BIO 200 Lecture Notes - Lecture 18: Turgor Pressure, Ctenophora, Coelom
11 Nov 2017
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Document Summary
Almost all groups of animals occur in marine environments. What makes an animal: heterotrophic, multi-cellular (without cell walls, motility, sexual reproduction, characteristic embryonic development, shared hox genes drive development, specialized tissues (except sponges) All monophyletic: symmetry, radial symmetry typically leads to spherical or circular organisms. Any plane along the central body axis (anemone, jelly fish) (sponges lack symmetry: bilateral symmetry leads to cephalization. Dorsal (back), anterior (head), posterior (tail), ventral (belly) A single plane through the anterior-posterior midline divides the animal into mirror- images halves cephalization (head forming) Radial evolved from bilateral: sponges have undifferentiated tissues. Tissues allow for increased specialization -> allows for differentiation in cell types -> complexity in form -> big gains in size. Nervous tissue: animals form two major groups, monoblastic/diploblastic animals, triploblastic (bilaterians) strongly monophyletic, shared bilateral symmetry, centralized nervous system, 7 different shared hox genes. Bilaterians are further divided into two groups. Protostome mouths develop before their anuses first mouth .
