evolution

Question 1

outline how evolution occurs

Answer 1

natural selection- organisms which are better adapted to the environment are more likely to survive and reproduce to produce offspring that are successful

Question 2

outline how natural selection works

Answer 2

• in any population there is variation due to random mutations
• individuals within a population have the potential to produce large numbers of offspring but are limited by carrying capacity
• as pop increases competition begins with only the fittest surviving and passing on genetics
• over many generations a group which may have belonged to one species may give rise to 2 different groups
• if the environment changes the process of natural selection will continue

Question 3

provide the model answer of any four or five marker surrounding natural selection

Answer 3

1) variation in X is due to random mutations in the population
2) these individuals have a selective advantage because X
3) this allows them to survive and reproduce passing on their advantageous alleles to the next generation
4) over many generations allele frequency will increase

Question 4

what is speciation

Answer 4

the formation of a new species due to the evolution of 2 reproductively separated populations

Question 5

list the factors which may influence speciation

Answer 5

1) genetic drift
2) mutations
3) natural selection
these all cause big changes in the equilibrium of the gene pool

Question 6

define genetic drift

Answer 6

variations in allele frequency in small populations due to chance rather than selection pressures

Question 7

define the founder effect

Answer 7

when a small number of individuals becomes isolated forming a new population with a limited gene pool and the allele frequency doesn’t reflect that of the original population, if the population remains small it may undergo genetic drift

Question 8

what is the bottle nose effect

Answer 8

as a result of a disaster the population size becomes drastically reduced therefore allele frequency may have changed increasing chance of genetic drift

Question 8

what is the bottle nose effect

Answer 8

as a result of a disaster the population size becomes drastically reduced therefore allele frequency may have changed increasing chance of genetic drift

Question 9

what are the two types of speciation and what are the differences

Answer 9

1) sympatric= the formation of a new species due to the evolution of 2 reproductively separated populations
2) allopatric= formation of a new species as a result of the 2 populations becoming geographically separated

Question 10

what factors may cause sympatric speciation

Answer 10

• habitat change
• changes in behavioural mechanisms
• morphology
• breeding mechanisms
• seasonal isolation

Question 11

what is hybrid sterility

Answer 11

a factor which may cause sympatric speciation as the sets of chromosomes from each parent are different and cant pair up in meiosis 1 and produce gametes

Question 11

what is hybrid sterility

Answer 11

a factor which may cause sympatric speciation as the sets of chromosomes from each parent are different and cant pair up in meiosis 1 and produce gametes