³1username³2JoshuaGrosse³2name³2text_default³2version³21³2ts³2980725280³2ip³2129.97.182.3³2data³2text³3Parazoan and mesozoan animals:

* PhylumPorifera
* PhylumRhombozoa
* PhylumOrthonectida
* PhylumPlacozoa

Lower metazoa:

* PhylumCnidaria (=Ctenophora)
* PhylumCtenophora
* PhylumPlatyhelminthes - probably paraphyletic to higher groups
* PhylumRotifera
* PhylumAcanthocephala

Trochozoa:

* PhylumNemertea
* PhylumMollusca (e.g. AbalonE)
* PhylumSipuncula
* PhylumEchiura
* PhylumPogonophora
* PhylumVestimentifera
* PhylumAnnelida

Ecdysozoa:

* PhylumCephalorhyncha (=priapulids, kinorhynchs, loriciferans)
* PhylumNematoda
* PhylumNematomorpha
* PhylumOnychophora
* PhylumTardigrada
* PhylumArthropoda

Lophophorata:

* PhylumBrachiopoda
* PhylumEctoprocta (=Bryozoa)
* PhylumPhoronida

Deuterostomia:

* PhylumChaetognatha
* PhylumEchinodermata
* PhylumHemichordata
* PhylumChordata (e.g. HomoSapiens, AardvarK)
³3minor³31³3newauthor³30³3summary³3*³2tscreate³2980585709³2keepts³2981181232³2id³21076³2host³2cnts2p03.uwaterloo.ca³2revision³28³1username³2LarrySanger³2name³2text_default³2version³21³2ts³2981181232³2ip³224.234.246.58³2data³2newauthor³31³3minor³30³3text³3Parazoan and mesozoan animals:

* PhylumPorifera
* PhylumRhombozoa
* PhylumOrthonectida
* PhylumPlacozoa

Lower metazoa:

* PhylumCnidaria (=Ctenophora)
* PhylumCtenophora
* PhylumPlatyhelminthes - probably paraphyletic to higher groups
* PhylumRotifera
* PhylumAcanthocephala

Trochozoa:

* PhylumNemertea
* PhylumMollusca (e.g. AbalonE)
* PhylumSipuncula
* PhylumEchiura
* PhylumPogonophora
* PhylumVestimentifera
* PhylumAnnelida

Ecdysozoa:

* PhylumCephalorhyncha (=priapulids, kinorhynchs, loriciferans)
* PhylumNematoda
* PhylumNematomorpha
* PhylumOnychophora
* PhylumTardigrada
* PhylumArthropoda

Lophophorata:

* PhylumBrachiopoda
* PhylumEctoprocta (=Bryozoa)
* PhylumPhoronida

Deuterostomia:

* PhylumChaetognatha
* PhylumEchinodermata
* PhylumHemichordata
* PhylumChordata (e.g. HomoSapiens, AardvarK, WolF)
³3summary³3*³2tscreate³2980585709³2keepts³2981183793³2id³21001³2host³2dhcp058.246.lvcm.com³2revision³29³1username³2JoshuaGrosse³2name³2text_default³2version³21³2ts³2981183793³2ip³2129.97.182.44³2data³2text³3''I'd like to start filling in some of these categories, so that new animals can be filed into a tree rather than a flat list.  However, I'm not entirely sure I like the naming system I originally came up with.  Does anyone have an opinion on whether subcategories should be things like PhylumPorifera, PoriFera or SpongE?''

Parazoan and mesozoan animals:

* PhylumPorifera
* PhylumRhombozoa
* PhylumOrthonectida
* PhylumPlacozoa

Lower metazoa:

* PhylumCnidaria (=Ctenophora)
* PhylumCtenophora
* PhylumPlatyhelminthes - probably paraphyletic to higher groups
* PhylumRotifera
* PhylumAcanthocephala

Trochozoa:

* PhylumNemertea
* PhylumMollusca (e.g. AbalonE)
* PhylumSipuncula
* PhylumEchiura
* PhylumPogonophora
* PhylumVestimentifera
* PhylumAnnelida

Ecdysozoa:

* PhylumCephalorhyncha (=priapulids, kinorhynchs, loriciferans)
* PhylumNematoda
* PhylumNematomorpha
* PhylumOnychophora
* PhylumTardigrada
* PhylumArthropoda

