4.4 GENETIC DIVERSITY AND ADAPTATION

Question 1

Define

population

Answer 1

all the organisms of a particular species that live in the same place

Question 2

define

allele

Answer 2

different forms of a particular gene, found at the same locus on a chromosome

Question 3

define

genetic diversity

Answer 3

the total number of different alleles in a population

Question 4

state

the advantage of high genetic diversity

Answer 4

ability to adapt to a change in environment; allows natural selection to occur

Question 5

explain

natural selection leading to development in new characteristics

Answer 5

• random mutations result in new alleles
• some alleles provide an advantage, making an individual more likely to survive and reproduce
• their offspring receive the new allele and frequency continues to increase over many generations

Question 6

define

directional selection

Answer 6

• occurs when environmental conditions change
• individuals with phenotypes suited to the new conditions with phenotypes suited to the new conditions will survive and pass on their genes
• over time the mean of the population will move towards these characteristics

Question 7

state

example of directional selection

Answer 7

• antibiotic resistance
• bacteria w/ a mutation allowing them to survive in the presence o antibiotics will reproduce
• therefore frequency of this allele will increase and population will shift to have greater antibiotic resistance

Question 8

define

stabilising selection

Answer 8

• occurs when environmental conditions stay the same
• individuals closest to the mean are favoured and any new characteristics are selected against
• results in low diversity

Question 9

state

example of stabilising selection

Answer 9

• birth weight
• babies that weigh around 3kg are more likely to survive than those at lower or higher weights

Question 10

define

niche

Answer 10

the role of a species within its environment
- species sharing the same niche will compete with eachother

Question 11

state

3 types of adaptation w/ examples

Answer 11

• anatomical (changes to body structure) e.g. claws
• physiological (changes to bodily processes) e.g. venom production
• behavioural (changes to actions) e.g. hibernation