includes the land plants. Karol et al. (2001). As mentioned above, our working definition is Quercus (oak) > Chlamydomonas. The Charophyta have recently been referred to as the Streptophyta, but the reasons given for this change in nomenclature are probably insufficient. Unfortunately, the name is also frequently, and wrongly, used in place of Charophycea or Charales to describe the stoneworts -- one of several distinct groups of charophytes.

The synapomorphies of the group are said to include the the dissolution of the nuclear membrane during mitosis and the presence of paired flagella (when flagella are present at all) directed perpendicularly to each other. In addition, the charophytes are strongly inclined toward growth as long filaments.

=== Embryophyta ===

LiverwortThe Embryophyta constitute the terrestrial or land plants, the first representatives of which appeared during the Silurian or possibly even the Middle or Late Ordovician period. The most primitive of these are nonvascular land plants, a group that classically includes liverworts (Hepatophyta / Hepaticopsida), hornworts (Anthocerotophyta / Antheroceratopsida) and mosses (Bryophyta). The majority of land plants however are included within the huge and diverse clade traditionally called Tracheophyta, or Vascular Pants, and which we will refer to as the Rhyniophyta.

We treat Embryophyta in a specialized sense, as Quercus + moss. This may be a mistake, as this definition probably excludes the liverworts (see image) and perhaps even the hornworts. Both of these groups have traditionally been thought of as embryophytes.

Embryophytes (including liverworts) have the following synapomorphies: 1) a life cycle with alternation of generations 2) apical cell growth (some kind of meristem-like growth organization), 3) cuticle (needed to control water loss on land), 4) antheridia (male gametophyte organs), and 5) archegonia (female gametophyte organs). The more derived embryophytes are vascular plants. Vascular plants have an elaborate system of conducting cells, consisting of xylem - in which water and minerals are transported) and phloem (in which carbohydrates are transported). This method of internal support enables them to stand and grow upright and pull up nutrients against the force of gravity. There are two developmental grades - those that reproduce by means of spores, and hence are dependent on water or extensive moisture (e.g. ferns), and those that reproduce by means of seeds (e.g. conifers and flowering plants). The most primitive forms reproduce by means of spores (haploid (1N) spores). They generally require a moist environment, because the flagellated sperm require water for fertilization.

The Embryophytes, then, are plants with an alternation of generations and some ability to live on land. The basal embryophytes were still not land plants, since they required, and still require, open water to propogate. As we define the Embryophyta, they split basally into mosses (Bryophyta) and land plants (Rhyniophyta). The Rhyniophytes two important groups: the Lycophytina (lycopods and the extinct zosterophylls) and the Euphyllophytina (ferns and seed plants).
Embryophyta

[[Chlorobionta|Back to Chlorobionta]]

Evolution of Paleozoic Land Plants

Admin — Sat, 19 Aug 2006 19:15:36 GMT

Admin:

=== Green Algae ===

The Green Algae - the Chlorophyta and Charophyta - include a number of mostly aquatic forms, including some unicellauar and primitive colonial forms. and other multi-cellular types that however lack a true root system

They are very closely related to (and probably the ancestors of) the higher plants in the kingdom Plantae. Molecular and cellular similarities between green algae, particularly the charophytes, and land plants include the following:

(1) Both the green algae and plants have chlorophyll b and beta-carotene

(2) Green algae and plants both have special intracellular membranes (the thylakoid membranes) which contain the chlorophyll stacked into grana.

(3) Charophytes have a cellulose content of 20 to 25% of the cell wall, a composition similar to that of plants.

(4) Cell division in green algae is very similar to that of land plants. Both use microtubules to bring vesicles containing new material in to form the cell plate which will divide the cell into two.

(5) Nuclear genes and RNA are similar between charophytes and plants.

=== Plants Conquer the Land ===

The Early Devonian Rhynie Chert Flora - from Life Before Man by Zdenek V. Spinar, illustrated by Zdenek BurianIf the great evolutionary radiation of metazoa (multicellular animals) in the earliest Cambrian oceans was the first great dramatic even of the Phanerozoic era (indeed ushering in the Phanerozoic), the conquest of land by multicellular plants was the next, and of equal importance. Indeed, without the plants no animals would ever have been able to survive on land.

But whereas the Cambrian explosion was very rapid, in the order of perhaps 3 to 5 million years for the origin of all major phyla (and many others now extinct), the colonization of the land by vegetation was a much slower and more protracted. The reason for this is not hard to understand. Cambrian animals were moving into a favorable new environment with no competitors. Plants had to brave desiccation, extremes of temperature, and harsh ultra-violet radiation.

Enigmatic traces are known from the early and middle Ordovician, These are fossils of spores, cuticles, and tubes and don't reveal much about the structures or nature of these plants. All we can say is that these plants were probably of a bryophyte grade of evolution - small, non-vascular, and lacking morphological differentiation into roots, stems, and leaves, like modern mosses and liverworts.

The first unambiguous record of land plants is from the Silurian period. They were mostly small, primitive forms, dependent on the proximity of water, and with the most rudimentary stem and leaf structure.

A common middle Silurian to early Devonian plant is Cooksonia, which had dichotomous branching and terminal sporangia (spore cases) at the tips of its green leafless stems. It is not known whether Cooksonia was a proper vascular (tracheid-bearing) plant. True vascular plants evolved and began to diversify during the Latest Silurian and Early Devonian.

[[Chlorobionta|Back to Chlorobionta]]

Devonian Plant Evolution

Admin — Sat, 19 Aug 2006 19:14:01 GMT

Admin: /* The Carboniferous Period */

The development of plant root depth during the [[Devonian]] period marked a major shift in plant evolution and terrestrial ecosystems. Early Devonian plants such as the rhyniophytes, zosterophyllophytes and lycophytes have features such as vascular tissue, stomata, a cuticle to protect against drying, rhizoids, and sporangia at the tips of short lateral branches instead of terminal as in Cooksonia. These forms were small, non-rooted or shallowly rooted, lacked woody tissue and hence were unable to grow beyond the height of small bushes. These plants reproduced by means of spores, which requires a moist habitat. They were therefore confined to moist, lowland habitats, thus having little effect on their physical environment

The first shrub and tree-like plants, such as Progymnosperms and lycopsids, had evolved by the middle Devonian. By the late Devonian the first real trees, such as Archaeopteris ("ancient fern" - not to be confused with Archaeopteryx, "ancient wing", the first bird!), had appeared. Trees have special vascular systems to allow for water circulation and nutrient flow against the pull of gravity. At the very end of the Devonian seed-bearing (gymnosperm) plants appeared for the first time, breaking free of the dependence on moisture that limits spore-bearing (pteridophyte) plants. Along with these developments came the development of advanced root systems and the production of soils, increased weathering, and huge ecological feedback.

The black & white figure shows the increasing terrestrial plant root depth penetration with time during the Devonian, leading to increasing soil depth and weathering. "Rhyniophytes" are a basal radiation of land plants such as Aglaophyton or Horneophyton. Trimerophytes include such plants as Psilophyton. Lycophytes arrived in the Middle Devoinian. They originally appeared as low-lying herbaceous forms, such as Asteroxylon or Drepanophycus. Tree-sized lycopods (e.g., Lepidosigillaria and Cyclostigma) appeared by the end of the Middle Devonian. Progymnosperms, such as Tetraxylopteris, arose in the Frasnian. By the Famennian, Archaeopteris forests are common. At the very end of the Devonian, Archaeopteris is found together with early gymnosperms, such as Elkinsia and Moresnetia, and zygopierid ferns such as Rhacophyton.

=== The Carboniferous Period ===

Despite the origin of the seed habit, the majority of Carboniferous plants reproduced by spores. The moist swampy environments of the time provided a nurturing environment. Lycophytes (scale trees and club mosses), which had evolved as small plants during the late Silurian? or early Devonian, and diversified greatly during the succeeding Devonian period, continued and thrived throughout the Carboniferous, but being dependent on water and moist conditions, most died out with the increasing aridity at the end of the Paleozoic, only a few small ones making it through. Calamites and ferns were other spore-bearing plants that appeared during the Devonian and flourished during the following Carboniferous period.

[[Chlorobionta|Back to Chlorobionta]]

Chlorobionta

Admin — Sat, 19 Aug 2006 19:13:29 GMT

Admin: /* The Devonian Period */

== Chlorobionta (Green Plants) ==

<table border=1>
<tr><td>
LIFE (=Archaea?)
|--Eubacteria
`--Eukarya
|--+--Rhodophyta
| `--CHLOROBIONTA
| |--Chlorophyta
| `--Charophyta
| |--(various green algae)
| `--Embryophyta
| |--Bryophyta
| `--Rhyniophyta
| |--Lycophytina
| `--Euphyllophytina
| |--Moniliformopses
| `--Spermatophytata
| |--trimerophytes
| `--Spermatopsida
`--+--Fungi
`--Metazoa
|--Deuterostomata
`--Protostomata
</td><td>
Lists
Glossary
Taxa
References
"The Wearing of the Green"
Evolution of Land Plants
Green Algae
Plants Conquer the Land
The Devonian Period
The Carboniferous Period
The Diversity of Plants
Chlorobionta (Prasinophyta)
Chlorophyta
Charophyta
Embryophyta
Bryophyta
Rhyniophyta
Lycophytina
Euphyllophytina
Moniliformopses
Spermatophytata
Links
</td></tr></table>

== Lists ==

A. Glossary of terms and abbreviations.
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

B. Taxon Index: alphabetical list of taxa.
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

C. References: literature citations by author.
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

== "The Wearing of the Green" ==

Beginning in the [[Archean]] era, Cyanobacteria evolved photosynthesis, which enabled them to use sunlight to draw carbon dioxide from the atmosphere and convert it to oxygen, water and glucose (a simple carbohydrate). These could be considered the first simple "plants" Plants therefore might be seen as any organism that is able to use sunlight, carbon dioxide, and water, to manufacture its own food, that is, as a special class of autotroph. However, that's far too broad. It would include all kinds of things like diatoms, chromists, and photosynthetic bacteria which have nothing to do with plants in a phylogenetic sense. They are, to be sure, all within the subject matter of a General Botany class. All of these groups share some essential biochemistry. However, what they don't share is a common ancestor to the exclusion of all other organisms. This similarity arises from (a) convergent evolution and (b) the exchange of plastids.

The description above also fails because it is only partially correct, even as a general description. Plants not only breathe out (respire) oxygen, but parts of their tissues also respire carbon dioxide, just as animals (heterotrophs) do. These processes provide the plant with energy for growing and maintaining its life support systems, and go on at all times. During the sunlit day, more carbon dioxide is consumed than is released in respiration, but at night photosynthesis ceases and the plant respires only carbon dioxide, returning a portion of its carbon to the atmosphere.

One better approach to defining "plants" is the "Chlorobionta" hypothesis, as used on the Tree of Life site:

There are two major lineages of green plants. One consists of most of what have been classically considered "green algae" -- mostly microscopic freshwater forms and large seaweeds. The other lineage contains several groups of "green algae" that are more closely related to land plants. Because these two lineages are monophyletic, they have been placed in a single monophyletic group called green plants, or, in technical parlance, the subkingdom Chlorobionta ...

