unit 7b

Question 1

speciation

Answer 1

process by which one species splits into two species

Question 2

microevolution

Answer 2

changes in allele frequency in population over time

Question 3

macroevolution

Answer 3

broad patterns of evolutionary change above species level

Question 4

biological species concept

Answer 4

members of group of populations of a species
- can interbreed
- produce viable fertile offspring
- don’t produce viable offspring w members of other groups
- gene flow between populations hold a species tg genetically

Question 5

reproductive isolation

Answer 5

when biological barriers impede members of two species from interbreeding and producing viable offspring

Question 6

prezygotic barriers

Answer 6

block fertilization from occuring by
- impeding different species from attempting to mate
- preventing successful mating
- hindering fertilization if mating’s successful

Question 7

temporal isolation (prezygotic barrier)

Answer 7

species that breed different times of day/seasons/years can’t mix gametes

Question 8

mechanical isolation (prezygotic barrier)

Answer 8

mating’s attempted but morphological differences prevent its success

Question 9

gametic isolation (prezygotic barrier)

Answer 9

sperm of one species can’t fertilize eggs of another species

Question 10

postzygotic barriers

Answer 10

prevent hybrid zygotes from developing into viable, fertile adults through
- reduced hybrid viability
- reduced hyrid fertility
- hybrid breakdown

Question 11

reduced hybrid viability (postzygotic barrier)

Answer 11

genes of different parent species may interact in ways that impair hybrid’s development/survival

Question 12

reduced hyrid fertility (postzygotic barrier)

Answer 12

meiosis may fail to produce normal gametes, resulting in sterility, if the parent species have chromosomes of different number/structure

Question 13

hybrid breakdown (postzygotic barrier)

Answer 13

first-gen hybrids are viable and fertile, but offspring in next gen aren’t

Question 14

allopatric speciation

Answer 14

gene flow is interrupted when a population is divided into geographically isolated subpopulations

Question 15

sympatric speciation

Answer 15

occurs in populations that live in same geographic area
occurs if gene flow is reduced by factors such as
- polyploidy
- sexual selection
- habitat differentiation

Question 16

polyploidy

Answer 16

presence of extra sets of chromosomes

Question 17

autopolyploids

Answer 17

more than two sets of chromosomes, all derived from a single species

Question 18

allopolyploids

Answer 18

more than two sets of chromosomes, all derived from different species

Question 19

hybrid zone

Answer 19

region in which members of different species mate and produce hybrid offspring

Question 20

sister taxa

Answer 20

groups that share a common ancestor that’s not shared by any other group

Question 21

rooted tree

Answer 21

includes a branch to represent the most recent common ancestor of all taxa in the tree

Question 22

basal taxon

Answer 22

lineage that diverges from all other members of the group early in the history of the group

Question 23

homologies

Answer 23

phenotypic and genetic similarities due to shared ancestry

Question 24

analogy

Answer 24

similarity due to convergent evolution

Question 25

monophyletic groups

Answer 25

ancestor and all of its descendants - clades

Question 26

paraphyletic groups

Answer 26

ancestral species and some, not all, of the descendants

Question 27

polyphyletic groups

Answer 27

distantly related species but not their most recent common ancestor

Question 28

shared ancestral character

Answer 28

character that originated in an ancestor of the taxon

Question 29

shared derived character

Answer 29

evolutionary novelty unique to particular clade

Question 30

maximum parsimony

Answer 30

assumes that most likely tree is the one that requires the fewest evolutionary events