Bio 2 Ch. 22/23

Blue flower color (B allele) is dominant to white (b allele). If a population of plants in Hardy-Weinberg equilibrium contains white flowers (bb) at a frequency of 0.04, what is the frequency of the heterozygous genotype?

0.32 or 32%

In a population of 100 four-o'clock flowers there are 40 red-flowered plants (CRCR), 38 pink-flowered plants (CRCW), and 22 white-flowered plants (CWCW). What is the frequency of the CW allele in this population?

0.41 or 41%

What would be the frequency of pink flowers in a population where the allele frequency of CR is 0.4 and the population is in Hardy-Weinberg equilibrium? Assume that CR CR is red, CRCW is pink, and CwCw is white.

0.48 or 48%

Fitness is a measure of reproductive success. If an individual with genotype BB produces 6 offspring, and a heterozygous individual (Bb) produces 10 offspring, and a third individual with genotype bb produces 5 offspring, what is the fitness value for the individual with BB genotype?

0.6

Blue flower color (B allele) is dominant to white (b allele). If a population of plants in Hardy-Weinberg equilibrium contains white flowers (bb) at a frequency of 0.04, what is the frequency of the blue flower allele (B)?

0.8 or 80%

In the Hardy-Weinberg equation, p + q =_______, where p and q represent ________.

1, allele frequencies

Genotype Qq produces 10 offspring per year. Genotype QQ has a fitness value of 0.4 and genotype qq has a fitness value of 0.2. How many offspring does genotype qq produce each year?

2

To analyze genetic variation in populations, one approach is to consider the frequency of alleles. When calculating an allele frequency for a diploid species, how many alleles are present for each gene?

2

In the Hardy-Weinberg equation , the genotype frequency of heterozygotes is represented by

2pq

Which of the following situations would be MOST likely to produce a new species?

A group of polyploid individuals arises by an abnormal meioses. The polyploids can only produce viable offspring by mating with each other.

Which of the following would most likely result in a bottleneck event?

A hurricane blows through a coastal swamp inhabited by an apple snail population. The hurricane drastically changes the hydrology of the swamp, killing 98% of the apple snails.

Which of the examples below are polymorphic traits? Select all that apply.

A population of lilies that contains equal proportions of both blue and white flowering individuals. Lactose tolerance and intolerance in humans. The A, B, and O blood

Select the examples that can undergo microevolution.

A small group of Cactus finches living in the Galapagos Islands. A cluster of endangered Venus Flytraps in North Carolina's Green Swamp. A large herd of caribou in Alaska.

If a population satisfies the Hardy-Weinberg equilibrium model, what can you assume about that population?

Allele and genotype frequencies are stable.

How would you best explain the correlation between an increase in Hox genes and an increase in animal body complexity?

An increase in the number of Hox genes allows for greater specialization in different body regions.

GGG and GGC are codons for the amino acid, glycine. A mutation caused the insertion of a cytosine in place of the guanine during DNA replication. Over many generations the DNA changes so that the frequency of GGC is similar to that of GGG. What effect does this mutation have on the population's mean fitness?

As the frequency of the GGC codon increases, the population's mean fitness level will remain the same.

In comparing the development of the unwebbed foot of the chicken and webbed foot of a duck, what differences are there in the expression ofBMP4 and gremlin?

BMP4 is expressed similarly in both chicken and duck feet, while gremlin is not expressed between the toes of chicken feet.

Dandelions, Taraxacum officinale, are plants that asexually produce fruitlike propagules. Sexual reproduction is very rare in this organism. Which species concept would be LEAST useful in defining dandelions as a species?

Biological species concept.

There is a population of frogs living in a pond, 25 are green, 25 are brown, 25 are yellow with green spots and 25 are all yellow. A drought occurred and 75% of the frogs died. The remaining frogs were green and brown, after 25 generations the frogs still were green and brown, yellow frogs never appeared in the population again. Which of the following best explains this phenomenon?

Bottleneck effect.

