Chap 12 Forces of Evolutionary Change

Question 1

Evolution occurs in…?

Answer 1

populations

Question 2

Evolution does not occur in…?

Answer 2

individuals

Question 3

Why does evolution not occur in individuals?

Answer 3

because an individuals alleles do not change

Question 4

In a population what changes from one generation to the next?

Answer 4

allele frequencies (some become more common, some less common)

Question 5

Whose voyage provided evidence for evolution?

Answer 5

Darwin’s

Question 6

What were the ideas of evolution Darwin came up with?

Answer 6

descent with modification

natural selection

Question 7

What changes allele frequencies?

Answer 7

artificial selection

Question 8

What gave Darwin the idea for natural selection as an evolutionary force?

Answer 8

artificial selection/selective breeding

Question 9

How do humans alter allele frequencies?

Answer 9

artificially

Question 10

What happens in artificial selection?

Answer 10

a human chooses desired features, then allows only the individuals that best express those qualities to reproduce. This increases the frequency of the desired alleles in the population

Question 11

Darwin proposed what as a mechanism for evolution?

Answer 11

natural selection

Question 12

What were the observations of nature?

Answer 12

genetic variation
limited resources
overproduction of offspring

Question 13

What were the inferences from observations?

Answer 13

struggle for existence

unequal reproductive success (natural selection)

descent with modification

Question 14

What is descent with modification?

Answer 14

over many generations, a population’s characteristics can change by natural selection, even giving rise to new species

Question 15

What is overproduction of offspring?

Answer 15

more individuals are born than survive to reproduce

Question 16

What are the common misconception of evolution theory?

Answer 16

explains the origin of life

it is a random process

in all changing environments all individuals in a population simultaneously develop beneficial adaptations

Question 17

What is the answer to the misconception that biological evolution explains the origin of life?

Answer 17

biological evolution did not begin until life existed

Question 18

What is the answer to the misconception that evolution is a random process?

Answer 18

some mechanisms of evolution, such as mutations, do occur randomly. Natural selection, however, is nonrandom because the environment selects against poorly adapted individuals.

Question 19

What is the answer to the misconception that in all changing environments all individuals in a population simultaneously develop beneficial adaptations?

Answer 19

adaptations become “fixed” in a population over multiple generation, as individuals with beneficial adaptations are most likely to survive, reproduce, and pass their genes to the next generation

Question 20

What molds evolution?

Answer 20

Natural selection

Question 21

Natural selections doe not…?

Answer 21

create alleles (instead, it strongly selects for alleles that arise by chance)

Question 22

What enhances reproductive success?

Answer 22

adaptations

Question 23

What are adaptations?

Answer 23

heritable features that improve an organism’s ability to survive and reproduce (e.g. some people produce more gametes than others)

Question 24

What does not constitute evolution?

Answer 24

short-term changes in an individual

Question 25

What creates natural selection for resistant bacteria?

Answer 25

antibiotics (bacteria that are resistant to antibiotics have an adaptive trait that nonresistant bacteria lack. When antibiotics are present, the resistant bacteria can survive and reproduce better then the others)

Question 26

What eliminates poorly adapted phenotypes?

Answer 26

natural selection (as environmental conditions change, the phenotypes that natural selection favors will also change. Adaptations that seem "perfect" in one environment would be completely wrong in another)

Question 27

What can eliminate entire species?

Answer 27

natural selection

Question 28

How can natural selection eliminate entire species?

Answer 28

if the right alleles aren't available at the right time, an environmental change may wipe out a species

Question 29

Evolution does not have a what?

Answer 29

goal (an orchid and wasp pollinator have evolved along side each other. But the orchid does not evolve in order to be better-pollinated by the wasp. the wasps created a selective advantage for orchids with just the right shape for wasps)

Question 30

What is fitness?

Answer 30

reproductive success

Question 31

By itself, what is not enough for evolutionary fitness?

Answer 31

survival

Question 32

Fitness depends on what?

