Ch 24: Origin of Species

Question 1

What is the biological concepts?

Answer 1

a population or populations of organisms that are capable, or potentially capable of interbreeding with one another. Results of matings produce viable, fertile offspring.

Question 2

What is reproductive isolation?

Answer 2

is the existence of biological factors (barriers) that impede two species from producing viable, fertile offspring

Question 3

What are hybrids?

Answer 3

the offspring of crosses between different species (ex. donkey + horse = mule)

Question 4

What are prezygotic reproductive barriers?

Answer 4

prevent or reduce the probability of mating ot fertilization

Question 5

What are the four examples of prezygotic reproductive barriers?

Answer 5

habitat isolation, behavioral isolation, mechanical isolation, and temporal isolation

Question 6

What is habitat isolation?

Answer 6

members of two populations evolve two different habitat preferences

Question 7

What is behavioral isolation?

Answer 7

populations of one species evolve different courtship behaviors

Question 8

What is mechanical isolation?

Answer 8

incompatibility of body structures which prevents mating

Question 9

What is temporal isolation?

Answer 9

different timing of reproductive events

Question 10

What are postzygotic reproductive barriers?

Answer 10

inability of hybrid zygotes to develop into a viable, fertile adult

Question 11

What are the three examples of postzygotic reproductive barriers?

Answer 11

reduced hybrid viability, reduced hybrid fertility, and hybrid breakdown

Question 12

What is reduced hybrid viability?

Answer 12

the offspring dies quickly

Question 13

What is reduced hybrid fertility?

Answer 13

the offspring are fertile

Question 14

What is hybrid breakdown?

Answer 14

low-quality offspring

Question 15

What are the limitations of the biological species concept?

Answer 15

the biological species concept is difficult to apply to asexually reproducing organisms and situations where gene flow does occur between populations of distinct species

Question 16

What are the three alternatives to the biological species concept?

Answer 16

morphological species concept, ecological species concept, and phylogenetic species concept

Question 17

What is allopatric speciation?

Answer 17

populations become isolated from one another due to separation by a geographical barrier

Question 18

What is sympatric speciation?

Answer 18

genetic isolation occurs without geographic isolation. Genetic isolation occurs as a result of “accidents” during cell division (ex autoploidy and allopalyploidy)

Question 19

What is polyploidy?

Answer 19

presence of extra sets of chromosomes due to accidents during cell division (much more common in plants than in animals)

Question 20

What is autoploidy?

Answer 20

an individual with more than two chromosomes sets, derived from a single species

Question 21

What is allopolyploid?

Answer 21

a species with multiple sets of chromosomes derived from different species

Question 22

What is a hybrid zone?

Answer 22

region where members of different species mate and produce hybrids

Question 23

What are the three possible outcomes of a hybrid zone?

Answer 23

strengthening of reproductive barriers, weakening of reproductive barriers, and continued formation of hybrids

Question 24

What is punctuated equilibrium?

Answer 24

speciation characterized by periods apparent stasis punctuated by sudden change