What is genetic diversity, and why is it important for species survival?

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Accepted Answer

The variety of genes within a species, which provides the raw material for adaptation to changing environmental conditions. Genetic diversity refers to the variety of genes and alleles within a species or population. It is crucial for species survival because it provides the raw material for natural selection and adaptation to changing environmental conditions. Populations with high genetic diversity are more likely to contain individuals with traits that allow survival in the face of disease, climate change, or other environmental stresses. Low genetic diversity, often resulting from small population sizes or inbreeding, makes species more vulnerable to extinction.

The number of different species in a habitat describes species diversity (or species richness), which is a different level of biodiversity. The diversity of ecosystems on a continent describes ecosystem diversity, which is yet another level. The number of individuals in a population is population size (abundance), which is related to but distinct from genetic diversity - a large population can still have low genetic diversity if it went through a population bottleneck.

The three levels of biodiversity - genetic, species, and ecosystem diversity - are fundamental concepts on the DSST Environment and Humanity exam. Students should understand why genetic diversity matters for conservation (the minimum viable population concept, inbreeding depression, genetic drift), how bottleneck events reduce genetic diversity (such as the cheetah population bottleneck), and how conservation genetics tools are used in species recovery programs to maintain genetic health.

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