Answer 32

the ability to reproduce (the organism's genetic contribution to the next generation)

Question 33

What is unavoidable?

Answer 33

evolution

Question 34

Why is evolution unavoidable?

Answer 34

in real populations, allele frequencies will inevitably change over time because they are affected by so many selective forces

Question 35

Can scientists test evolution?

Answer 35

yes

Question 36

How do scientists test evolution?

Answer 36

test evolution and measure allele frequencies do or do not change from one generation to the next

Question 37

What doe Hardy-Weinberg equilibrium rely on?

Answer 37

assumption about the population

Question 38

What assumptions need to be met for a population to be at Hardy-Weinberg equilibrium?

Answer 38

``` random mating no migration no genetic drift no mutation no natural selection (basically the allele frequencies do not change) ```

Question 39

We can calculate what?

Answer 39

allele and genotype frequencies

Question 40

What must be met to get equations representing the relationship between allele frequencies and genotype frequencies?

Answer 40

Hardy-Weinberg equilibrium

Question 41

What always changes?

Answer 41

allele frequencies

Question 42

What is always violated in real populations and what does this mean?

Answer 42

the assumption of Hardy-Weinberg equilibrium evolution is taking place

Question 43

Natural selection can shape what?

Answer 43

populations

Question 44

What are the different types of natural selection?

Answer 44

directional selection disruptive selection stabilizing selection

Question 45

Directional selection favors what?

Answer 45

favors one phenotype over another (e.g. darker tree color allows darker moths to survive and reproduce more than light moths. over time dark moths become more frequent in the population)

Question 46

Disruptive selection favors what?

Answer 46

extreme phenotypes (e.g. the light and dark rocks allow light and dark snails to survive and reproduce more than the intermediate colored snails. over time the medium snails become less frequent in the population)

Question 47

Stabilizing selection favors what?

Answer 47

intermediate phenotypes (e.g. health problems allow medium-sized babies to survive and reproduce more than the very large or very small babies. over time medium-sized babies become more frequent in the population)

Question 48

Why are harmful alleles sometimes maintained in a population?

Answer 48

heterozygote advantage (in which a heterozygote is favored over homozygotes)

Question 49

Sickle cell heterozygotes are resistant to what?

Answer 49

malaria

Question 50

Where are sickle-celled alleles more frequent?

Answer 50

parts of the world where catching malaria is common

Question 51

Sickle cell alleles confer what when malaria is a threat?

Answer 51

heterozygote advantage

Question 52

Heterozygotes of the sickle cell alleles do not have/protect against what?

Answer 52

don't have sickle cell disease protect against malaria

Question 53

Is it possible for the offspring of two heterozygotes to have sickle cell disease?

Answer 53

yes (25% each time)

Question 54

What directly influences reproductive success?

Answer 54

sexual selection

Question 55

Can sexual selection favor traits that apparently reduce survival?

Answer 55

yes

Question 56

What causes evolution to occur?

Answer 56

mutations | gene flow

Question 57

Mutations create what?

Answer 57

genetic diversity

Question 58

How does mutation cause evolution?

Answer 58

beneficial mutations are passed on to the next generation, so their frequency increases over generations

Question 59

What is genetic drift?

Answer 59

sampling error

Question 60

How does genetic drift occur?

Answer 60

sometimes by random, only some individuals in a population reproduce causing a change in allele frequency to occur purely by chance

Question 61

What causes genetic drift?

Answer 61

the founder effect | population bottlenecks

Question 62

What is the founder effect?

Answer 62

when a few individuals migrate away to establish a new population, the allele frequency might change

Question 63

What causes population bottleneck?

Answer 63

if the size of the population becomes greatly reduced. genetic diversity in the new population decreases as many of the alleles are lost. only the alleles in the surviving individuals will be maintained

Question 64

What is gene flow?

Answer 64

moves alleles between populations and increases the genetic diversity. this can change the allele frequencies in both populations

Question 65

Why study evolution?

Answer 65

it is based on a wide range of evidence it offers an explanation for life's diversity- the features seen in all different organisms on earth