Extinction and Biodiversity

Question 1

Name four factors that have contributed to mass extinctions (loss of biodiversity)

Answer 1

WAVES:
Warm/hypoxic oceans
Asteroid/meteorite impacts
Volcanism
Snowball earth events

Question 2

A mass extinction occurs when…

Answer 2

At least 60% of the species present are wiped out within 1 million years

Question 3

What causes mass extinctions?

Answer 3

Catastrophic events

Question 4

What is background extinction?

Answer 4

Lower, average rate of extinction

Question 5

How many historic mass extinctions are usually recognized?

Answer 5

5

Question 6

Background extinctions occur when….

Answer 6

Populations are reduced to zero

Question 7

Name four causes of a background extinction

Answer 7

Do Not Call Prius:
Disease
Normal environmental change
Competition with other species
Predation pressure

Question 8

Mass extinctions result from…

Answer 8

Extraordinary and sudden changes in the environment, which can trigger a chain reaction of additional changes

Question 9

How many precambrian mass extinctions were associated with snowball earth effects?

Answer 9

3

Question 10

Which piece of evidence points to an asteroid impact at the end of the cretaceous, resulting in the loss of the dinos?

Answer 10

Global distribution of iridium