Bio 171- quiz 9

Genetic drift, acting alone, cannot change allele frequencies in a population. Other evolutionary processes are required to change allele frequencies.

False

You begin an experiment with 2 populations of E. coli that are each composed of 100 cells. The cells are all genetically identical (i.e., they are clones). You grow these populations in flasks on a lab bench under identical conditions with unlimited resources. Is the following statement about the populations true or false? After 100 generations both populations will still be genetically the same, having accumulated the same mutations over time.

False

You begin an experiment with 2 populations of E. coli that are each composed of 100 cells. The cells are all genetically identical (i.e., they are clones). You grow these populations in flasks on a lab bench under identical conditions with unlimited resources. Is the following statement about the populations true or false? Natural selection cannot occur because bacteria are haploid so there is no individual variation.

False

When the conditions of the Hardy-Weinberg equilibrium are met: (select all correct choices) genotype frequencies in the population do not change over time. genotype frequencies in the population change over time. evolution occurs. evolution does not occur. allele frequencies in the population change over time.

genotype frequencies in the population do not change over time. evolution does not occur.

If there are 100 individuals in a population and 20 are homozygous for B, 60 are heterozygous, and 20 are homozygous for b, what is the allele frequency of B?

50%

Which of the following is NOT a condition of Hardy-Weinberg equilibrium? No differences in the survival and reproductive success of individuals No mutation No migration Random mating All of the conditions listed ARE conditions of Hardy-Weinberg equilibrium.

All of the conditions listed ARE conditions of Hardy-Weinberg equilibrium

A population that is IN Hardy-Weinberg equilibrium is evolving.

false

If a population is not in Hardy-Weinberg equilibrium for the gene under study, we can conclude that:

evolution has occurred or inbreeding has occurred.

Which of the following statements about evolutionary processes is ACCURATE? Genetic drift and gene flow both reduce levels of genetic variation between populations. Mutations alone can significantly change allele frequencies in a population of animals. Genetic drift and gene flow can increase or decrease the mean fitness of the population. Balancing natural selection reduces levels of genetic variation in the population. Stabilizing and directional sexual selection reduce levels of genetic variation and change the average value of the selected trait.

Genetic drift and gene flow can increase or decrease the mean fitness of the population.

hich of the following is (are) NOT (a) valid statement(s)? Choose all that apply. Genetic drift and natural selection can both increase the frequency of an allele that has negative effects on fitness. Genetic drift occurs in small populations whereas natural selection occurs in large populations. Genetic drift and natural selection both require variation in a population in order to occur. Genetic drift can increase the frequency of neutral alleles whereas natural selection cannot. Genetic drift and natural selection both cause changes in allele frequencies. Genetic drift and natural selection can occur in the same population at the same time. Genetic drift is a random process whereas natural selection is not random.

Genetic drift and natural selection can both increase the frequency of an allele that has negative effects on fitness. Genetic drift occurs in small populations whereas natural selection occurs in large populations.

Why is Hardy-Weinberg such a valuable tool when examining populations?

It enables us to identify if a population is evolving or if inbreeding is occurring.

Male peacock spiders engage in an elaborate dance when females are nearby. They wave their first two pairs of legs in the air rhythmically while moving back & forth to attract the female's attention. Male peacock spiders also have brightly colored patches and patterns which make them quite beautiful and very noticeable to predators. Which of the following is true about male peacock spiders? Choose all that apply. Males with bright colors and good dancing skills will outcompete other males through intersexual selection. Fitness in male peacock spiders is limited by available resources such as food and availability of nesting sites. Males with drab colors and poor dancing skills will outcompete other males by being skilled fighters. Males with the brightest colors may be killed by predators before mating due to the high visibility of male spiders. It is likely that males with drab colors and poor dancing skills have fewer offspring compared to males with bright colors who are good dancers.

Males with the brightest colors may be killed by predators before mating due to the high visibility of male spiders. It is likely that males with drab colors and poor dancing skills have fewer offspring compared to males with bright colors who are good dancers. Males with bright colors and good dancing skills will outcompete other males through intersexual selection.

Which of the following statements best describes the difference between artificial and natural selection? Artificial selection has produced many of the most delicious food items for humans; natural selection has not. Natural selection is limited to morphological traits and artificial selection is not. Natural selection works on all species, but artificial selection only applies to laboratory-raised species. Natural selection has never been observed but artificial selection has been observed in many species that humans have domesticated. Natural selection generally acts without the input of humans whereas artificial selection requires human input.

Natural selection generally acts without the input of humans whereas artificial selection requires human input.

You study a small population of birds on one very isolated island and notice that the frequency of individuals with a green band on their wings increases over the course of 3 years. The green band appears heritable (offspring resemble parents), but, despite extensive experiments, you cannot identify any selective advantage of the green band. What would an evolutionary biologist be MOST likely to conclude?

The change in frequency of the band is most likely due to genetic drift.

What is the result of a mutation that occurs in somatic cells?

The mutation may be expressed in the individual, but will not be passed along to its offspring.

Intrasexual selection can to lead to sperm competition, where sperm of different males compete for fertilization even though there is no direct physical competition between males.

True

True or false? Genetic drift, acting alone, can change allele frequencies in a population.

True

There are three alleles at a specific locus in a population of humans. Allele D1, D2, and D3 with frequencies 0.42, 0.30, and 0.28 respectively. True or false or cannot determine: Allele D1 is dominant.

cannot determine

Choose all that apply. Genetic variation in a population can be reduced by disruptive intersexual selection directional natural selection directional artificial selection stabilizing intrasexual selection balancing selection

directional natural selection directional artificial selection stabilizing intrasexual selection

Genetic variation in a population refers to which of the following?

multiple alleles within a gene pool

You find that a wild population of antelope is not in Hardy-Weinberg equilibrium for a particular gene. From this information alone, can you determine which evolutionary process is acting on the antelope population?

no

Consider two isolated populations of lady slipper orchids. These populations are hundreds of miles apart; one is in Northern Minnesota and the other is in the Upper Peninsula of Michigan. They are so far apart that pollinators cannot possibly transfer pollen between the two populations. Based on this information, you expect there to be _________________ between these two populations.

no gene flow

In northern elephant seals, body size is determined by at least 8 genes. Males compete for territories on the beach and larger males are more likely to win fights. In this example, inheritance of body size is ________________, intrasexual selection on male body size is ____________________, which results in _______________ in mean male body size in subsequent generations.

polygenic / directional / increases

Genetic drift is defined as

random changes in allele frequencies

Ferrets are unable to withstand long periods of cold weather and must hibernate throughout much of the winter. Hibernating sites are in short supply, and ferrets only survive if they can find holes in trees that fit their body size. Very small tree holes are in short supply because they are generally colonized by stinging wasps that chase away ferrets. Very large tree holes are in short supply because they are colonized by snakes that eat ferrets. The limited supply of tree holes should result in:

stabilizing selection on ferret body size

The phrase "Modern Synthesis" refers to:

the synthesis of Darwin's ideas about natural selection and Mendelian genetics.

The allele frequency of all the alleles of one gene present in the population must add up to 1. (Allele frequencies of all alleles for a gene must always add up to be 1, which is 100% of the population.)

true