Bio 303 Exam 2

Front 1

Biologists use two summary statistics to summarize allele frequencies
1. ____ ________
2. ________ __ ________ _____

Back 1

1. Mean heterozygosity
2. Percentage of polymorphic genes

Front 2

The _______ ______ can be interpreted two equivalent ways:
1. As the average frequency of heterozygotes across loci (particular places)
2. As the fraction of genes that are heterozygous in the genotype of the average individual.

Back 2

Mean Heterozygosity

Front 3

The ______ __ _______ ___ is the fraction of genes in a population that have at least two alleles.

Back 3

Percentage of Polymorphic Loci

Front 4

Early efforts to study allelic diversity in populations were based on a technique called _____ __________. It involved isolating proteins from a large sample of individuals, separating the proteins in an electrophoresis gel, and then staining the gel to visualize the proteins produced by a particular gene.If the alleles present in the population were different enough that their protein products had different sizer or charges, then the proteins would migrate differently in the gel and would show up as different bands.

Back 4

allozyme electrophoresis

Front 5

_____ _________ studies demonstrated that most natural populations harbor substantial genetic variation.

Back 5

allozyme electrophoresis

Front 6

Genetic diversity is maintained by (1.)_______ _______ - In favor of rare individuals, in favor of heterozygotes, or in favor of different alleles at different times and places. In contrast, the (2.)____ ______ claims that most of the alleles at most polymorphic loci are functionally and selectively equivalent and are maintained by genetic drift.

Back 6

1. natural selection
2. neutral theory

Front 7

The population genetic models and experiments that we introduced in part 2 revealed four mechanisms of evolution: _______ _________, _________, ________, and _____ ___.

Back 7

Natural Selection
Mutation
Migration
Genetic Drift

Front 8

Of the four mechanisms of evolution, _______ _______ is the only evolutionary process that results in adaptation.

Back 8

Natural Selection

Front 9

________ is a trait that allows an individual to leave more offspring than it would if it lacked the trait.

Back 9

Adaptation

Front 10

Rock pigeons have tiny hooks on the tips of their beaks to do what?

Back 10

Kill feather-eating lice on their body to maintain superior feathers.

Front 11

A trait, or integrated suite of traits, that increases the fitness of its possessor is called an (1)_________ and is said to be (2)______

Back 11

1 adaptation
2 Adaptive

Front 12

This research effort is called the ________ ______. Roughly speaking, in order to demonstrate that a trait is an adaptation, we need first to determine what a trait is for and then show that individuals possessing the trait contribute more genes to future generations than individuals lacking it.

Back 12

adaptationists program

Front 13

Paul Weeks spent a year in Zimbabwe observing _______ feed from domestic cattle. He seldom witnessed ________ eating ticks from the cattle. More often he watched them ignore ticks (on the cattle) that Weeks himself could plainly see.

Back 13

Oxpeckers

Front 14

Paul Weeks observed the Oxpeckers devote 85% of their feeding time to three activities:
1. ________
2. ________
3. ________

Back 14

1. licking blood from open wounds
2. probing the host's (cattle's) ears for wax
3. Scissoring their beaks through the host's hair, extracting and eating dead skin.

Front 15

Do oxpeckers have an effect on the amount of ticks on domestic cattle?

Back 15

NO

Front 16

Do oxpeckers have an effect on the amount of open wounds on domestic cattle? if so, why?

Back 16

Yes, cattle with oxpeckers on them have considerable more wounds than cattle who are protected from oxpeckers. Oxpeckers drink the blood from open wounds on cattle and enlarge wounds on cattle. Preventing wounds to heal.

Front 17

Do oxpeckers have an effect on the amount of earwax in the ears of domestic cattle?

Back 17

Yes, oxpeckers eat a considerable amount of earwax from the ears of cattle.

Front 18

Do oxpeckers have a mutualistic relationship with cattle? Meaning both the oxpecker and the cattle benefit from each other. Or is the oxpecker more of a parasite for the cattle?

