Biology / Unit 10 Bio 2215 short lesson, about 20 seconds
Embryonic Development: Blastula and Gastrulation
Captions available
The idea
An animal embryo divides into a hollow blastula, then folds inward during gastrulation, forming layered germ layers that give rise to all adult structures.
In practice
Gastrulation in a sea urchin embryo creates a pouch-like archenteron, the precursor to its future digestive cavity.
Where people slip
Gastrulation is shared across the animal kingdom, not a trait found only in complex, later-diverging lineages.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
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