3.7 Mass Extinction and Biodiversity

Question 1

Define ‘Biodiversity’

Answer 1

Biodiversity is the total variation that exists amongst all living things

Question 2

What is ‘Extinction’ and when does it occur?

Answer 2

Extinction is the complete demise of a group of organisms. It occurs when the organisms fail to adapt to their environment.

Question 3

What suggests there have been multiple mass extinctions in the earth’s history?

Answer 3

Fossil Evidence

Question 4

What is ‘Mass Extinction’

Answer 4

Mass Extinction is a period of time in Earth’s history when an abnormally large number of species die out within a short time frame

Question 5

Following a mass extinction how is biodiversity regained?

Answer 5

Adaptive Radiation of Survivors

Question 6

Explain what adaptive radiation is?

Answer 6

Adaptive Radiation is where the survivors of an extinction become suited to their environment and are able to successfully reproduce and recolonise

Question 7

What are mass extinctions usually a result of?

Answer 7

Change to global climate

Question 8

What is ‘Extinction Rate’?

Answer 8

Extinction Rate is the number of species that become extinct in a given area per unit time

Question 9

Why is extinction rate and estimation of extinction dates not always accurate?

Answer 9

Fossil evidence is biased, some creatures(vertebrate for example) fossile better.

Question 10

What coincided with the arrival of homo sapiens?

Answer 10

Extinction of the Megafauna

Question 11

What are ‘Megafauna’

Answer 11

Large or giant animals

Question 12

Why is it important to maintain biodiversity?

Answer 12

• Access to raw materials
• Access to fuels
• Aesthetics
• Access to food
• Maintain the genetic diversity

Question 13

What are the three measurable components of biodiversity?

Answer 13

Genetic Diversity
Species Diversity
Ecosystem Diversity

Question 14

Define <em>‘Genetic Diversity’</em>

Answer 14

Genetic diversity comprises the genetic variation shown by the NUMBER AND FREQUENCY OF ALLELES IN A POPULATION

Question 15

What is a measure of genetic diversity?

Answer 15

Number and Frequency of alleles in a population

Question 16

Define <em>‘Species Diversity’</em>

Answer 16

Species diversity comprises the species richness and the relative abundance of the ecosystem

Question 17

What is ‘species richness’?

Answer 17

The number of species present in an ecosystem

Question 18

What is ‘relative abundance’?

Answer 18

The proportion of each species in an ecosystem

Question 19

Define <em>‘Ecosystem Diversity’</em>

Answer 19

The number of distinct ecosystems in an area

Question 20

What is Island Biogeography?

Answer 20

Study of the factors that affect the distribution and diversity of species on island

Question 21

What are the two types of island and describe the differences between them?

Answer 21

True island - a land mass surrounded by water

Habitat Island - area surrounded by an unlike ecosystem

Question 22

How does area and isolation of ecosystem affect its species diversity?

Answer 22

The SMALLER and MORE ISOLATED an ecosystem, the <strong> LOWER </strong> the species diversity

Question 23

What is the effect of a dominant species on species diversity?

Answer 23

An ecosystem with a dominant species will have a LOWER species diversity than an ecosystem with the same species richness