3.3 Biodiversity and variation.

Question 1

What levels can biodiversity occur on?

Answer 1

It can exist within an ecosystem, with a species and within individual genes?

Question 2

What is ecosystem diversity?

Answer 2

It is the variety habitats, biological communities and ecological processes that occur in the biosphere.

Question 3

What is species diversity?

Answer 3

It is the number of different species within an ecosystem.

Question 4

What is genetic diversity?

Answer 4

Variation of genetic characters within a single species.

Question 5

Why is genetic diversity important?

Answer 5

It allows organisms to adapt to certain conditions allowing increased survival.

Question 6

What is mutation?

Answer 6

Mutation is the source of genetic variation.W

Question 7

What do mutations do?

Answer 7

They change the characteristics of organisms.
e.g white mouse > black mouse.

Question 8

What is an adaptation?

Answer 8

An adaptation is a special feature or characteristic that improves an organism’s chance of survival.

Question 9

What are the different types of adaptations?

Answer 9

structural adaptations (such as hair to keep warm or the colour of a moth)

behavioural adaptations (such as courtship display to attract a mate)

physiological adaptations (such as the ability to produce concentrated urine to conserve water)
(From JacPlus)

Question 10

What is an allele?

Answer 10

An allele is an alternate form of a gene (found in the same place in the chromosome).

Question 11

How can variation occur during meiosis?

Answer 11

It can occur due to:

• The independent assortment of chromosomes
• The ‘crossing over’ of maternal and paternal chromosomes.

(JacPlus 3.3 has a good diagram (source 3.14 and 3.15))

Question 12

What is a genotype?

Answer 12

The genotype is the combination of alleles for a particular trait within an individual.

Question 13

What is a gene pool?

Answer 13

It is the alleles for a particular trait within a population.

Question 14

What is gene flow?

Answer 14

The movement of individuals and their alleles between populations.

Question 15

What is genetic drift?

Answer 15

It is the changes in allele frequency due to chance events such as floods and fires.

Question 16

What is natural selection?

Answer 16

The process where organisms better adapted for an environment are more likely to pass their genes on to the next generation.

Question 17

What can impact allele frequencies?

Answer 17

Natural selection and genetic drift.

Question 18

Explain gene flow.

Answer 18

It is when certain organisms move out (emigration) or move in (immigration) which either removes alleles from a population or adds new alleles to a population.

Question 19

Which reproductive technologies unbalance natural levels of biodiversity?

Answer 19

Artificial selection, artificial insemination, IVF and cloning.

Question 20

How does artificial selection (selective breeding) reduce biodiversity?

Answer 20

It makes it so its likely that only some (wanted) traits are passed on.

Question 21

How does artificial insemination reduce biodiversity?

Answer 21

Only males with wanted traits will have their sperm sampled.

Question 22

How does IVF reduce biodiversity?

Answer 22

Embryos are chosen meaning natural process is lost.

Question 23

How does cloning reduce biodiversity?

Answer 23

Creates more copies of certain alleles.

Question 24

What are the consequences of reduced biodiversity?

Answer 24

Extinction. When an environmental change or threat occurs there will be no variation that allows some species to survive. Some species won’t survive to reproduce.