microevolution

Question 1

Genetic variation

Answer 1

a difference in genes between individuals

Question 2

Where genetic variation comes from

Answer 2

1. making new alleles
2. changing gene number or position
3. rapid reproduction
4. sexual reproduction

Question 3

1. Making new alleles

Answer 3

1. point mutation

2. sex will shuffle the existing alleles

Question 4

neutral variation

Answer 4

mutation/change in DNA that’s not harmful or beneficial

Question 5

2. Changing gene number or position

Answer 5

gene copying because of mitosis error

big pieces of chromosome that are copied = harmful therefore small pieces= not harmful

Question 6

3. Rapid reproduction

Answer 6

how fast mutation happens is low in animals and plants

Question 7

4. sexual reproduction

Answer 7

animals have sex = shuffling alleles = new combination

1. crossing over
2. independent assortment
3. fertilisation

Question 8

Hardy-Weinberg equation

Answer 8

p + q = 1

Question 9

frequency of genotype equation

Answer 9

p^2 + 2pq + q^2 = 1

Question 10

Conditions for Hardy-Weinberg equilibrium

Answer 10

1. no mutations
2. random mating
3. no natural selection
4. big population
5. no gene flow

Question 11

example of hardy-weinberg equilibrium

Answer 11

PKU (phenlyketonumia)

1. low mutation rate
2. random mating
3. no natural selection - only happens on homozygous individuals
4. large population
5. migration has no effect

Question 12

What changes allele frequencies in a population ?

Answer 12

1. natural selection
2. genetic drift
3. gene flow

Question 13

1. Natural Selection

Answer 13

inheritable characteristics individuals have to increase survival. More likely to reproduce that those who don’t

Question 14

2. Genetic drift

Answer 14

unpredictable change in allele frequency between generations, especially in a small population

Question 15

3. Gene flow

Answer 15

how alleles go in or out of population because individual moves around.

Question 16

What are the impacts of genetic drift

Answer 16

1. founder effect

2. bottleneck effect

Question 17

1. founder effect

Answer 17

a few individuals will separate from the main population and create a new one with a different gene pool

Question 18

2. bottleneck effect

Answer 18

population will have a huge decrease in size because of environment ( e.g fire)
remaining population won’t have same gene pool as original even if it goes back to original size

Question 19

Types of Natural selection

Answer 19

1. Relative fitness’
2. directional, disruptive, stabilising selection
3. sexual selection
4. balancing selection

Question 20

Relative fitness

Answer 20

how 1 individual contributes to gene pool compared to to others

Question 21

directional selection

Answer 21

individuals with extreme phenotypic range are favoured by environment
curve will go one way or another
happens when population migrates or when environment changes

Question 22

disruptive selection

Answer 22

individuals with extreme or medium phenotype will be favoured by environment

Question 23

stabilising selection

Answer 23

individuals who with extreme or medium phenotype are not favoured by environment and will most likely die.

Question 24

sexual selection

Answer 24

individuals with a certain trait are more likely to find mates than those who don’t

Question 25

types of sexual selection

Answer 25

1. intrasexual

2. intersexual

Question 26

1. intrasexual

Answer 26

males compete with each other to get female mate

Question 27

2. intersexual

Answer 27

females choose their mates based on male appearance or behaviour

Question 28

Balancing selection

Answer 28

some loci will remain which means phenotype is preserved

Question 29

types of balancing selection

Answer 29

1. frequency-dependent selection

2. heterozygote advantage

Question 30

1. frequency-dependent selection

Answer 30

genotype fitness of population is dependent on frequency

Question 31

2. heterozyote advantage

Answer 31

individuals who are heterozygotes will be more fit (contribute more to gene pool) than homozygous individuals

Question 32

Why Natural selection can’t make perfect organisms

Answer 32

1. it operates on already existing features and traits
2. adaptation has it’s disadvantages
3. into only favours the fittest phenotype in a population (survival of the fittest)