Factors affecting evolution

Question 1

What needs to occur for the existence of different alleles?

Answer 1

• mutation
• formation of new alleles leads to genetic variation

Question 2

How does sexual selection lead to evolution?

Answer 2

• leads to an increase in frequency of alleles which code for characteristics that improve mating sucess

Question 3

What is gene flow?

Answer 3

• the movement of alleles between population
• immigration and emigration result in changes of allele frequency within a population

Question 4

What is genetic drift?

Answer 4

• occurs in small population
• this is a change in allele frequency due to the random nature of mutation
• the appearaence of a new allele will have a greater impact in a smaller population
  
  • (is more likely to increase in nubmer)
  • than in a larger population where there is a greater number of alleles present in the gene pool

Question 5

How does natural selection lead to evolution?

Answer 5

• natural selection leads to an increase in the number of individuals that have characterisitcs that improve their chances of survival
• reproduction rates of these individuals will increase
  
  • as will the freq of the alleles coding for these characteristics
• this is how changes in the environment can lead to evolution