Animal Nutrition I (Ch

Animal Nutrition I (Ch. 41)

Keywords

Heterotroph
Autotroph
Herbivore
Carnivore
Omnivore
Intracellular digestion
Food vacuole
Extracellular digestion
Gastrovascular cavity
Alimentary canal
Basic parts of alimentary canal
Roles of mouth and stomach in digestion

Some of the best known and fascinating adaptations of animals involve their feeding and digestion

Examples:

Reptile swallowing prey
Baleen whales

Python

Starfish

Chiasmodon niger

Cryptopsaras couesi

Eurypharynx pelecanoides

Categories

I. Autotroph
II. Heterotroph
A. Herbivore
B. Carnivore
C. Omnivore

Today we’ll focus on heterotrophs:
Digestion

Basic principles
Invertebrates
Humans

Why is digestion necessary?

Macromolecules cannot easily enter cell

Small molecules such as amino acids can

Even if macromolecules are taken in…

They cannot be readily incorporated

Unless broken down first

This lecture will focus on how animals break down food

I. Intracellular digestion
A. food vacuoles
II. Extracellular digestion
A. outside organism
B. gastrovascular cavity
C. alimentary canal

I. Intracellular digestion

A. food vacuoles

Intracellular digestion without vacuoles

Intracellular digestion
with vacuoles

Digestion in Paramecium

Intracellular digestion
vs.
Extracellular digestion

Extracellular digestion

A. outside organism

B. gastrovascular cavities

C. alimentary canal

Extracellular digestion

A. outside organism

B. gastrovascular cavities

C. alimentary canal

Gastrovascular cavity: Hydra

Extracellular digestion

A. outside organism

B. gastrovascular cavities

C. alimentary canal

Gastrovascular cavity vs. Alimentary Canal

Alimentary canal: a simple view

Basic parts of alimentary canal

Alimentary canal: mammalian

Mouth

Mechanical
enzymatic

Stomach

Digestive mechanisms in stomach

Mechanical
Chemical
enzymatic