Crash Course Biology
Simple Animals: Sponges, Jellies, & Octopuses
S1 • E22 Jun 24, 2012 15m
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.