This suffers only from being vague. Is there anything else in the box besides green algae and land plants? The ToL authors don't suggest any other content. Alternatively, this Gelidium coulteri might be an attempt to suggest a crown group: "the last common ancestor of Chlorophyceae and evergreens and all of its descendants," or something like that. That sounds like a workable definition, but that can't be right, since they include the prasinophytes among the Plants. Some, but not all, prasinophytes would be excluded from the plants by a crown group definition. We think what the ToL authors actually had in mind is an even better choice: the stem group "green algae > red algae." This includes all of the prasinophytes, all other green algae and all plants, as those terms are normally used, but not much of anything else.

Why do we care about definitions? The price of admission to doing good science taking an explicit position, so that others can prove you wrong. A vague definition, such as ToL's original formulation, is not good science. Unless we know precisely what they mean by "plant" we can't really make testable statements about what are or are not plants, nor about what characteristics plants have or do not have, nor about whence they might have derived their characteristics. Without really crisp definitions, these issues quickly get bogged down in semantics and arm-waving. Arguably that is exactly what happened to the whole business of taxonomy for the better part of a century.

Of course, definitions can never be "wrong," in a logical sense. However, they can be useless, if they fail to draw lines within our area of Quercus alba interest. A vague definition is always useless because it draws no line at all. Phylogenetic definitions have revived the whole business of evolutionary systematics because they are quite precise and refer to historical events (e.g., the evolution of red and green algae from a common ancestor), rather than to some man-made list of (sometimes fuzzy) characteristics. However, this precision also comes at a price. A phylogenetic definition is built around a phylogenetic hypothesis. Unlike a definition, a hypothesis can be wrong. If so, any definition based on that hypothesis usually must be abandoned, and a lot of good work may go down the tubes.

Suppose for example, that we interested in the evolution of birds. Our hypothesis is that birds are the sister group of dinosaurs, and that some "dinobird" was their last common ancestor. We thus define birds as Struthio (ostrich) > Struthiomimus (a theropod dinosaur which looked like an ostrich) and dinosaurs as Struthiomimus > Struthio. Sadly, after years of frustrating labor sorting out the characteristics of the supposed dinobird ancestor, we realize that birds are dinosaurs. Oops. Our definition of "bird" turns out to include embarrassingly unbirdlike things like therizinosaurs, while our definition of "dinosaur" includes only tyrannosaurids and ornithomimosaurs. How to explain this little faux pas to those notoriously humorless folk whose grants supported our research the last three years? Again, that is simply the price of doing good science.

For that reason, we should be careful, as well as explicit, in framing the definition and articulating the underlying hypothesis. Here, the hypothesis is that red algae, in a colloquial sense, are closely related to green plants, in an equally colloquial sense. This then allows us to define both rigorously in terms of that relationship. Strictly speaking, we should do so in terms of particular anchor taxa, just in case either group turns out to be polyphyletic (which is possible). By all means, then, let's do so. On the red algae side, we'll pick Gelidium coulteri, a randomly chosen species of a well-known and very successful genus of red algae. On the green plant side, let's use an angiosperm, a highly derived group, and Quercus albus, because (as any citizen of the state of Connecticut will know) it symbolizes the willingness to take risks to vindicate historical truth. Based on our phylogenetic hypothesis, our working definitions are Chlorobionta (plants) = Q. alba > G. coulteri, and Rhodophyta (red algae) = G. coulteri > Q. alba.

Was that so hard? Of course not. But then, unlike ToL, we are not subject to the temptations to waffle which come with peer review and the caprice of granting agencies. Lest we be misunderstood, we support both peer review and post hoc review by grantors as excellent things for science; but they are not unmixed blessings. The inducements to please everyone may become irresistable. Now, unlike ToL, the purpose of Palaeos is only to amuse those who write it. However, if we can, occasionally, counterweight the temptation for others to hide behind intentionally vague and inconsistent pronouncements made in the service of their own comfort, perhaps it may serve another purpose as well.

== [[Evolution of Paleozoic Land Plants]] ==
(''See article for details'')

== [[Devonian Plant Evolution|The Devonian Period]] ==
(''See article for details'')

== The Diversity of Plants ==

We will cover the higher taxa of lower plants in two blocks: Chlorobionta and Embryophyta. The prasinophytes (basalmost chlorobionts), chlorophytes and charophytes are essentially algae, which normally impinge on our consciousness just long enough to apply a little wasabi and shoyu. Arigato, and next I'll have ni unagi, kudasai. Don't try that with an embryophyte. There's a differnce between sushi and soba. Embryophytes are mostly land plants, and it was the ability of plants to live on land that allowed all the other branches of life to live on land as well. In fact, only the plants can really be said to have adapted to land. With few exceptions, the rest of life simply adapted to plants.

=== Chlorobionta ===

Halosphaera viridisThe general characteristics of the green plants are touched on above. The purpose of this section is to introduce the prasinophytes. These are a paraphyletic group of green algae which radiate from the base of the Chlorobionta. Most are photosynthetic flagellates. In addition, the prasinophytes are the only mixotropic plants, i.e., they obtain food both by photosynthesis and phagotrophy. This is, presumably, how they obtained chloroplasts in the first place.

The phycomate prasinophytes (those with large, thick-walled floating stages, or "phycomata") have received special attention because of their extremely long fossil record. Phycomata are known as acritarchs well into Proterozoic time. One genus (Tasmanites) dates back to 600 Mya. Javaux et al. (2004) have turned up an entire menagerie of forms from the Mesoproterozoic, and even beyond (at least 1500 Mya), which are almost certainly eukaryotic and could well be prasinophytes, or somewhat stemward of the plants. They cannot be too distantly related, as the presence of thick organic walls, with extreme resistance to degradation, seems to be a trait of the plant-chromist lineage. One of these in particular, Leiosphaeridia crassa, from the c. 1460 Mya Roper Fm. of northern Australia, is being investigated as a possible green alga. Interestingly, in Recent or merely Paleozoic forms, these relatively large, thick-walled morphs are associated with moderately anoxic conditions and nutrient exhaustion during algal blooms.

=== Chlorophyta ===

UlvaWithin the Chlorobionta are two large clades making up the "green algae." The green algae, as currently conceived, have no formal taxonomic name. We will define the group as Quercus + Chlamydomonas. The corresponding stem clades are Chlorophyta (Chlamydomonas > Quercus) and Charophyta (Quercus > Chlamydomonas). "Chlorophyta" is also the old name for all green algae, so this is perhaps unnecessarily confusing. Tough luck. The ambiguity is now so embedded in the literature that there's nothing anyone can do about it.

The Chlorophyta have largely been delineated by molecular techniques, so it is a bit difficult to describe their characters. We know of two possible synapomorphies of the Chlorophyta. First, chlorophyte sexual forms bear paired apical flagellae usually separated by 180�, but sometimes at the same end. Second, they retain the nuclear envelope during mitosis. Indeed, chlorophytes seem to be distinguished by a variety of bizarre variations on the usually pedestrian theme of mitosis; however those variations are not entirely consistent within the group.

Like the land plant lineage, they tend to form large aggregates, with some tissue differentiation (primarily holdfasts and reproductive structures). They are very often found in terrestrial and fresh water environments, with a distinct preference for very cold environments, such as under snow cover, or even within Antarctic ice. Various species are important in forming symbiotic relationships with fungi, i.e., lichens. As with all green algae, chlorophytes tend to have a double cell wall -- an inner wall of cellulose and an outer gelatinous wall of protein, particularly pectin, known in higher plants as a marker for parenchyma. Starch stored in pyrenoids, located inside the chloroplasts.

=== Charophyta (= Streptophyta) ===

KlebsormidiumThe Charophyta are the other lineage of green algae, the group which includes the land plants. Karol et al. (2001). As mentioned above, our working definition is Quercus (oak) > Chlamydomonas. The Charophyta have recently been referred to as the Streptophyta, but the reasons given for this change in nomenclature are probably insufficient. Unfortunately, the name is also frequently, and wrongly, used in place of Charophycea or Charales to describe the stoneworts -- one of several distinct groups of charophytes.

The synapomorphies of the group are said to include the the dissolution of the nuclear membrane during mitosis and the presence of paired flagella (when flagella are present at all) directed perpendicularly to each other. In addition, the charophytes are strongly inclined toward growth as long filaments.

=== Embryophyta ===

LiverwortThe Embryophyta constitute the terrestrial or land plants, the first representatives of which appeared during the Silurian or possibly even the Middle or Late Ordovician period. The most primitive of these are nonvascular land plants, a group that classically includes liverworts (Hepatophyta / Hepaticopsida), hornworts (Anthocerotophyta / Antheroceratopsida) and mosses (Bryophyta). The majority of land plants however are included within the huge and diverse clade traditionally called Tracheophyta, or Vascular Pants, and which we will refer to as the Rhyniophyta.

We treat Embryophyta in a specialized sense, as Quercus + moss. This may be a mistake, as this definition probably excludes the liverworts (see image) and perhaps even the hornworts. Both of these groups have traditionally been thought of as embryophytes.

Embryophytes (including liverworts) have the following synapomorphies: 1) a life cycle with alternation of generations 2) apical cell growth (some kind of meristem-like growth organization), 3) cuticle (needed to control water loss on land), 4) antheridia (male gametophyte organs), and 5) archegonia (female gametophyte organs). The more derived embryophytes are vascular plants. Vascular plants have an elaborate system of conducting cells, consisting of xylem - in which water and minerals are transported) and phloem (in which carbohydrates are transported). This method of internal support enables them to stand and grow upright and pull up nutrients against the force of gravity. There are two developmental grades - those that reproduce by means of spores, and hence are dependent on water or extensive moisture (e.g. ferns), and those that reproduce by means of seeds (e.g. conifers and flowering plants). The most primitive forms reproduce by means of spores (haploid (1N) spores). They generally require a moist environment, because the flagellated sperm require water for fertilization.

The Embryophytes, then, are plants with an alternation of generations and some ability to live on land. The basal embryophytes were still not land plants, since they required, and still require, open water to propogate. As we define the Embryophyta, they split basally into mosses (Bryophyta) and land plants (Rhyniophyta). The Rhyniophytes two important groups: the Lycophytina (lycopods and the extinct zosterophylls) and the Euphyllophytina (ferns and seed plants).
Embryophyta

== Embryophyta ==

=== Bryophyta ===

Bryophyte Life Cycle If the mosses had not survived into the present, we would be forced to invent them as just the sort of intermediate we might expect between essentially aquatic algae and fully terrestrial plants. Mosses do have differentiated stems. Although these are generally only a few millimeters tall, they are still designed to provide mechanical support against gravity without help from water -- the first such structure in any kingdom. Bryophytes also have leaves. These are typically one cell thick and lack veins, although they may have a central thickening for support. Mosses also have rhizomes. These may have some function in extracting soil nutrients, although their primary function seems to be mechanical attachment to the substrate. Thus they are not true roots, but do approach that condition.

The bottom line is that, structurally, mosses really differ from rhyniophytes in only one aspect: mosses lack specialized vascular tissues. That alone is sufficient to explain the lack of big leaves, long stems, and true roots. This whole complex of characters is thus probably primitive. The other distinctive character of mosses is that the plant we normally observe is the haploid, gametophyte stage. But this character is shared with liverworts (basal embryophytes) and so is also probably plesiomorphic.

