BIOL 1001 - EXAM 4 (Ch.14-17)

15.1 In a population of 100 hamsters, there are 30 total alleles for black fur. What is the frequency of the black fur allele?

** 0.15 (If there are 100 hamsters, there are 200 total alleles. Dividing 30 by 200 gives 0.15.)

15.2 If q in a population is 0.3, what is p?

** 0.7 (Remember that p + q = 1)

15.2 How many new, heritable mutations are estimated to occur in each human child?

** 1-2 (Mutations occur at a frequency of 1 per 100,000 copies of an allele, but each human carries many alleles.)

How many finch species did Darwin send to the British Museum?

** 13

17.2 Assume that you want to use radiometric dating to determine the age of a particular layer of rock. You are measuring the decay of radioactive potassium with a half-life of 1.25 billion years. How long would it take 75% of the radioactive potassium to break down?

** 2.5 billion years

16 Quiz How big do great white shark teeth get?

** 2.5 inches

16 Quiz Which of the following is a common reason for hybrid infertility?

** A common reason for hybrid infertility is the failure of chromosomes to pair properly during meiosis. (For this reason, hybrid sperm and eggs fail to develop)

16.2 Why do the abalones (a type of mollusk) rarely produce hybrids?

** Abalone eggs are surrounded by a membrane that can be penetrated only by sperm containing a particular enzyme (The enzyme allows the sperm to penetrate only the membrane of a member of the same species.)

17.6 Hominin fossils indicate that humans and their fossil relatives diverged from apes between 5 million and 8 million years ago in _____.

** Africa

What kind of structures is produced by convergent evolution?

** Analogous structures (Analogous structures come from two independent evolutionary lines arriving at a similar structure.)

A few of your friends are speculating about what humans will look like in the future. They know you're taking a biology class, so they ask you how human evolution will proceed in the next few centuries. How do you answer?

** Any traits that result in a human having more children will be increased in the population. (Remember that the only traits that increase in frequency are those that result in more offspring.)

Who invented the idea of the "ladder of nature"?

** Aristotle (This is an ancient concept of life progressing from imperfection to perfection.)

Adult male guppies use brightly colored patches to attract female mates. Juvenile guppies are colorless. The original predator in the Trinidad guppy experiment was the pike-cichlid, which feeds only on adult guppies. Populations with no pike-cichlid predators had more brightly colored adults than populations that lived with the pike-cichlid. The killifish is another predator that feeds on guppies, but it only feeds on juveniles. A population of guppies is taken from a pond with pike-cichlids and placed in a pond with killifish. What will happen to coloration in this population?

** Brightly colored males will become more common with each generation. (Because being brightly colored is an advantage to mating and the predator doesn't feed on adults, males with bright colors will have more offspring.)

17.4 What is the best explanation for why the arthropods, such as insects, spiders, and crabs, were the first animals to move onto land?

** By chance, they already possessed structures suited to life on land so the transition was easier. (An example of a structure is the exoskeleton that is waterproof and strong.)

Who first proposed the idea of natural selection as a mechanism for evolution?

** Charles Darwin (Darwin was the first to propose a correct mechanism for evolution, that of natural selection.)

17 Quiz Clay may have been important in forming larger molecules as a prerequisite to early life on Earth. Why?

** Clay particles attract molecules, thus bringing them sufficiently close together to allow chemical reactions between them.

Who was the first scientist to state that species change over time?

** Comte de Buffon (Georges Louis LeClerc, also called Comte de Buffon, was credited with the idea of species gradually changing.)

17 Quiz Which of the following was a successful seed-bearing plant that protected its developing seeds inside cones?

** Conifers

Which of the following answers is the most ancient homologous feature of all life?

** DNA as genetic material (All living things use DNA to store information, so it represents one of the most ancient homologous structures on the planet.)

17.1 DNA was not the first informational molecule in evolving cells. What choice best supports this statement?

** DNA can replicate only with the help of enzymes, but the code for enzyme construction is found in the DNA. (Stated another way, DNA requires proteins, but proteins also require DNA.)

