Comparative Anatomy of Vertebrates
from http://www.exploratorium.edu/frogs/poisonarrow.html
I. Introduction
What adaptations are necessary to make the transition from an aquatic to a terrestrial environment?
-most animal phyla live in water
II. Origins of Vertebrates
1. vertebrates are deuterostomes (body plan with coelom)
What is the function of a body cavity?
2. What are the four anatomical structures found in all groups of chordates?
-dorsal, hollow nerve cords
-pharyngeal slits
-post-anal tail
III. Introduction to Vertebrates
What are the characteristics of vertebrate chordates?
1. neural crest ---> vertebrate cranium (head)
2. skeleton
IV. Example Vertebrate Classes
A. Class Amphibia
1. Amphibians are tetrapods
-ancestors of tetrapods were fishes
-(extant species of fishes provide clues about the ancestry of amphibians: bony fishes: ray-finned, (cichlid), lobe-finned (coelacanth), lung fishes)
2. Modern Amphibians
a) 4800 species frogs, salamanders, caecilians
B. Class Aves
1. Birds are amniotes
2. Birds began as feathered reptiles
3. Characteristics of birds
b. absence of organs ovary teeth
c. high energy metabolism
-endothermic
-surface to volume ratio
-four-chambered heart
e. large brains
f. wings
C. Class Mammalia
2. Groups of mammals
a. Monotremes
b. Marsupials
c. Placental (Eutherian)
-convergent evolution; compare marsupial and placental mammals in similar niche
Cockatoo