Curiously, in hornworts (also basal embryophytes) the sporophyte generation is dominant. In addition, it turns out that the leaves of moss probably evolved independently from the leaves of higher plants. So the relationships of the mosses and basal embryophytes are still uncertain. What really does seem to set mosses apart is their unique form of leaf. What really seems to unite mosses with higher plants is (a) the presence of stomata to control water loss and (b) meristem (apical growth) in the sporophyte generation. See, Friedman et al. (2004). Phylogenetically, we treat Bryophyta as Moss > Quercus.

=== Rhyniophtya ===

HorneophytonSee Rhyniophyta. That section covers the basal rhyniophytes, such as Horneophyton, which were the first real land plants. These probably evolved in the Ludlow and formed the stem group for all other land plants. Consequently, they are paraphyletic. Rather than abandoning this name and its rich history, we use it to mean all land plants. Our working phylogenetic definition is definition is Quercus > moss.

This group is characterized by the ability to reproduce without open water. Anatomically, in all rhyniophytes, the (diploid) sporophyte generation is dominant, and the sporophyte is branched. For this reason, the taxon is often referred to as the Polysporangiophytes. In addition, the archegonium develops inside the body of the plant, rather than being superficial as in mosses and most basal embryophytes. Kenrick & Crane (1997).

Horneophyton and a few other basal forms lack tracheids. That is, they are avascular plants. However, almost all other rhyniophytes have some development of specialized vascular tissues. The most basal tracheid type, present in most stem rhyniophytes, appears to be the S-type tracheid.

=== Lycophytina ===

The Lycophytina includes the lycopods, zosterophylls, and related forms, including (probably) a number of plants often treated as basal rhyniophytes, such as Baragwanathia. Kenrick & Crane (1997). Since they are a complex group and are treated extensively elsewhere, we will defer discussion to a revision of the existing materials.
Euphyllophytina

The clade that unites oak trees and ferns is Euphyllophytina = Quercus + Equisetum. The two complementary stem clades are Moniliformopsida and Spermatophytata. Euphyllophytines are characterized (Kenrick & Crane, 1997) by monopodial or pseudomonopodial branching, helical arrangement of branches, small, pinnule-like vegetative branches, the branch apex is recurved or coiled, paired sporangia which split open along one side through a single slit, and radially-alligned xylem in the larger axes. Only early euphyllophytines have P-type tracheids. Kenrick & Crane identified this clade based entirely on morphological characters. However, Euphytophytina has also been recovered, with essentially the same structure, using ssu rDNA. Duff & Nickrent (1999).

=== Moniliformopses ===

Psilotum nudumThe Moniliformopses are the horsetails and ferns, including the Psilotidae (whisk ferns). They are closely related to the seed plants. Pryer et al. (2001). So, for example, they exhibit apical growth (meristem) in both sporophyte and gametophyte generations. They have well-developed roots megaphyllous leaves and the vascular system needed to make use of both. However, both may have been evolved independently of higher plants. Friedman et al. (2004). In addition, Moniliformopses lack a complete vascular cambium, and growth of xylem is restricted to lobes of the primary xylem strand.

Since this is a new clade -- discovered, for all practical purposes, by Preyer's group, we have little to say about Moniliformopses as a taxon, and defer discussion to a fuller consideration of its three component parts. The Psilotidae are the most basal, followed by the horsetails, then the remainder of the ferns.

We apply a crown group defiition to Moniliformopses: Equisetum + ferns.

=== Spermatophytata ===

PsilophytonThe clade that unites oaks and lycopsids is Euphyllophytina. The two complementary stem clades are Lycopsida and Spermatophytata = Quercus > Lepidodendron. A second way to look at Spermatophytata is as the stem group leading to angiosperms. It includes Trimerophyta and the progymnosperms, in fact everything up to and including the seed plants (Spermatopsida). However, we will only be concerned with the more basal forms for now. A third way of considering Spermatophytata is as the seed plants. However, this applies only to living forms. The basal Trimerophyta and their immediate descendants (assuming Trimerophyta is paraphyletic) lacked seeds, true leaves, or even, perhaps, roots. It is quite likely that virtually all the important land plant adaptations were independently developed in the moniliformopsid and spermatophytate lineages.

What seems to have set Spermatophytata apart quite early is not, in fact, the development of seeds, but the evolution of a full vascular cambium which permitted secondary growth. Early plants with apical growth were able to use that trait to grow taller and (a) get more sunlight (b) shade their competition and (c) have a better shot at spore dispersal. However, supporting a long stalk is much easier with a wider central column. Less derived groups either had no way to do this, or developed lateral lobes of the apical meristem. The latter worked, but required the tree to grow wide before it grew tall. The evolution of a complete vascular cambium permitted the tree to grow just wide enough to suit its height -- growing continuously wider as it grew tall.

The evolution of seeds follwed this innovation. Seeds are embryonic sporophytes, held in a sort of metabolic stasis and provided with enough food to get started once their growth has been re-stared by exposure to suitable growing conditions. Well adapted seeds combined sexual reproduction with spore-like wide dispersal and so made the alternation of generations obsolete. However, early seeds, which might lack these refinements, probably evolved on tall trees which gave any sort of propagule a head start in dispersal.

The Spermatophytata are the stem group for our next major division, the Spermatopsida.

== Links ==

[http://www.ucmp.berkeley.edu/plants/plantae.html Introduction to the Plantae - The green kingdom]

[http://www.ucmp.berkeley.edu/IB181/HpageIB181.html Integrative Biology 181/181L - Paleobotany]

[http://www.science.siu.edu/landplants/ Land Plants On-line - covers recent plants only, links to images etc]

[http://www.uni-wuerzburg.de/mineralogie/tapho/tapho1.html International Plant Taphonomy Meeting] - The purpose of the International Plant Taphonomy Meetings is to stimulate scientific research and to promote contacts among scientists engaged in the study of plant taphonomy including living and fossil plants of all geological periods.

[http://www.science.smith.edu/biology/bio240/xsmith/BotLinks.htm Botany]

=== Web Sites by Subject ===

Excellent annotated list of links to Botany and related subjects - note, some of these links are no longer current.

[http://taggart.glg.msu.edu/bot335/botclass.htm A BASIC BIOLOGICAL CLASSIFICATION OF PLANT-LIKE ORGANISMS]

[http://www.uni-muenster.de/GeoPalaeontologie/Palaeo/Palbot/ewald.html#1 A History of Palaeozoic Forests] - Hans Kerp - very informative - originally published in German.  Deals with forests of the Devonian, Carboniferous, and Permian periods.

[http://www.xs4all.nl/~steurh/home.html Hans' Paleobotany Pages] - info on the earliest land plants and on the lycopod Lepidodendron

[http://taggart.glg.msu.edu/isb200/carbfor.htm Carboniferous Forests] Ralph E. Taggart - good non-technical intro, covers main groups of Carboniferous plants, also brief mention of insects, amphibians, and reptiles'

[http://www.abdn.ac.uk/rhynie/ The Biota of Early Terrestrial Ecosystems: The Rhynie Chert] - includes useful information on Early Devonian plants from this location

[http://scitec.uwichill.edu.bb/bcs/bl14apl/conq.htm The First Land Plants] - The Conquest of the Land - gives a good introduction to basic concepts regarding the transition of plants from water to land

[http://www.ortobotanico.unina.it/Museopaleo/paleo_eng.doc Orto Botanico] - somewhat technical but not too difficult coverage of plants and paleobotany. Includes glossary.

[http://www.ucmp.berkeley.edu/IB181/HpageIB181.html Integrative Biology 181/181L] - Paleobotany - at UC Berkeley - includes material on Paleozoic plants.  A bit technical but if you stick at it you will learn a lot.

Devonian Plant Evolution

Admin — Sat, 19 Aug 2006 18:53:49 GMT

Admin: part 2

Evolution of Paleozoic Land Plants

Admin — Sat, 19 Aug 2006 18:50:38 GMT

Admin: Splitting Chlorobionta into separate pages, part 1

Chlorobionta

Admin — Sat, 19 Aug 2006 18:50:09 GMT

Admin: /* Evolution of Paleozoic Land Plants */

== Chlorobionta (Green Plants) ==

<table border=1>
<tr><td>
LIFE (=Archaea?)
|--Eubacteria
`--Eukarya
|--+--Rhodophyta
| `--CHLOROBIONTA
| |--Chlorophyta
| `--Charophyta
| |--(various green algae)
| `--Embryophyta
| |--Bryophyta
| `--Rhyniophyta
| |--Lycophytina
| `--Euphyllophytina
| |--Moniliformopses
| `--Spermatophytata
| |--trimerophytes
| `--Spermatopsida
`--+--Fungi
`--Metazoa
|--Deuterostomata
`--Protostomata
</td><td>
Lists
Glossary
Taxa
References
"The Wearing of the Green"
Evolution of Land Plants
Green Algae
Plants Conquer the Land
The Devonian Period
The Carboniferous Period
The Diversity of Plants
Chlorobionta (Prasinophyta)
Chlorophyta
Charophyta
Embryophyta
Bryophyta
Rhyniophyta
Lycophytina
Euphyllophytina
Moniliformopses
Spermatophytata
Links
</td></tr></table>

== Lists ==

A. Glossary of terms and abbreviations.
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

B. Taxon Index: alphabetical list of taxa.
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

C. References: literature citations by author.
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

== "The Wearing of the Green" ==

Beginning in the [[Archean]] era, Cyanobacteria evolved photosynthesis, which enabled them to use sunlight to draw carbon dioxide from the atmosphere and convert it to oxygen, water and glucose (a simple carbohydrate). These could be considered the first simple "plants" Plants therefore might be seen as any organism that is able to use sunlight, carbon dioxide, and water, to manufacture its own food, that is, as a special class of autotroph. However, that's far too broad. It would include all kinds of things like diatoms, chromists, and photosynthetic bacteria which have nothing to do with plants in a phylogenetic sense. They are, to be sure, all within the subject matter of a General Botany class. All of these groups share some essential biochemistry. However, what they don't share is a common ancestor to the exclusion of all other organisms. This similarity arises from (a) convergent evolution and (b) the exchange of plastids.

The description above also fails because it is only partially correct, even as a general description. Plants not only breathe out (respire) oxygen, but parts of their tissues also respire carbon dioxide, just as animals (heterotrophs) do. These processes provide the plant with energy for growing and maintaining its life support systems, and go on at all times. During the sunlit day, more carbon dioxide is consumed than is released in respiration, but at night photosynthesis ceases and the plant respires only carbon dioxide, returning a portion of its carbon to the atmosphere.

One better approach to defining "plants" is the "Chlorobionta" hypothesis, as used on the Tree of Life site:

There are two major lineages of green plants. One consists of most of what have been classically considered "green algae" -- mostly microscopic freshwater forms and large seaweeds. The other lineage contains several groups of "green algae" that are more closely related to land plants. Because these two lineages are monophyletic, they have been placed in a single monophyletic group called green plants, or, in technical parlance, the subkingdom Chlorobionta ...

