Describe an environmental factor that could influence natural selection and decrease genetic diversity. Pick a specific example to illustrate your point.
Answer (2)
Habitat destruction is an environmental factor that influences natural selection and decreases genetic diversity, as seen in the deforestation of the Amazon rainforest. It causes population declines, leads to inbreeding, and creates selective pressures that narrow genetic diversity. This can make species more vulnerable to extinction.
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An environmental factor that can influence natural selection and decrease genetic diversity is a disease or epidemic.
Example: The Tasmanian Devil Facial Tumor Disease (DFTD)
Who : The Tasmanian devil, a carnivorous marsupial native to Tasmania, Australia.
What : DFTD is a contagious cancer that affects Tasmanian devils. The disease is transmitted through biting, a common behavior among devils.
When : The disease was first identified in the 1990s and continues to affect populations today.
Where : It primarily affects Tasmanian devils in Tasmania.
Why : The disease reduces genetic diversity because it leads to high mortality rates, which can drastically reduce population sizes. With fewer individuals left, the genetic pool becomes smaller, limiting genetic variation.
How : With a reduced number of individuals, there are fewer genetic variations within the remaining population. This results in a bottleneck effect, where only a small portion of the original genetic diversity is present in the surviving population. As natural selection favors individuals that can survive and resist the disease, over time, the genetic diversity of the population may further decrease as specific traits become dominant.
Conclusion : This example illustrates how an epidemic can act as a selective pressure, influencing which members of a species survive and reproduce, potentially decreasing genetic diversity in the process. Such instances highlight the importance of understanding the balance between natural selection and genetic diversity in maintaining healthy populations.
