by Sarah Downie

Created on: January 27, 2007   Last Updated: May 04, 2007

A predator is defined as an organism that consumes and kills other organisms for food and energy. The interactions between predators and prey are like a cycle but not exactly in time. The predator numbers slightly lag behind those of the prey. Predator and prey interactions have factors that regulate them, for example, disease, climate change and the availability of food for both prey and predators.

Predators are used to maintain the diversity of species in an ecosystem by controlling the numbers of the more dominant competitors. This allows the weaker competitors to have a chance of survival.

Many adaptations have occurred to prevent prey from being eaten by predators, for example, camouflage, warning colouration (aposematic colouration) and mimicry. An animal is said to be camouflages when it blends into the background and cannot be seen by the predator, for example, a white seal pup is camouflaged in snow. Prey animals give warnings that they are dangerous to eat by having distinctly bright colours that usually indicate a poisonous species, for example, the brightly coloured poison arrow frog. Mimicry is when the prey mimics a much more harmful species to deter predators. There are two types. Batesian mimicry is when an edible species mimics another inedible species that is usually harmful, for example, the harmless hoverfly mimics the colouration of a wasp. In Mullerian mimicry, two or more inedible species have 'evolved' to have similar warning signals, for example, the black and yellow social wasps, solitary digger wasps and the caterpillars of the cinnabar moths.

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