This suffers only from being vague. Is there anything else in the box besides green algae and land plants? The ToL authors don't suggest any other content. Alternatively, this Gelidium coulteri might be an attempt to suggest a crown group: "the last common ancestor of Chlorophyceae and evergreens and all of its descendants," or something like that. That sounds like a workable definition, but that can't be right, since they include the prasinophytes among the Plants. Some, but not all, prasinophytes would be excluded from the plants by a crown group definition. We think what the ToL authors actually had in mind is an even better choice: the stem group "green algae > red algae." This includes all of the prasinophytes, all other green algae and all plants, as those terms are normally used, but not much of anything else.

Why do we care about definitions? The price of admission to doing good science taking an explicit position, so that others can prove you wrong. A vague definition, such as ToL's original formulation, is not good science. Unless we know precisely what they mean by "plant" we can't really make testable statements about what are or are not plants, nor about what characteristics plants have or do not have, nor about whence they might have derived their characteristics. Without really crisp definitions, these issues quickly get bogged down in semantics and arm-waving. Arguably that is exactly what happened to the whole business of taxonomy for the better part of a century.

Of course, definitions can never be "wrong," in a logical sense. However, they can be useless, if they fail to draw lines within our area of Quercus alba interest. A vague definition is always useless because it draws no line at all. Phylogenetic definitions have revived the whole business of evolutionary systematics because they are quite precise and refer to historical events (e.g., the evolution of red and green algae from a common ancestor), rather than to some man-made list of (sometimes fuzzy) characteristics. However, this precision also comes at a price. A phylogenetic definition is built around a phylogenetic hypothesis. Unlike a definition, a hypothesis can be wrong. If so, any definition based on that hypothesis usually must be abandoned, and a lot of good work may go down the tubes.

Suppose for example, that we interested in the evolution of birds. Our hypothesis is that birds are the sister group of dinosaurs, and that some "dinobird" was their last common ancestor. We thus define birds as Struthio (ostrich) > Struthiomimus (a theropod dinosaur which looked like an ostrich) and dinosaurs as Struthiomimus > Struthio. Sadly, after years of frustrating labor sorting out the characteristics of the supposed dinobird ancestor, we realize that birds are dinosaurs. Oops. Our definition of "bird" turns out to include embarrassingly unbirdlike things like therizinosaurs, while our definition of "dinosaur" includes only tyrannosaurids and ornithomimosaurs. How to explain this little faux pas to those notoriously humorless folk whose grants supported our research the last three years? Again, that is simply the price of doing good science.

For that reason, we should be careful, as well as explicit, in framing the definition and articulating the underlying hypothesis. Here, the hypothesis is that red algae, in a colloquial sense, are closely related to green plants, in an equally colloquial sense. This then allows us to define both rigorously in terms of that relationship. Strictly speaking, we should do so in terms of particular anchor taxa, just in case either group turns out to be polyphyletic (which is possible). By all means, then, let's do so. On the red algae side, we'll pick Gelidium coulteri, a randomly chosen species of a well-known and very successful genus of red algae. On the green plant side, let's use an angiosperm, a highly derived group, and Quercus albus, because (as any citizen of the state of Connecticut will know) it symbolizes the willingness to take risks to vindicate historical truth. Based on our phylogenetic hypothesis, our working definitions are Chlorobionta (plants) = Q. alba > G. coulteri, and Rhodophyta (red algae) = G. coulteri > Q. alba.

Was that so hard? Of course not. But then, unlike ToL, we are not subject to the temptations to waffle which come with peer review and the caprice of granting agencies. Lest we be misunderstood, we support both peer review and post hoc review by grantors as excellent things for science; but they are not unmixed blessings. The inducements to please everyone may become irresistable. Now, unlike ToL, the purpose of Palaeos is only to amuse those who write it. However, if we can, occasionally, counterweight the temptation for others to hide behind intentionally vague and inconsistent pronouncements made in the service of their own comfort, perhaps it may serve another purpose as well.

== [[Evolution of Paleozoic Land Plants]] ==
(''See article for details'')

== The Devonian Period ==

Devonian plant root depthThe Devonian period. marked a major shift in plant evolution and terrestrial ecosystems. Early Devonian plants such as the rhyniophytes, zosterophyllophytes and lycophytes have features such as vascular tissue, stomata, a cuticle to protect against drying, rhizoids, and sporangia at the tips of short lateral branches instead of terminal as in Cooksonia. These forms were small, non-rooted or shallowly rooted, lacked woody tissue and hence were unable to grow beyond the height of small bushes. These plants reproduced by means of spores, which requires a moist habitat. They were therefore confined to moist, lowland habitats, thus having little effect on their physical environment

The first shrub and tree-like plants, such as Progymnosperms and lycopsids, had evolved by the middle Devonian. By the late Devonian the first real trees, such as Archaeopteris ("ancient fern" - not to be confused with Archaeopteryx, "ancient wing", the first bird!), had appeared. Trees have special vascular systems to allow for water circulation and nutrient flow against the pull of gravity. At the very end of the Devonian seed-bearing (gymnosperm) plants appeared for the first time, breaking free of the dependence on moisture that limits spore-bearing (pteridophyte) plants. Along with these developments came the development of advanced root systems and the production of soils, increased weathering, and huge ecological feedback.

The black & white figure shows the increasing terrestrial plant root depth penetration with time during the Devonian, leading to increasing soil depth and weathering. "Rhyniophytes" are a basal radiation of land plants such as Aglaophyton or Horneophyton. Trimerophytes include such plants as Psilophyton. Lycophytes arrived in the Middle Devoinian. They originally appeared as low-lying herbaceous forms, such as Asteroxylon or Drepanophycus. Tree-sized lycopods (e.g., Lepidosigillaria and Cyclostigma) appeared by the end of the Middle Devonian. Progymnosperms, such as Tetraxylopteris, arose in the Frasnian. By the Famennian, Archaeopteris forests are common. At the very end of the Devonian, Archaeopteris is found together with early gymnosperms, such as Elkinsia and Moresnetia, and zygopierid ferns such as Rhacophyton.

=== The Carboniferous Period ===

Despite the origin of the seed habit, the majority of Carboniferous plants reproduced by spores. The moist swampy environments of the time provided a nurturing environment. Lycophytes (scale trees and club mosses), which had evolved as small plants during the late Silurian? or early Devonian, and diversified greatly during the succeeding Devonian period, continued and thrived throughout the Carboniferous, but being dependent on water and moist conditions, most died out with the increasing aridity at the end of the Paleozoic, only a few small ones making it through. Calamites and ferns were other spore-bearing plants that appeared during the Devonian and flourished during the following Carboniferous period.

== The Diversity of Plants ==

We will cover the higher taxa of lower plants in two blocks: Chlorobionta and Embryophyta. The prasinophytes (basalmost chlorobionts), chlorophytes and charophytes are essentially algae, which normally impinge on our consciousness just long enough to apply a little wasabi and shoyu. Arigato, and next I'll have ni unagi, kudasai. Don't try that with an embryophyte. There's a differnce between sushi and soba. Embryophytes are mostly land plants, and it was the ability of plants to live on land that allowed all the other branches of life to live on land as well. In fact, only the plants can really be said to have adapted to land. With few exceptions, the rest of life simply adapted to plants.

=== Chlorobionta ===

Halosphaera viridisThe general characteristics of the green plants are touched on above. The purpose of this section is to introduce the prasinophytes. These are a paraphyletic group of green algae which radiate from the base of the Chlorobionta. Most are photosynthetic flagellates. In addition, the prasinophytes are the only mixotropic plants, i.e., they obtain food both by photosynthesis and phagotrophy. This is, presumably, how they obtained chloroplasts in the first place.

The phycomate prasinophytes (those with large, thick-walled floating stages, or "phycomata") have received special attention because of their extremely long fossil record. Phycomata are known as acritarchs well into Proterozoic time. One genus (Tasmanites) dates back to 600 Mya. Javaux et al. (2004) have turned up an entire menagerie of forms from the Mesoproterozoic, and even beyond (at least 1500 Mya), which are almost certainly eukaryotic and could well be prasinophytes, or somewhat stemward of the plants. They cannot be too distantly related, as the presence of thick organic walls, with extreme resistance to degradation, seems to be a trait of the plant-chromist lineage. One of these in particular, Leiosphaeridia crassa, from the c. 1460 Mya Roper Fm. of northern Australia, is being investigated as a possible green alga. Interestingly, in Recent or merely Paleozoic forms, these relatively large, thick-walled morphs are associated with moderately anoxic conditions and nutrient exhaustion during algal blooms.

=== Chlorophyta ===

UlvaWithin the Chlorobionta are two large clades making up the "green algae." The green algae, as currently conceived, have no formal taxonomic name. We will define the group as Quercus + Chlamydomonas. The corresponding stem clades are Chlorophyta (Chlamydomonas > Quercus) and Charophyta (Quercus > Chlamydomonas). "Chlorophyta" is also the old name for all green algae, so this is perhaps unnecessarily confusing. Tough luck. The ambiguity is now so embedded in the literature that there's nothing anyone can do about it.

The Chlorophyta have largely been delineated by molecular techniques, so it is a bit difficult to describe their characters. We know of two possible synapomorphies of the Chlorophyta. First, chlorophyte sexual forms bear paired apical flagellae usually separated by 180�, but sometimes at the same end. Second, they retain the nuclear envelope during mitosis. Indeed, chlorophytes seem to be distinguished by a variety of bizarre variations on the usually pedestrian theme of mitosis; however those variations are not entirely consistent within the group.

Like the land plant lineage, they tend to form large aggregates, with some tissue differentiation (primarily holdfasts and reproductive structures). They are very often found in terrestrial and fresh water environments, with a distinct preference for very cold environments, such as under snow cover, or even within Antarctic ice. Various species are important in forming symbiotic relationships with fungi, i.e., lichens. As with all green algae, chlorophytes tend to have a double cell wall -- an inner wall of cellulose and an outer gelatinous wall of protein, particularly pectin, known in higher plants as a marker for parenchyma. Starch stored in pyrenoids, located inside the chloroplasts.

=== Charophyta (= Streptophyta) ===

KlebsormidiumThe Charophyta are the other lineage of green algae, the group which includes the land plants. Karol et al. (2001). As mentioned above, our working definition is Quercus (oak) > Chlamydomonas. The Charophyta have recently been referred to as the Streptophyta, but the reasons given for this change in nomenclature are probably insufficient. Unfortunately, the name is also frequently, and wrongly, used in place of Charophycea or Charales to describe the stoneworts -- one of several distinct groups of charophytes.

The synapomorphies of the group are said to include the the dissolution of the nuclear membrane during mitosis and the presence of paired flagella (when flagella are present at all) directed perpendicularly to each other. In addition, the charophytes are strongly inclined toward growth as long filaments.

=== Embryophyta ===

LiverwortThe Embryophyta constitute the terrestrial or land plants, the first representatives of which appeared during the Silurian or possibly even the Middle or Late Ordovician period. The most primitive of these are nonvascular land plants, a group that classically includes liverworts (Hepatophyta / Hepaticopsida), hornworts (Anthocerotophyta / Antheroceratopsida) and mosses (Bryophyta). The majority of land plants however are included within the huge and diverse clade traditionally called Tracheophyta, or Vascular Pants, and which we will refer to as the Rhyniophyta.

