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Animals are heterotrophs that must expend energy to acquire food from their environment. Most animals either move through the environment to where food is located or move the environment and the food it contains to them.
learning outcomes
You should be able to:
Summarize common adaptations of herbivores.
Summarize features that predators use to capture and subdue their prey.
Distinguish among predators, parasites, and filter feeders.
How can you distinguish among filter feeders, predators, and parasites—
Filter feeders filter water or air and trap small food particles they contain. These particles may include small animals, but the filter feeder does not typically actively chase and feed on individual prey. Predators, in contrast, actively seek out and feed on other individual animals, killing them in the process. Parasites also feed on other animals, usually without killing them; a parasite may reside inside another animal or feed on its parts from the outside (such as a mosquito or a tick does).
What adaptations are necessary for animals that eat plants? What adaptations are needed for a predatory lifestyle?
Herbivores must digest relatively fibrous, tough plant material. So they usually need a longer gut (compared with carnivores) or a digestive system that permits fermentation of plant material. They usually need mouthparts that allow chewing of leaves or sucking of plant fluids. A predator needs to be able to move quickly enough to catch its prey and needs adaptations for subduing the prey (such as teeth, jaws, claws, venom, constriction, etc.).
As an animal grows from a single-