Chapter 1 Reading Quiz

Artificial selection could be described as all of the following, EXCEPT __________.

a. the process of human-directed selective breeding
b. an increase in the frequency of traits that are associated with increased survival and increased reproductive frequency in the wild
c. humans' choice of which individuals get to reproduce
d. an improvement in the quality and yield of crops and livestock
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Artificial selection could be described as all of the following, EXCEPT __________.

a. the process of human-directed selective breeding
b. an increase in the frequency of traits that are associated with increased survival and increased reproductive frequency in the wild
c. humans' choice of which individuals get to reproduce
d. an improvement in the quality and yield of crops and livestock
b. Artificial selection is a counterpart to natural selection. Under natural selection, fitness values—in other words, survival and reproductive rates—determine the persistence and success of given phenotypes. Under artificial selection, some phenotypes are favored over others, regardless of their natural fitness. In this way, humans can give higher reproductive rates to individuals that would not have them in the wild.
b. The three domains of life pictured in this phylogeny correspond to the three main branches of the tree of life—Bacteria, Archaea, and Eukaryotes. The tree of life represents all of the species that live or ever have lived, illustrating the branching network of relationships between living organisms.
Charles Darwin and his colleague Thomas Henry Huxley proposed that humans share a common ancestor with the great apes (chimpanzees, gorillas, and orangutans). How did they come up with such a hypothesis?

a. They looked at the amino acid sequences of these primate species.
b. They compared the DNA sequences of these primate species.
c. They looked at the morphological characteristics of living primate species.
d. They compared morphological characteristics in the fossils of these primate species from Africa.
c. Darwin and Huxley lived more than 150 years ago. There was no knowledge of amino acid sequencing or DNA sequencing during their time, nor had fossils of the early hominoids been discovered in Africa yet. Huxley and Darwin came to this hypothesis of the shared common ancestry from the morphological data (such as skeletons) from living primates. Read Section 1.2 titled "Empirical and Theoretical Approaches to the Study of Evolution" and examine Figure 1.14.
a. This is a basic question regarding the work that Darwin was exposed to (such as the geological evidence that Earth must be older) and his unique contribution. An idea of evolution already existed during Darwin's time, but no one before Darwin proposed the mechanism of how evolution might work. Darwin realized that changes that have occurred in species are primarily a result of natural selection, a gradual process in which forms that are better suited to their environment increase in frequency in a population over sufficiently long periods of time.
Empirical research is very important in evolutionary biology. There are two main types of such research, which could be classified as __________.
a. mathematical modeling and systems studies
b. observation and theoretical biology
c. statistical analysis and manipulation
d. observation and manipulation
d. The theory of evolution has been greatly supported by empirical research, both in observational and manipulative studies. Look over the examples of empirical and theoretical approaches to studies of evolution in Chapter 1. Find an example of a manipulative-type study (intersexual competition) and observational-type study (a comparison of human and chimp genomes) in this chapter.
Gorillas and orangutans have single-male breeding systems, where females mate with only one male. Chimps, in contrast, have a multi-male breeding system, where females mate with multiple males. Evolutionary biologists hypothesize that multi-male breeding systems will favor the evolution of large testes size. Do the data in the figure shown support this hypothesis?

a. No, testes size decreases as the number of mates increases.
b. No. The data only demonstrate that testes size increases with increasing body size, but they do not address the hypothesis regarding mating systems.
c. Larger males have larger testes, which supports the hypothesis.
d. Yes. Testes size increases with body weight, but in multi-male systems, testes size is disproportionately larger.
d. The data in this figure show that testes size increases as body size increases. This is true for all species. However, looking at the differences between the red and green dots shows that species with multi-male systems are mostly above the line of best fit, which supports the hypothesis that multi-male systems result in selection for increased testes size.Read the subsection titled "Primate Breeding Systems and Testes Size" in Section 1.2 and see Figure 1.17.
How do theory and experiment work together in evolutionary biology?

a. Theory must come first, and then experiments can be performed to test that theory.
b. Experiments must first provide data before theory can be developed.
c. Theory and experiments can each provide feedback to the other.
d. Theory and experiments are independent ways of studying evolutionary biology and do not inform each other.
c. Theory can either precede or postdate experiments. Theory may be built on data that already have been generated, and it may lead to new hypotheses that can be tested by experiments. This can create a powerful feedback loop that results in advances in both theory and experiments. See the subsection titled "Theory and Experiment" in Section 1.2.
a. This is the definition of evolutionary relationships—closely related species share a recent common ancestor. There is no reason to necessarily expect closely related species to share a similar environment though. They may or may not be similar in size and morphology depending on the extent of morphological evolution that has occurred since their divergence. Likewise, they may or may not compete depending on whether they live in similar environments and have evolved to be in similar or different niches.
Penicillin once was considered a miracle drug that would permanently eradicate tuberculosis and many other bacterially caused diseases. Today, we encounter resistance to this and many other antibiotics in numerous bacterial species. What could we have done differently to slow the evolution of penicillin resistance?

