[Home]History of Animalia

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Revision 30 . . (edit) October 17, 2001 9:14 am by Josh Grosse
Revision 29 . . (edit) October 16, 2001 9:51 pm by The Cunctator
Revision 23 . . July 13, 2001 11:43 pm by (logged).236.235.xxx
  

Difference (from prior major revision) (minor diff, author diff)

Changed: 1c1
Introduction

Introduction




Changed: 3c3
Animalia is the name of the animal kingdom in standard taxonomy, coming directly from the Latin animalis, which in turn comes from anima. Also the title of a book by [Graeme Base]? full of illustration and aliteration: see [Graeme Base/Animalia]?.
Animalia is the name of the animal kingdom in standard taxonomy, coming directly from the Latin animalis, which in turn comes from anima. Also the title of a book by [Graeme Base]? full of illustration and aliteration: see [Graeme Base/Animalia]?.

Removed: 5,6d4
Blah, blah, blah.
Yahooo!!!

Changed: 8c6
Development and evolution

Development and evolution




Changed: 10c8
Animals are eukaryotes, and diverged from the same group of flagellate protozoa that gave rise to the fungi and choanoflagellates?. The last are especially close relatives, with collared cells appearing only among them, the sponges, and rarely in certain other animal forms. In all these groups motile cells have a single posterior flagellum with similar ultrastructure.
Animals are eukaryotes, and diverged from the same group of flagellate protozoa that gave rise to the fungi and choanoflagellates?. The last are especially close relatives, with collared cells appearing only among them, the sponges, and rarely in certain other animal forms. In all these groups motile cells have a single posterior flagellum with similar ultrastructure.

Changed: 12c10
Adult animals are typically diploids, producing small motile sperm and large non-motile eggs. In all forms the fertilized zygote intiallvy 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.
Adult animals are typically diploids, producing small motile sperm and large non-motile eggs. In all forms the fertilized zygote intiallvy 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.

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Classification

Classification




Changed: 20c18
In Linnaeus' original scheme, the animals were one of three kingdoms, divided into the classes of Vermes?, Insecta, Pisces, Amphibia, Aves, and Mammalia. Since then the last four have all been subsumed into a single phylum, the Chordata, whereas the various other forms have been separated out. When they were first discovered, the Protozoa were included as an animal phylum or subkingdom, but as they are generally unrelated and often as similar to plants as animals, a new kingdom, the Protista, was devised to hold them.
In Linnaeus' original scheme, the animals were one of three kingdoms, divided into the classes of Vermes?, Insecta, Pisces, Amphibia, Aves, and Mammalia. Since then the last four have all been subsumed into a single phylum, the Chordata, whereas the various other forms have been separated out. When they were first discovered, the Protozoa were included as an animal phylum or subkingdom, but as they are generally unrelated and often as similar to plants as animals, a new kingdom, the Protista, was devised to hold them.

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Phylum Ectoprocta?

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Traditionally the Arthropoda - the largest animal phylum including insects, spiders, crabs, and kin - and two small phyla related thereto, the Onychophora? and Tardigrada?, have been held to be close relatives of the annelids on account of their common segmented body plan. This relationship is now in doubt, and it appears that the arthropods may instead belong with various pseudocoelomate worms - the Nematoda? (roundworms), Nematomorpha? (horsehair worms), Kinorhyncha?, Loricifera?, and Priapulida? - that share with them the characteristic of moulting.
Traditionally the Arthropoda - the largest animal phylum including insects, spiders, crabs, and kin - and two small phyla related thereto, the Onychophora? and Tardigrada?, have been held to be close relatives of the annelids on account of their common segmented body plan. This relationship is now in doubt, and it appears that the arthropods may instead belong with various pseudocoelomate worms - the Nematoda? (roundworms), Nematomorpha? (horsehair worms), Kinorhyncha?, Loricifera?, and Priapulida? - that share with them the characteristic of moulting. More work will be needed to resolve between these possibilities.

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