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Genetic diversity is important for a species to adapt and fight off parasites. Domesticated species have low levels of diversity due to preferential breeding. Human genetic diversity varies based on geographic location and can help researchers understand human origins. Biodiversity is important for ecosystem health and adaptability.
Genetic diversity is the variation of hereditary characteristics present in a population of the same species. It plays an important role in evolution by enabling a species to adapt to a new environment and fight off parasites. It is applicable to domesticated species, which typically have low levels of diversity. Studying genetic diversity in humans can help researchers formulate theories about human origins.
Living beings contain in their cells the basic instructions, or blueprints, for their own development. Many of these instructions, called genes, determine physical characteristics that influence how organisms interact with their environment. Variations of these characteristics within the same species give rise to genetic diversity. For a species to adapt to an ever-changing ecosystem, there must be a significant level of variation. Those individuals that possess favorable characteristics will go on to reproduce, while those that do not tend to pass their characteristics on to many offspring.
Domestic species often have low levels of genetic diversity. This is caused by artificial selection, or preferential breeding, of crops and animals for traits that humans find preferable. While this may have short-term positive results, such as a richer harvest, low diversity among domesticated species carries risks. A newly evolved virus or strand of bacteria can very quickly invade a population of nearly identical organisms. The protection that diversity generally affords in wild populations is lost in this scenario.
The Irish Potato Famine of 1845-1852 was caused by a pest invading a large population of nearly identical potatoes. The parasite was a water mold called Phytophthora infestans. This famine caused the Irish population, which depended heavily on potatoes for food, to decrease by 20 to 25 percent.
Human genetic diversity typically varies based on the geographic location of a population. This has led biologists and anthropologists to study these levels of diversity in an attempt to understand human origins. Levels of genetic diversity in Africa, for example, were found to be higher than in many areas of the world. Researchers have developed models of human origins from this evidence. The recent Out-of-Africa model, which suggests that modern humans have a common origin in Africa, is one example.
Biodiversity refers to the level of variation of all living things within an ecosystem. The importance of biodiversity for an ecosystem is analogous to the importance of genetic diversity for a population. Both forms of diversity contribute to the health and robustness of the larger system. As these levels of diversity decrease, both systems are less able to adapt to a changing environment.
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