Mass Extinctions:

Question 1

When were the five mass extinctions?

Answer 1

End-Ordovician: 440 mya
End-Devonian: 360 mya
End-Permian: 250 mya
End-Triassic: 200 mya
End-Cretaceous (KT): 65 mya

Question 2

What happened during the End-Ordovician extinction?

Answer 2

Many marine species, especially those adapted to warm, shallow seas, were lost, creating new niches for early vertebrates to exploit, including the first jawed fish

Question 3

What occurred during the late Devonian extinction?

Answer 3

There was a diversification of ray-finned fish and early tetrapods, as well as the extinction of placoderms, which opened up niches for surviving groups.

Question 4

What were the consequences of the End-Permian extinction

Answer 4

Over 95% of marine species and 70% of terrestrial vertebrate species went extinct, allowing archosaurs and mammal-like reptiles (cynodonts) to diversify.

Question 5

What happened at the End-Triassic extinction (200 mya)?

Answer 5

Dinosaurs became dominant terrestrial vertebrates as large amphibians and some early dinosaur groups went extinct, allowing surviving dinosaurs to diversify.

Question 6

What were the effects of the K-T extinction (65 mya)?

Answer 6

Mammals and birds rapidly diversified into many new ecological roles, with bony fish also undergoing significant diversification.

Question 7

How do mass extinctions support the argument for determinism in evolution?

Answer 7

Mass extinctions create predictable patterns of ecological opportunities, allowing surviving lineages to diversify and adapt to new niches. This suggests that certain evolutionary outcomes are likely following these events.

Question 8

What is the significance of vacant niches after mass extinctions?

Answer 8

Vacant niches allow surviving species to evolve new adaptations and fill roles left by extinct species, leading to predictable diversification patterns that support determinism.

Question 9

How does selective survival based on functional traits relate to determinism?

Answer 9

Certain traits enhance survival and reproduction, leading to predictable evolutionary paths where advantageous traits become more common in populations, reinforcing deterministic outcomes.

Question 10

What role do historical traits play in future diversification?

Answer 10

Historical traits can influence which adaptations are favored in subsequent generations, suggesting that past evolutionary paths can determine future outcomes.

Question 11

What factors contribute to the survival of species after a mass extinction?

Answer 11

Generalist diet
Fast adaptability
Smaller size