Why was credit for the discovery of natural selection given to Charles Darwin and not Alfred Wallace?

** Darwin published a book in addition to presenting his paper on natural selection. (Both scientists received little support when they first presented their papers, but Darwin went on to publish a book on the subject (several books actually). The book had a much larger effect than the scientific paper.)

17.1 Because the mechanisms of the origin of life left no record, what would be the best approach to solving the mystery of the origin of life?

** Develop a hypothetical scenario and conduct laboratory investigations to determine if the scenario is chemically and biologically possible and plausible. (Most biologists suggest that the origin of life was the consequence of the working of natural laws.)

15.3 What is meant by directional selection?

** Directional selection favors an extreme version of a trait. (Directional selection refers to a shift in allele frequencies, not in the location of the population)

16.3 Who developed the biological species concept and recognized that speciation depends on isolation and genetic divergence acting on a pair of populations?

** Dr. Ernst Mayr (he was an ornithologist)

15.2 Which of the following would be a situation similar to genetic drift?

** Flip a coin twice and write down the results. Do this four times. The coin comes up heads each time. (Even though the frequency of heads and tails should be equal, when the coin is flipped a very few times, this frequency can shift to one side. This is similar to mating in a very small population.)

17 Quiz Flowering plants are pollinated by insects and other animals. What is the advantage of this method of reproduction?

** Flower pollination by insects and animals is much more efficient than pollination that relies on the wind.

17.5 Evolutionary history includes mass extinctions that are characterized by the sudden disappearance of a wide variety of species. What is another important consequence of mass extinctions?

** Following a mass extinction, there is always a burst of life's diversity. (New situations lead to adaptations of survivors of mass extinctions.)

Which of the following observations best indicates that living things evolved in different time periods?

** Fossil A always appears in a layer below fossil B. (The order of fossils, discovered by William Smith, strongly suggests an order of evolution.)

15.2 How do founder effect, genetic drift, and a bottleneck relate to each other?

** Founder effect and bottleneck are types of genetic drift. (Genetic drift doesn't have to be caused by a founder effect or a bottleneck, but these are two specific examples of genetic drift.)

15 Quiz What causes two different populations of the same species to have many of the same alleles, even if the alleles first arose after the populations had split?

** Gene flow occurs between populations.

In what way did the guppies in Trinidad help to support evolution?

** Guppies were more colorful in the absence of predators. (Once the disadvantage of being brightly colored was removed, the population shifted toward the advantage of color in attracting a mate.)

17 Quiz Humans are _____.

** Homo sapiens

The Galápagos Islands are cooled by the _____.

** Humboldt Current (The Humboldt carries cool water northward from Antarctica.)

15 Quiz In humans, the allele for Huntington's disease is dominant. What does this mean?

** Huntington's disease will occur in someone with both a healthy allele and a Huntington allele.

15.3 Why is natural selection based entirely on reproductive success?

** If more offspring carrying an allele are created, the frequency of the allele increases. (The more times an allele is passed on, the more common the allele becomes. In the next generation, the same successful allele will result in each of the offspring having many children as well.)

17 Quiz What does the endosymbiont hypothesis propose?

** It proposes that early eukaryotic cells acquired the precursors of mitochondria and chloroplasts by engulfing certain types of bacteria.

16.3 A recent biology graduate was studying the evolution of a particular organism when she realized that she did not have enough data to determine the particular order of recent evolutionary events that formed her species. Given this information, how would you suggest she interpret her findings?

** It seems that her findings are the result of the process of adaptive radiation. (It appears obvious that multiple speciation events took place)

Both Lamarck and Darwin proposed mechanisms to explain how evolution occurs. What was different about these mechanisms?

** Lamarck focused on genetic changes in an individual. Darwin focused on genetic changes in a population. (Lamarck's beliefs focused on genetic changes inside an individual, which we now know do not happen very often.)