Back 18

Parasite

Front 19

When testing hypotheses, differences among populations or species are not always _______. There are two species of oxpeckers; one has red bills(beaks), the other yellow. It is possible that each color is ________ for the species that wears it. But it is also possible that the difference in bill color is not ______ at all.

Back 19

Adaptive

Front 20

Not every trait of an organism, or every use of a trait by an organism, is an ________. While feeding on large mammals, oxpeckers may sometimes meet a potential mate. This does not necessarily mean that feeding on large mammals evolved because it creates mating opportunities.

Back 20

Adaptation

Front 21

Not every _______ is perfect. Feeding on the blood and earwax of large mammals may provide oxpeckers with high-quality meals. But because many large mammals migrate long distances, it may also expose oxpeckers to the risk of an unpredictable food supply.

Back 21

Adaptation

Front 22

______ are the most powerful method for testing hypotheses. A good _________ restricts the difference between study groups to a single variable

Back 22

Experiment

Front 23

________ tended to retreat from flies that gave the wing-waving display with marked wings, but attacked flies that lacked either wing markings, wing waving, or both.

Back 23

Jumping Spiders

Front 24

_________ experiments allow researchers to understand how precise their estimate is by measuring the amount of variation in the data.

Back 24

Replicated

Front 25

1)__________ experiments or 2)___________ reduce the amount of distortion in the estimate caused by unusual individuals or circumstances

Back 25

1) replicated
2) observations

Front 26

What did Darwin notice about the giant land tortoises on the Galapagos islands?

Back 26

Each island had populations of turtles with distinctly different shell shapes

Front 27

The documentary discussed how the various pieces of DNA work together, one controlling the other. What is the correct sequence: (not all are used)
A.) Gene producing a protein
B.) Body Plan Gene
C.) Switch
D.) Control Gene

Back 27

Body plan gene --> Switch --> Gene producing a protein

Front 28

Darwin referred to his thought process of synthesizing and processing new ideas as:

Back 28

Mental rioting

Front 29

Which of the following observations of embryos gave Darwin insight into evolution?
a.) snake embryos has limb buds
b.) whale embryos had teeth when adults did not
c.) Human embryos had slits that looked like gills
d.) all of the above
e.) none of the above

Back 29

d.) all of the above

Front 30

Considering the human muscle that closes the jaw in comparison to the same muscle in chimps, which of the choices below is correct?
a.) the chimp gene has a much longer sequence of base pairs
b.) multiple genes control this muscle
c.) our gene is badly mutated
d.) the chimp gene is badly mutated

Back 30

c.) our gene is badly mutated

Front 31

What was the conclusion darwin made from examining embryos?

Back 31

We came from fish

Front 32

__________ is defined as the chance difference between the frequency of a trait in a subset of individuals from a population vs the frequency of a trait from the entire population

Back 32

Sampling error

Front 33

_________ is the reduction in mean fitness of a population due to the presence of deleterious alleles

Back 33

Genetic Load

Front 34

The PAP locus had two alleles; the slow allele (S) and the fast allele (F). The researchers sampled 33 otters and found the genotypes to be SS = 16, SF = 7, FF = 10. What are the frequencies of S:____ and F:____?

Back 34

S: .59
F: .41

Front 35

Heterozygosity declines more rapidly in:
a) large populations
b) small populations
c) mid-sized populations
d) populations of all sizes

Back 35

Small populations

Front 36

Polymorphisms are more frequent in:
a) large populations
b) small populations
c) mid-sized populations
d) populations of all sizes

Back 36

Large populations

Front 37

_________ is the reduced fitness of populations resulting from kin matings

Back 37

Inbreeding depression

Front 38

__________ is a situation in which heterozygotes at a particular locus tend to have higher fitness than homozygotes

Back 38

Overdominance

Front 39

__________ is a situation in which heterozygotes at a particular locus tend to have lower fitness than homozygotes

Back 39

Underdominance

Front 40

________ ________ occurs when one phenotype has higher fitness when it is rare and lower fitness when it is common

Back 40

Frequency-Dependence

Front 41

Which is not one of the assumptions of the Hardy-Weinberg equilibrium:
a) there is no mutation
b) there is no selection
c) there are no chance events
d) there is no evolution
e) individuals mate at random
f) there is no migration