We treat Embryophyta in a specialized sense, as Quercus + moss. This may be a mistake, as this definition probably excludes the liverworts (see image) and perhaps even the hornworts. Both of these groups have traditionally been thought of as embryophytes.

Embryophytes (including liverworts) have the following synapomorphies: 1) a life cycle with alternation of generations 2) apical cell growth (some kind of meristem-like growth organization), 3) cuticle (needed to control water loss on land), 4) antheridia (male gametophyte organs), and 5) archegonia (female gametophyte organs). The more derived embryophytes are vascular plants. Vascular plants have an elaborate system of conducting cells, consisting of xylem - in which water and minerals are transported) and phloem (in which carbohydrates are transported). This method of internal support enables them to stand and grow upright and pull up nutrients against the force of gravity. There are two developmental grades - those that reproduce by means of spores, and hence are dependent on water or extensive moisture (e.g. ferns), and those that reproduce by means of seeds (e.g. conifers and flowering plants). The most primitive forms reproduce by means of spores (haploid (1N) spores). They generally require a moist environment, because the flagellated sperm require water for fertilization.

The Embryophytes, then, are plants with an alternation of generations and some ability to live on land. The basal embryophytes were still not land plants, since they required, and still require, open water to propogate. As we define the Embryophyta, they split basally into mosses (Bryophyta) and land plants (Rhyniophyta). The Rhyniophytes two important groups: the Lycophytina (lycopods and the extinct zosterophylls) and the Euphyllophytina (ferns and seed plants).
Embryophyta

== Embryophyta ==

=== Bryophyta ===

Bryophyte Life Cycle If the mosses had not survived into the present, we would be forced to invent them as just the sort of intermediate we might expect between essentially aquatic algae and fully terrestrial plants. Mosses do have differentiated stems. Although these are generally only a few millimeters tall, they are still designed to provide mechanical support against gravity without help from water -- the first such structure in any kingdom. Bryophytes also have leaves. These are typically one cell thick and lack veins, although they may have a central thickening for support. Mosses also have rhizomes. These may have some function in extracting soil nutrients, although their primary function seems to be mechanical attachment to the substrate. Thus they are not true roots, but do approach that condition.

The bottom line is that, structurally, mosses really differ from rhyniophytes in only one aspect: mosses lack specialized vascular tissues. That alone is sufficient to explain the lack of big leaves, long stems, and true roots. This whole complex of characters is thus probably primitive. The other distinctive character of mosses is that the plant we normally observe is the haploid, gametophyte stage. But this character is shared with liverworts (basal embryophytes) and so is also probably plesiomorphic.

Curiously, in hornworts (also basal embryophytes) the sporophyte generation is dominant. In addition, it turns out that the leaves of moss probably evolved independently from the leaves of higher plants. So the relationships of the mosses and basal embryophytes are still uncertain. What really does seem to set mosses apart is their unique form of leaf. What really seems to unite mosses with higher plants is (a) the presence of stomata to control water loss and (b) meristem (apical growth) in the sporophyte generation. See, Friedman et al. (2004). Phylogenetically, we treat Bryophyta as Moss > Quercus.

=== Rhyniophtya ===

HorneophytonSee Rhyniophyta. That section covers the basal rhyniophytes, such as Horneophyton, which were the first real land plants. These probably evolved in the Ludlow and formed the stem group for all other land plants. Consequently, they are paraphyletic. Rather than abandoning this name and its rich history, we use it to mean all land plants. Our working phylogenetic definition is definition is Quercus > moss.

This group is characterized by the ability to reproduce without open water. Anatomically, in all rhyniophytes, the (diploid) sporophyte generation is dominant, and the sporophyte is branched. For this reason, the taxon is often referred to as the Polysporangiophytes. In addition, the archegonium develops inside the body of the plant, rather than being superficial as in mosses and most basal embryophytes. Kenrick & Crane (1997).

Horneophyton and a few other basal forms lack tracheids. That is, they are avascular plants. However, almost all other rhyniophytes have some development of specialized vascular tissues. The most basal tracheid type, present in most stem rhyniophytes, appears to be the S-type tracheid.

=== Lycophytina ===

The Lycophytina includes the lycopods, zosterophylls, and related forms, including (probably) a number of plants often treated as basal rhyniophytes, such as Baragwanathia. Kenrick & Crane (1997). Since they are a complex group and are treated extensively elsewhere, we will defer discussion to a revision of the existing materials.
Euphyllophytina

The clade that unites oak trees and ferns is Euphyllophytina = Quercus + Equisetum. The two complementary stem clades are Moniliformopsida and Spermatophytata. Euphyllophytines are characterized (Kenrick & Crane, 1997) by monopodial or pseudomonopodial branching, helical arrangement of branches, small, pinnule-like vegetative branches, the branch apex is recurved or coiled, paired sporangia which split open along one side through a single slit, and radially-alligned xylem in the larger axes. Only early euphyllophytines have P-type tracheids. Kenrick & Crane identified this clade based entirely on morphological characters. However, Euphytophytina has also been recovered, with essentially the same structure, using ssu rDNA. Duff & Nickrent (1999).

=== Moniliformopses ===

Psilotum nudumThe Moniliformopses are the horsetails and ferns, including the Psilotidae (whisk ferns). They are closely related to the seed plants. Pryer et al. (2001). So, for example, they exhibit apical growth (meristem) in both sporophyte and gametophyte generations. They have well-developed roots megaphyllous leaves and the vascular system needed to make use of both. However, both may have been evolved independently of higher plants. Friedman et al. (2004). In addition, Moniliformopses lack a complete vascular cambium, and growth of xylem is restricted to lobes of the primary xylem strand.

Since this is a new clade -- discovered, for all practical purposes, by Preyer's group, we have little to say about Moniliformopses as a taxon, and defer discussion to a fuller consideration of its three component parts. The Psilotidae are the most basal, followed by the horsetails, then the remainder of the ferns.

We apply a crown group defiition to Moniliformopses: Equisetum + ferns.

=== Spermatophytata ===

PsilophytonThe clade that unites oaks and lycopsids is Euphyllophytina. The two complementary stem clades are Lycopsida and Spermatophytata = Quercus > Lepidodendron. A second way to look at Spermatophytata is as the stem group leading to angiosperms. It includes Trimerophyta and the progymnosperms, in fact everything up to and including the seed plants (Spermatopsida). However, we will only be concerned with the more basal forms for now. A third way of considering Spermatophytata is as the seed plants. However, this applies only to living forms. The basal Trimerophyta and their immediate descendants (assuming Trimerophyta is paraphyletic) lacked seeds, true leaves, or even, perhaps, roots. It is quite likely that virtually all the important land plant adaptations were independently developed in the moniliformopsid and spermatophytate lineages.

What seems to have set Spermatophytata apart quite early is not, in fact, the development of seeds, but the evolution of a full vascular cambium which permitted secondary growth. Early plants with apical growth were able to use that trait to grow taller and (a) get more sunlight (b) shade their competition and (c) have a better shot at spore dispersal. However, supporting a long stalk is much easier with a wider central column. Less derived groups either had no way to do this, or developed lateral lobes of the apical meristem. The latter worked, but required the tree to grow wide before it grew tall. The evolution of a complete vascular cambium permitted the tree to grow just wide enough to suit its height -- growing continuously wider as it grew tall.

The evolution of seeds follwed this innovation. Seeds are embryonic sporophytes, held in a sort of metabolic stasis and provided with enough food to get started once their growth has been re-stared by exposure to suitable growing conditions. Well adapted seeds combined sexual reproduction with spore-like wide dispersal and so made the alternation of generations obsolete. However, early seeds, which might lack these refinements, probably evolved on tall trees which gave any sort of propagule a head start in dispersal.

The Spermatophytata are the stem group for our next major division, the Spermatopsida.

== Links ==

[http://www.ucmp.berkeley.edu/plants/plantae.html Introduction to the Plantae - The green kingdom]

[http://www.ucmp.berkeley.edu/IB181/HpageIB181.html Integrative Biology 181/181L - Paleobotany]

[http://www.science.siu.edu/landplants/ Land Plants On-line - covers recent plants only, links to images etc]

[http://www.uni-wuerzburg.de/mineralogie/tapho/tapho1.html International Plant Taphonomy Meeting] - The purpose of the International Plant Taphonomy Meetings is to stimulate scientific research and to promote contacts among scientists engaged in the study of plant taphonomy including living and fossil plants of all geological periods.

[http://www.science.smith.edu/biology/bio240/xsmith/BotLinks.htm Botany]

=== Web Sites by Subject ===

Excellent annotated list of links to Botany and related subjects - note, some of these links are no longer current.

[http://taggart.glg.msu.edu/bot335/botclass.htm A BASIC BIOLOGICAL CLASSIFICATION OF PLANT-LIKE ORGANISMS]

[http://www.uni-muenster.de/GeoPalaeontologie/Palaeo/Palbot/ewald.html#1 A History of Palaeozoic Forests] - Hans Kerp - very informative - originally published in German.  Deals with forests of the Devonian, Carboniferous, and Permian periods.

[http://www.xs4all.nl/~steurh/home.html Hans' Paleobotany Pages] - info on the earliest land plants and on the lycopod Lepidodendron

[http://taggart.glg.msu.edu/isb200/carbfor.htm Carboniferous Forests] Ralph E. Taggart - good non-technical intro, covers main groups of Carboniferous plants, also brief mention of insects, amphibians, and reptiles'

[http://www.abdn.ac.uk/rhynie/ The Biota of Early Terrestrial Ecosystems: The Rhynie Chert] - includes useful information on Early Devonian plants from this location

[http://scitec.uwichill.edu.bb/bcs/bl14apl/conq.htm The First Land Plants] - The Conquest of the Land - gives a good introduction to basic concepts regarding the transition of plants from water to land

[http://www.ortobotanico.unina.it/Museopaleo/paleo_eng.doc Orto Botanico] - somewhat technical but not too difficult coverage of plants and paleobotany. Includes glossary.

[http://www.ucmp.berkeley.edu/IB181/HpageIB181.html Integrative Biology 181/181L] - Paleobotany - at UC Berkeley - includes material on Paleozoic plants.  A bit technical but if you stick at it you will learn a lot.

Talk:Chlorobionta

Admin — Sat, 19 Aug 2006 03:46:17 GMT

Admin:

Talk:Archaea

Admin — Fri, 18 Aug 2006 18:54:08 GMT

Admin:

There is noting on this page but a diagram?!? --[[User:Bmeyers3535|Ben]]
:We'll add more stuff later.--[[User:Admin|Stanton]] 14:54, 18 August 2006 (EDT)

Deiphon

Admin — Fri, 18 Aug 2006 18:34:52 GMT

Admin:

<div style="float:right;">
<table border="1" cellspacing="0" cellpadding="2">
<tr><th bgcolor="#CCCCCC">'''Arthropoda'''</th></tr>
<tr><td>
*[[Domain]]: [[Eukarya]]
*[[Kingdom]]: [[Animalia]]
*[[Phylum]]: [[Arthropoda]]
*[[Subphylum]]: [[Chelicerata]]
*[[Infraphylum]]: [[Trilobitomorpha]] ?
*[[Class]]: '''[[Trilobita]]'''
</td></tr>
<tr><td>
'''Order:'''
*[[Phacopida]] † <br />
</td></tr>
<tr><td>
'''Family'''
*[[Cheiruridae]] [[extinction|†]] <br />
</td></tr>
<tr><td>
'''Genus'''
*''Deiphon'' † <br />
</td></tr>
<tr><td>
'''Species'''
*D. forbesi † (type species)<br />
*D. barrandei † <br />
*D. fleur † <br />
*D. salmoni † <br />
*D. americanus † <br />
*D. dikella † <br />
*D. brabrooki † <br />
*D. grovesi † <br />
*D. pisum † <br />
</td></tr>
<tr><td>
Fossil_range:
[[Silurian]]
</td></tr>
</table>
</div>

'''''Deiphon''''' was a distinctive genus of [[phacopid]] [[trilobites]] found in Western and Central Europe, and in Central and Eastern United States. The type [[species,]] ''D. forbesi'', from Bohemia, in what is now the Czech Republic, was discovered and described by the French paleontologist, [[Joachim Barrande]] in 1850.