Lophophorata:

* PhylumBrachiopoda
* PhylumEctoprocta (=Bryozoa)
* PhylumPhoronida

Deuterostomia:

* PhylumChaetognatha
* PhylumEchinodermata
* PhylumHemichordata
* PhylumChordata (e.g. HomoSapiens, AardvarK, WolF)
³3minor³30³3newauthor³31³3summary³3Formatting question³2tscreate³2980585709³2keepts³2981193476³2id³21076³2host³2cnts2p44.uwaterloo.ca³2revision³210³1username³2JoshuaGrosse³2name³2text_default³2version³21³2ts³2981193476³2ip³2129.97.130.47³2data³2newauthor³30³3minor³31³3text³3''I'd like to start filling in some of these categories, so that new animals can be filed into a tree rather than a flat list.  However, I'm not entirely sure I like the naming system I originally came up with.  Does anyone have an opinion on whether subcategories should be things like PhylumPorifera, PoriFera or SpongE?''

Characteristics that set cells off from other eukaryotes:
* Oogamous, with anteriorly uniflagellate sperm
* Multicellular diploid individuals with an initial blastula stage (ie zygote divides to form a hollow sphere)
* Cells separated by septate junctions, presence of collagen in extracellular matrix
...and that's about it.  In the "higher" animals (Metazoa) the individuals are differentiated into a variety of cell types, usually grouped to form distinct organs, and typically include muscles and nerves.  The individual is radially or bilaterally symmetrical and has a definite adult morphology (unlike a plant, which just sort of grows).

Parazoan and mesozoan animals:

* PhylumPorifera
* PhylumRhombozoa
* PhylumOrthonectida
* PhylumPlacozoa

Lower metazoa:

* PhylumCnidaria (=Ctenophora)
* PhylumCtenophora
* PhylumPlatyhelminthes - probably paraphyletic to higher groups
* PhylumRotifera
* PhylumAcanthocephala

Trochozoa:

* PhylumNemertea
* PhylumMollusca (e.g. AbalonE)
* PhylumSipuncula
* PhylumEchiura
* PhylumPogonophora
* PhylumVestimentifera
* PhylumAnnelida

Ecdysozoa:

* PhylumCephalorhyncha (=priapulids, kinorhynchs, loriciferans)
* PhylumNematoda
* PhylumNematomorpha
* PhylumOnychophora
* PhylumTardigrada
* PhylumArthropoda

Lophophorata:

* PhylumBrachiopoda
* PhylumEctoprocta (=Bryozoa)
* PhylumPhoronida

Deuterostomia:

* PhylumChaetognatha
* PhylumEchinodermata
* PhylumHemichordata
* PhylumChordata (e.g. HomoSapiens, AardvarK, WolF)
³3summary³3*³2tscreate³2980585709³2keepts³2981193499³2id³21076³2host³2cnts3p47.uwaterloo.ca³2revision³211³1username³2JoshuaGrosse³2name³2text_default³2version³21³2ts³2981193499³2ip³2129.97.130.47³2data³2text³3''I'd like to start filling in some of these categories, so that new animals can be filed into a tree rather than a flat list.  However, I'm not entirely sure I like the naming system I originally came up with.  Does anyone have an opinion on whether subcategories should be things like PhylumPorifera, PoriFera or SpongE?''

Characteristics that set animals off from other eukaryotes:
* Oogamous, with anteriorly uniflagellate sperm
* Multicellular diploid individuals with an initial blastula stage (ie zygote divides to form a hollow sphere)
* Cells separated by septate junctions, presence of collagen in extracellular matrix
...and that's about it.  In the "higher" animals (Metazoa) the individuals are differentiated into a variety of cell types, usually grouped to form distinct organs, and typically include muscles and nerves.  The individual is radially or bilaterally symmetrical and has a definite adult morphology (unlike a plant, which just sort of grows).

