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Animal Evolutionary Classification. Chapter 29. KEY evolutionary events. Choanaflagellate (top box) Common ancestor of animals. Next evolutionary split. EUMETAZOA true tissues all other animals. PARAZOA no true tissues sponges.
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Animal Evolutionary Classification Chapter 29
KEY evolutionary events • Choanaflagellate (top box) • Common ancestor of animals
Next evolutionary split • EUMETAZOA • true tissues • all other animals PARAZOA • no true tissues • sponges This is a layer of sponge made up of a cluster of choanocytes
evolutionary split in Eumetazoa • Radial Symmetry • um...round • jellyfish, hydra and corals Bilateral Symmetry • right/left side • dorsal/ventral
Bilateral animals splits into 3 distinct groups • Coelomates • Pseudocoelomates • Acoelomates
Coelomates • Coelom = a fluid filled body cavity • Coelomates have a true fluid filled body cavity • The coelom is between the body wall and gut • Completely lined by mesoderm • What??? Just write it and we will go into it more – promise!
Pseudocoelomates • Pseudo = fake • Fake coelom because they have a fluid filled body cavity but… • it is NOT enclosed by the mesoderm • Ex. roundworms
Acoelomates • A=without • Acoelomates do not have a fluid-filled body cavity • Ex. Flatworms (planaria and sea slugs)
Coelomates divide yet again • Protostomes • Deuterostomes
Protostomes vs Deuterostomes “The key differences between these coelomate animals is in embryonic development – we’ll get into this more as well, promise! So just write the terminology down for now.” -Hartford
Protostomes • Blastopore becomes the mouth • Spiral determinate cleavage • Coelom form from solid mass of mesoderm splitting
Deuterostomes • Blastopore becomes anus • Radial indeterminate cleavage • Coelom forms from out-pockets of mesoderm
Coelom and germ layers PAGE 532 – Add to notes
Don’t be grossed out but… ECTODERM DIGESTIVE TRACT (inside tube) MESODERM ENDODERM
Fun stuff: Parasitic Roundworms • Filarial worm causes this…
INVERTEBRATES • Aquatic to terrestrial – what evolutionary developments?