Describe an environmental factor that could influence natural selection and decrease genetic diversity

The process of being selected by the nature to survive in the current condition is called natural selection. Only those species can be naturally selected who are ready to change and adapt themselves according to environmental needs.

These are the factors that support natural selection.

Many species are not able to mate with the other species due to geographical barriers and also not being able to migrate to other habitats.  

For example- Australia is separated from the other continents, the marsupials are only restricted to the specific landmass and are not able to mate with other animals from other countries.

Increases in temperature harm cold-blooded animals. They can not able to maintain the normal body temperature and lead to the death

Therefore, The factors which affect natural selection are geographical barriers and a rise in temperature.

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Availability of sunlight.

Explanation:

Some living organisms need a lot of sunlight to survive and cannot stand living in the shade, as is the case with some plants. In this case, the availability of sunlight presents itself as an environmental factor that will influence natural selection, because with less availability of sunlight, the less adapted organisms will die and the more adapted organisms will resist and pass this trait to their descendants.

Natural selection tends to decrease genetic variability because only a few genotypes will be selected. In addition, it also contributes to the permanence of a certain characteristic in the population.