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Extinctions quiz #3 Flashcards

Extinctions quiz #3
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  • Describe the main events and consequences of the Permian extinction, also known as the 'great dying.'
    The Permian extinction occurred about 252 million years ago, wiping out about 96% of marine species and 70% of terrestrial species. It was mainly caused by massive volcanic activity, which led to global warming, acid rain, ocean acidification, and low oxygen levels, drastically altering the course of life on Earth.
  • Why do scientists believe a sixth mass extinction may be occurring now, and what is the primary driver of this event?
    Scientists believe a sixth mass extinction may be underway because current extinction rates are 10 to 100 times higher than background rates, mainly due to human activities such as habitat loss, pollution, and climate change.
  • What is the difference between background extinction and mass extinction?
    Background extinction occurs sporadically at a low rate due to competition or environmental changes, while mass extinction is a catastrophic event that wipes out a large percentage of species across many groups at once.
  • How many major mass extinction events, known as the 'big five,' have occurred since the Cambrian period?
    There have been five major mass extinction events, called the 'big five,' since the Cambrian period.
  • What were the main causes and consequences of the Permian extinction, also known as the 'great dying'?
    The Permian extinction was mainly caused by massive volcanic activity, leading to global warming, acid rain, ocean acidification, and low oxygen levels, resulting in the extinction of about 96% of marine species and 70% of terrestrial species.
  • What catastrophic event is believed to have caused the Cretaceous (KT) extinction, and what were its immediate effects?
    A large meteorite impact near the Yucatan Peninsula caused the Cretaceous extinction, leading to mega tsunamis, worldwide firestorms, and a global winter lasting about three years.
  • Why did some mammals survive the Cretaceous extinction event while most dinosaurs did not?
    Some small, generalist mammals survived because they could eat a variety of foods and were less dependent on specific resources that disappeared after the extinction event.
  • What evidence suggests that a sixth mass extinction may be occurring now, and what is the primary cause?
    Current extinction rates are 10 to 100 times higher than background rates, mainly due to human activities such as habitat loss, pollution, and climate change.
  • How long does it typically take for biodiversity to recover after a mass extinction event?
    It can take 5 to 100 million years for similar levels of biodiversity to return after a mass extinction event.
  • What is the significance of mass extinctions in shaping the course of life on Earth?
    Mass extinctions drastically alter which species survive and diversify, reshaping the evolutionary trajectory and composition of life on Earth.