Key Points

Nutrition in Animals

Important Points

  • Animals are heterotrophs — they cannot make their own food.
  • They take in food and digest it into simple substances.
  • The main parts of the digestive system are: mouth, oesophagus, stomach, small intestine and large intestine.
  • Nutrients are absorbed in the small intestine.
  • The undigested food is removed from the body as waste.

Remember This

  • Small intestine → Absorption of nutrients.
  • Large intestine → Water absorption.
  • Rumen (in cattle) → First stop for grass.

Exam Tips

  • Draw a labelled diagram of the alimentary canal — one clear diagram scores full marks.
  • Learn the five steps of nutrition in order; questions often ask for the correct sequence.
  • Do not confuse absorption (small intestine) with assimilation (in cells).

Definitions

Heterotroph
An organism that cannot make its own food and must eat other living things.
Digestion
Breaking large food particles into smaller, soluble molecules the body can absorb.
Absorption
Movement of digested nutrients from the intestine wall into the blood.
Rumen
First chamber of a ruminant's stomach where grass is partly digested.
Pseudopodia
Temporary arm-like extensions used by amoeba to capture food and move.