6.2 speciation

Question 1

what is speciation?

Answer 1

speciation is the splitting of a genetically similar population into two or more populations leading to genetic differentiation and is no longer able to interbreed and produce fertile offspring

Question 2

what is formed when speciation occurs?

Answer 2

a new species is formed when speciation occurs

Question 3

what are sub-species?

Answer 3

sub-species are populations which are different but are still able to interbreed

Question 4

what changes leads to a new species being formed?

Answer 4

sufficient genetic, behavioural and physiological changes in the population so they can no longer interbreed produces a new species

Question 5

what are the two main types of isolation mechanisms?

Answer 5

the two main types of isolating mechanisms are geographical isolation and reproductive isolation

Question 6

when does geographical isolation occur?

Answer 6

geographical isolation occurs when physical barriers divide a population

Question 7

what are examples of physical barriers that lead to geographical isolation?

Answer 7

examples of physical barriers that lead to geographical isolation include lakes, rivers, oceans and mountains

Question 8

what may the genetic changes be a result of when geographical isolation occurs?

Answer 8

genetic changes may be a result of mutation, selection and genetic drift

Question 9

what type of speciation is geographical isolation?

Answer 9

geographical isolation is a type of speciation called allopatric speciation

Question 10

what does allopatric mean?

Answer 10

allopatric means in different countries

Question 11

what is an example of a population that has undergone allotropic speciation?

Answer 11

finches have undergone allotropic speciation where the head shape of some species are different

Question 12

what is reproductive isolation?

Answer 12

reproductive isolation is where changes in the population prevents interbreeding

Question 13

what changes may cause reproductive isolation?

Answer 13

changes which may cause reproductive isolation include biological, behavioural and genetic changes

Question 14

what is an example of a behavioural change which may lead to reproductive isolation?

Answer 14

some organisms of a population may change their foraging behaviour and become active at dawn, dusk or at night than during the day then they are unlikely to interbreed with members of the other populations

Question 15

what is example of a genetic change that can also need to reproductive isolation?

Answer 15

an example of a genetic change that can also lead to reproductive isolation is a change in the chromosome number

Question 16

what may a change in the chromosome number of a population lead to?

Answer 16

a change in the chromosome number may:

• prevent gamete fusion
• make the zygotes less visitor, so they fail to develop
• lead to infertile hybrid offspring with an odd number of chromosomes, so that chromosomes pairing during meiosis cannot occur

Question 17

what may the mating between members of the reproductively isolated population also be prevented by?

Answer 17

the mating between members of the reproductively isolated populations may also be prevented by mutations

Question 18

what do mutations lead to changes in?

Answer 18

mutations may lead to changes in:

• courtship behaviour
• animal genitalia or plant flower structure

Question 19

what is speciation resulting from reproductive isolation called?

Answer 19

speciation resulting from reproductive isolation is called sympatric speciation

Question 20

what does sympatric mean?

Answer 20

sympatric means in the same country