Heterotrophs are organisms that cannot produce their own food and must consume other organisms for energy and nutrients. They are classified by feeding habits:
- Carnivores: Eat other animals (e.g., lions, sharks).
- Herbivores: Eat plants (e.g., cows, elephants).
- Omnivores: Eat both plants and animals (e.g., humans, bears).
- Detritivores: Feed on dead organic matter (e.g., earthworms, vultures).
- Parasites: Live on or in a host and derive nutrients from it (e.g., ticks, tapeworms).
Fungi and bacteria are also heterotrophic but use unique nutritional mechanisms that differ from animals.