Chapter 24

Question 1

speciation

Answer 1

process when i species splits into two or more species

Question 2

Biological Species Concept

Answer 2

species is a group of populations whose members can interbreed in nature and produce viable, fertile offspring

do not breed successfully with other populations

Question 3

What does gene flow between a population do?

Answer 3

holds the phenotype of a population together

Question 4

reproductive isolation

Answer 4

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

Question 5

hybrid

Answer 5

offspring of crosses between different species

Question 6

2 types of reproductive isolation

Answer 6

pre-zygotic barriers

post-zygotic barriers

Question 7

pre-zygotic barriers

Answer 7

block fertilization from occurring

Question 8

how do pre-zygotic barriers block fertilization from occuring?

Answer 8

impeding different species from attempting to mate

preventing the successful completion of mating

hindering fertilization if mating is successful

Question 9

post-zygotic barriers

Answer 9

prevent the hybrid zygote from developing into a viable, fertile adult

Question 10

how do post-zygotic barriers prevent hybrids from developing into a viable, fertile adult?

Answer 10

reducing hybrid viability
reducing hybrid fertility
hybrid breakdown

Question 11

what are 2 ways in which speciation occurs?

Answer 11

allopatric speciation

sympatric speciation

Question 12

allopatric speciation

Answer 12

gene flow is interrupted or reduced when a population is geographically divided into subpopulations

Question 13

sympatric speciation

Answer 13

speciation takes place in geographically overlapping populaitons

Question 14

what are 3 types of symatric speciation?

Answer 14

polyploidy
habitat differentiation
sexual selection

Question 15

polyploidy

Answer 15

presence of extra sets of chromosomes due ti accidents during cell division

Question 16

habitat differentiation

Answer 16

appearance of new ecological niches

Question 17

hybrid zone

Answer 17

regions in which members of different species mate and produce hybrids

Question 18

offspring produced in the hybrid zone have..?

Answer 18

reduced fitness

Question 19

when closely related species meet in a hybrid zone, what are the 3 outcomes?

Answer 19

strengthening of reproductive barriers
weakening of reproductive barriers
continued formation of hybrid individuals

Question 20

when doe reinforcment of barriers occur?

Answer 20

when hybrids are less fit then the parent species

Question 21

reinforcement of barriers

Answer 21

reproductive barriers should be stronger for sympatic than allopatric species

Question 22

fusions

Answer 22

weakens reproduction barriers

if hybrid is as fit as the parent, there can be substantial gene flow between species