The species of ''Deiphon'' were highly modified for a [[pelagic]] existence. The [[glabellum]] was inflated, and globular-shaped, and covered in small wart-like bumps. If it was filled with fat, or oil, the glabellum would have helped to have made the creature positively buoyant. The cheeks of the [[cephalon]] formed a pair of long, curved spines, and the segments of the [[pleural lobes]] were separated and elongated to form rib-like struts. These modifications, along with the [[pygidium]] forming a "V," give these trilobites a sort of cartoon "fish-skeleton" appearance. However, the spherical glabellum and the curved, rib cage-like pleural lobes would have been hindrances for hydrodynamic streamlining, so it is presumed that ''Deiphon'' species were not fast swimmers. Instead, ''Deiphon'' may have fed on phytoplankton, or small, slow-moving zooplankton, living at a slow, easy going pace compared to its streamlined, torpedo-like cousin ''[[Crotalocephalus]]''.

==Links==

Reconstruction of ''D. forbesi'' [http://www.deviantart.com/deviation/33737908/]

Reconstruction of ''D. forbesi'' in comparison to ''Eurypterus remipedes'' [http://www.deviantart.com/deviation/36974185/]

[[Category:Prehistoric invertebrates]]
[[Category:Trilobita]]

Three Domains

Admin — Fri, 18 Aug 2006 18:28:40 GMT

Admin: grafting 3 Domains image in

The Three Domains of Life include the Archaea, including the halophiles, methanogens, and thermophiles, the Eubacteria, including gram-positive and gram-negative bacteria, and cyanobacteria, and the Eukarota, including protists, plants, animals, and fungi.

[[Image:Fig01 16.JPG]]

Three Domains

Admin — Fri, 18 Aug 2006 18:15:06 GMT

Admin: Starting Three Domains

Talk:Main Page

Admin — Fri, 18 Aug 2006 16:41:20 GMT

Admin:

--[[User:Bmeyers3535|Ben]] 11:05, 18 August 2006 (EDT) - I have aped the content from the original Palaeos.com home page here. Under the subheaders, I pasted the opening paragraph from the linked page. I suppose that each of the three primary headers should end up on separate pages to accomodate content growth. Can someone edit the title for the third header which I set to "Other"?
::How about "Science and Literature"?--[[User:Admin|Stanton]] 12:41, 18 August 2006 (EDT)

Main Page

Admin — Fri, 18 Aug 2006 16:40:31 GMT

Admin: /* Other */

Welcome to PaleosWiki!

Here, we intend to create a catalogue of prehistoric organisms!

== Life ==

This section is the heart of Palaeos. We have to begin this section somewhere, and so this is also the Beginning of [[Life]]. If time permits, we will one day add sections on the definition of "life" and the ways it may have begun. However, that kind of systematic treatment is not exactly what this site is all about (see, infra, the Purpose of Life). So instead, we'll get right to business.

=== Bacteria ===

Bacterial phylogenetics and systematics are areas that are fraught with controversy, confusion and very little concordance. To attempt to fit some sort of analysis of them within the confines of a single web-page, and without years of study to give oneself authority, would be the height of folly. With that in mind, feel free to read on, as we strive to raise ourselves to greater heights than ever before. If any of the arguments presented seem somewhat circular and self-contradictory, they probably are. You have been warned.

=== Eukarya ===

Organisms in which the genetic material is contained within a nuclear membrane are known as Eukaryotes, the name means "true kernel". This domain includes all multicellular forms of life: Plants, Fungi, and Animals. However, in this section, we will deal only with the group classically called "Protista," single-celled Eukarya. In fact, the line is a bit vague. By convention, slime molds are treated as "protists" while sponges and Cnidaria (or at least most of them, as we will see) are treated as Metazoa. Similar uncertainty marks the borderlands of the plants and fungi.

=== Fungi ===

The Fungi are the great saprophytes, the master recyclers. They are the black rot, the dry rot, and the white rot, the colorful fate of last week's lasagna left too long in the 'fridge, and the great, grey walls of stinking mould that can destroy whole buildings. But, they are also the baker's yeast and the brewer's yeast. They are the difference between grape juice and Chateauneuf du Pape. They are the portobellos and the morels and the cloud ears and the truffles. In fact, the French could not be half so obnoxious about their cuisine were it not for the Fungi. But, then again, perhaps they could [1].

=== Plants ===

Beginning in the Archean era, Cyanobacteria evolved photosynthesis, which enabled them to use sunlight to draw carbon dioxide from the atmosphere and convert it to oxygen, water and glucose (a simple carbohydrate). These could be considered the first simple "plants" Plants therefore might be seen as any organism that is able to use sunlight, carbon dioxide, and water, to manufacture its own food, that is, as a special class of autotroph. However, that's far too broad. It would include all kinds of things like diatoms, chromists, and photosynthetic bacteria which have nothing to do with plants in a phylogenetic sense. They are, to be sure, all within the subject matter of a General Botany class. All of these groups share some essential biochemistry. However, what they don't share is a common ancestor to the exclusion of all other organisms. This similarity arises from (a) convergent evolution and (b) the exchange of plastids.

=== Invertebrates ===

=== Chordates ===

== Time ==

Geologists and Paleontologists measure the age of the Earth and the history of life in ages of millions and even billions of years. The entire history of humankind is but a blink of an eye next to the vastness of geological time. For this reason a special sort of "calendar" or "almanac" is required; one that measures not days, weeks, months or years, but millions and tens of millions of years. This is the Geological Time-Scale

=== [[Hadean]] ===

The name Hadean was coined by geologist Preston Cloud for the pre-Isuan sequence whose record may not be preserved on Earth but is better known from Moon rocks. Consequently, the time sequence and stratigraphy of the Hadean are largely based on lunar events. For example the Nectarian Era is defined by reference to the formation of the Nectaris Basin (southwestern Nearside). The Hadean has no place in the ICS system followed in the rest of Palaeos. The ICS lumps everything earlier than 3600 Mya into the Eoarchean Era of the Archean Eon.

=== Archean ===

Rocks of the Lower Archean (in geology time is often referred to vertically, because younger rocks are deposited above older ones) are rare, and include the oldest known terrestrial rocks, from 3.8 to 4.2 billion years ago. Most of the oldest rocks are so altered through subsequent metamorphic processes it is difficult to know under what conditions they were formed. The situation is rather brighter with the more numerous rocks of the Younger ("Upper") Archean, from 3 to 2.5 or 2.6 billion years ago. These are mostly volcanic in nature, consisting of pillow-like structures identical to those of present-day lavas which have formed underwater. The implication is that at this time the entire Earth was covered by ocean. Perhaps the bulk of the continental masses, formed through volcanic outpourings, had yet to appear from beneath the waves.

=== Proterozoic ===

Beginning in the Archean era, Cyanobacteria evolved photosynthesis, which enabled them to use sunlight to draw carbon dioxide from the atmosphere and convert it to oxygen, water and glucose (a simple carbohydrate). These could be considered the first simple "plants" Plants therefore might be seen as any organism that is able to use sunlight, carbon dioxide, and water, to manufacture its own food, that is, as a special class of autotroph. However, that's far too broad. It would include all kinds of things like diatoms, chromists, and photosynthetic bacteria which have nothing to do with plants in a phylogenetic sense. They are, to be sure, all within the subject matter of a General Botany class. All of these groups share some essential biochemistry. However, what they don't share is a common ancestor to the exclusion of all other organisms. This similarity arises from (a) convergent evolution and (b) the exchange of plastids.

=== Paleozoic ===

The early Paleozoic saw the continents clustered around the equator, with Gondwanaland (representing the bulk of old Rodinia) slowly drifting south to the poles, and Siberia, Laurentia and Baltica converging in the tropics. There was a large ocean between Laurentia and Eastern Gondwanaland.

=== Mesozoic ===
=== Cenozoic ===

== Science and Literature ==
=== Evolution ===
=== Geochronology ===
=== Systematics ===
=== The Earth ===
=== Ecology ===
=== Books ===

Eurotamandua

Admin — Fri, 18 Aug 2006 03:45:23 GMT

Admin:

<div style="float:right;">
<table border="1" cellspacing="0" cellpadding="2">
<tr><th bgcolor="#CCCCCC">'''[[Mammalia]]'''</th></tr>
<tr><td>
*[[Domain]]: [[Eukarya]]
*[[Kingdom]]: [[Animalia]]
*[[Phylum]]: [[Chordata]]
*[[Subphylum]]: [[Vertebrata]]
*[[Infraphylum]]: [[Gnathostomata]]
*[[Class]]: '''[[Mammalia]]'''
</td></tr>
<tr><td>
'''Order:'''
*[[Pholidota]] <br />
</td></tr>
<tr><td>
'''Family:'''
*[[Manidae]]
</td></tr>
<tr><td>
'''Genus:'''
*'''''Eurotamandua'''''[[extinction|†]]
</td></tr>
<tr><td>
Fossil_range:
[[Eocene]]
</td></tr>
</table>
</div>

'''''Eurotamandua''''' ('[[Europe]]an tamandua') is an extinct genus of [[pangolin]]. It was about 90 cm (3 ft) long. When it was first discovered, it was originally thought to be an [[anteater]], as it did not have the characteristic fused-hair scales of other pangolins.

''Eurotamandua'' was one of the first members of the family, but aside from its lack of scales, it already bore all typical characteristics: long [[claw]]s, a long [[tail]], a strongly elongated snout and most likely the same long, sticky [[tongue]]. Presumably it also fed on [[ant]]s and [[termite]]s. ''Eurotamandua'' got its name because it strongly resembled modern arboreal anteaters of the genus ''[[Tamandua]]''.

While ''Eurotamandua'' is the most primitive known pangolin, it is not the ancestor of modern pangolins, as the [[Eocene]] pangolin, ''[[Eomanis]]'' is its contemporary. It is presumed that ''Eomanis'' and ''Eurotamandua'' diverged from a common ancestor either during the late [[Paleocene]], or the early [[Eocene]].