A population of voles (small mammals) live in a shady forest. Originally, the voles are a light tan color, but then a dark brown coloration arises by a new mutation. The darker voles are harder for predators to see in the leaf litter, thus they are less susceptible to predation. After 10 generations the majority of voles in the population are the dark brown color. What type of selection are the population of voles going through?

Directional selection.

What field of biology compares the development of organisms in order to better understand mechanisms of evolutionary change?

Evolutionary developmental biology.

What phenomenon would violate the conditions for Hardy-Weinberg equilibrium?

Females select males based on secondary sex traits.

Which of the following statements is true regarding Seehausen and van Alphen's African cichlid experiment?

Females show sexual selection based on males' coloration.

Podos measured finch beak depth and correlated this with characteristics of their songs. Using the figure below what species of bird with a vocal constraint between 2 and 3 has the largest beak depth?

G. fortis

What phenomena tends to increase genetic variation in a population?

Gene flow

A storm blows a small group of migrating birds off course and they land on an island where they remain for 100 generations. At this time a second storm brings more birds from the mainland population to the island. These new birds cannot mate with the established birds even though they are woriginally from the same population. What mechanisms are likely to have been involved in bringing about this speciation?

Genetic drift

What mechanism leads to changes in allele frequencies due to random chance?

Genetic drift

Female peahens choose a male peacock for mating because of the male's long, colorful tail feathers and their courtship display. This is which type of selection? Select all that apply.

Intersexual Directional

Male deer have large antlers that are used to challenge each other in fights for territory and females. The females of this group actively choose the strongest males. Which type of sexual selection is occurring with the deer population?

Intersexual and intrasexual selection are both occurring.

Based on the figure below, how many groups (clusters) of Hox genes does each type of animal have?

Mammals: 4 groups; Flatworms: 4 groups; Sponge: 1 groups; Anemones: 2 group.

What criteria can be used to identify species? Select all that apply.

Molecular similarity The ability to interbreed Evolutionary relationships Ecological factors

The figure below shows three mouse populations and their associated changes in the frequency of B, the allele for dark fur. The recessive b allele codes for white fur. After 20 generations, in which population would you be most likely to encounter a white mouse?

N3

Select the TRUE statement(s) concerning natural selection.

Natural selection is a way for evolution to occur. Natural selection results in better adapted populations when the environment is constant.

What are the two principle factors that lead to microevolution?

New genetic variation and evolutionary mechanisms

A population of mountain goats are split because of the formation of a glacier. After 500 years the glacier melts and the two goat populations are free to move between the two areas. Under what conditions might a hybrid zone occur?

Reproductive isolation is incomplete.

Which of the following is NOT related to genetic drift?

Sexual selection

A scientist is studying a population of crickets and finds that there is variation in the songs used by males to call for mates. Some males call with high-pitched three-chirp songs and some call with low-pitched four-chirp songs. However, offspring from the two types of males are able to interbreed so the scientist classifies the population as a single cricket species and goes on to another project. One year later a mutation arises in a female cricket that makes her unable to hear high frequencies. Ten years later a graduate student returns to the same cricket population and discovers that there are now two distinct cricket species in the area although they appear morphologically identical. What is the most likely explanation?

Sexual selection has led to sympatric speciation.

Your senior thesis project involves working out the taxonomy of Florida skinks. To accomplish this you examine skink specimens for morphological differences compare nucleotide and amino acid sequences and observe the skinks reproductive behavior and habitat types. Once you have completed the taxonomy and written the thesis you give it to your professor for comments. She tells you that you did a great job and should try to get your work published. However she suggests you indicate in the introduction what species concepts you used to make your classifications. What statement would you add?

Taxonomic determinations were made based on the general lineage species concepts.

Adaptive radiation is likely to have led to which of the following?

The 1,000 species of Drosophila found dispersed throughout the Hawaiian Islands.

The human b-globin gene has two alleles, HS and HA. Individuals that are homozygous for HS have sickle-cell anemia and a lower fitness. Individuals that are heterozygotes (HSHA) do not show sickle-cell symptoms and have a resistance to malaria. Individuals that are homozygous for HA have the highest fitness but are susceptible to malaria. If a vaccine for malaria was created that was 100% effective, affordable, and widely available, what would happen to the frequency of the HS allele?