Back 41

d) there is no evolution

Front 42

If allele A1 has a frequency of .30 and allele A2 has a frequency of .70, then what are the genotype frequencies?
A1A1:___ A1A2:___ A2A2:___

Back 42

A1A1: .3 x .3 = .09
A1A2: (.3 x .7) x 2 = .42
A2A2: .7 x .7 = .49

Front 43

If you have 241 individuals with the following genotype frequencies: ZZ = 231, Zz = 10, and zz = 0. What are the allele frequencies?
Z =
z =

Back 43

Z = (231+5)/241 = .98
z = (5)/241 = .02

Front 44

• Individuals who inherit 2 copies of the mutant allele of the CCRB gene, called the CCR5-Δ35 (32 Base pair deletion) are resistant to HIV-1.

1. Crucial Events in life cycle of population:
a. Adults produce gametes, gametes combine to make zygotes, zygotes develop into juveniles, juveniles grow into next generation of adults

Back 44

o The Hardy-Weinberg Equilibrium principle

Front 45

o Adults choose their mates at random
o Gene pool: the set of all copies of all alleles in a population that could potentially be contributed by the members of one generation to the members of the next
o Alleles in one complete turn of the population life cycle have ending frequencies that differ from their starting frequency – population evolves.
o Blind luck in pulling gametes from the gene pool gives a different # if zygotes with each genotype – Blind luck can cause a population to evolve unpredictably. This mechanism of evolution is called genetic drift

Back 45

o The Hardy-Weinberg Equilibrium principle

Front 46

____ believed that if a single copy of allele A appeared and a mutation in a population whose gene pool otherwise contained copies of a, then the allele A would Automatically increase in frequency until copies of it constituted ½ of the gene pool.

Back 46

Yule

Front 47

o Two alleles: A1 and A2
o 3 possible diploid genotypes for codominant, dominant, and recessive:
• A1A1, A1A2, A2A2
o Frequency of A1 will be called P and Frequency of A2 will be called Q
• Since only 2 alleles in a population: P + Q = 1
o First the gametes in the gene pool combine to make zygotes
• A1A1: P x P= P^2
• A1A2: P x Q + Q x P= 2PQ
• A1A2: Q x Q = Q^2
• So P^2+2PQ+Q^2=1
o This shows the allele frequency in gene pool to the genotype frequency of zygotes.
o Next zygotes develop into Juveniles, become adults, adults produce gametes and make next generation’s gene pool

Back 47

o The Hardy-Weinberg Equilibrium principle

Front 48

Total fraction of ______ in gene pool carry copies of A1 is: P^2 + (1/2) x 2PQ = P^2 +PQ
Substitute (1 – P) for Q
P^2 + PQ = P^2 + P (1 – P)
= P^2 + P – P^2
=P

Back 48

gametes

Front 49

• The Hardy-Weinberg Equilibrium Principle:

o Conclusion___:If the allele frequency in a population are given by P and Q, the genotype frequency will be given by P^2, 2PQ, and Q^2
o Conclusion ___: the allele frequency in a population will not change, generation after generation

Back 49

2
1

Front 50

• A population in which conclusions 1 and 2 hold is said to be in __________ __________ Equilibrium

Back 50

Hardy-Weinberg

Front 51

• A _______ is a group of Interbreeding individuals and their offspring.
These adults produce gametes, the gametes combine to make zygotes, the zygotes develop into juveniles, and the juveniles grow up to become the next generation of adults.

