evolution

Question 1

what is the gene pool

Answer 1

the complete range of alleles present in a population

Question 2

what is allele frequency

Answer 2

how often an allele occurs in a population usually given as a percentage of the total population

Question 3

what is evolution

Answer 3

the change in allele frequency in a population over a period of time

Question 4

what is the process of evolution

Answer 4

1. variation in alleles caused by mutations
2. selection pressure creates survival struggle
3. better adapted individual more likely to survives be
4. advantageous alleles survive and passed onto offspring’s
5. frequency of advantageous allele increases

Question 5

what is stabilising selection

Answer 5

when environment isn’t changing much individuals with alleles for characteristics towards the middle of the range are more likely to surge leading to reduction off possible phenotypes

Question 6

what is directional selection

Answer 6

due to change in environment indivisible with allele for characteristics of an extreme type are more likely to survive and reproduce

Question 7

what factors affect evolution

Answer 7

mutations
natural selection
gene flow
genetic drift
sexual selection

Question 8

what is genetic drift

Answer 8

the process by which an allele becomes more common in a population due to chance

Question 9

what are genetic bottlenecks

Answer 9

an event e.g natural disaster that causes a big reduction in population side leading to gene pool reduction

Question 10

what is the founders effect

Answer 10

small population arise due to establishment of new colonies by isolated individuals, extreme examples of genetic drift, smaller gene pools, less variation, any rare allele from original population in new one will have a bigger impact during selection

Question 11

what is the Hardy-Weinburg principle

Answer 11

has to be a large population with no one entering or leaving

random mating

Question 12

what are the hardy weinbyrg equations

Answer 12

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

Question 13

what is artificial selection

Answer 13

when humans select individuals in a population to breed together to get desirable traits

Question 14

what are the issues of artificial selection

Answer 14

gene pool is reduced
health problems
genetic diseases
over exaggeration of certain traits

Question 15

what is speciation

Answer 15

the development of new species

Question 16

what is species

Answer 16

a group of organism that can reproduce to give fertile offspring

Question 17

what is allopatric speciation

Answer 17

when populations are reproductively isolated through a combination of geographical separation and natural selection

Question 18

how does reproductive isolation occur

Answer 18

seasonal changes
mechanical changes
behavioural changes

Question 19

what is sympatric speciation

Answer 19

speciation without geographical isolation

random mutations occur within population preventing members of that population from breeding with other members of the population