Lecture 7 - vertebrate evolution Flashcards
Pikaia is one of the oldest known ancestors of all _____
cephalochordates
The first animals to develop a vertebral column did not have ___
jaws
Gnathostomes. Jaws likely evolved from pre-existing support structures in the ___
gills
Osteichthyes
Fish with hard, mineralized skeletons
Sarcopterygii
Lobe-finned fish
Tiktaalik is called a
fishpod because it has weight-bearing elbows, simple wrist bones, and simple fingers. It also had a swim bladder. Probs didn’t venture onto land, but these adaptations would speed up the transition
Ichthyostega
Early tetrapod, among first vertebrates to live on land
Two groups of the amniota
Synapsids - single pair of openings behind the eyes
Diapsids - two pairs
Monophyletic group defn
group of organisms that includes a common ancestor and all its descendants
Synapsids are ___ dinosaurs. Give two examples
NOT. Dimetrodon and Woolly Mammoths
What category of amniota are Dinosaurs?
Diapsids
Two categories of diaspids
Lepidosauromorphs - short, non-overlapping vertebrae neck (snake)
Archosaurmorphs - long vertebrae in the neck which overlap for support (croc)
Lepidosauromorphs
short, non-overlapping vertebrae neck (snake)
Archosauromorphs
long vertebrae in the neck which overlap for support (croc)
Archosauria
subset of archosauromorphs that have additional openings in front of the eyes
