inheritance and evolution

Question 1

what are the conditions for the hardy-weinburg principle?

Answer 1

• there is a large population
• mating is random
• one allele does not confer an advantage so natural selection does not occur
• there are no emigrants or immigrants
• no mutations occur

Question 2

equation to predict allele frequency

Answer 2

p + q = 1

Question 3

equation to predict genotype frequency

Answer 3

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

Question 4

what does p represent in hardy weinberg?

Answer 4

frequency of dominant allele

Question 5

what does q represent in hardy weinberg?

Answer 5

frequency of recessive allele

Question 6

what does p2 represent in hardy weinberg?

Answer 6

frequency of homozygous dominant genotype

Question 7

what does 2pq represent in hardy weinberg?

Answer 7

frequency of heterozygous genotype

Question 8

what does q2 represent in hardy weinberg?

Answer 8

frequency of homozygous recessive genotype

Question 9

when calculated value is less than the critical value, do you reject or accept the null hypothesis?

Answer 9

accept

Question 10

when calculated value is greater than the critical value, do you reject or accept the null hypothesis?

Answer 10

reject

Question 11

what is epistasis?

Answer 11

when one gene masks the expression of a different gene

Question 12

what is co-dominance?

Answer 12

both alleles are equally dominant and are both expressed in the phenotype

Question 13

what is allele frequency?

Answer 13

the proportion of an allele in a gene pool

Question 14

4 causes of genetic variation

Answer 14

• gene mutations
• independent segregation
• random fusion of gametes
• crossing over

Question 15

what are the 3 types of natural selection?

Answer 15

stabilising, directional, disruptive

Question 16

describe disruptive selection

Answer 16

environment favours both extremes. after many generations may result in 2 different breeding populations (speciation)

Question 17

what are the 2 types of speciation?

Answer 17

• allopatric (away)
• sympatric (same)

Question 18

describe allopatric speciation

Answer 18

• sub group geographically isolated (physical barrier)
• isolated population experiences different environmental conditions
• directional selection occurs, changes allele frequencies
• random mutations occur, causes genetic drift
• over generations there are so many differences in the gene pools, the two populations become reproductively isolated and have become separate species

Question 19

describe sympatric speciation

Answer 19

• 2 populations occupy the same habitat but become reproductively isolated
  seasonal changes: species may be in season at different times of year so do not interbreed
  mechanical changes: gene mutation change shape/size of genitalia so species physically cannot mate
  behavioural changes: sub group may develop a different courtship ritual or may be active a different times of day

Question 20

phenotype definition

Answer 20

the expression of genes in physical appearance caused by the genotype and the environment