Animal Nutrition


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Animals obtain their nourishment from producers such as plants, other animals, or a combination of both. In any case all animals are consumers.

Diet or
Herbivore
Carnivore
Omnivore
Kinds of Food
plants or algae
animals
both plants and animals

Of course there are specialists which are restricted to a narrow range of foods including animals which are:

apivorous

eating bees

batrachivorous

consuming frogs

carpophagus

fruit eating

coprophagous

feeding upon dung

detritovorous

eating detritus

fungivorous

eating fungi

galactophagous

milk-drinking

geophagous

earth eating

hematophagous

feeding on blood

hylophagous

feeding on wood

ichthyophagous

eating fish

mellivorous

eating or living on honey

oophagous

living or feeding on eggs

saprophagous

feeding on decaying substances

seminivorous

feeding on seeds

vermivorous

feeding on worms

Animals have evolved a number of feeding mechanisms to catch and ingest their repasts including:

Feeding Mechanisms
Examples
suspension feeders
clams and other bivalves
substrate feeders
Mediterranean Fruit Fly
fluid feeders
mosquito, vampire bat
bulk feeders
most animals

Animals process food in four stages which are:

  • ingestion
  • digestion
  • absorption
  • elimination

Of these four we will concentrate on the digestion and absorption of food.


Digestion

Where does digestion take place?

 

  1. Within food vacuoles inside a cell obtained by endocytosis. This is intracellular digestion and occurs in protozoans and white blood cells.
  2. Within gastrovascular cavities or in alimentary canals. Animals ingest their food, but it remains outside the body proper. This is extracellular digestion.
    1. gastrovascular cavities require the same opening for ingestion and elimination. Once inside the cavity, food is both digested and transported to areas that need nourishment.
    2. alimentary canals are continuous passages from mouth to anus. Food is moved from chamber to chamber by smooth muscle contractions called peristalsis.

Compartments within the alimentary canal include:

  • Oral cavity
  • Pharynx
  • Esophagus
  • Stomach
  • Small Intestine
  • Large Intestine