In 1959, doctors began using the powerful antibiotic methicillin to treat infections of Staphylococcus aureus, but within two years, methicillin-resistant strains of S. aureus (MRSA) appeared. How did the resistant strains of S. aureus emerge? -In response to treatment of Staphylococcus aureus infections with methicillin, some bacteria began to synthesize cell walls using a protein that was not affected by methicillin. These bacteria survived the methicillin treatments and reproduced at higher rates than did other individuals. Over time, these resistant individuals became increasingly common. -Staphylococcus aureus bacteria that were able to synthesize cell walls using a protein that was not affected by methicillin survived the methicillin treatments and reproduced at higher rates than did other individuals. Over time, these resistant individuals became increasingly common. -In response to treatment of Staphylococcus aureus infections with methicillin, bacterial populations gradually began to synthesize cell walls using a protein that was not affected by methicillin.
  • organisms had adapted to new environments, giving rise to new species
  • Staphylococcus aureus bacteria that were able to synthesize cell walls using a protein that was not affected by methicillin survived the methicillin treatments and reproduced at higher rates than did other individuals. Over time, these resistant individuals became increasingly common.
  • The first and fourth answers are correct.Members of a population vary in their heritable traits. Although organisms can produce huge numbers of offspring, many of these offspring do not survive.
  • Characteristics acquired during an organism's life are generally not passed on through genes.
Varieties of Staphylococcus aureus that are resistant to the drug methicillin _____. -developed in response to the use of methicillin -already existed in the population before methicillin was developed -always have an advantage in every environment -were strongly selected for as methicillin became widely used to treat bacterial infections -The second and fourth answers are correct.
  • humans and chimpanzees share a relatively recent common ancestor.
  • In this wild mustard, there is enough heritable variation to permit these different varieties.
  • The second and fourth answers are correct:-already existed in the population before methicillin was developed-were strongly selected for as methicillin became widely used to treat bacterial infections Resistant varieties existed in the population but did not confer any advantage until the environment changed with the introduction of the drug methicillin.
  • It must be homologous to some feature in an ancestor.Vestigial: A feature of an organism that is a historical remnant of a structure that served a function in the organism's ancestorsAnalogous: Having characteristics that are similar because of convergent evolution, not homology
#5 Part DWhich of the following organisms could be produced by artificial selection? -A cow that produces a large quantity of milk. -A chimpanzee that communicates through sign language. -A dog that serves as the "eyes" for a blind individual. -A rabbit that is housebroken.
  • Adaptation
  • A cow that produces a large quantity of milk.
  • isolated and show little ecological diversity
  • Large hen, large rooster
The greatest number of endemic species is expected in environments that are _____. -isolated and ecologically diverse -easily reached and ecologically diverse -easily reached and show little ecological diversity -isolated and show little ecological diversity
  • choose which organisms reproduce
  • humans and chimpanzees share a relatively recent common ancestor.
  • isolated and show little ecological diversity
  • all individual variation is due only to environmental factors
Which of the following observations led to Darwin's major inferences? -Members of a population vary in their heritable traits. -Body parts that are not used deteriorate over time. -Organisms only go extinct when catastrophes occur. -Although organisms can produce huge numbers of offspring, many of these offspring do not survive. -The first and fourth answers are correct.
  • organisms had adapted to new environments, giving rise to new species
  • Staphylococcus aureus bacteria that were able to synthesize cell walls using a protein that was not affected by methicillin survived the methicillin treatments and reproduced at higher rates than did other individuals. Over time, these resistant individuals became increasingly common.
  • The first and fourth answers are correct.Members of a population vary in their heritable traits. Although organisms can produce huge numbers of offspring, many of these offspring do not survive.
  • Characteristics acquired during an organism's life are generally not passed on through genes.
Part AWhich of the following statements about natural selection is true? -Natural selection favors individuals that reproduce more than others. -Natural selection occurs in opposition to evolution. -Natural selection is a process whereby genes are selected randomly for preservation in the next generation. -Natural selection can be used by farmers to generate organisms with desirable traits.
  • Natural selection favors individuals that reproduce more than others.
  • humans and chimpanzees share a relatively recent common ancestor.
  • Simple morphologies convey some advantage in most parasites.
  • Natural selection in an aquatic environment resulted in significant changes to whale forelimb anatomy
The upper forelimbs of humans and bats have fairly similar skeletal structures, whereas the corresponding bones in whales have very different shapes and proportions. However, genetic data suggest that all three kinds of organisms diverged from a common ancestor at about the same time. Which of the following is the most likely explanation for these data? -Whales are not properly classified as mammals. -Genes mutate faster in whales than in humans or bats. -Natural selection in an aquatic environment resulted in significant changes to whale forelimb anatomy. -Forelimb evolution was adaptive in people and bats, but not in whales. -Humans and bats evolved by natural selection, and whales evolved by Lamarckian mechanisms.
  • Triazine-resistant weeds were more likely to survive and reproduce.
  • Natural selection in an aquatic environment resulted in significant changes to whale forelimb anatomy
  • In this wild mustard, there is enough heritable variation to permit these different varieties.
  • Under particular circumstances that persisted for long periods, each of these structures presented greater costs than benefits.
