BIO 121 Lecture Notes - Lecture 13: Choanoflagellate, Antibody, Protostome
10 Dec 2020
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Ectoderm is outside, mesoderm is middle, endoderm is inside. Cnidarians are diploblastic; all bilaterians are triploblastic. Protostome: blastula- process of gastrulation- blastopore will become mouth, anus forms second( blastopore is the indentation) Deuterostome: blastopore become anus, mouth forms secondary. Radial symmetry: equal in all directions around oral-aboral axis. Oral side with mouth, entry to gut. Pseudocoelomates: have pseudocoelom; mesoderm lines body walls, not digestive tract; ex are nematodes. Coelomates: have true coelom; mesoderm lines boyd wall and digestive tract; ex. Many other invertebrates filled with coelomic fluid. Coelom only matters for triploblasts of true coelom in. Collar= closely packed collar of microvilli, surrounds single flagellum. Eats bacteria; flagella draws water carrying food through collar. Some species form colonies, others are solitary. Colonialism could be first animal mulitcellularity looked like. Evidence from genomes; have some families of cell singaling and cell adhesion proteins that were unknown before. Specialize cells; larger size=escape predators and new movements that are faster.
