Macroevolution

Question 1

Define species

Answer 1

related organisms that maintain distinct set of traits in nature

Question 2

What is a species concept?

Answer 2

approach to distinguish one species from another

Question 3

Morphological Species Concept

Answer 3

based on physical characteristics

pros: applied to asexual organisms and extant and extinct organisms
cons: variation, sexual dimorphism

Question 4

Ecological Species Concept

Answer 4

occupies an ecological niche

pros: applied to asexual organisms and extant and extinct organisms
cons: variation within species, niches are difficult to define

Question 5

Phylogenetic Species Concept

Answer 5

described as the smallest group of organisms that share a common ancestor

pro: applied to asexual organisms and extant and extinct organisms
cons: variation

Question 6

Biological Species Concept

Answer 6

based on potential to interbreed

pro: easy to define, easy to measure
cons: cannot be applied to asexual organisms and extant and extinct organisms

Question 7

Requirements for Speciation

Answer 7

1. Microevolution

2. Reproductive Isolation

Question 8

Reproductive Isolating Mechanisms

Answer 8

1. Prezygotic Isloating mechanism

2. Postzygotic Isolating mechanism

Question 9

Habitat Isolation

Answer 9

Prezygotic; occurs due to a geographic barrier or habitat choice that prevents contact

Question 10

Temporal Isolation

Answer 10

Prezygotic; reproduce at different times (day/year)

Question 11

Behavioral Isolation

Answer 11

Prezygotic; traits associated with mate choice (song)

Question 12

Mechanical Isolation

Answer 12

Prezygotic; morphological features prevent successful mating

Question 13

Gametic Isolation

Answer 13

Prezygotic; gametes fail to unite (fertilization unsuccessful)

Question 14

Hybrid Inviability

Answer 14

Postzygotic; eggs fertilized but impaired embryonic development or survival in environment

Question 15

Hybrid Sterility

Answer 15

Postzygotic; interspecies hybrid is viable, but sterile

Question 16

Hybrid Breakdown

Answer 16

Postzygotic; hybrids viable and fertile, but subsequent generations have decreased fitness

Question 17

Modes of Speciation

Answer 17

1. Allopatric Speciation

2. Sympatric Speciation

Question 18

Allopatric Speciation

Answer 18

geographic barrier impedes interbreeding between populations (canyon); population could move to a new geographic region; split into 2 populations; raised isolated in different environments; merged populations=assortative mating

Question 19

Sympatric Speciation

Answer 19

no geographic barrier impedes gene flow between populations

1. Polyploidy–> chromosomal alteration in which an individual possesses more than 2 chromosome sets
2. Habitat Differentiation–> populations diverge due to adaptations (habitat isolation or temporal isolation)
3. Sexual Selection–> reproductive isolation results from divergence in mate choice (behavioral isolation)

Question 20

Hybrid Zone

Answer 20

region where 2 species produce hybrids

Question 21

Gradualism

Answer 21

new species evolve continuously through time

Question 22

Punctuated equilibrium

Answer 22

species remain unchanged for many generations punctuated by rapid periods of change