Term
Characteristics of Animals
.Sister group to animals are? nearly identical to?
.inges?and digest? with?
.structure?held together by ?
Formation of? |
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Definition
Sister group to animals are single-celled, sometimes colonial organisms called Choanoflagellates: nearly identical to some cells in sponges (Fig. 32.3)
•Ingest food and digest it internally with enzymes
•Multicellular with no cell walls- held together by proteins (collagen, etc.)
•Formation of a blastula/gastrula (hollow ball of cells that indents to form a cavity)
•Origin probably ~800 million years ago, first fossils at 565 million years ago, most animal phyla appear during Cambrian Explosion (~530 million years ago) |
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Definition
| hollow ball of cells in early embryonic development |
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Definition
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Definition
| envagination of blastocoel wall |
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Term
Endoderm
will form?
____ animals have?....._____ for a _____ in ______ |
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Definition
| will eventually form lining of digestive tract: Diblastic animals have endoderm+ectoderm, Triploblastic (generally bilaterally symmetric) form a third mesoderm layer in between |
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Term
Earliest animals
.were probably ?
.___ still only have
.radiall symmetric animals have? |
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Definition
were probably gastrula-like with specialized cells for reproduction:
Sponges still only have specialized cells with no tissue
Radially symmetric animals (comb jellies, jellyfish, etc. ) have two tissue layers (endoderm & ectoderm)
Bilaterally symmetric animals have all 3 tissue layers (endoderm, mesoderm, & ectoderm) (see figure on page 665) |
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Term
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Definition
Animals that lack a backbone
Defined by an ancestral characteristic, not a synapomorphy, so they would be a paraphyletic group (Fig. 33.2)
95% of known animal species |
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Term
Porifera-
.no specialized, can, no
.filter
.ofter have |
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Definition
Sponges
-No specialized tissues (though some cells are individually specialized- can shift and change function), no symmetry
-Filter gallons of water a day through their body cavities to catch food particles
-Often have added structural support and predator defense from silica or calcium carbonate Spicules |
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