evolution 1.7

Question 1

what is directional selection?

Answer 1

form of selection that results in a progressive shift in a population’s mean value for a trait

Question 2

what is disruptive selection?

Answer 2

form of selection that results in a population being split into two or more distinct groups, each with its own mean value for a trait

Question 3

what is stabilising selection?

Answer 3

form of selection that leads to a reduction in genetic diversity without a change in populations mean value for a trait

Question 4

what is evolution?

Answer 4

process of gradual change on a population of organisms over successive generations resulting from genomic variations

Question 5

what is horizontal inheritance?

Answer 5

transfer of genetic material “sideways” between contemporary members of a population

Question 6

what is vertical inheritance?

Answer 6

transfer of genetic sequences from one generation “down” to the next by sexual or asexual reproduction

Question 7

what is natural selection?

Answer 7

non-random increase in frequency of DNA sequences which confer an advantage and increase the chance of survival

Question 8

what is allopatric speciation?

Answer 8

form of speciation where gene flow between populations of a species is prevented by a geographical barrier

Question 9

what is sympatric speciation?

Answer 9

form of speciation where gene flow between populations of a species is prevented by a behavioural or ecological barrier

Question 10

what is a species?

Answer 10

group of organisms that produce fertile offspring and share the same chromosome complement

Question 11

what is a gene pool?

Answer 11

total of all the genomic sequences (alleles) present in the genotypes of the members of a species

Question 12

what is a selective advantage?

Answer 12

a benefit gained by mutant organisms in an environment that suits them but not other members of the population

Question 13

what is an isolating mechanism?

Answer 13

geographical, ecological or behavioural barrier that prevents genetic exchange between populations of a species

Question 14

what is speciation?

Answer 14

generation of new biological species by evolution as a result of isolation, mutation and natural selection

Question 15

what is a neutral mutation?

Answer 15

type of mutation whose genetic sequence differs from the original but which still codes for the functional protein