Comparative Anatomy of Vertebrates


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) 

Body plans of coelomates

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

2. vertebrate cranium

3. skeleton

4. closed circulatory system

IV. Example Vertebrate Classes

A. Class Amphibia

1. Amphibians are tetrapods

-ancestors of tetrapods were fishes

-bony fishes: ray-finned, lobe-finned (coelacanth), lung fishes)

2. Modern Amphibians

a) 4800 species

b) What is an amphibian?

B. Class Aves

1. Birds are amniotes

2. Birds began as feathered reptiles


3. Characteristics of birds

a. honey-combed bones

b. absence of organs ovary teeth

c. high energy metabolism


-surface to volume ratio

higher metabolic rate? A or B


-brown fat

-countercurrent exchange


-four-chambered heart

d acute vision

e. large brains

f. wings

C. Class Mammalia

1. Mammalian characteristic

a. mammary glands

b. active metabolism

c. born not hatched

d. largest brain size

e. differentiation of teeth

2. Groups of mammals

a. Monotremes


b. Marsupials


c. Placental (Eutherian)

-convergent evolution; compare marsupial and placental mammals in similar niche