3.4.4 Genetic Diversity And Adaptation

Question 1

What is genetic diversity?

Answer 1

The number of different alleles of genes in a population

Question 2

Genetic diversity enables what to occur?

Answer 2

Natural selection

Question 3

The greater the genetic diversity, the more likely …?

Answer 3

The greater the genetic diversity the more likely that individuals in a population will survive an environmental change

Question 4

Why does a greater genetic diversity mean that individuals in a population are more likely to survive an environmental change?

Answer 4

Because there is a wider range of alleles and this means there is a wider range of characteristics. Therefore there is a greater possibility that an individual will posses a charateristic that suits the new conditions.

Question 5

What are the factors that can increase genetic diversity within a population?

Answer 5

1. Genetic mutations
2. New alleles being introduced
3. Meiosis
4. Random fertilisation of gametes during sexual reproduction

Question 6

How does genetic mutations increase GD within population?

Answer 6

Mutations leads to new alleles

Question 7

How can new alleles be introduced into a population?

Answer 7

Mutation
Or individuals from other populations migrate into the population and reproduce with them

Question 8

Describe the process of natural selection.

Answer 8

1. New alleles formed by random mutations in genetic material
2. Many mutations are harmful, which may mean that the individual with the mutated allele dies out, or the mutation is corrected by the ‘proof-reading’ mechanisms of the cell. However, sometimes an allele (or combination of alleles) gives an individual an advantage, leading to increased chance of survival and reproductive success.
3. These individuals pass on their advantageous alleles to the next generation.
4. Overmany generations, the new allele increasesin frequency in the population.

Question 8

What is the primary source of genetic variation?

Answer 8

Mutation

Question 9

What is step 1 of the process of natural selection?

Answer 9

1. New alleles formed by random mutations in genetic material

Question 10

What is step 2 of the process of natural selection?

Answer 10

2. Many mutations are harmful, which may mean that the individual with the mutated allele dies out, or the mutation is corrected by the ‘proof-reading’ mechanisms of the cell. However, sometimes an allele (or combination of alleles) gives an individual an advantage, leading to increased chance of survival and reproductive success.

Question 11

What is step 3 of the process of natural selection?

Answer 11

3. These individuals pass on their advantageous alleles to the next generation.

Question 12

What is step 4 Of the process of natural selection?

Answer 12

4. Over many generations, the new allele increases in frequency in the population

Question 13

What are the types of selection?

Answer 13

1. Directional
2. Stabilising
3. Disruptive (covered later)

Question 14

What does continuous variation cause?

Answer 14

A normal distribution when you measure the given trait in the individuals of a population.

Question 15

What is variation in traits caused by?

Answer 15

Random mutations in genetic material

Question 16

What is directional selection?

Answer 16

When individuals with alleles for characteristics of an extreme type are more likely to survive and reproduce.

Question 17

What is an example of directional selection?

Answer 17

Antibiotic resistance in bacteria

Question 18

In directional selection where does the mean shift to? The mean is …? Does the distribution around the mean change?

Answer 18

Mean shifts in direction of more favourable trait
Mean is equally common
Same distribution around the mean

Question 19

Exam Q template; why does the frequency of (this trait) increase in the population?

Answer 19

-(trait) [state the trait] has a genetic basis
-random mutations over time = genetic variation
^explain how this trait is of an advantage (selection pressure) and state the type of selection
-individuals with this allele are more likely to survive, reproduce and pass on this allele to their offspring.
-over many generations the frequency of this allele increases in the population and therefore so does the trait

Question 20

What is stabilising selection?

Answer 20

When individuals with alleles for characteristics towards the middle range are more likely to survive and reproduce (extremes of phenotype are at a disadvantage)

Question 21

What is an example of stabilising selection?

Answer 21

Human birth rates

Question 22

Does the mean change/ move in stabilising selection? How common is the mean? Has the distribution around the mean changed?

Answer 22

-mean stays the same
-mean more common
-smaller distribution around the mean

Question 23

What does natural selection result in?

Answer 23

Natural selection results in species that are better adapted to their environment

Question 24

What are the types of adaptions?

Answer 24

Behavioural Physiological Anatomical

Question 25

What are behavioural adaptations?

Answer 25

Changes in the way an organism acts that increases its chance of survival

Question 26

What are psychological adaptations?

Answer 26

Process is inside an organism’s body that increase its chance of increase the chance of survival.

Question 27

What are anatomical adaptations?

Answer 27

Changes in the features of an organisms body that increases its change of survival