Parazoan and mesozoan animals:

* PhylumPorifera
* PhylumRhombozoa
* PhylumOrthonectida
* PhylumPlacozoa

Lower metazoa:

* PhylumCnidaria (=Ctenophora)
* PhylumCtenophora
* PhylumPlatyhelminthes - probably paraphyletic to higher groups
* PhylumRotifera
* PhylumAcanthocephala

Trochozoa:

* PhylumNemertea
* PhylumMollusca (e.g. AbalonE)
* PhylumSipuncula
* PhylumEchiura
* PhylumPogonophora
* PhylumVestimentifera
* PhylumAnnelida

Ecdysozoa:

* PhylumCephalorhyncha (=priapulids, kinorhynchs, loriciferans)
* PhylumNematoda
* PhylumNematomorpha
* PhylumOnychophora
* PhylumTardigrada
* PhylumArthropoda

Lophophorata:

* PhylumBrachiopoda
* PhylumEctoprocta (=Bryozoa)
* PhylumPhoronida

Deuterostomia:

* PhylumChaetognatha
* PhylumEchinodermata
* PhylumHemichordata
* PhylumChordata (e.g. HomoSapiens, AardvarK, WolF)
³3minor³31³3newauthor³30³3summary³3*³2tscreate³2980585709³2keepts³2981196864³2id³21076³2host³2cnts3p47.uwaterloo.ca³2revision³212³1username³2JoshuaGrosse³2name³2text_default³2version³21³2ts³2981196864³2ip³2129.97.182.12³2data³2newauthor³30³3minor³30³3text³3''I'd like to start filling in some of the phyla, so that new animals can be filed into a tree rather than a flat list.  However, I'm not entirely sure I like the naming system I originally came up with.  Does anyone have an opinion on whether subcategories should be things like PhylumPorifera, PoriFera or SpongE?''

'''Characteristics of Animals'''

Animals are all multicellular, heterotrophic eukaryotes.  The adults are all diploids and oogamous, ie there is a large non-motile female gamete and a tiny male gamete, which has a characteristic posterior flagellum.  The one finds the other and they fuse to form a zygote, which divides to form a hollow sphere of cells.  

Other groups have reached this level of organization, eg the green alga ''Volvox.''  But animals have been able to develop much further, thanks to the way the cells are held together.  Instead of being rigidly bound by cell walls, they are linked by much more elastic septate junctions, composing an extracellular matrix including the unique structural protein collagen.  This forms a framework in which cells can be moved about, allowing for much more complicated differentiation.

The result of this flexibility is an incredible diversity of animal forms.  Except for a few phyla, most notably the sponges, all animals are metazoans: the body is composed of three separate layers (the endoderm, mesoderm, and ectoderm) with distinct tissues, including muscles and nerves, and is often separated out to form organs.  Most metazoans have a clear adult form, as compared with other multicellular organisms that usually just grow.

'''Phyla of animals'''

Parazoan and mesozoan animals:

* PhylumPorifera
* PhylumRhombozoa
* PhylumOrthonectida
* PhylumPlacozoa

Lower metazoa:

* PhylumCnidaria (=Ctenophora)
* PhylumCtenophora
* PhylumPlatyhelminthes - probably paraphyletic to higher groups
* PhylumRotifera
* PhylumAcanthocephala

Trochozoa:

* PhylumNemertea
* PhylumMollusca (e.g. AbalonE)
* PhylumSipuncula
* PhylumEchiura
* PhylumPogonophora
* PhylumVestimentifera
* PhylumAnnelida

Ecdysozoa:

* PhylumCephalorhyncha (=priapulids, kinorhynchs, loriciferans)
* PhylumNematoda
* PhylumNematomorpha
* PhylumOnychophora
* PhylumTardigrada
* PhylumArthropoda

Lophophorata:

* PhylumBrachiopoda
* PhylumEctoprocta (=Bryozoa)
* PhylumPhoronida

Deuterostomia:

* PhylumChaetognatha
* PhylumEchinodermata
* PhylumHemichordata
* PhylumChordata (e.g. HomoSapiens, AardvarK, WolF)
³3summary³3A short intro³2tscreate³2980585709³2keepts³2981196920³2id³21076³2host³2cnts2p12.uwaterloo.ca³2revision³213³1username³2JoshuaGrosse³2name³2text_default³2version³21³2ts³2981196920³2ip³2129.97.182.12³2data³2text³3''I'd like to start filling in some of the phyla, so that new animals can be filed into a tree rather than a flat list.  However, I'm not entirely sure I like the naming system I originally came up with.  Does anyone have an opinion on whether subcategories should be things like PhylumPorifera, PoriFera or SpongE?''