The role that humans play in artificial selection is to _____. -determine who lives and who dies -perform artificial insemination -choose which organisms reproduce -create genetic diversity
  • isolated and show little ecological diversity
  • genetic variation among individuals
  • choose which organisms reproduce
  • A cow that produces a large quantity of milk.
Structures as different as human arms, bat wings, and dolphin flippers contain many of the same bones, which develop from similar embryonic tissues. These structural similarities are an example of _____. -the evolution of similar appearance as a result of common function -homology -convergent evolution -the evolution of common structure as a result of common function
  • Natural selection favors individuals that reproduce more than others.
  • Triazine-resistant weeds were more likely to survive and reproduce.
  • homologySimilarity in characteristics resulting from a shared ancestry
  • Simple morphologies convey some advantage in most parasites.
Darwin and Wallace's theory of evolution by natural selection was revolutionary because it _____. -proved that individuals acclimated to their environment over time -dismissed the idea that species are constant and emphasized the importance of variation and change in populations -was the first time a biologist had proposed that species changed through time -was the first theory to refute the ideas of special creation
  • dismissed the idea that species are constant and emphasized the importance of variation and change in populations
  • artificial selection, because changes in these traits co-occurred with human selection for high milk output and high muscle content
  • the fossil record
  • humans and chimpanzees share a relatively recent common ancestor.
Which of the following must exist in a population before natural selection can act upon that population? -the population has predators -genetic variation among individuals -sexual reproduction -variation among individuals caused by -environmental factors
  • all individual variation is due only to environmental factors
  • A cow that produces a large quantity of milk.
  • genetic variation among individuals
  • isolated and show little ecological diversity
Over long periods of time, many cave-dwelling organisms have lost their eyes. Tapeworms have lost their digestive systems. Whales have lost their hind limbs. How can natural selection account for these losses? -Natural selection cannot account for losses, but accounts only for new structures and functions. -The ancestors of these organisms experienced harmful mutations that forced them to lose these structures. -Under particular circumstances that persisted for long periods, each of these structures presented greater costs than benefits. -Natural selection accounts for these losses by the principle of use and disuse.
  • A and E This cross would result in an average corn yield of 189.5 bushels/acre and have a medium-high drought resistance, which is the best you can get for both traits.
  • artificial selection, because changes in these traits co-occurred with human selection for high milk output and high muscle content
  • Under particular circumstances that persisted for long periods, each of these structures presented greater costs than benefits.
  • In this wild mustard, there is enough heritable variation to permit these different varieties.
DNA sequences in many human genes are very similar to the sequences of corresponding genes in chimpanzees. The most likely explanation for this result is that -humans and chimpanzees share a relatively recent common ancestor. -convergent evolution led to the DNA similarities. -chimpanzees evolved from humans. -humans and chimpanzees are not closely related. -humans evolved from chimpanzees.
  • humans and chimpanzees share a relatively recent common ancestor.
  • homologySimilarity in characteristics resulting from a shared ancestry
  • Simple morphologies convey some advantage in most parasites.
  • Natural selection favors individuals that reproduce more than others.
Which of the following is(are) homologous to the bones in this image? (images of various animal bones)It's got the teradactal bone structure.
  • genetic variation among individuals
  • flipper
  • C
  • A - the cat one.The digits of a cat are homologous to those of these whale bones.
Starting from the wild mustard Brassica oleracea, breeders have created the strains known as Brussels sprouts, broccoli, kale, and cabbage. Therefore, which of the following statements is correct? -Heritable variation is low in wild mustard otherwise this wild strain would have different characteristics. -In this wild mustard, there is enough heritable variation to permit these different varieties. -In wild mustard, most of the variation is due to differences in soil or other aspects of the environment. -Natural selection is rare in wild populations of wild mustard.
  • In this wild mustard, there is enough heritable variation to permit these different varieties.
  • Triazine-resistant weeds were more likely to survive and reproduce.
  • Natural selection in an aquatic environment resulted in significant changes to whale forelimb anatomy
  • artificial selection, because changes in these traits co-occurred with human selection for high milk output and high muscle content
An adaptation is _____. -a trait that gives an organism a reproductive advantage in the current environment -an individual's attempt to conform to its environment -a trait that gives rise to a new species -the cause of natural selection -all of the above
  • A cow that produces a large quantity of milk.
  • all individual variation is due only to environmental factors
  • proposed natural selection as the mechanism of evolution Although Wallace submitted his work for publication first, Darwin's work was known to have pre-dated Wallace's work and was much more detailed; therefore, Darwin was given credit for the theory.
  • a trait that gives an organism a reproductive advantage in the current environment
From his observations of organisms in the Galapagos islands, Darwin reasoned that _____. -the organisms in the Galapagos had been specially created to thrive in that environment -the shape of a bird's beak does not affect its ability to survive and reproduce -organisms had adapted to new environments, giving rise to new species -all island species should be similar to each other -none of the above
  • organisms had adapted to new environments, giving rise to new species
  • Natural selection favors individuals that reproduce more than others.
  • Simple morphologies convey some advantage in most parasites.
  • humans and chimpanzees share a relatively recent common ancestor.
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