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5.5 Environmental Effects on Phenotype




⏱️  2 min read

written by

Caroline Koffke

caroline koffke

Natural Selection

Environmental conditions may play a role in which phenotypes are prevalent in a certain environment. This goes back to the concept of natural selection, in which environmental conditions can determine which individuals survive and reproduce more than others.

Environmental Changes

A classic example of environmental changes in phenotype is the coloration of certain mice species. In an environment that has been covered in permafrost for the past few thousand years, the majority of mice are light in color.

This allows these mice to easily blend in to the environment that they live in and, therefore, protects them from predators. They are more able to survive and reproduce, and their phenotype is dominant over the brown and black mice.


Image courtesy of Giphy.

Due to global warming, the layer of permafrost begins to melt, and the dark volcanic soil underneath begins to become more prevalent. If this were to occur, we would see a shift in the phenotypes of the mice.

Light mice would become more susceptible to predation, as they are easier to spot. Darker mice would have the advantage of being able to blend into the environment and would survive and reproduce more frequently.

Because of this, the phenotypes of the entire population would shift to become darker. The lighter mice would become less and less common, and the environment has changed the frequency of alleles in the population by creating an advantage for some phenotypes and not others.

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