Ch 32- intro to amimal evolution

What is an animal? 

Multicellular, heterotrophic, eukaryotes

Zygote

Cleavage

Morula

Solid ball

Blastula

Hollow ball

Know what the agreements are between the two trees?

Protostomes (cleavage)

Spiral and determinate

Protostomes (Coelom formation)

Solid masses of mesoderm split to form coelom

Protostomes (Fate of blastopore)

Mouth develops from blastopore

Deuterostomes (cleavage)

Radial and indeterminate

Deuterostomes (coelom)

Folds of archengeron form coelom

Deuterostomes (Fate of blastopore)

Anus develops from blastopore

Spiral

Cells on top, don’t sit directly over cells below

Determinate

Cells are destined to become certain types of embryotic cells very early

Schizocelous

Formed from specialized 4D cells

Blastopore fate

Becomes the moth and the secondary opening develops separately (the anus)

Radial

Cells on top, sit directly over cells below

Indeterminate

Cells aren’t destined for any particular type

Enterocoelous

Intestine is formed from an unfolding to make pockets with archenteron which forms mesoderm

Blastopore fate

Becomes the anus and the secondary opening (the mouth) develops separately

Points of agreement (1)

All animals have a common ancestor

Points of agreement (2)

Sponges are a sister group to all other animals

Points of agreement (3)

All other animals have true tissue

Points of agreement (4)

Most animals are bilateral

Points of agreement (5)

Chordates and Echinodems are related