Interdependence and Competition


All organisms have relationships with one another. The rise or fall in the population of one organism will affect other organisms in the ecosystem. For example, let’s look at a simple food chain:

Grass Grasshopper Bird

The grasshopper has a relationship with the grass it eats and the bird that preys on it.

If the population of birds that prey on the grasshopper declines, this will increase the population of grasshoppers. As a result, the amount of grass will also reduce, because more grasshoppers are eating it.

However, in reality, these relationships are more complicated. The grasshopper will most likely have other predators and more sources of food. This means that a change in the ecosystem will be difficult to predict. But small changes to an ecosystem can have relatively large consequences.

Different species in a community depend on one another. This is called interdependence.


One of the most important processes in an ecosystem is competition. In order to survive and reproduce, there are a few resources that organisms need to compete for. For animals, this includes food, water, mates and territory. Whereas, plants compete for light, water, space and mineral ions.

An organism that has more resources is more likely to survive and reproduce.

There are two types of competition:

  • Interspecific competition – The competition between individuals of different species.
  • Intraspecific competition – The competition between individuals from the same species.