Chapter 3: Speciation

Question 1

process of species splitting into two/more species

Answer 1

Speciation

Question 2

able to produce viable and fertile offspring

Answer 2

species

Question 3

for speciation to occur

Answer 3

a reproductive barrier is needed

Question 4

barrier that prevents species form mating (physical or non physical)

Answer 4

reproductive barrier

Question 5

a founder effect isolating population from the original can _____ odds of speciation a lot when natural selection occurs

Answer 5

increase

Question 6

based on biological species concept what is a species and what are the two kinds of reproductive isolation

Answer 6

species- able to create viable and fertile offsprings

Reproductive isolation prevents species from producing viable fertile offspring
types:
> Prezygotic barrier
> Postzygotic barriers

Question 7

reproductive barrier that prevents zygote from forming by:

> preventing different species from mating
preventing successful mating
preventing fertilization

Answer 7

Pre-zygotic barriers

Question 8

5 types of pre-zygotic barriers

Answer 8

Habitat, Temporal, Behavioral, Mechanical, Gametic isolation

Question 9

Pre-zygotic barrier where 2 species have different habitats

Answer 9

habitat isolation

Question 10

Pre-zygotic barrier where species breed at different times

Answer 10

Temporal isolation

Question 11

Pre-zygotic barrier where species have different behaviors (courtship rituals)

Answer 11

behavioral isolation

Question 12

Pre-zygotic barrier where physical (morphological) differences

Answer 12

Mechanical isolation

Question 13

Pre-zygotic barrier where fertilization don’t occur for two different species

Answer 13

gametic isolation

Question 14

3 types of Post-zygotic barriers

Answer 14

reduced hybrid variability, reduced hybrid fertility, hybrid breakdown

Question 15

post-zygotic barrier where hybrid is too weak and dies or isn’t alive

Answer 15

reduced hybrid viability

Question 16

post-zygotic barrier where hybrids are sterile

Answer 16

reduced hybrid fertility

Question 17

post-zygotic barrier where if not 1st gen hybrid then next generations of hybrids will be either weak/sterile

Answer 17

hybrid breakdown

Question 18

2 types of speciation

Answer 18

allopatric speciation
sympatric speciation

Question 19

speciation type where:
geographic isolation / physical barrier causes gene flow to be interrupted

ex: species in diff countries

Answer 19

allopatric speciation

Question 20

gene flow interrupted bc of other reasons that is not a physical barrier (reproductive barrier)
ex: same country

Answer 20

sympatric speciation

Question 21

3 ways Sympatric speciation occurs

Answer 21

polyploidy, habitat differentiation and sexual selection

Question 22

sympatric speciation where a random event that leads to extra sets of chromosomes bc of cell division accidents

ex plants can be isolated bc of this (w/out physical barrier) and they can only reproduce successfully by self pollination or by reproducing with other plants that went through the same thing

Answer 22

polyploidy

Question 23

sympatric speciation where new species are born when ancestral species split up into 2 different habitats (bc new ecological niches) and evolved separately

Answer 23

habitat differentiation

Question 24

sympatric speciation which is also a form of natural selection where individuals are so picky when choosing a mate and the cycle continues with their offsprings enough for speciation to occur

Answer 24

sexual selection

Question 25

another term for reproductive barrier

Answer 25

reproductive isolation

Question 26

an area which members of different species mate and produce hybrids

Answer 26

Hybrid zone

Question 27

3 possible outcomes for hybrid zone

Answer 27

Reinforcement, Fusion, Stability

Question 28

hybrid is less fit than parent species, strengthening of reproductive barriers, divergence between species continues

Answer 28

Reinforcement of hybrid zone

Question 29

hybrid is more fit than both parent species, weakening of reproductive barriers, two species become one

Answer 29

Fusion of hybrid zone

Question 30

fit hybrids continue to be produced and no significant change to bariers

Answer 30

Stability of hybrid zone

Question 31

Rates of speciation

Answer 31

speciation can occur rapidly or slowly and can result from changes in few or a lot of genes

genetic mutation precedence of natural selection

Question 32

Gradual Pattern VS Punctuated Equilibrium

(Speciation rates: can be 4,000 yrs - 40,000, 000 yrs)

Answer 32

Punctuated speciation - occurs rapidly (suggested with fossil records)

theory of gradual pattern/gradualism - is constant and consistent change over long period of time w/out sudden development.