Extinctions And Changes In Biodiversity

Question 1

What are the 2 biggest threats to organisms from humans?

Answer 1

Exploitation and habitat loss

Question 2

What factors make species more vulnerable to extinction?

Answer 2

• small populations and/or small geographical range
• species tied to habitats favoured by humans
• large organisms
• species higher in food chain

Question 3

How many precious Mass Extinction events?

Answer 3

5
Late Ordovician 
Late Devonian
Late Permian
Late Triassic 
End-Cretaceous (dinosaurs)

Question 4

What classes as a mass extinction?

Answer 4

75% of species left

Question 5

What is the Pleistocene?

Answer 5

Period of time recently where many large mammals species were lost

Question 6

What are the 2 hypotheses for extinction of the large mammals in present interglacial?

Answer 6

environmental deterioration

Human over kill

Question 7

What are the two patterns of changes in diversity with time?

Answer 7

1. General increase (usually with periods of much lower numbers)
2. An increase (usually with periods of decline) then a continued decline to extinction

Question 8

How long ago was Pangea?

What are the north and south parts called?

Answer 8

220mya (Triassic)

• Laurasia
• Gondwanaland is

Question 9

3 pieces of evidence for continental drift?

Answer 9

• jigsaw fit
• similar geology
• similarities in fossils of plants and animals found