Exam 1

Question 1

What were Darwin & Wallace’s thoughts on evolution?

Answer 1

Species change over time based on select traits that provide an advantage in survival and reproduction (fitness)

Question 2

Descent with modification

Answer 2

New species form from the continued evolution of their ancestors based on selected traits

Question 3

How does the vastness of geologic time help prove the theory of evolution?

Answer 3

rock layers and fossils

Question 4

What are transitional features?

Answer 4

They link older and younger species by serving as a middle ground between the current anatomy of a population and the anatomy of its ancestors

Question 5

What are homologies?

Answer 5

a structure that is similar across species and is derived from a common ancestor

Question 6

Structural homology

Answer 6

Similarities in adult structures across species that are derived from a common ancestor

Question 7

Genetic homology

Answer 7

Similarities in genetic code across species that derive from a common ancestor

Question 8

plasticity

Answer 8

different phenotypic expressions of the same allele based on environmental factors

Question 9

directional selection

Answer 9

shifts the average expression of a trait in a population over to one extreme or the other

Question 10

stabilizing selection

Answer 10

selection against the extremes

Question 11

disruptive selection

Answer 11

favors BOTH of the extreme phenotypes

Question 12

what form of selection can be the first step in speciation?

Answer 12

disruptive

Question 13

what form of selection causes a loss of variation in the gene pool?

Answer 13

stabilizing

Question 14

balancing selection

Answer 14

no phenotype has a distinct advantage

Question 15

which form of selection maintains variation?

Answer 15

balancing

Question 16

frequency dependent selection

Answer 16

fitness depends on the rarity of the phenotype

Question 17

intersexual selection

Answer 17

mate choice

Question 18

intrasexual selection

Answer 18

competition for mates

Question 19

sexual dimorphism

Answer 19

differences between the sexes

Question 20

________ is the only evolutionary process that results in adaptation.

Answer 20

natural selection

Question 21

genetic drift

Answer 21

random events cause allele frequencies to fluctuate randomly from generation to generation

Question 22

what causes genetic drift?

Answer 22

sampling error

Question 23

Sampling error causes a loss of ______ and is more common in ______ populations.

Answer 23

heterozygosity, smaller

Question 24

founder effect

Answer 24

a few individuals get separated from the original group –> new population is started with a differing gene pool

Question 25

bottleneck effect

Answer 25

sudden change in environment drastically reduces the size of a population --> surviving alleles are a result of chance

Question 26

gene flow

Answer 26

movement of alleles between two separate populations

Question 27

What is the ultimate source of genetic variation?

Answer 27

mutation

Question 28

describe the biological species concept

Answer 28

-(a mechanism used to differentiate species) -a population (or a group of populations) that are reproductively isolated from other groups.

Question 29

describe the morphospecies concept

Answer 29

-(a mechanism used to differentiate species) -species are identified by differences in size, shape or other morphological features

Question 30

describe the phylogenetic species concept

Answer 30

-(a mechanism used to differentiate species) -identifies species based on the evolutionary history of populations

Question 31

monophyletic group

Answer 31

an ancestor + all the descendants

Question 32

synapomorphy (shared derived trait)

Answer 32

a trait that is found in certain groups of organisms + their common ancestors, but not in its more distant ancestors

Question 33

What are the two causes of speciation?

Answer 33

-genetic isolation -genetic drift: mutation, selection, and genetic drift in isolated populations cause divergence

Question 34

speciation

Answer 34

the process of creating a new species

Question 35

What are the two kinds of reproductive isolation?

Answer 35

-prezygotic isolation -postzygotic isolation: zygotes are formed, bot offspring do not survive or are infertile

Question 36

allopatry

Answer 36

when populations become geographically isolated

Question 37

what are the two kinds of allopatric speciation?

Answer 37

dispersal + vicariance

Question 38

describe allopatric speciation by dispersal

Answer 38

-a few individuals leave the main population -these individuals have a small portion of the genes in the original population -due to genetic drift, mutation, and selection they become 2 different species

Question 39

describe allopatric speciation by vicariance

Answer 39

-a chance event physically separates a population (can be fast or slow) -due to genetic drift, mutation, and selection they become 2 different species

Question 40

What were Plato's thoughts on evolution?

Answer 40

He thought everything was created and stayed exactly as it was

Question 41

What were Aristotle's thoughts on evolution?

Answer 41

He thought there was a hierarchy of organisms, with humans at the top

Question 42

What were Lamarck's thoughts on evolution?

Answer 42

He thought the actions of parents changed the traits of the offspring

Question 43

What are Darwin's postulates (conditions for evolution)?

Answer 43

1. individuals within species are variable 2. some of these variations are heritable 3. individuals that reproduce the most are the ones with the most favorable variations