Predator and prey populations
A An animal that hunts, kills and eats other animals for food. is an animal that hunts, kills and eats other animals for food. Organisms that predators kill for food. is a term used to describe organisms that predators kill for food.
Predator/prey relationships can be illustrated in a diagram called a A sequence (usually shown as a diagram) of feeding relationships between organisms, showing which organisms eat what and the movement of energy through trophic levels. or A network of food chains, showing how they all link together..
Plants that begin food chains by making energy from carbon dioxide and water. make their own food using energy from an abiotic source. For example plants carry out photosynthesis to make food using light energy from the sun. An organism that obtains its energy by eating other organisms. get food from a biotic source by eating the biomass of producers or other consumers.
Within food chains and webs there are organisms that will only consume particular types of food:
- A An animal that feeds only on plants. is an organism that only consumes plant material.
- A An animal that eats meat or flesh only. is an organism that only consumes animal material.
- An An animal that eats both plants and meat. is an organism that will consume both plant and animal material.
There is a continuous struggle between predators and their prey:
- Predator species need to be adapted for efficient hunting if they are to catch enough food to survive.
- Prey species must be well adapted to escape predators for their species to continue.
If the prey population in an ecosystem grows, predator numbers will respond to the increased food supply by increasing as well. Growing predator numbers will eventually reduce the food supply to the point where it can no longer sustain the predator population ... and so on.
If an organism is removed from a food chain or web all together, for example due to overhunting, then this can have a catastrophic effect on the other populations in the food web.