The HS allele would decrease in regions where malaria is prevalent and remain stable in regions where malaria is absent or rare.

Which gene is correctly matched with its evolutionary significance?

The Hox genes - evolution of body plans.

To prepare for a hiking trip in the Appalachian mountains you buy several field guides for the region from a used bookstore. You notice that the older guides list a single species of tiger swallowtail butterfly Papilio glaucus and an Appalachian morph of this species. However the newest guide list two separate species P. glaucus and P. appalachiensis. The authors of this guide state that the biological species concept was used in determining their classifications. What do you think led them to list two separate species of tiger swallowtail?

The discovery that P. glaucus and P. appalachiensis do not interbreed in the wild.

Based on the figure below, what statement could you make about the development of human versus chimpanzee skulls.

The human and chimp skulls develop similarly until the infant stage, when human jaw development slows down relative to the chimpanzee.

The Northern leopard frog (Rana pipiens) and Southern leopard frog (Rana utricularia) are morphologically similar, but their mating calls sound very different. Based on this, what is the best explanation for why these frogs are considered separate species?

They have undergone behavioral isolation which prevents them from interbreeding.

Development of an animal is connected to the genes that are expressed during development. What roles have been proposed for Hox genes in the evolution and morphology of animal species? Select all that apply.

Variation in the number of Hox genes has led to the evolution of new animal species. The greater the number of Hox genes the more complex the body plan of the animal.

A tick population in a rural, wooded area uses deer as its primary host species. Eventually, humans begin to move into the area, bringing their pets along with them. Certain individuals within the tick population start to use dogs as their primary hosts, and eventually start to prefer dogs over deer. Other individuals continue to use deer for their primary host. Could this difference in host preference lead to speciation? Why or why not? Select all correct answers.

Yes, because the ticks' host preference may be inherited, leading to an accumulation of genetic differences between ticks that use deer and ticks that use dogs. Yes, because temporal isolation could occur due to differences in host quality.

What events would lead to directional selection?

a new allele arises that increases fitness a population's main food source changes

A gene pool is

all the genes in a population

You discover a new species of lily that has 10 chromosomes (2n=10). Genetic testing reveals that it arose from the interbreeding of two other species of lilies, one of which has 12 chromosomes, and one of which has 8 chromosomes. What is the correct term for the new lily species?

allodiploid

Approximately 3.5 million years ago the Isthmus of Panama formed. This new landmass severed the connection between the Pacific Ocean and the Caribbean Sea. An ancestral fish population (porkfish) was split in two by this event; the two populations no longer interbreed and are two distinct species. This type of speciation is called

allopatric speciation.

The figure below illustrates that

although the mammal eye possesses more cell types and greater complexity than the Drosphilia eye, both arose from genetic changes to an ancestral Pax6 gene.

The human b-globin gene has two alleles, HS and HA, individuals that are homozygous for HS have sickle-cell anemia and a lower fitness. Individuals that are heterozygotes (HSHA) do not show sickle-cell symptoms and have a resistance to malaria. Individuals that are homozygous for HA have the highest fitness but are susceptible to malaria. In areas where malaria is prevalent the HS allele is maintained in the population. Which type of selection is occurring with the b-globin gene?

balanced

Over generations in a population, traits seen in individuals with higher fitness values will

become more prevalent in the population.

Allopatric speciation occurs because a population

becomes geographically isolated and undergoes genetic change.

A group of individuals that can interbreed in nature and produce viable offspring would be considered to be a species according to the

biological species concept.

The function of BMP4 is to ________ while the function of gremlin is to ________ BMP4.

cause apoptosis; inhibit the function of

Microevolution involves ________

changes in a population's gene pool

The Pax6 gene

codes for a protein that controls the expression genes related to eye development.

A mutation arises in an individual that decreases its fitness. This means that this individual's

contribution to the gene pool of the next generation will decrease.

The diagram below shows inbreeding between ________, which over time could lower the fitness of the population. This lowering of fitness because of inbreeding is called ________.

cousins; inbreeding depression

Over several generations in a population, inbreeding tends to

decrease the likelihood of heterozygotes.

