The theory of evolution by natural selection is one of the fundamental concepts in biology that explains how organisms change over time. One of the key components of this theory is variations, which play a crucial role in shaping the course of evolution. In this article, we will explore how variations are part of the theory of evolution by natural selection.

What are Variations?

Variations refer to differences that exist among individuals within a population. These differences can be physical, such as height, weight, or coloration, or they can be genetic, such as different alleles for a particular gene. Variations arise due to mutations in DNA, genetic recombination during sexual reproduction or environmental factors.

How do Variations Arise?

As mentioned earlier, variations arise due to mutations in DNA. Mutations are random changes that occur in the genetic material of an organism.

They can be caused by various factors such as exposure to radiation or chemicals or errors during DNA replication. Mutations can either be harmful neutral or beneficial.

Neutral mutations do not affect an organism’s fitness and may accumulate over time without any consequences. Harmful mutations decrease an organism’s fitness and may lead to its death or reduced reproductive success. Beneficial mutations increase an organism’s fitness and may provide it with an advantage over other individuals within its population.

How do Variations Influence Evolution?

Variations play a crucial role in shaping the course of evolution because they provide the raw material upon which natural selection acts. Natural selection is the process by which certain traits become more common within a population over time because they increase an organism’s chances of survival and reproduction.

Natural selection involves three key components: variation, heritability, and differential reproductive success. Variation provides different traits for natural selection to act upon; heritability allows those traits to be passed down from one generation to another; and differential reproductive success means that individuals with certain traits are more likely to survive and reproduce than others.

An Example of Natural Selection in Action

Let’s take the example of a population of deer living in a forest. Suppose that within this population, there is variation in the length of their necks.

Some deer have longer necks, while others have shorter necks. Now, let’s say that due to a drought, the vegetation in the forest becomes scarce, and the only available food is high up on trees.

In this situation, deer with longer necks have an advantage over those with shorter necks because they can reach higher up and access more food. As a result, they are more likely to survive and reproduce than those with shorter necks. Over time, this leads to an increase in the frequency of genes for longer necks within the population.

Conclusion

Variations are a crucial part of the theory of evolution by natural selection because they provide the raw material upon which natural selection acts. Without variations, there would be no differences among individuals within a population for natural selection to act upon. Understanding how variations arise and how they influence evolution is essential for understanding how organisms change over time.