a. Larger doses of penicillin should have been prescribed.
b. Penicillin treatment should have been continued for months past the infection.
c. Penicillin should not have been prescribed unless necessary.
d. Penicillin should never have been prescribed.
c. Resistant strains are more likely to evolve if an antibiotic is widely used. Often, antibiotics are prescribed when unnecessary or ineffective, for example, to treat a viral infection. Less frequent use would not have stopped the evolution of resistance, but it may have slowed it so that use of the drug, when necessary, would render it effective in treating infections. Read the subsection titled "Evolutionary Change and Pharmaceuticals" in Section 1.1.
Sir Ronald A. Fisher's mathematical model of sex ratio was tested in nature on blue moon butterflies (Hypolimnas bolina), a species of butterfly from the Samoan islands, where the sex ratio deviated strongly from one to one (99% females). Which of the following is TRUE regarding this test?

a. The shift back to an even sex ratio refuted Fisher's mathematical model, demonstrating that theory should not precede empirical research.
b. A new mutant arose on one of the islands and the sex ratio among the blue moon butterflies on the island returned to approximately 1:1, supporting Fisher's mathematical model.
c. The shift back to an even sex ratio was the result of changes in a pathogenic bacterium (a new variety of Wolbachia). These bacteria could no longer affect the sex ratio, so Fisher's mathematical model was not supported in this case.
d. A new mutant butterfly arose on one of the islands and the sex ratio among the blue moon butterflies on the island returned to approximately 1:1, supporting Fisher's mathematical model.
d. Fisher's sex ratio model states that if the sex ratio (male to female) should deviate from one to one, natural selection would strongly favor genotypes that restore the even ratio. In other words, when the sex ratio becomes unbalanced, we expect a return to a one to one ratio so long as variation exists to reach this ratio. Based on this theory, if there were to arise a genetic variant of the blue moon butterfly that produced as many males as females, despite infection by Wolbachia, this variant would spread rapidly. Even though female butterflies on the island were still infected with the same bacteria as in 2001, they now produced as many surviving males as females. Examine the subsection titled "Testing the Sex Ratio Model - A Rapid Change of Sex Ratio" in Section 1.2 and see Figure 1.18.
The antibiotic ciprofloxacin often is prescribed for serious cases of food poisoning caused by the bacterium Campylobacter jejuni, which is common in the intestines of farm animals and is not harmful to them, but may cause acute food poisoning in humans. Which of the following is correct given prolonged use of this antibiotic? a. Prior to antibiotic treatment, most Campylobacter are ciprofloxacin-resistant. b. Ciprofloxacin treatment kills or halts the growth of the sensitive strains, yet the resistant strains survive. c. Repeating the treatment of the same patient or a population multiple times results in a strain of Campylobacter that is more susceptible to the antibiotic. d. Treatment with ciprofloxacin causes the patient to evolve resistance such that the next time the patient gets an infection, it will no longer be effective.b. At the start of treatment with this or another antibiotic, the antibiotic may be deadly to the pathogens. However, bacterial cells divide quickly and have a high mutation rate. A random mutation might be present already at a low frequency or it might occur randomly among the bacterial survivors. In a patient being treated with ciprofloxacin, this new strain may outcompete the susceptible strain, allowing the resistant Campylobacter to eventually become the dominant form. Repeating this process multiple times results in a strain of Campylobacter that is highly resistant to the antibiotic. Read the subsection titled "Evolutionary Change and Pharmaceuticals" in Section 1.1. Examine the case of ciprofloxacin resistance and study Figure 1.6.The evolution of antibiotic resistance is the result of __________. a. artificial selection b. natural selection c. genetic engineering d. inheritance of the acquired resistanceb. The evolution of antibiotic resistance is a consequence of the widespread use and misuse of antibiotics in the past half century. The evolution of resistance in general, and in bacteria in particular, is the result of natural selection. Humans have created the environment that causes the selection to occur, but are not actively choosing which individuals survive and reproduce; thus, this is not artificial selection.The following figure shows two possible groups of species on which to focus conservation efforts. Why might you choose a conservation strategy that would save the two species in blue rather than the three species in red? a. Saving the blue species preserves more phylogenetic diversity. b. The red species are not important to the ecology of their habitat. c. Saving two closely related species preserves more phylogenetic history than saving three more distantly related species. d. The blue species are easier to preserve because they have not evolved as much as the red species.a. FEEDBACK: So long as species D, G, H, and J are not at risk of extinction, preserving their close relatives E, F, and I will not do as much to save the phylogenetic diversity as preserving B and C, which have no other close relatives. If B and C are lost, a whole long lineage in the phylogeny is lost. See Figure 1.11.We often see pesticide resistance evolve in insects that feed on crop plants. Which of the following statements best describes how these changes occur? a. Individual insects that have been exposed to pesticides develop new mutations capable of breaking down pesticide