== Links ==
Photo of fossil [http://www.uvm.edu/~jdecher/Eurotamandua.JPG]

[[Category:Prehistoric mammals]]
[[Category:Pangolins]]
[[Category:Eocene mammals]]
[[Category:Eocene extinctions]]

Eomanis

Admin — Fri, 18 Aug 2006 03:44:48 GMT

Admin:

<div style="float:right;">
<table border="1" cellspacing="0" cellpadding="2">
<tr><th bgcolor="#CCCCCC">'''[[Mammalia]]'''</th></tr>
<tr><td>
*[[Domain]]: [[Eukarya]]
*[[Kingdom]]: [[Animalia]]
*[[Phylum]]: [[Chordata]]
*[[Subphylum]]: [[Vertebrata]]
*[[Infraphylum]]: [[Gnathostomata]]
*[[Class]]: '''[[Mammalia]]'''
</td></tr>
<tr><td>
'''Order:'''
*[[Pholidota]] <br />
</td></tr>
<tr><td>
'''Family:'''
*[[Manidae]]
</td></tr>
<tr><td>
'''Genus:'''
*'''''Eomanis'''''[[extinction|†]]
</td></tr>
<tr><td>
Fossil_range:
Middle [[Eocene]]
</td></tr>
</table>
</div>
'''''Eomanis''''' is the earliest known true [[pangolin]] from the Middle [[Eocene]] [[Europe]]. [[Fossil]]s collected from the [[Messel Pit]], [[Germany]], indicate that this 50 cm long [[animal]] was rather similar to the extant pangolins. However, unlike modern pangolins, its tail and legs did not bear scales. According to the stomach contents of the excellently preserved Messel specimens, ''Eomanis’'' [[diet (nutrition)|diet]] consisted of both [[insect]]s and [[plant]]s. Its contemporary was the scale-less, [[anteater]]-like ''[[Eurotamandua]]''.

== References ==
* {{cite book | author=Cox, Barry; Savage, R.J.G.; Gardiner, Brian; Dixon, Dougal | year=1988 | title=Macmillan Illustrated Encyclopedia of Dinosaurs and Prehistoric Animals | chapter=Insectivores and creodonts | editor= | others= | pages=213 | publisher=Macmillan London Limited | id=ISBN 0-333-48699-4 | url= | authorlink= }}

[[Category:Pangolins]]
[[Category:Prehistoric mammals]]
[[Category:Eocene mammals]]

Megacerops

Admin — Fri, 18 Aug 2006 03:26:43 GMT

Admin:

Megacerops

Admin — Fri, 18 Aug 2006 03:24:47 GMT

Admin:

Brontotheriidae

Admin — Fri, 18 Aug 2006 03:15:38 GMT

Admin:

<div style="float:right;">
<table border="1" cellspacing="0" cellpadding="2">
<tr><th bgcolor="#CCCCCC">'''Mammalia'''</th></tr>
<tr><td>
*[[Domain]]: [[Eukarya]]
*[[Kingdom]]: [[Animalia]]
*[[Phylum]]: [[Chordata]]
*[[Subphylum]]: [[Vertebrata]]
*[[Infraphylum]]: [[Gnathostomata]]
*[[Class]]: '''[[Mammalia]]'''
</td></tr>
<tr><td>
'''Order:'''
*[[Perissodactyla]] <br />
</td></tr>
<tr><td>
'''Family'''
*[[Brontotheriidae]] [[extinction|†]]<br />
</td></tr>
<tr><td>
Fossil_range:
[[Eocene]]
</td></tr>
</table>
</div>

'''Brontotheriidae''', also called '''Titanotheriidae''', was a [[family]] of [[extinct]] [[mammal]]s belonging to the order [[Perissodactyla]], the order that includes [[horse]]s, [[Rhinoceros|rhino]]s, and [[tapir]]s. Although '''brontotheres''' were probably most closely related to horses, they bore a strong, yet superficial resemblence to [[rhinoceros]]es, with which they are often confused, even though the brontotheres were not true rhinos. They lived around 58-30 million years ago, from the early to late [[Eocene]]. In their time, the brontotheres were highly successful, radiating out from their origins within North America into Asia, then Europe, before they became extinct at the end of the Eocene period.

Brontotheres retained four toes on their front feet and three toes on their hind feet. Their teeth are adapted to shearing (cutting) relatively nonabrasive vegetation. Their [[molars]] have a characteristic W-shaped [[ectoloph]] (outer shearing blade). The earliest brontotheres, such as ''[[Eotitanops]]'', were rather small, no more than a meter in height, and were hornless. Later brontotheres evolved massive body sizes, although some small species, such as ''[[Nanotitanops]]'' did persist through the Eocene. Some genera, such as ''[[Dolichorhinus]]'', [[Evolution|evolved]] highly elongate skulls. Later brontotheres were massive in size, up to 2.5 m in height, and had evolved bizarre hornlike appendages. For instance the [[North America]]n brontothere ''[[Megacerops]]'' evolved large [[sexual dimorphism|sexually dimorphic]] paired horns above their noses. The sexually dimorphic horns suggest that brontotheres were highly gregarious (social) and males may have performed some sort of head clashing behavior in competition for mates. However, unlike rhinos, the horns of brontotheres are composed of bone, the [[frontal bone]] and [[nasal bone]], and were placed side-to-side rather than front-to-back.

==Classification of Brontotheres==

Two classification systems for the Brontotheriidae are presented below. The first contains 43 genera and 8 subfamilies and although it is based on a recent publication (McKenna and Bell, 1997), it summaries research that was conducted before 1920 and is badly outdated. The second classification is based on very recent research (Mihlbachler et al., 2004a, 2004b; Mihlbachler, 2005). It indicates that many of the previous subfamily names are invalid. Also several recently discovered brontotheres are included in the newer classification. Note that although ''[[Lambdotherium]]'' and ''[[Xenicohippus]]'' were previously included in the Brontotheriidae, they are no longer considered to be members of this family. ''Lambdotherium'', though excluded, may be the closest known relative to brontotheres. ''Xenicohippus'' is now thought to be an early member of the horse family, [[Equidae]].

Old Classification (summarized by McKenna and Bell, 1997):

*'''Family Brontotheriidae'''
**''[[Pakotitanops]]'' ''[[incertae sedis]]'', from [[Pakistan]]
**''[[Nanotitanops]]'' ''[[incertae sedis]]'', from [[Asia]]
***Subfamily Lambdotheriinae
****''[[Lambdotherium]]'', from North America
****''[[Xenicohippus]]'', from North America
***Subfamily Palaeosyopinae
****''[[Palaeosyops]]'' (including ''Eotitanops''), from North America, 0.5 m tall
****''[[Mulkrajanops]]'', from [[Pakistan]], 1.25 m tall
***Subfamily Dolichorhininae
****''[[Metarhinus]]'', from North America, 1 m tall
****''[[Sphenocoelus]]'', from North America, 1.25 m tall
****''[[Mesatirhinus]]'', from North America, 1 m tall
***Subfamily Brontotheriinae
****''[[Duchesneodus]]'', from North America
****''[[Brontotherium]]'', from North America
****''[[Megacerops]]'', from North America, 2.5 m tall
***Subfamily Embolotheriinae
****''[[Titanodectes]]'', from Asia
****''[[Embolotherium]]'', from [[Mongolia]], 2.5 m tall
****''[[Protembolotherium]]'', from Outer Mongolia, 2 m tall
***Subfamily Brontopinae
****''[[Brachydiastematherium]]'', from [[Eastern Europe]], 2 m tall
****''[[Pachytitan]]'', from Inner Mongolia, 2 m tall
****''[[Dianotitan]]'', from China, 2 m tall
****''[[Gnathotitan]]'', from Inner Mongolia, 2.5 m tall
****''[[Microtitan]]'', from Inner Mongolia, 0.75 m tall
****''[[Epimanteoceras]]'', from Inner Mongolia, 2 m tall
****''[[Protitan]]'', from Inner Mongolia, 2 m tall
****''[[Rhinotitan]]'', from Inner Mongolia, 2.5 m tall
****''[[Metatitan]]'', from Mongolia, 1.5 m tall
****''[[Protitanotherium]]'', from North America, 2 m tall
****''[[Parabrontops]]'', from Mongolia, 2 m tall
****''[[Oreinotherium]]'', from North America
****''[[Brontops]]'', from North America
****''[[Protitanops]]'', from North America, 2 m tall
****''[[Pygmaetitan]]'', from China, 0.5 m tall
***Subfamily Telmatheriinae
****''[[Acrotitan]]'', from Inner Mongolia, 0.3 m tall
****''[[Desmatotitan]]'', from Inner Mongolia, 1.25 m tall
****''[[Arctotitan]]'', from China
****''[[Hyotitan]]'', from Inner Mongolia, 2.2 m tall
****''[[Sthenodectes]]'', from North America, 1.25 m tall
****''[[Telmatherium]]'' (including ''Metatelmatherium''), from North America and Inner Mongolia, 1.5 m tall
****''[[Sivatitanops]]'', from Asia and Europe
***Subfamily Menodontinae
****''[[Diplacodon]]'', from North America, 2 m tall
****''[[Eotitanotherium]]'', from North America
****''[[Notiotitanops]]'', from North America, 2 m tall
****''[[Menodus]]'', from Europe and North America
****''[[Ateleodon]]'', from North America

New classification (Mihlbachler et al., 2004a, 2004b; Mihlbachler, 2005):

*'''Family Brontotheriidae'''
**''[[Pakotitanops]]'' ''[[incertae sedis]]'', from [[Pakistan]]
**''[[Mulkrajanops]]'' ''[[incertae sedis]]'', from [[Pakistan]], 1.25 m tall
**''[[Eotitanops]]'', from North America, 0.5 m tall
**''[[Palaeosyops]]'', from North America, 1 m tall
**Subfamily Brontotheriinae
***''[[Bunobrontops]]'', from [[Asia]]
***''[[Mesatirhinus]]'', from North America, 1 m tall
***''[[Dolichorhinus]]'', from North America, 1.25 m tall
***''[[Sphenocoelus]]'', from North America, 1.25 m tall
***''[[Desmatotitan]]'', from Inner Mongolia, 1.25 m tall
***''[[Fossendorhinus]]'', from North America
***''[[Metarhinus]]'', from North America, 1 m tall
***''[[Microtitan]]'', from Inner Mongolia, 0.75 m tall
***''[[Sthenodectes]]'', from North America, 1.25 m tall
***''[[Telmatherium]]'', from North America, 1.25 m tall
***''[[Metatelmatherium]]'', from North America and Inner Mongolia, 1.25 m tall
***''[[Epimanteoceras]]'', from Inner Mongolia, 2 m tall
***''[[Hyotitan]]'' ''[[incertae sedis]]'', from Inner Mongolia, 2.2 m tall
***''[[Nanotitanops]]'' ''[[incertae sedis]]'', from [[Asia]]
***''[[Pygmaetitan]]'' ''[[incertae sedis]]'', from China, 0.5 m tall
***''[[Acrotitan]]'' ''[[incertae sedis]]'', from Inner Mongolia, 0.3 m tall
***''[[Arctotitan]]'' ''[[incertae sedis]]'', from China
***''[[Qufutitan]]'' ''[[incertae sedis]]'', from China
***Tribe Brontotheriini
****''[[Protitan]]'', from Inner Mongolia, 2 m tall
****''[[Protitanotherium]]'', from North America, 2 m tall
****''[[Rhinotitan]]'', from Inner Mongolia, 2.5 m tall
****''[[Diplacodon]]'' (including ''Eotitanotherium''), from North America, 2 m tall
****''[[Pachytitan]]'', from Inner Mongolia, 2 m tall
****''[[Brachydiastematherium]]'', from [[Eastern Europe]], 2 m tall
****''[[Sivatitanops]]'', from Asia and Europe
****Subtribe Embolotheriina
*****''[[Gnathotitan]]'', from Inner Mongolia, 2.5 m tall
*****''[[Aktautitan]]'', from Kazakstan, 2.5 m tall
*****''[[Metatitan]]'', from Mongolia, 1.5 m tall
*****''[[Nasamplus]]'', from Inner Mongolia
*****''[[Protembolotherium]]'', from Outer Mongolia, 2 m tall
*****''[[Embolotherium]]'' (including ''Titanodectes''), from [[Mongolia]], 2.5 m tall
****Subfamily Brontotheriina
*****''[[Parabrontops]]'', from Mongolia, 2 m tall
*****''[[Protitanops]]'', from North America, 2 m tall
*****''[[Notiotitanops]]'', from North America, 2 m tall
*****''[[Dianotitan]]'', from China, 2 m tall
*****''[[Duchesneodus]]'', from North America
*****''[[Megacerops]]'' (including ''Menodus'', ''Brontotherium'', ''Brontops'', ''Menops'', ''Ateleodon'', and ''Oreinotherium''), from North America, 2.5 m tall

==References==

*McKenna, M. C, and S. K. Bell. 1997. Classification of Mammals Above the Species Level. Columbia University Press, New York, 631 pp.

