When two populations of the same species attempt to occupy the same niche, competition occurs. This is because both populations are vying for the same resources, such as food, water, and space. Competition can take different forms, such as:

Exploitation competition: This is when one species directly uses resources that the other species needs. For example, two species of birds may compete for the same type of food, such as insects.

Interference competition: This is when one species directly interferes with the other species' ability to obtain resources. For example, two species of animals may compete for the same territory, and they may fight each other to defend their territory.

Apparent competition: This is when two species interact with a third species in a negative way. For example, two species of plants may be pollinated by the same species of insect, but one of the plants may attract more of the insects than the other.

Competition can have a number of negative effects on both species, such as:

Reduced growth: Both species may grow more slowly than they would if they were not competing with each other.

Reduced reproduction: Both species may produce fewer offspring than they would if they were not competing with each other.

Increased mortality: Both species may have a higher death rate than they would if they were not competing with each other.

In some cases, competition may lead to one species being driven to extinction. This can happen if one species is unable to adapt to the competition and is unable to find new resources.

Competition is a major factor in evolution. It drives species to adapt and evolve in order to better compete for resources. Competition can also lead to the formation of new species as populations diverge from each other in order to exploit different niches.