Overview of Animal Nutrition and Ingestion

Nutrition: process of consuming and using food and nutrients
Nutrient: any substance consumed by an animal that is needed for survival, growth, development, tissue repair, or reproduction
All organisms require nutrients to survive

Five categories of organic nutrients * Carbohydrates * Proteins * Lipids * Nucleic acids * Vitamins
Inorganic nutrients * Water and minerals

Essential amino acids: in order for protein synthesis to occur in human adults, eight amino acids must be available simultaneously and in the correct relative amounts. * Can be obtained from meat.
Essential fatty acids: important for phospholipid membrane; and principal storage compound. * Found mostly in plants.
Vitamins: organic molecules in small amounts; serve as coenzymes * Water soluble and fat soluble
Minerals: inorganic molecules in small amounts

Herbivores: mainly eat plants and algae * Gorillas, cows, hares, snails
Carnivores: eat other animals * Sharks, hawks, spiders, snakes
Omnivores: consume animals, plants, and algae * Roaches, crows, bears, raccoons, humans
Most animals are opportunistic: eating food

that are outside their main dietary category

Ways in which an animal obtains its food are related to its environment
Suspension feeding: filter organic matter out of water * Bivalve molluscs, sea squirts, baleen whale
Bulk feeding: they use many modified body parts like tentacles, beaks, claws, pincers, etc. * Eat food in large pieces
Fluid feeding: lick or suck fluid from plants or animals * Do not need teeth except, perhaps, to puncture an animal’s skin

Nutrients must be absorbed by the epithelial cells lining the digestive tract
Three ways: * Passive diffusion * Facilitated diffusion * Active transport