Back 51

Population

Front 52

We take all the eggs and sperm produced by all the adults in the population, dump them together in a barrel, and stir. This barrel is known as the _____ ______

Back 52

Gene Pool

Front 53

The fact that blind luck can cause a population to evolve unpredictably is an important result of population genetics. This mechanism of evolution is called _____ _____

Back 53

genetic drift

Front 54

Our idealized population does not evolve. This conclusion is known as the _____ ______ _______ _______

Back 54

Hardy-Weinberg equilibrium principle

Front 55

o _______ is differential reproductive success: Some individuals have more offspring than others
o ________ can lead to evolution when the phenotypes that exhibit difference in reproductive success are heritable – when certain phenotypes are associated with certain genotypes

Back 55

Selection

Front 56

________ are typically used to predict genotypes among offspring of a particular male and female

Back 56

o Punnett squares

Front 57

_______ _________ can also be used to predict genotypes among offspring of entire populations.

Back 57

o Punnett squares

Front 58

o When blind luck plays no role, the allele frequencies for A and a in a population are at _______: They don’t change from one generation to the next. The population does not evolve

Back 58

equilibrium

Front 59

Genetic drift is rapid in 1)______ populations and slow in 2)______ populations.

Back 59

1)Small
2)Large

Front 60

______ occurs when an allele frequency hits 1.

Back 60

Fixation

Front 61

An allele is said to be lost forever when it hits an allelic frequency of ___

Back 61

zero

Front 62

When the frequency of A1 alleles reaches 0 or 1, the frequency of heterozygotes falls to ____.

Back 62

zero

Front 63

The frequency of heterozygotes in a population is sometimes called the population's _________.

Back 63

Heterozygosity

Front 64

Empirical data from a natural experiment confirm that small isolated populations lose their genetic diversity as a result of ______

Back 64

Drift

Front 65

Also known as overdominance, ________ is where heterozygotes have higher fitness than either homozygote. An example of this is where viable allele "V" and lethal allele "L" are in a population with 50% heterozygotic (VL) allelic frequency of both alleles. The idea is that all the organisms created for each future generation with LL will die and so the V allele will drastically dominate future generations. But what really happened is that the allelic frequency of V went up to .79 and stayed steady there, while the allelic frequency of L stayed at .29. This is called _____ _______

Back 65

Heterozygote Superiority

Front 66

________ occurs when heterozygotes at a particular locus tend to have lower fitness than homozygotes

Back 66

underdominance

Front 67

______ _____ ______ occurs when an individual's fitness depends on the frequency of its phenotype in the population; typically occurs when a phenotype has higher fitness when it is rare and lower fitness when it is common

Back 67

Frequency-dependent selection

Front 68

_____ ______ _______ can be represented by the elderflower example. Where two different colored elderflowers remain close to equilibrium in a population because bees transport pollen from a yellow elderflower to a purple elderflower. The bees tend to check either a yellow or purple elderflower looking for a reward, but they don't find a reward, thinking the reward may be in the other colored elderflower, the bee then flies into the purple flower. If one color flower becomes more dominant than the other, the bees will quickly balance them out.

Back 68

Frequency-dependent selection

Front 69

Adding _______ to the Hardy-weinber analysis: _______ in allele frequency, for example can cause 1 copy of the dominant allele to change to a deleterious recessive allele per 10,000 for every generation. So after 1000 generations the allele frequency which was once .80 "A" to .20 "a", will now be .79 "A" to .21 "a".

Back 69

Mutation

Front 70

When the rate at which copies of a deleterious allele are being eliminated by selection is exactly equal to the rate at which new copies are being created by mutation, the frequency of the allele is at equilibrium. This situation is called ______ _______ _______

Back 70

Mutation-selection balance

Front 71

If the selection coefficient is small (the allele is only mildly deleterious) and the mutation rate is high, then the equilibrium frequency of the allele will be relatively ____

Back 71

high

Front 72

If the selection coefficient is large (the allele is highly deleterious) and the mutation rate is low, then the equilibrium frequency of the allele will be ____

Back 72

low

Front 73

Mutations are more effective in changing the allele frequencies of ______ populations than _____ populations

Back 73

small
Large