In a population of rabbits, f (C$_{1}$) = $0.70$ and f (C$_{2}$) = $0.30$. The alleles exhibit an incomplete dominance relationship in which C$_{1}$C$_{1}$ produces black rabbits, C$_{1}$C$_{2}$ tan-colored rabbits, and C$_{2}$C$_{2}$ rabbits with white fur. If the assumptions of the Hardy-Weinberg principle apply to the rabbit population, what are the expected frequencies of black, tan, and white rabbits?

The frequency of tasters and nontasters of PTC varies among populations. In population A, $64$ percent of people are tasters (an autosomal dominant trait) and $36$ percent are nontasters. In population B, tasters are $75$ percent and nontasters $25$ percent. In population C, tasters are $91$ percent and nontasters are 9 percent.

a. Calculate the frequency of the dominant (T) allele for PTC tasting and the recessive (t) allele for nontasting in each population.

b. Assuming that Hardy-Weinberg conditions apply, determine the genotype frequencies in each population.

The Luria-Delbrück fluctuation test is consistent with the random mutation theory. How would the results have been different if the physiological adaptation hypothesis had been correct?

Two inbred lines of sunflowers (P$_{1}$ and P$_{2}$) produce different total weights of seeds per flower head. The mean weight of seeds (grams) and the variance of seed weights in different generations are as follows.

a. Use the information above to determine V$_{G}$, V$_{E}$, and V$_{P}$ for this trait.

b. Determine H$_{2}$ for this trait.

Suppose the length of maize ears has narrow sense heritability (h$^{2}$) of $0.70$. A population produces ears that have an average length of 28 cm, and from this population a breeder selects a plant producing $34$-cm ears to cross by self-fertilization. Predict the selection differential (S) and the response to selection ( R ) for this cross

Using cell phones to dial 911 to report emergencies is a relatively new procedure. How does dialing 911 help you?

How a major change in global climate could lead to a mass extinction?

Explain the difference between each pair of terms below. Then explain how the terms are related. background extinction, mass extinction

What is the role of cytochrome c in apoptosis?

What is inbreeding depression? Why is inbreeding depression a serious concern for animal biologists involved in species-conservation breeding programs?

Biologists have proposed that the use of antibiotics to treat human infectious disease has played a role in the evolution of widespread antibiotic resistance in several bacterial species, including Staphylococcus aureus and the bacteriacausing gonorrhea, tuberculosis, and other infectious diseases. Explain how the evolutionary mechanisms mutation and natural selection may have contributed to the development of antibiotic resistance.

a. Why is it impossible to induce nonsense mutations (represented at the mRNA level by the triplets UAG, UAA, and UGA) by treating wild-type strains with mutagens that cause only

$$\mathrm { A } \cdot \mathrm { G } \rightarrow \mathrm { T } \cdot \mathrm { C }$$

transitions in DNA? b. Hydroxylamine (HA) causes only

$$\mathrm { G } \cdot \mathrm { C } \rightarrow \mathrm { A } \cdot \mathrm { T }$$

transitions in DNA. Will HA produce nonsense mutations in wild-type strains? c. Will HA treatment revert nonsense mutations?

A pair of homologous chromosomes in Drosophila has the following content (single letters represent genes):

Chromosome $1$ $\,\,\,\,\,\,\,\,\,\,\,\,$ RNMDHBGKWU Chromosome $2$ $\,\,\,\,\,\,\,\,\,\,\,\,$ RNMDHBDHBGKWU

a. What term best describes this situation?

b. Diagram the pairing of these homologous chromosomes in prophase I.

c. What term best describes the unusual structure that forms during pairing of these chromosomes?

d. How does the pairing diagrammed in part (b) differ from the pairing of chromosomes in an inversion heterozygote?

Complete each sentence. Use either a simile, a metaphor, or an example of personification in each new sentence. To Shakespeare, youth _____