Comparative Vertebrate Anatomy

• Study of descriptive & functional morphology

a. Morphology (Gross Anatomy, Cytology, Histology, Embryology)

b. Physiology – living functions

c. Taxonomy – systematic classification

d. Ecology – relationship of animals & environment

e. Paleontology - fossils/ remains

f. Genetics – heredity & variation

g. Evolution – origin, history & changes through time

Chordates vs. craniates & vertebrates

Chordates – with notochord

– Craniates: chordates w/ neurocranium

– Vertebrates: chordates w/ vertebrae

Kingdom Animalia

Phylum Chordata

Subphylum Urochordata

Subphylum Cephalochordata

Subphylum Craniata

(1) Hagfish – w/o vertebrae

(2) Vertebrates

Class Myxini

e.g. hagfishes

• CRANIATES

– Cranium

– 3-part brain

– Neural crest & derivatives

– Paired external sense organs

– cartilage

• VERTEBRATES

– Vertebral column

– 2 semicircular canals

– Electroreception

– Lateral line canal

– Soft tissue specialization

General body plan

• Head, Trunk and Tail

• Bilateral symmetry

• Metamerism

– Homonomous

– Heteronomous

• INTERNAL HETERONOMOUS

Phylum Chordata (THE BIG “4”)

1. Notochord & Vertebral Column

A. Fishes

- Persists the length of the trunk & tail

B. Modern reptiles (birds) mammals

- obliterated

- vestige in mammals (PULPY NUCLEUS)

- no vestige in modern reptiles

Notochord: rod of living cells ventral to the CNS

& dorsal to the alimentary canal

• Lampreys

– Notochord grows w/ notochord sheath

– Paired lateral neural cartilages

2. Pharynx• Fish gills

• Tetrapod lungs and middle ear cavity

• Jaw skeleton and musculature

• Endocrine glands

• Initial cells of human fetus immune system

1. Pharyngeal/ gill pouches slits

2. Pharyngeal arches

- Mandibular arch

- Hyoid arch• Support

• Striated muscles operating the arch

• Cranial nerves for muscle innervation

• Aortic arch

3. Dorsal Hollow CNS

• Neural tube Brain & Spinal cord

• Peripheral NS nerves, ganglia & plexi

4. Postanal tail

• Other Characteristics1. Integument – dermis + epidermis2. Respiratory Mechanism3. Coelom

– Pericardial cavity: heart– Pleural cavity: lungs– Peritoneal cavity: viscera– Scrotal cavities: testes

4. Digestive system – cloaca; anus5. Urogenital organs6. Circulatory system7. Skeleton – axial & appendicular8. Muscles – skeletal, smooth, & cardiac9. Sense organs

a) Exteroreceptorsb) Visceral receptors