'''Characteristics of Animals'''

Animals are all multicellular, heterotrophic eukaryotes.  The adults are all diploids and oogamous, ie there is a large non-motile female gamete and a tiny male gamete, which has a characteristic posterior flagellum.  The one finds the other and they fuse to form a zygote, which divides to form a hollow sphere of cells called a ''blastula.''

Other groups have reached this level of organization, eg the green alga ''Volvox.''  But animals have been able to develop much further, thanks to the way the cells are held together.  Instead of being rigidly bound by cell walls, they are linked by much more elastic septate junctions, composing an extracellular matrix including the unique structural protein collagen.  This forms a framework in which cells can be moved about, allowing for much more complicated differentiation.

The result of this flexibility is an incredible diversity of animal forms.  Except for a few phyla, most notably the sponges, all animals are metazoans: the body is composed of three separate layers (the endoderm, mesoderm, and ectoderm) with distinct tissues, including muscles and nerves, and is often separated out to form organs.  Most metazoans have a clear adult form, as compared with other multicellular organisms that usually just grow.

'''Phyla of animals'''

Parazoan and mesozoan animals:

* PhylumPorifera
* PhylumRhombozoa
* PhylumOrthonectida
* PhylumPlacozoa

Lower metazoa:

* PhylumCnidaria (=Ctenophora)
* PhylumCtenophora
* PhylumPlatyhelminthes - probably paraphyletic to higher groups
* PhylumRotifera
* PhylumAcanthocephala

Trochozoa:

* PhylumNemertea
* PhylumMollusca (e.g. AbalonE)
* PhylumSipuncula
* PhylumEchiura
* PhylumPogonophora
* PhylumVestimentifera
* PhylumAnnelida

Ecdysozoa:

* PhylumCephalorhyncha (=priapulids, kinorhynchs, loriciferans)
* PhylumNematoda
* PhylumNematomorpha
* PhylumOnychophora
* PhylumTardigrada
* PhylumArthropoda

Lophophorata:

* PhylumBrachiopoda
* PhylumEctoprocta (=Bryozoa)
* PhylumPhoronida

Deuterostomia:

* PhylumChaetognatha
* PhylumEchinodermata
* PhylumHemichordata
* PhylumChordata (e.g. HomoSapiens, AardvarK, WolF)
³3minor³31³3newauthor³30³3summary³3³2tscreate³2980585709³2keepts³2981197736³2id³21076³2host³2cnts2p12.uwaterloo.ca³2revision³214³1username³2JoshuaGrosse³2name³2text_default³2version³21³2ts³2981197736³2ip³2129.97.13.28³2data³2newauthor³30³3minor³31³3text³3''I'd like to start filling in some of the phyla, so that new animals can be filed into a tree rather than a flat list.  However, I'm not entirely sure I like the naming system I originally came up with.  Does anyone have an opinion on whether subcategories should be things like PhylumPorifera, PoriFera or SpongE?''

'''Characteristics of Animals'''

Animals are all multicellular, heterotrophic eukaryotes.  The adults are all diploids and oogamous, ie there is a large non-motile female gamete and a tiny male gamete, which has a characteristic posterior flagellum.  The one finds the other and they fuse to form a zygote, which divides to form a hollow sphere of cells called a ''blastula.''

Other groups have reached this level of organization, eg the green alga ''Volvox.''  But animals have been able to develop much further, thanks to the way the cells are held together.  Instead of being rigidly bound by cell walls, they are linked by much more elastic septate junctions, composing an extracellular matrix including the unique structural protein collagen.  This forms a framework in which cells can be moved about, allowing for much more complicated differentiation.

The result of this flexibility is an incredible diversity of animal forms.  Except for a few phyla, most notably the sponges, all animals are metazoans: the body is composed of three separate layers (the endoderm, mesoderm, and ectoderm) with distinct tissues, including muscles and nerves, and is often separated out to form organs.  Most metazoans have a clear adult form, as compared with other multicellular organisms that usually just grow.

