20.5

Question 1

Give equations used in hardy weinberg and what they stand for

Answer 1

p+q=1 (alle frequency)
p2+2PQ+q2=1 (genotype frequency)
p= dominant allele or homozygous dominant genotype
2PQ= heterozygous genotype
q= recessive allele or homozygous recessive genotype

Question 2

What factors affect evolution

Answer 2

mutations,
Changes in population size - density dependent or independent factors lead to gene flow(smaller changes to population size)- migration
genetic bottleneck (larger changes in population size)
Genetic drift - founder effect (small population)
natural selection
Sexual selection (increase in alleles that promote mating success)

Question 3

What is evolution

Answer 3

Frequency of an allele in a population changes overtime. Heavily reliant on natural selection

Question 4

what is natural selection

Answer 4

The process by which organisms best adapted to their selection pressure survive and reproduce - passing on their favorable characteristics to offspring.
Greater proportion of next generation inherit advantageous allele- repoduce- pass on gene so allele increases

Question 5

How do mutations affect evolution

Answer 5

formation of new alleles come about from mutations - which leads to genetic variation

Question 6

gene pool?

Answer 6

total sum of genes in a population

Question 7

allele frequency ?

Answer 7

frequency of a specific allele in a population

Question 8

what is natural selection? steps

Answer 8

• organisms different alleles
• different selection pressure (competition for mates,disease,predation) create struggle for survival
• individuals with advantageous allele more likely to reproduce (pass on genes)and survive selection pressures
• this increases allele frequency allele in a population

Question 9

how does gene flow affect evolution

Answer 9

gene flow is the movement of alleles between population caused by immigration (entering new country) emigration (leaving home country) causes change of allele frequency in a population

Question 10

What is genetic drift and ph have how does It affect evolution

Answer 10

• idea that chance dictates which alleles are passed on NOT ENVIRONMENTAL FACTORS

Question 11

what are the population bottleneck and its effects?

Answer 11

large reductions in population size that last for at least one generation. Leads to reduced gene pool and genetic diversity

Question 12

Genetic drift vs genetic bottleneck

Answer 12

Bottleneck is caused by event that drastically reduces gene pool e.g hunting to point of extinction,environmental disaster,
Genetic drift occurs in places w small population- changes such as new selection pressure,random mutation

Question 13

3 types of natural selection

Answer 13

Stabilising selection - not much change in environmental so individuals with alleles in middle range more likely to survive - offspring middle allele high frequency
Directional selection change in environment- one extreme most likely to survive as reproduce - allele frequency if offspring lies more to the side
Disruptive selection - change in environment - 2 allies most likely to survive and reproduce

Question 14

What is founder effect

Answer 14

Variation in genotype
Some of these individuals start a nee population (small population)
By chance an allele is most particular in the group
Population has smaller gene pool than original population- display less genetic variation