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Animal Nutrition (ch. 41)

Essential Nutrients
A bear about to get its nutrition
A bear about to get its nutrition


All animals need to absorb molecules from their environment or from other animals in order to fuel themselves and the processes going on within them. This process of feeding is called an animal's nutrition: food being taken in and used by the animal. An animal can get its nutrition from plants, other animals, or a mixture of both. Animals that specifically eat plants are called herbivores, animals specializing in eating other animals are called carnivores, and an animal that will eat whichever one it comes across is called an omnivore. The survival of the animal as a whole depends on the chemical activity in it's cells. ATP is constantly being used up, and the animal needs to absorb chemicals in order to replenish ATP. Materials (such as preassembled organic molecules and some minerals) that an animal's cells cannot make on their own, but require for survival, are called essential nutrients. Some nutrients are required by all animals, while others are required only by certain species. These nutrients are divided in to four self-explanatory classes: essential amino acids, essential fatty acids, minerals, and vitamins. The first two explain themselves: they are amino acids and fatty acids that need to be ingested. Minerals are inorganic nutrients that are required in small amounts, such as iron. Minerals are used for a variety of functions in the animal's body, but can be harmful if too much is ingested, as this upsets the body's homeostasis. Vitamins are nearly the same as minerals, but instead are organic molecules. They are also required in small amounts, and having excess wont necessarily be harmful.

Consequences of deficiencies in essential nutrients



  • Feeding mechanisms: suspension, bulk, substrate, and fluid feeding
  • Compare digestion/alimentary canal structure of an earthworm, grasshopper, bird, and human
  • Closer look at human digestion
  • Dentition and diet in mammals
  • Special digestive adaptations: herbivores vs. carnivores, mutualistic adaptations in ruminants
  • Digestion, storage, and appetite regulation