Why is genetic diversity important within a population?

Genetic diversity within a population is the variety of different alleles (versions) of genes present, which lead to a variety of phenotypes. It is important for a number of reasons, such preventing inbreeding and allowing the population to more adaptable to changing environments. Having genetic diversity means that if an organism has one allele for a bad, recessive mutation, there is more chance that its other allele will be a healthy, dominant one. Only one allele is shown in the phenotype, so the organism can remain healthy. When an offspring is created from two individuals that are too closely related, there is more chance that it will be homozygous for recessive mutations that have negative effects on fitness. Secondly, genetic diversity allows a population as a whole to be better adapted to changes in the environment, such as a new disease, a changing climate or the introduction of new predators/prey. When these occur, the more genetic diversity a population has, the more chance that some individuals will contain mutations that enable them to be resistant and deal with this change. These resistant individuals will be able to survive and reproduce, keeping the population alive.