Hank discusses the process by which organisms grow and develop, maintaining that, in the end, we're all just tubes.

It took a very long time, but we are finally finished with the clade Protostomia, or first mouths. Now it's time to tackle Deuterostomia, or second mouths, a clade containing only three phyla. This will take some time, since one of those...

Lesson on Gastrulation and the Formation of the 3 Germ Layers known as the Ectoderm, Mesoderm and Endoderm. Gastrulation is a process whereby a bilaminar disc (comprising the epiblast and hypoblast cells) gets transformed into a...

Before diving into animal diversity, we need a bit more information about animal development, as it will help us understand what we're looking at later. We know that animals reproduce sexually, so a sperm fertilizes an egg to yield a...