'''Phyla of animals'''

Parazoan and mesozoan animals:

* PhylumPorifera
* PhylumRhombozoa
* PhylumOrthonectida
* PhylumPlacozoa

Lower metazoa:

* PhylumCnidaria (=Coelentrata)
* PhylumCtenophora
* PhylumPlatyhelminthes - probably paraphyletic to higher groups
* PhylumRotifera
* PhylumAcanthocephala

Trochozoa:

* PhylumNemertea
* PhylumMollusca (e.g. AbalonE)
* PhylumSipuncula
* PhylumEchiura
* PhylumPogonophora
* PhylumVestimentifera
* PhylumAnnelida

Ecdysozoa:

* PhylumCephalorhyncha (=priapulids, kinorhynchs, loriciferans)
* PhylumNematoda
* PhylumNematomorpha
* PhylumOnychophora
* PhylumTardigrada
* PhylumArthropoda

Lophophorata:

* PhylumBrachiopoda
* PhylumEctoprocta (=Bryozoa)
* PhylumPhoronida

Deuterostomia:

* PhylumChaetognatha
* PhylumEchinodermata
* PhylumHemichordata
* PhylumChordata (e.g. HomoSapiens, AardvarK, WolF)
³3summary³3*³2tscreate³2980585709³2keepts³2981280775³2id³21076³2host³2cnts6p28.uwaterloo.ca³2revision³215³1username³2JoshuaGrosse³2name³2text_default³2version³21³2ts³2981280775³2ip³2129.97.130.43³2data³2text³3'''Introduction'''

'''Development and evolution'''

Adult animals are typically diploids, producing small motile sperm and large non-motile eggs.  In all forms the fertilized zygote intially divides to form a hollow sphere called a ''blastula''.  This then undergoes rearrangement and differentiation.  Blastulae are probably representative of the sort of colonies animals evolved from; similar forms occur among other flagellates, e.g. ''Volvox''.  However none of these other groups really ever progressed further, and large multicellular forms tend to develop by progressive growth instead.

What makes animals different?  The answer lies in the way the cells are held together.  Instead of being simply stuck together or held in place by thick walls, animal cells are linked by septate junctions, composed mainly of elastic proteins - collagen is characteristic - that make up the extracellular matrix.  Sometimes this is calcified to form shells, bones, or spicules, but otherwise it's fairly flexible and can serve as a framework, upon which cells can move about and be reorganized.

The animals other than the sponges, and a few problematic phyla, form a clear subgroup called the Metazoa.  In these forms the blastula invaginates and cells migrate or pinch into the interior.  The resulting form is called a ''gastrula'' and has a clear digestive tract, with three separate layers of cells - called the ectoderm, mesoderm, and endoderm - that differentiate into various tissues, including muscles and nerves.

The first forms that might represent animals appear in the fossil record around the end of the Precambrian.  These are called Vendians and are exceedingly difficult to relate to later forms.  Other than them, virtually every phylum makes a more or less simultaneous appearance during the Cambrian.  This massive adaptive radiation may have come about because of climate change or a simple genetic innovation, and is so sudden that it is usually called the CambrianExplosion.

'''Systematics and ecology'''

'''Phyla of animals'''

Parazoan and mesozoan animals:

* PhylumPorifera
* PhylumRhombozoa
* PhylumOrthonectida
* PhylumPlacozoa

Lower metazoa:

* PhylumCnidaria (=Coelentrata)
* PhylumCtenophora
* PhylumPlatyhelminthes - probably paraphyletic to higher groups
* PhylumRotifera
* PhylumAcanthocephala

Trochozoa:

* PhylumNemertea
* PhylumMollusca (e.g. AbalonE)
* PhylumSipuncula
* PhylumEchiura
* PhylumPogonophora
* PhylumVestimentifera
* PhylumAnnelida

Ecdysozoa:

* PhylumCephalorhyncha (=priapulids, kinorhynchs, loriciferans)
* PhylumNematoda
* PhylumNematomorpha
* PhylumOnychophora
* PhylumTardigrada
* PhylumArthropoda

Lophophorata:

* PhylumBrachiopoda
* PhylumEctoprocta (=Bryozoa)
* PhylumPhoronida

Deuterostomia:

* PhylumChaetognatha
* PhylumEchinodermata
* PhylumHemichordata
* PhylumChordata (e.g. HomoSapiens, AardvarK, WolF)
³3minor³30³3newauthor³30³3summary³3³2tscreate³2980585709³2keepts³2982036294³2id³21076³2host³2cnts3p43.uwaterloo.ca³2revision³216