By the end of this page you should know:
- that living things compete with each other for the things they need
- that predators compete with each other for prey
- that animal population are affected by numbers of predators and by competition for resources.
A
Charles Darwin described life as a struggle for survival.Animals compete with each other for resorces. The savannah is a hot, grassy plan in africa.There are very few trees and many of them have sharp thorns.The grass provides food for huge herds of zebras, wildebeest, gazelles and many other species.Because they all eat the same food, these animal compete for the best grass.Competition between different species,such as zebra and wildebeest, is called inter-species competition. competition within a single species competition.
As a general rule the strongest, best-adapted animals get to eat most of the food.These animals survive and breed so their population increases at the expense of other weaker,less adapted species. Sometimes species adapt so that they can live comfortable side by side.In addition to food, animals compete for water, shelter, a suitable mate and places to breed.
B
Predators are hunters which kill and eat other animals.The animal which is hunted is called the prey.Scavengers are animals which eat the `left-overs` of animals killed by predators.The large herbivores on the savannah are prey to animals like lions and cheetahs.Other predators and scavengers eat smaller herbivores such as gazelles and dik-diks.The plants and animals on the savannah are interdependent.Changes in the numbers of one organism affect the numbers of other organisms.
How populations of a predator and its prey change over time.
Have you ever wondered:
Does the numbers of foxes control the number of rabbits or does the number of rabbits control the number of foxes?
In years when there is plenty of grass, competition between the herbivores is reduced.The number of herbivores will increase.Young herbivores are easy prey for predators.This extra source of meat allows predators to successfully raise more young.When the grass fails to grow, or if there are too many predators, the herbivore population will drop. Figure C shows how the populations change over a long period of time.
As a general rule the strongest, best-adapted animals get to eat most of the food.These animals survive and breed so their population increases at the expense of other weaker,less adapted species. Sometimes species adapt so that they can live comfortable side by side.In addition to food, animals compete for water, shelter, a suitable mate and places to breed.
B
Predators are hunters which kill and eat other animals.The animal which is hunted is called the prey.Scavengers are animals which eat the `left-overs` of animals killed by predators.The large herbivores on the savannah are prey to animals like lions and cheetahs.Other predators and scavengers eat smaller herbivores such as gazelles and dik-diks.The plants and animals on the savannah are interdependent.Changes in the numbers of one organism affect the numbers of other organisms.
How populations of a predator and its prey change over time.
Have you ever wondered:
Does the numbers of foxes control the number of rabbits or does the number of rabbits control the number of foxes?
In years when there is plenty of grass, competition between the herbivores is reduced.The number of herbivores will increase.Young herbivores are easy prey for predators.This extra source of meat allows predators to successfully raise more young.When the grass fails to grow, or if there are too many predators, the herbivore population will drop. Figure C shows how the populations change over a long period of time.
No comments:
Post a Comment