How do mass extinctions affect biodiversity?

Mass extinctions decrease biodiversity.

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Biodiversity is a measure of the variety of life that is found in a particular ecosystem or on the entire planet itself. Essentially, biodiversity is the entire variety of life.

Biodiversity can be measured in a couple of different ways. The most common measure of biodiversity is to count the...

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Biodiversity is a measure of the variety of life that is found in a particular ecosystem or on the entire planet itself. Essentially, biodiversity is the entire variety of life.

Biodiversity can be measured in a couple of different ways. The most common measure of biodiversity is to count the number of species in a particular area. A rain forest might have more than 1,000 species of birds alone, while a desert might have fewer than 100. By this metric, the rain forest has a high degree of biodiversity. Another way to measure biodiversity is to measure the genetic variety within a particular species.

A mass-extinction event will certainly negatively impact biodiversity by either metric of measurement. Any species extinction reduces biodiversity. If there are fewer species in an area than there were before, diversity has been lost. If the forest had a 1,000 bird species and a mass-extinction event eliminates 700 of those species, the biodiversity of the forest has been dramatically reduced.

The mass-extinction event isn't the only thing to worry about, though. Don't be fooled into thinking that the remaining species will be fine and can flourish. The lost species all existed within food chains and food webs. Unless remaining species can adapt to a new food source, those species will also face extinction. It would be a ripple effect throughout the entire ecosystem.

Even if every species managed to survive a mass extinction event, biodiversity would still be negatively impacted by the second metric. In this situation, no species went extinct; however, perhaps the event reduced the population numbers of all species by ninety percent. Biodiversity has been lost/reduced because the gene pool is now much smaller. Inbreeding may result, and that always introduces strong chances of genetic mutations that further reduce overall fitness. This is what happened to the Florida panther and resulted in mutations like undescended testicles and kinked tails.

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