During normal climatic conditions with regular rainfall, the average beak depth for a population of finches was 6.8mm. Researchers found that after a drought, average beak depth increased to 8.8mm. Birds with deep beaks (>9mm) were better able to eat large, hard seeds. Small hard seeds were also available after the drought, but could only be eaten by birds with shallow beaks (<7mm). Choose the graphical representation and term that best represents what would happen in the post-drought finch population if both types of seeds continue to be available.

disruptive (diversifying) selection.

Under the ________ , species are identified based on their unique habitat requirements.

ecological species concept

Cryptic female choice is a type of intrasexual selection.

false

The pace of evolution remains constant despite sudden environmental shifts such as climate change.

false

A confused frog deposits its sperm onto a toad's eggs as they are being laid. No offspring develop because the frog's sperm are unable to penetrate the toad's egg. This is an example of

gametic isolation.

In a small population, both ________ and ________ would violate the conditions of Hardy-Weinburg equilibrium

gene flow, genetic drift

The most important concept in the field of population genetics is

genetic variation.

According to the concept of ________, species evolve continuously over long spans of time.

gradualism

The phenomenon in which one region of the body grows faster than another among different species is called

heterochrony.

What mechanism makes it difficult to classify bacteria into distinct species groups?

horizontal gene transfer.

If goats are crossed with sheep, embryos will form but cease development and spontaneously abort. This is an example of

hybrid inviability.

A liger is an offspring produced from a mating between a male lion and a female tiger. Male ligers cannot produce offspring. This is an example of

hybrid sterility.

The process of evolutionary changes that result in formation of new species and groups of species is called

macroevolution.

During spring time in Maine, male moose often enter a cow pasture and begin calling to the female cows. The moose may even try to mount the female but the male genitalia do not fit properly inside the female genitalia. This is an example of

mechanical isolation.

In a species of salamander, there are two forms, red and yellow. As the yellow form becomes less common due to predation and the red form more common, the yellow form becomes less likely to be eaten and more likely to survive and reproduce. The yellow form then becomes more common and roles of red and yellow forms reverse. This is an example of

negative frequency-dependent selection.

GGG and GGC are codons for the amino acid, glycine. A mutation caused the insertion of a cytosine in place of the guanine during DNA replication. Over many generations the DNA changes so that the frequency of GGC is similar to that of GGG. What is this phenomenon called?

neutral variation

The phenotypic changes shown in the figure above represent

punctuated equilibrium.

Reproductive isolation in Darwin's finches was studied by Podos. He measured beak size and found a correlation between this and the finches'

song and ability to attract certain mates.

In ________ selection, individuals intermediate in a phenotypic distribution have greater reproductive success.

stabilizing

If two populations are geographically restricted groups of the same species, but display one or more traits that are somewhat different, the two groups are sometimes classified as

subspecies

Two species of salamander have similar ranges, but one breeds from January to March, while the second one breeds from March to May. This is an example of

temporal isolation

Studies of the Pax6 gene and its homologs suggest that

the eyes of many different species are descended from a common ancestor.

Sympatric speciation differs from allopatric speciation because in sympatric speciation

there are no physical barriers against interbreeding.

A disadvantage of using DNA or RNA sequences to identify species is that

there are no rules for determining the number of sequence differences needed for a new species.

The gene pool of the next generation is derived from

those individuals of a population that reproduce and have viable offspring.

A population undergoing microevolution would show Hardy-Weinberg disequilibrium.

true

In red-winged blackbirds, females tend to choose males with the most desirable territories and males compete with each other for territories.True or false: Redwing blackbirds demonstrate both intersexual selection and intrasexual selection.

true

Neutral variation is supported by the observation that most changes in codons occur in the third position within the codon, which often has no effect on the sequence of amino acids in the protein.

true

Two species of three-spined stickleback fish live in a single lake in British Columbia. They are closely related but occupy different niches. They exist nowhere else. These species most likely arose by sympatric speciation from a single species of three-spined stickleback.

true