Variation And Evolution

Question 1

Causes of genetic variation

Answer 1

1) mutations
2) meiosis (crossing over and independent assortment)
3) fusion of gametes

Question 2

Define gene pool

Answer 2

All the alleles of all the genes of all the individuals in a population

Question 3

Define allelic frequency

Answer 3

The proportion of an allele for a gene within a gene pool

Question 4

Define natural selection

Answer 4

Process by which organisms that are better adapted to their environment survive and breed, whilst those less adapted fail to do so

Question 5

Define natural selection

Answer 5

An environmental factors that can alter the frequency of alleles in a population, when it is limiting

Question 6

Define genetic drift

Answer 6

Chance variations in allele frequencies in a population

Question 7

Define speciation

Answer 7

The evolution/development of a new species from an existing species. It occurs when populations of the same species become reproductively isolated

Question 8

Define reproductive isolation

Answer 8

The prevention of reproduction and, therefore, gene flow between breeding groups within a species

Question 9

Define pre-zygotic isolation

Answer 9

Gametes are prevented from fusing s a zygoteis not formed

Question 10

Define post-zygotic isolation

Answer 10

Gametes fuse andba zygotr forms. Even if the organism develops and grows it is sterile and so the genes of the parent species are kept separate and the species do not merge