Adaptations, interdependence and competition - EdexcelInterdependence in a community
Organisms depend on each other for survival. This is called interdependence. Both living and non-living factors will affect the abundance and distribution of organisms in a habitat.
All organisms in an ecosystemThe living organisms in a particular area, together with the non-living components of the environment. depend upon each other. If the populationAll of the members of a single species that live within a geographical area. of one organism rises or falls, then this can affect the rest of the ecosystem.
A simple food chainA sequence (usually shown as a diagram) of feeding relationships between organisms, showing which organisms eat what and the movement of energy through trophic levels. is:
grass 鈫 rabbit 鈫 fox
If the foxes in the food chain above were killed, the population of rabbits would increase because they are no longer prey to the foxes. As a result the amount of grass would decrease because the increased population of rabbits would be eating it.
Often very small changes to ecosystems have large consequences, which can be difficult to predict. This means that all the organisms in an ecosystem are dependent upon each other. We call this interdependenceRefers to the fact that all organisms that live in an ecosystem depend upon each other, for food, protection, shelter, etc, in order to survive..
Competition
All photosynthesisA chemical process used by plants to make glucose and oxygen from carbon dioxide and water, using light energy. Oxygen is produced as a by-product of photosynthesis. Algae subsumed within plants and some bacteria are also photosynthetic. plants and algae in an ecosystem compete for light, space, water and minerals from the soil. Animals in an ecosystem compete for food, mates and their territory. Organisms which have more of these resources tend to grow more healthily and are more likely to have offspring. Competition can be interspecific competitionThe competition which occurs between organisms of different species for a common resource. or intraspecific competitionThe competition between organisms within the same species. depending on whether organisms from different species or the same species are competing for resources.
Stable communities
A stable community is one in which the size of the populations of all species remain relatively constant over time. In the example above the amount of grass and the numbers of rabbits and foxes all remain relatively constant. The different populations are living in a healthy balance with their environment.