molecules. b. Insects tend to learn from their parents and relatives how to avoid the locations that have been recently treated with pesticides. c. The variants in the treated population that already have mutations that confer resistance to the pesticide treatment will survive and proliferate. d. Artificial selection for pesticide resistance in insects occurs when humans select which insects will become parents for the next generation.c. Pesticide treatment does not induce new mutations, but rather it selects on the variation in resistance that is already present in a population. This type of selection is natural selection, not artificial selection, because the conditions of the environment, rather than the direct actions of humans, are determining which individuals will survive and reproduce.What was the approximate time when Homo sapiens began to use domestic crops and settle in one habitat? 2000 years ago 5000 years ago 10,000 years ago 50,000 years ago10,000 years; The transition from the hunter-gatherers to crop-growers was a very important change in our ancestors' lifestyle, since agriculture ultimately led to cultural evolution and the beginning of the first human civilizations. According to the numerous archeological findings around the world, this was a widespread behavior before and around 10,000 years ago.When we compare primate karyotypes (chromosome sets), interesting evidence of our genetic relatedness is revealed. What is the main difference between the human karyotype and the karyotypes of the great apes? a. Chromosomes of humans, chimps, gorillas, and orangutans are identical. b. The karyotypes are similar in number, yet there are very different lengths of the chromosome arms across the karyotypes. c. Humans have one fewer pair of chromosomes as a result of the fusion of chromosomes 2p and 2q in chimpanzees. d. Humans have one extra pair of chromosomes as a result of the breakage of chromosomes 2p and 2q in chimpanzees.c. As shown in the image of Figure 1.15, humans have one fewer pair of chromosomes (23 pairs) than the great apes. Otherwise, chromosomes of humans, chimpanzees, gorillas, and orangutans are very similar. While karyotypes of chimpanzees, gorillas, and orangutans are almost identical, with 24 chromosome pairs and strikingly similar banding patterns, the human karyotype is slightly different, with 23 chromosome pairs. This appears to be the result of a fusion of two human and primate chromosomes, providing evidence for the recent divergence of these species.Which is correct regarding the sources of data for testing models of evolution? a. Evolutionary biologists no longer use fossil data. b. Molecular data were available before embryological data. c. Behavioral data often are used in evolutionary studies. d. There are very few sources of data for use in evolutionary biology.c. There are many sources and types of data used in evolutionary biology. Evolutionary biologists continue to use fossil data, in addition to behavioral and many other types of data. Embryological data were used before molecular data were available to evolutionary biologists.Which of the following best describes the difference between humans and modern chimps? a. Chimp and human genomes differ by about 15%. b. Chimps and humans have identical genomes, but humans have less body hair. c. Chimps have very unusual reproductive behavior that never existed in our human ancestors. d. Chimp and human genomes differ by only 1.3%, yet patterns of gene expression may differ.d. Human and chimp genomes differ, but in only 1.3% of sequences. This seems insufficient to account for the morphological and behavioral differences between these species. Therefore, it is likely that differences are due primarily to the ways genes are expressed in the cells. Current evidence supports a role of changes in gene expression in human and chimp testes, which likely is due to selection acting on different mating systems in the two species. See the subsection titled "Molecular Genetics and Evolution in Chimps and Humans" in Section 1.2.Which of the following helps explain why most species display an even sex ratio? a. When males are rare, a parent that produces more males will have more grandchildren on average. b. When males are rare, females have a benefit because they have a better chance of finding a mate. c. Natural selection favors an even sex ratio because of chromosomal sex determination. d. In most species, males have a higher fitness than females, so more females need to be produced to reach the same total fitness.a. When one sex is rare, that sex is more likely to find a mate, and therefore have a higher fitness. Thus, if a parent produces more offspring of the rarer sex, that parent will have more grandoffspring, thereby increasing the frequency of the rare sex until it is no longer rare. This process eventually will result in both sexes occurring at the same frequency. The process does not depend on the mechanism of sex determination. See the subsection titled "Why Is There an Even Sex Ratio?" in Section 1.2.Woolly mammoths (Mammuthus primigenius) once lived in the Northern Hemisphere and were a contemporary of modern humans. Due to various factors including human hunting, the mammoth became extinct approximately 10,000 years ago. According to the following phylogeny, which species is the closest relative of the woolly mammoth? a. African elephant (Loxodonta Africana) b. Asian elephant (Elephas maximus) c. dugong (Dugong dugon) d. rock hyrax (Procavia capensis)b. The phylogeny shows that the mammoth shares the most recent common ancestors with Elephas maximus, while the other three branches share earlier ancestry and therefore are not as closely related to the Mammuthus genus. Examine Figure 1.10 on woolly mammoth extinction to understand the phylogenetic relationships between modern elephants and mammoths, as well as other species.