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Predation

A lion is an example of predator.

     All consumers are predators. The organisms eaten by consumers are prey. A wolf that eats a sheep is a predator. The sheep is the wolf's prey. When a sheep eats grass, the sheep is the predator and the grass is the prey. Predation is a density-dependent limiting factor because it has its greatest effect on large populations; a large population of prey animals can lead to an increase in the population of predator population.

     Suppose a prey population of rabbits increases in size. Populations of predators, like bobcats, that feed on the rabbits will also increase in size. In turn, a larger number of bobcat kittens will survive because they and their mothers are well fed. As the number of bobcats increases, more rabbits will be killed and eaten, reducing the size of the rabbit population. When the rabbit supply decreases, the bobcat population will decrease as well. Changes in the sizes of predator-prey populations often occur in cycles.

     A similar interaction occurs between the rabbits and their food, the plants. A temporary increase in size of the rabbit population will result in more plants being eaten, decreasing the total rabbit food supply. The decreased food supply will cause the size of the rabbit population to decrease.

     Predator-prey relationships are a strong force in natural selection. Natural selection favors traits in predators that enable them to capture. At the same time, natural selection favors traits that allow prey to escape or avoid predators. Prey that escape predators reproduce more and pass traits that enabled them to escape on to their offspring. At the same time, predators that capture the most food are likely to become stronger and produce more young. Their offspring will inherit the traits that made their parents efficient predators. Both predator and prey evolve together.

     Some examples of this kind of relationship are:

        a. Hawk which eats rats and chicks

        b. Milkfish eats algae

        c. Venus flytrap and the pitcher plant eats insects with their leaves

 

 

 

Earth and water, if not blatantly abused, can be made to produce again and again for the benefit of all.. The key is wise stewardship.

~Stewart L. Udall