speciation

Question 1

what is speciation

Answer 1

process by which one species splits into 2+ species

Question 2

(T/F) Speciation links microevolutionary processes with macroevolutionary patterns

Answer 2

T

Question 3

at what point does speciation occur?

Answer 3

when 2 taxa cannot form fertile hybrids

Question 4

what is the biological species concept (BSC)

Answer 4

biological species are groups that actually/potentially interbreed and produce fertile offspring in nature

Question 5

what is reproductive isolation

Answer 5

biological features that reduce/prevent gene exchange with members of other groups
–> result of reproductive barriers

Question 6

advantages of BSC

Answer 6

biologically relevant: lack of gene exchange is yardstick for species status

Question 7

disadvantages of BSC

Answer 7

• can’t be applied to asexual taxa/fossils
• hard to assay reproductive battiers
• many ‘good species’ exchange genes with natural selection maintaining divergence

Question 8

what is morphological species concept

Answer 8

defines species based on morphological similarity

Question 9

wwhat is ecological species concept?

Answer 9

defines species based on ecological niche (physical/environmental conditions it requires)

Question 10

what are the 2 kinds of reproductive barriers

Answer 10

prezygotic: prevents attempted mating from being successful

postzygotic: reduces survival/reproductive success of hybrids

Question 11

what are the prezygotic barriers before mating

Answer 11

• habitat isolation
• temporal isolation
• behavioural isolation

Question 12

what are prezygotic barriers after mating?

Answer 12

• mechanical isolation
• gametic isolation

Question 13

what are the kinds of postzygotic barriers

Answer 13

• genetic incompatibilities
• ecologically-dependent postzygotic isolation –> reduction in fitness due to mismatch between phenotype and environment

Question 14

what is allopatric speciation

Answer 14

when gene flow is interrupted by an extrinsic barrier and populations evolve independently

Question 15

what is sympatric speciation

Answer 15

speciation in the abscence of any barrier
–> requires gene flow between groups to be reduced by some factor
–> thought to involve evolution of prezygotic barriers that prevent mating

Question 16

what are the mechanisms of speciation

Answer 16

• ecological
• polyploidization
• reinforcement of prezygotic barrier

Question 16

wha

Question 17

what is ecological speciation

Answer 17

reproductive isolation arises as by-produce of adaption to different environments/niches

Question 18

what is divergent natural selection

Answer 18

natural selection differs in each population due to unique biotic/abiotic environments they inhabit

Question 19

what is polyploidization

Answer 19

increase in the # of whole sets of chromosomes

Question 20

what are the 2 kinds of polyploidization

Answer 20

autopolyploid: individual with more than 2 chromosome sets derived from a SINGLE species

allopolyploid: individual with more than 2 chromosome sets derived from DIFFERENT species

Question 21

what are the ways speciation can be studied

Answer 21

• lab studies
• speciation in nature

Question 22

what is experimental evolution

Answer 22

technique in which multiple replicate populations are derived from a common ancestor
–> evolution is tracked under controlled conditions

Question 23

what is ecologically-dependent posyzygotic isolation

Answer 23

occurs when hybrid fitness is reduced bc of mismatch of phenotype with environment