evolution of species 3.6

Question 1

mutation

Answer 1

a random change to genetic material, they are spontaneous and are the only source of new allele

Question 2

what could the change in genetic material be

Answer 2

the number or types of bases found in DNA or the number or length of chromosomes

Question 3

mutant

Answer 3

if the change in the genotype result in a change in phenotypes

Question 4

types of mutations

Answer 4

neutral, advantageous and disadvantageous

Question 5

neutral

Answer 5

results in a protein which doesn’t affect the organisms, eg: many silent mutations

Question 6

advantageous

Answer 6

results in a protein which confers in an advantage on the organisms, eg: 6 fingers

Question 7

disadvantageous

Answer 7

the mutation results in a protein which confers a disadvantage in an organisms, eg: cystic fibrosis

Question 8

mutagenic agents

Answer 8

environmental factors which increase the chance of mutations occurring

Question 9

examples of mutagenic agents

Answer 9

ionising radiation, UV radiation and chemical mutagens (mustard gas)

Question 10

variation

Answer 10

within a population makes it possible for a population to evolve over time in response to changing environmental conditions

Question 11

adaptation

Answer 11

an inherited characteristic that makes an organism well suited to survival in it’s environment or niche

Question 12

the types of adaptation

Answer 12

structural and behavioural

Question 13

selection pressures

Answer 13

• every species produces far more offspring that the environment can sustain
• this often leads to many offspring dying before reaching reproductive age

Question 14

things that lead to selection pressure

Answer 14

competition, lack of food, overcrowding, predation and disease

Question 15

natural selection

Answer 15

when the best adapted individuals in a population survive to reproduce, passing on the favourable alleles that confer the selective advantage and the offspring who’s phenotypes are least well suited to the environment die before reproductive age

Question 16

speciation

Answer 16

the process of the formation of a new species

Question 17

the stages of speciation

Answer 17

1) isolation
2) mutation
3) natural selection

Question 18

isolation in speciation

Answer 18

species become cut off from the other members of the species for a very long time or permanently by an isolation barrier

Question 19

different isolation barriers

Answer 19

geographical
-mountains and rivers

ecological
-different habitats including temperature, pH or humidity

behavioural
-different breeding seasons

Question 20

mutation in speciation

Answer 20

different mutations occur in each sub-population and any new variations which arise in one group is not shared by the other group

Question 21

natural selection in speciation

Answer 21

natural selection selects for different mutations in each group, due to different selection pressures and each sub-population evolves until they become so genetically different that they are two different species, therefore they can not interbreed successfully