Exam 1

Question 2

What are the three factors of Natural Selection?

Answer 2

1. variation in a trait
2. heritable trait
3. differences in fitness

Question 3

What are the two theories of evolution?

Answer 3

macroevolution and microevolution

Question 4

Macroevolution

Answer 4

evolution as a pattern
-fossile record
- think of evolution as descent with modification
ex. pattern of bones

Question 5

microevolution

Answer 5

evolution as a process
- changes is allele frequencies
-proportions of a population

Question 6

What are the three factors that are used as evidence of evolution?

Answer 6

1. Direct evolutions
2. Homology
3. Fossil record

Question 7

Direct evolutions

Answer 7

example the soapberry bug: difference of beak length in different locations

Question 8

homology

Answer 8

evolution as a process of decent of modification and ancestral traits are altered by natural selection over time (bones in the bat, whale, and human)

Question 9

Fossil record

Answer 9

documents gradual change through time

Question 10

what are the forces of evolution?

Answer 10

1. mutation
2. natural selection
3. genetic drift
4. gene flow

Question 11

Mutation

Answer 11

-random changes in DNA; can be beneficial, neutral, or harmful
-ultimate source of variation

Question 12

Natural selection

Answer 12

only force that leads to adaptations

Question 13

Genetic Drift

Answer 13

ALWAYS OCCURRING
-random changes in the frequency in the trait over time (can greatly impact small populations)
-force of genetic drift; fixation=allele frequency becomes 100%

Question 14

Gene flow

Answer 14

-migration that is purposeful
- An individual that changes allele frequencies
- can lead to patterns that differ than we expect by natural selection

Question 15

Fixation

Answer 15

allele frequency becomes 100% due to genetic drift

Question 16

speciation

Answer 16

process of species splits into two

Question 17

what is the link between microevolution and macroevolution?

Answer 17

speciation

Question 18

What are the Pre-zygotic barriers

Answer 18

geographical isolation
behavioral isolation
temporal isolation

Question 19

pre-zygotic

Answer 19

mechanisms prevent fertilization

Question 20

Post-zygotic

Answer 20

prevent a hybrid

Question 21

Geographical isolation

Answer 21

a geographic feature separating species

Question 22

Behavioral isolation

Answer 22

behaviors that prevent reproduction of different species

Question 23

Temporal Isolation

Answer 23

species can’t reproduce together b/c they reproduce at different times

Question 24

Post-zygotic barriers

Answer 24

Reduced hybrid viability
Reduced hybrid fertility
Hybrid breakdown

Question 25

What are the ecological contexts of speciation?

Answer 25

Allopatric and sympatric speciation

Question 26

Allopatric speciation

Answer 26

gene flow is restricted when a population is divided into 2 and geographically isolated

Question 27

Sympatric speciation

Answer 27

occurs in populations that live in the same geographical location; gene flow must be restricted by another mechanism

Question 28

Is speciation instantaneous?

Answer 28

no it takes billons

Question 29

stabilizing selection

Answer 29

form of selection in which individual with average (intermediate phenotypes are more fit)

Question 30

Directional selection

Answer 30

form of natural selection on which an extreme phenotype is favored

Question 31

Diversifying selection

Answer 31

form of natural selection which favors extreme values for a trait over intermediate values

Question 32

What is used as evidence for phylogenic trees?

Answer 32

molecular and morphigical

Question 33

molecular evidence

Answer 33

comparing nucleotide frequencies to view changes; assumptions is fewer difference the more closely related

Question 34

morphological evidence

Answer 34

powerful independent source pf evidence for testing

Question 35

what is the only evolutionary force that can be used to explain the match between traits and the environment?

Answer 35

natural selection

Question 36

root

Answer 36

represents ancestor that all lineages share

Question 37

tips

Answer 37

represent organisms; each tip a major group of organisms

Question 38

how does evolutionary flow on a phylogenic tree?

Answer 38

from root to tips

Question 39

node

Answer 39

the most common ancestor that all lineages on the tree have in common

Question 40

out-group

Answer 40

distantly related group of organisms; serves as a refrence

Question 41

sister taxa

Answer 41

share an immediate common ancestor