Lecture 23B and 23C

Question 1

speciation

Answer 1

formation of distinct species by genetic divergence leading to reproductive isolation

Question 2

what is the first steep of speciation

Answer 2

*genetic isolation due to separation in space time or behavior(allopatric or sympatric)

Question 3

what is the second step of speciation

Answer 3

genetic makeup of each population changes through selection, genetic drift, or mutation

Question 4

What is the third step speciation

Answer 4

reproductive isolating mechanisms evolve (results in a new species)

Question 5

can speciation still occcur if without spatial separation?

Answer 5

yea! it would be sympatric speciation meaning: they evolve without a geographic barrier

Question 6

what’s the most common mode of speciation in animals?

Answer 6

allopatric speciation(population becomes geographically divided)

Question 7

what can drive sympatric speciation

Answer 7

polyploidy
behavioral isolation
ecological specialization
temporal isolation

Question 8

what can drive allopatric speciation

Answer 8

geographic barriers
dispersal
vicariance
adaptive divergence
founder effect
differential selection pressures

Question 9

in allopatric speciation evolution can proceed independently through

Answer 9

mutation
genetic drift
natural selection
sexual selection

Question 10

vicariance

Answer 10

physical splitting of a habitat

Question 11

sympatric speciation

Answer 11

speciation without geographic separation

Question 12

1st step to sympatric speciation

Answer 12

individuals coexisting

Question 13

2nd step to sympatric speciation

Answer 13

mutation occurs that restricts or stops gene flow

Question 14

3rd step to sympatric speciation

Answer 14

2 populations are isolated in sympatry

Question 15

the initial gene flow in sympatric speciation is

Answer 15

biological:
-genetic(chromosomal change, aneuploidy resulting in nondisjunction)

-ecological(host shift)

-behavioral( changes in mate preferences)

Question 16

sympatric

Question 17

sympatric speciation by autopolyploidy occurs when there are

Answer 17

errors in meiosis

Question 18

Errors during meiosis causes

Answer 18

extra sets of chromosomes in khanates and offspring(polyploidy)

Question 19

Prezygotic Isolating Mechanisms

Answer 19

prevent mating and or fertilization

Question 20

posyzygotic isolating mechanisms

Answer 20

fertilization occurs but hybrid fails to reproduce or live

Question 21

prezygotic isolating barriers

Answer 21

behavioral, ecological/spatial, temporal, mechanical, gametic

Question 22

PRZI- behavioral

Answer 22

species use different courtship signals

Question 23

PRZI- ecological/spatial

Answer 23

species live in same area but use different habitats so they rarely encounter eachother

Question 24

PRZI- temporal

Answer 24

species breed at different times

Question 25

PRZI-mechanical

Answer 25

anatomical differences between individuals prevent mating

Question 26

PRZI-gametic

Answer 26

gametes of two species meet, but do not fuse

Question 27

POSTZY: hybrid incompatibility/and inavailability

Answer 27

hybrid embryos die

Question 28

POSTZY: Hybrid sterility

Answer 28

offspring lives but unable to reproduce

Question 29

what are the favorite that determine how fast a new species can form

Answer 29

*gene-flow *size of geographic barrier separating two populations *dispersal *natural selection *size of populations

Question 30

what’s the average time required for speciation

Answer 30

2 to 3 million years

Question 31

new species more commonly form instantaneously in

Answer 31

plants

Question 32

Adaptive radiation

Answer 32

fast speciation

Question 33

describe the two types of adaptive radiations

Answer 33

1) single ancestral species rapidly diversified jnto many descendant species 2) descendant species diverge into genetically different forms that occupy diff habitats