Chapter 14: What are Species?

Question 1

define speciation

Answer 1

process by which one species splits into two or more species

Question 2

What accounts for both the unity and diversity of life?

Answer 2

speciation

Question 3

describe the biological species concept

Answer 3

a species is a group of populations whose members can interbreed (produce fertile offspring) with each other but not with members of other species

Question 4

which concept emphasizes reproductive isolation?

Answer 4

biological species concept

Question 5

describe the morphological species concept

Answer 5

based on observable physical traits and can be applied to asexual organisms and fossils

Question 6

describe the ecological species concept

Answer 6

defines a species by its ecological niche and focuses on unique adaptations to a biological community

Question 7

describe the phylogenetic species concept

Answer 7

defines a species as the smallest group of individuals that share a common ancestor forming one branch of the tree of life

Question 8

What keeps species separate?

Answer 8

reproductive barriers

Question 9

purpose of reproductive barriers…

Answer 9

1. serve to isolate gene pools of species

2. prevent interbreeding

Question 10

How are reproductive barriers categorized?

Answer 10

as prezygotic and postzygotic

Question 11

examples of prezygotic barriers include…

Answer 11

• habitat isolation
• temporal isolation
• behavioral isolation
• mechanical isolation
• gametic isolation

Question 12

habitat isolation is the…

Answer 12

lack of opportunities to encounter each other

Question 13

behavioral isolation refers to…

Answer 13

different courtship rituals

Question 14

mechanical isolation refers to…

Answer 14

physical incompatibility of reproductive parts

Question 15

gametic isolation refers to…

Answer 15

the molecular incompatibility of eggs and sperm or pollen and stigma

Question 16

examples of postzygotic barriers

Answer 16

• reduced hybrid viability
• reduced hybrid fertility
• hybrid breakdown

Question 17

reduced hybrid viability refers to

Answer 17

the hybrid development/ survival impaired by interaction of parental gametes

Question 18

reduced hybrid fertility refers to..

Answer 18

the vigorous hybrids that cannot produce viable offspring

Question 19

hybrid breakdown refers to…

Answer 19

viable and fertile hybrids with feeble or sterile offspring

Question 20

define allopatric speciation

Answer 20

the interruption of gene flow between populations caused by physical/ geographical isolation

Question 21

How do reproductive barriers arise?

Answer 21

environment of isolated population may include different foods, pollinators, predators

Question 22

define sympatric speciation

Answer 22

a new species arises within the same geographical area as the parent species

Question 23

What can lead to sympatric and allopatric speciation?

Answer 23

habitat differentiation and sexual selection

Question 24

define polyploidy

Answer 24

duplication of the chromosome number due to errors in cell division

Question 25

many plant species have evolved through

Answer 25

polyploidy

Question 26

How does the development of polyploidy species happen?

Answer 26

• within a single species

- through hybirdization

Question 27

what leads to speciation?

Answer 27

sexual selection

Question 28

biologist can test hypothesis about the process of speciation by

Answer 28

studying species that arose recently

Question 29

what has been an important part of the diversification of cichlids in Lake Victoria?

Answer 29

sexual selection

Question 30

define adaptive radiation

Answer 30

evolution of diverse species from a common ancestor

Question 31

what has lead to adaptive radiations of species?

Answer 31

-repeated isolation
-recolonization
speciation

Question 32

define hybrid zones

Answer 32

regions in which population of different species overlap and produce a hybrid offspring

Question 33

what happens when separated population of closely related species come back into contact with one another?

Answer 33

hybrid zone occurs

Question 34

3 types of hybrid zones

Answer 34

1. reinforcement
2. fusion (collapse)
3. stability

Question 35

describe reinforcement

Answer 35

–

Question 36

describe fusion

Answer 36

bright colored stripped fish + black/white stripped fish = dull colored stripped fish

Question 37

describe stability

Answer 37

–

Question 38

what are the 2 models for the rate of speciation?

Answer 38

1. punctuated equilibria

2. gradualism

Question 39

define punctuated equilibria

Answer 39

evolutionary pattern where species change the most from ancestors and then very little for the rest of their lives

Question 40

define gradualism

Answer 40

evolutionary pattern where species evolve in a dispersed manner throughout generations (slight changes)