18.1population genetics

Question 1

gene pool

Answer 1

all of the alleles of all the genes of all the individuals in a population at a given time

Question 2

allelic frequency

Answer 2

the number of times an allele occurs within the gene pool

Question 3

hardy weinberg principle

Answer 3

the proportion of dominant and recessive alleles of any gene in a population remains constant over generations

Question 4

hardy weinberg conditions

Answer 4

1. no mutations
2. population is isolated
3. no selection occurs
4. population is large
5. mating in the population is random

Question 5

Hardy weinberg phenotype equations

Answer 5

p+q=1

Question 6

Genetic variation

Answer 6

1. mutations
2. meiosis
3. random fertilisation of gametes

Question 7

selection pressure

Answer 7

environmental factors that limit population

Question 8

Natural selection factors

Answer 8

1. organisms produce more offspring than can be supported by available food, light and space
2. genetic variety within populations of all species
3. variety of phenotypes that selection operated against

Question 9

Stabilising selection

Answer 9

• occurs in unchanging environment
• selection against extreme phenotypes
• standard deviation is reduced
• preserves average phenotype

Question 10

Directional selection

Answer 10

-occurs in changing phenotype
-favours one extreme phenotype so mean shifts towards
-selection against mean phenotype

Question 11

Disruptive selection

Answer 11

-occurs in changing environment
-favours both mean phenotypes
-selection against mean phenotype

Question 12

Species

Answer 12

Able to breed to produce healthy, fertile offspring

Question 13

Speciation

Answer 13

evolution of new species from existing ones

Question 14

allopatric speciation

Answer 14

different species form from different populatins in different areas

Question 15

sympatric speciation

Answer 15

different species form from the same population in the same area

Question 16

sympatric speciation explanation

Answer 16

1. occurs in the same habitat
2. mutation causes variation in behaviour/ ecology/temporal
3. reproductive isolation
4. different favourable alleles are passed on
5. change in allele frequency
6. populations can’t interbreed to produce fertile offspring

Question 17

allopatric speciation explanantion

Answer 17

1. geographical isolation occurs
2. different environmental conditions cause different selection pressures
3. random mutations cause variation
4. favourable alleles passed on to offspring
5. change in allele frequency

Question 18

behavioural

Answer 18

different courtship displays

Question 19

temporal

Answer 19

different breeding seasons
different feeding times

Question 20

mechanical

Answer 20

mismatch in reproductive parts
gamete incompatibility

Question 21

allele frequency

Answer 21

P^2 + 2pq + q^2 = 1

Question 22

genetic drift

Answer 22

change in frequency of existing gene variant in population due to random chance

Question 23

intra

Answer 23

within same species

Question 24

inter

Answer 24

across different species