Key Area 7-Mass Extinction and Biodiversity Flashcards Preview

Biology: Unit 3 > Key Area 7-Mass Extinction and Biodiversity > Flashcards

Flashcards in Key Area 7-Mass Extinction and Biodiversity Deck (14):
1

What is a mass extinction?

Total wipeout of a species

2

What type of evidence suggests there have been several mass extinctions?

Fossil evidence

3

What happens to biodiversity after a mass extinction?

It reduces

4

Why are there difficulties estimating mass extinctions?

Only based on approximations
Only have fossils from birds and mammals

5

When did the mega fauna become extinct?

When humans came around

6

Why are current species extinction rates thought to be higher than expected?

Human activities

7

What are the three measurable components of biodiversity?

-genetic
-species
-ecosystem

8

What is genetic diversity?

Genetic variation (numbers and frequency of alleles) in a population

9

What happens to the genetic diversity if a population dies?

Decreases

10

What is species diversity?

The number of different species in an ecosystem and their abundance

11

What reduces species diversity?

If some species are more dominant than others

12

What is the species diversity like if an area is very isolated?

Lowers the species diversity

13

What happens to the species diversity if the habitat surface area is small

Low species diversity

14

What is ecosystem diversity?

The number of distinct ecosystems in an area