COMPARATIVE ANATOMY3023

ByBrian Matchett and Alyson Walaskay

WHAT IS COMPARATIVE

ANATOMY?

Comparative Anatomy

• The study of and comparison of body parts of different species

Comparative Anatomy Includes:

• Change, adaptation, and mutation of species

• The invasion of new territories

• Species compatibility with surroundings

How Can Comparative Anatomy Help Us?

• Understand our history

• Consider plans for change

• Improve animal genetics

• Preserve endangered species

Why Should We be Aware of Comparative Anatomy?

• Variations in care for animals

• Differences in animal habits

Adaptation

• Genetic and physiological changes that occur due to pressures or changes in an animal’s environment

Adaptation Changes

Examples:

• Forelimb of humans used for manipulating

• Webbed foot of seal used for swimming

• Front feet of a mole used for digging

Structural Development

• Homologous Structures

• Analogous Structures

Homologous Structures

• Have similar structures, but different uses

• E.g. Turtle leg

and bird wing

Analogous Structures

• Body parts similar in use, but different in structure

• E.g. Bird wing and insect wing

Directional Terms

• Used to describe the positions of structures on the body relative to other structures or locations

Cranial – closer to the head of the animal

Caudal – closer to the tail

Medial – closer to the midline of the limb, trunk or head

Lateral – farther away from the midline

Dorsal – close rot the top side (back) of the animal

Ventral – closer to the bottom side (belly) of the animal

Proximal – closer to the attachment of the appendage to the body

Distal – farther away from the attachment of the body

Comparative Anatomy of Typical Farm Animal Species Includes

• Skeletal Structures

• Reproduction

• Digestive Systems

Skeletal Structures

• Protects vital organs and gives basic form and shape to an animals body

Reproduction

• The production of live, normal offspring

Puberty – age at which reproductive organs become functionally operative

Gestation – time from breeding or conception of a female until she gives birth to her young

Estrus – time for acceptance of the male and normally coincides approximately with ovulation “Heat”

Estrous Cycle – Estrus cycle or the time from one estrus to the next

Digestion

• Includes all the organs that are involved in the digestion of food

Types of Digestion

• Monogastric or Simple Stomach

• Ruminant

• Avian

Monogastric

• Characterized by the inability to digest roughage efficiently

• Enzymes used to break food down

• Includes: humans, swine, rabbits and horses

Ruminant

• Handles the breakdown of large amounts lignified fiber

• Has four different compartments:– Rumen - Omasum– Reticulum - Abomasum

• Includes: sheep, cows, goats

Avian

• Designed for grinding hard or encased food

• Has a gizzard

• Have no teeth

• Includes: all birds

WEB CITATIONS

• BSC Courseware http://tidepool.st.usm.edu/crswr/homologousstructs.html

• Homologous Structures http://www.kent.wednet.edu/staff/rlynch/sci_class/chap06/homologous.html

WEB CITATIONS cont.

• Animal Feeds and Nutrition http://www.cals.ncsu.edu/course/ans012/gi_tract.htm

• Michael's Photo Gallery

http://www.netaxs.com/~mhmyers/image.html