*Mihlbachler, M.C. 2004. Phylogenetic Systematics of the Brontotheriidae (Mammalia, Perissodactyla). Ph.D. Dissertation, Columbia University. 757 pp.

*Mihlbachler, M.C. , S.G. Lucas, and R.J, Emry. 2004a. The holotype specimen of Menodus giganteus, and the “insoluble” problem of Chadronian brontothere taxonomy. In S.G. Lucas, K. Zeigler, and P. E. Kondrashov (eds.), Paleogene Mammals. Bulletin of the New Mexico Museum of Natural History 26: 129-136.

*Mihlbachler, M.C., S.G. Lucas, R.J. Emry, and B. Bayshashov. 2004b. A new brontothere (Brontotheriidae, Perissodactla, Mammalia) from the Eocene of the Ily Basin of Kazakstan and a phylogeny of Asian "horned" brontotheres. American Museum Novitates 3439: 1-43.

[[Category:Brontotheres]]
[[Category:Eocene mammals]]

Brontops

Admin — Fri, 18 Aug 2006 03:14:18 GMT

Admin:

Brontotherium

Admin — Fri, 18 Aug 2006 03:13:29 GMT

Admin:

Brontotherium

Admin — Fri, 18 Aug 2006 03:12:21 GMT

Admin:

Brontotherium

Admin — Fri, 18 Aug 2006 03:12:03 GMT

Admin:

Mene rhombea

Admin — Fri, 18 Aug 2006 03:08:25 GMT

Admin:

'''''Mene rhombea''''' was a perciform fish found in the Tethys Ocean during the Eocene. As suggested by their fossils' small, upturned mouths, M. rhombea was a planktivore. Their fossils from the laggerstat Monte Bolca are greatly valued.

==Links==

Weigert-Fossil [http://www.weigert-fossil.de/html/coralf29.html]
Reconstruction of ''M. rhombea'' [http://www.deviantart.com/deviation/33325675/]

Mass extinction

Admin — Fri, 18 Aug 2006 02:52:44 GMT

Admin:

'''Mass extinction''' refers to the abrupt disappearance of a significant number of life forms in a relatively short time period. The surviving life forms then rapidly evolve to fill in the newly available [[niches]]. This leads to rapid [[speciation]]. Mass extinction is usually taken to be the result of a globally significant event, such as the impact of a large meteorite; the onset of an ice age; or a massive volcanic explosion. Classic examples in geologic history include the [[Permian]] - [[Triassic]] or [[PT-Boundary]] event in which some 90% of species became extinct and the [[Cretaceous]] - [[Tertiary]] or [[KT-Boundary]] event in which some 75% of species disappeared.

The current impact of [[humankind]] upon the [[biosphere]] is sometimes considered to rank alongside these examples. See: <i>The Sixth Extinction : Patterns of Life and the Future of Humankind</i> by Richard Leakey ( ISBN 0385468091 ).

More recent work on the topic (Bambach et al, 2004) suggests that differences in rate between extinction and origination of species may explain some events previously thought to be mass extinctions. The Ashgillian, Djhulfian, and Maastrichtian extinctions retain their characterization as mass extinctions in this perspective but the late Frasnian and Norian extinctions may now be considered as different. These stages show a dramatic decrease in origination rate below the mean while extinction rate remains constant. Other unknown processes appear to be at work supressing the rise of new species during the Frasnian and Norian stages. This process gives an appearance of extinction rate increasing when in fact it is a decrease of species originations that is responsible for the observed decline in biodiversity during these stages.

Mass extinctions are a key part of the [[Punctuated Equilibrium]] hypothesis of [[Stephen Jay Gould]] and [[Niles Eldredge]]. See: <i>Time Frames: The Evolution of Punctuated Equilibria</i> ( ISBN 0691024359 )

==References==
# Bambach, R., Knoll, A., Wang, S. 2004. Origination, extinction, and mass depletions of marine diversity. <i>Paleobiology</i> v30 p522-542

[[Category:Biogeography]]

Extinction

Admin — Fri, 18 Aug 2006 02:52:03 GMT

Admin:

'''Extinction''' is the technical term for what happens to a [[species]] when none of its members are living. It wasn't so very long ago that prominent [[Creationists]] declared it wasn't possible for any species to go extinct, because that would indicate that God had messed up somehow when He created the universe. [[Georges Cuvier]] first showed otherwise, demonstrating that [[mammoths]] are a now-extinct species of elephant, and that several other fossil species correspond to no living ones.

While extinction is usually the result of a species' chronic failure to reproduce, it should be noted that a species may also be reduced to a population of zero when, due to gradual accumulation of mutations over time, the species' current offspring can no longer be recognized as belonging to the ancestral species.

Extinction can also occur due to abiotic factors, e.g., extraterrestrial causation, volcanism, etc.

See [[Mass extinction]]

Necromanis

Admin — Fri, 18 Aug 2006 02:50:59 GMT

Admin: /* Links */

<div style="float:right;">
<table border="1" cellspacing="0" cellpadding="2">
<tr><th bgcolor="#CCCCCC">'''[[Mammalia]]'''</th></tr>
<tr><td>
*[[Domain]]: [[Eukarya]]
*[[Kingdom]]: [[Animalia]]
*[[Phylum]]: [[Chordata]]
*[[Subphylum]]: [[Vertebrata]]
*[[Infraphylum]]: [[Gnathostomata]]
*[[Class]]: '''[[Mammalia]]'''
</td></tr>
<tr><td>
'''Order:'''
*[[Pholidota]] <br />
</td></tr>
<tr><td>
'''Family:'''
*[[Manidae]]
</td></tr>
<tr><td>
'''Genus:'''
*'''''Necromanis'''''[[extinction|†]]
</td></tr>
<tr><td>
'''Species:'''
*'''''N. franconica''''' (type species)†<br />
*'''''N. quercyi'''''†<br />
*'''''N. edwardsi'''''†<br />
<tr><td>
Fossil_range:
[[Miocene]]
</td></tr>
</table>
</div>

'''''Necromanis''''' is an [[extinct]] [[genus]] of [[pangolin]]s from the [[Miocene]] of France. ''Necromanis'' is descended from the [[Eocene]] pangolins of genus ''[[Eomanis]]''.

From what can be derived from the fossil specimens, the species of ''Necromanis'' were, for the most part, identical to modern ''Manis'' pangolins in anatomy, diet, and behavior.

There are at least three [[species]] recognized.

== Links ==

Reconstruction of ''N. fraconica'' [http://www.deviantart.com/deviation/37240730/]

[[Category:Prehistoric mammals]]
[[Category:Pangolins]]

Necromanis

Admin — Fri, 18 Aug 2006 02:50:39 GMT

Admin:

<div style="float:right;">
<table border="1" cellspacing="0" cellpadding="2">
<tr><th bgcolor="#CCCCCC">'''[[Mammalia]]'''</th></tr>
<tr><td>
*[[Domain]]: [[Eukarya]]
*[[Kingdom]]: [[Animalia]]
*[[Phylum]]: [[Chordata]]
*[[Subphylum]]: [[Vertebrata]]
*[[Infraphylum]]: [[Gnathostomata]]
*[[Class]]: '''[[Mammalia]]'''
</td></tr>
<tr><td>
'''Order:'''
*[[Pholidota]] <br />
</td></tr>
<tr><td>
'''Family:'''
*[[Manidae]]
</td></tr>
<tr><td>
'''Genus:'''
*'''''Necromanis'''''[[extinction|†]]
</td></tr>
<tr><td>
'''Species:'''
*'''''N. franconica''''' (type species)†<br />
*'''''N. quercyi'''''†<br />
*'''''N. edwardsi'''''†<br />
<tr><td>
Fossil_range:
[[Miocene]]
</td></tr>
</table>
</div>

'''''Necromanis''''' is an [[extinct]] [[genus]] of [[pangolin]]s from the [[Miocene]] of France. ''Necromanis'' is descended from the [[Eocene]] pangolins of genus ''[[Eomanis]]''.

From what can be derived from the fossil specimens, the species of ''Necromanis'' were, for the most part, identical to modern ''Manis'' pangolins in anatomy, diet, and behavior.

There are at least three [[species]] recognized.

== Links ==

Reconstruction of ''N. fraconica'' [http://www.deviantart.com/deviation/37240730/]

[[Category:Prehistoric mammals]]
[[Category:Pangolins]]

{{stub}}

User:Admin

Admin — Fri, 18 Aug 2006 02:47:16 GMT

Admin:

<div style="border: 2px solid #fc0; background: #fe9; margin:0; padding: 1em; text-align:center"><big>'''Anyone, including you, can write for {{SITENAME}}!'''</big>

<small>Though, I reserve the right to edit or destroy the pages in this wiki. Mostly edit.</small>

<div style="border: 2px solid #fd6; background: #fff; margin:1em 1ex 1ex 1ex; padding: 1em; text-align:center">
{| cellpadding="8" cellspacing="0" border="0"
| align="right" |'''''Type a title:'''''<br/><small>then click "Create page"</small>
| align="left" |
<inputbox>type=create
width=45
</inputbox>
|}
</div>
</div>

Main Page

Admin — Fri, 18 Aug 2006 02:36:04 GMT

Admin:

Welcome to PaleosWiki!

Here, we intend to create a catalogue of prehistoric organisms!

Image logo url

Admin — Thu, 17 Aug 2006 20:35:25 GMT

Admin:

http://tn1-3.deviantart.com/fs10/150/i/2006/135/6/a/Mene_rhombea_by_avancna.jpg

Image logo url

Admin — Thu, 17 Aug 2006 20:35:00 GMT

Admin:

http://tn3-1.deviantart.com/fs10/300W/i/2006/135/6/a/Mene_rhombea_by_avancna.jpg