Hank introduces us to the "simplest" of the animals, complexity-wise: beginning with sponges (whose very inclusion in the list as "animals" has been called into question because they are so simple) and finishing with the most complex molluscs, octopuses and squid. We differentiate them by the number of tissue layers they have, and by the complexity of those layers.

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Table of Contents:
1) Porifera 1:33
2) Cnidaria 2:36
a) Diploblasts 2:48
3) Platyhelminthes 3:33
a) Triploblasts 3:56
b) Coelom 4:36
4) Biolography 5:36
5) Nematoda 7:26
6) Rotifera 7:57
7) Molusca 8:33

References for this episode can be found in the Google document here: http://dft.ba/-2V_c

crash course, biology, anatomy, animal, simple, complex, tissue complexity, tissue, sponge, development, porifera, multicellular, eukaryotic, eukaryote, species, cnidaria, jellies, anemone, hydra, coral, germ layer, body cavity, endoderm, ecotoderm, dipoloblast, stinging cell, cnidocyst, platyhelminthes, fluke, triploblast, coelom, acoelomate, biolography, cambrian explosion, adaptation, fossil, evolution, diversity, nematoda, pseudocoelomate, hookworm, rotifera, mollusca, chitin, snail, bivalve, octopus, squid, visceral mass, foot, mantle, radula, gastropod, cephalopod Support CrashCourse on Subbable: http://subbable.com/crashcourse