Genetic diversity is the variation of genes that exist within a species population. Genes are what make up our unique DNA code, carrying information that determines certain features or characteristics about you. These are called traits. Every individual in a species is unique because of these differences in traits. 

Think about your family and how you are all related yet each of you are different in your own way, either by physical differences, like being shorter or taller, or by differences in the way you think or behave, like being very social, more of a book-reader, or more creative and arty. 

Genetic diversity comes from changes in our DNA sequence that occur during cell replication. These changes are referred to as mutations. Most of the time these changes aren’t particularly beneficial or have no effect at all. But every now and again, a mutation will occur that provides a benefit to the individual which can be passed on to their offspring during reproduction.

With each generation, more and more mutations are added to the DNA in a species’ gene pool. One of these mutations could be a solution to changes in the environment. For example, if mutations in a particular primate result in webbed hands, this could have no effect. But if the individual lives near a waterway, as is the case for the proboscis monkey, and predator populations in the area have grown, having webbed hands gives an advantage in how they can escape through the waterways. Their ability to swim more efficiently provides a faster escape route that most predators cannot follow. It may also open up new foraging and nesting sites, as well as potential mating opportunities as waterways wouldn’t restrict their ability to move throughout their environment.

Think of a species with huge genetic diversity like a hardware store that contains all the tools, equipment, and materials needed for almost every situation. A species with very little genetic diversity is more of a basic toolbox with some tools available to them. Some can be used to fix a problem, but they may not be perfect for the job. Or, worse, none of the tools they have are suitable for the jobs they’re needed for.

Having a variety of characteristics allows a species to survive diseases, environmental changes, and ecosystem stresses because some individuals may possess certain traits that allow them to overcome such impacts of change. Individuals may die out, but the species will survive.