DonExodus2 | Embryological Evidence for Evolution @DonExodus2 | Uploaded June 2009 | Updated October 2024, 6 hours ago.
This is essential information which will be applied in a later video. I discuss how organisms develop, and how their developmental pathways can be used to determine their position in a phylogenetic tree of life.

I touch upon this subject lightly, and do not even mention cleavage, fate, symmetry, etc.
A quick glance at the following is recommended:

Aronra: youtube.com/watch?v=5MXTBGcyNuc&feature=channel_page

Me: youtube.com/watch?v=eblrphIwoJQ

Sparknotes: sparknotes.com/101/biology/animal_evolution_and_diversity/animal_origins_and_evolution.html

Tree image used in the video: yfrog.com/5aphylotreej