variation

Question 1

what factors cause variation

Answer 1

a combination of genetic, epigenetic and environmental factors

Question 2

what are the different types of variation

Answer 2

1) continuous
2) discontinuous
3) heritable
4) non-heritable

Question 3

outline the difference between continuous and discontinuous variation

Answer 3

1) continuous variation is controlled by a number of genes and features show a graduation from one extreme to the other creating a normal distribution curve
2) discontinuous variation is controlled by a single gene and features show no graduation, they are clear cut and easy to tell apart

Question 4

outline the difference between heritable and non-heritable variation

Answer 4

1) heritable variation refers to the genetic differences which can be passed down to offspring
2) non-heritable variation refers to differences in the phenotype as a result of the environment which cant be passed down to offspring

Question 5

what is the difference between interspecific competition and intra-specific competition

Answer 5

1) inter is competition between individuals of different species
2) intra refers to competition between individuals of the same species

Question 6

define gene pool

Answer 6

all the alleles of all the genes of all the individuals in a population at one time

Question 7

define allele frequency

Answer 7

a measure of the number of an allele on a locus within a population

Question 8

list some mechanisms which introduce heritable variation

Answer 8

1) crossing over between homologous chromosomes in prophase 1
2) random assortment during metaphase 1
3) random distribution of chromatids in metaphase 2

Question 9

what is meant by the term selection

Answer 9

the process by which an organisms is better adapted therefore survives and breeds whilst those less adapted fail to do so, selection pressures affect the survival of different phenotypes in a population