17 Quiz Which of the following distinguishes a mammal from a reptile?

** Mammals suckle their young whereas reptiles do not.

16.3 Polyploidy is more common in plants than in animals. Why?

** Many plants can either self-fertilize or reproduce asexually, or both, but animals cannot. (Therefore, a polyploid plant is more likely to become a new, polyploid species.)

Which of the following experiments might disprove the "inheritance of acquired characteristics"?

** Measure the tail lengths of a population of mice. Cut the tails off and then let them breed. Show that the children's tails are no shorter than their parents' tails. (This would show that losing use of the tail has no effect on the length of the tail in a future generation.)

Which of the following observations by other scientists would have helped Lamarck to form a better mechanism for evolution than inheritance of acquired traits?

** Mendel's observation that genes are passed unchanged from parent to offspring (Mendel observed that genes do not change going from parent to offspring and this is contrary to Lamarck's model. Neither Darwin nor Lamarck had the benefit of Mendel's work, but Darwin's model of natural selection fits well with it.)

17.2 Which statement provides evidence for the endosymbiont hypothesis?

** Mitochondria, chloroplasts, and centrioles in eukaryotic cells each contain their own minute and unique supply of DNA. (Biologists have shown that this DNA is related to bacteria.)

Consider a population of bacteria that came from a single ancestor. Because bacteria reproduce asexually, there should be no variation in this population, but that violates the first postulate of natural selection. How is it then that this population of bacteria can still evolve?

** Mutations must occur to create new variety in the population. (Mutation is the ultimate source of new variety on which natural selection can act.)

15.2 Which of the following is true about natural selection?

** Natural selection acts on individuals. (Even though evolution occurs at the level of a population, natural selection as a cause of evolution acts on individuals to bring about this change in the population.)

17.5 What is an effect of continental drift on biological species?

** Over time, an organism adapted to a particular climate may find it difficult to survive in the climate change associated with continental drift. (Plate tectonics has moved wet tropical lands into temperate and arctic regions.)

17.1 Early scientists working on the theory of spontaneous generation, such as Louis Pasteur in France, were able to disprove the theory. What was the basis of Pasteur's work?

** Pasteur determined that microbial life appeared in broth only if sterile broth was exposed to existing microorganisms in the environment (The environmental microbes multiplied in the broth, giving the appearance of spontaneous generation.)

16 Quiz The new findings in shark evolution are the result of studying fossils found where?

** Peruvian desert

According to Darwin's natural selection, what is the smallest unit of evolution?

** Population (A population is the smallest group that can evolve. An individual cannot evolve and a species includes many populations.)

15.1 What does the Hardy-Weinberg principle explain?

** Populations do not evolve when a specific set of conditions occurs. (If all conditions of the Hardy-Weinberg principle are met, the population will not evolve. Therefore, breaking these conditions is the cause of evolution.)

17.1 Which of the following is generally accepted as the origin of living organisms?

** Prebiotic chemical evolution gave rise to progressively more complex molecules and eventually to living organisms (It helps to know that prebiotic means "before life.")

17.1 Which of the following is a true statement concerning the origin of life on Earth?

** Prebiotic synthesis was neither very efficient nor very fast. (It took a few hundred million years for large quantities of organic molecules to accumulate in the early Earth's oceans to give rise to life.)

17.2 The period in which life began on Earth is known as the _____ era.

** Precambrian (This was the time period from the origin of our solar system until about 1,000 million years ago.)

17.2 What is the most outstanding characteristic of prokaryotic cells?

** Prokaryotic cells do not have a nuclear membrane. (They do not have a true nucleus)

15.2 Why do most mutations occur?

** Random errors in DNA replication cause mutation. (Mutation is a random event caused by errors in duplication.)

16 Quiz Assume that a massive land bridge is formed between two continents, allowing a variety of species to expand their range. What might be an important evolutionary result of this?

** Species will diversify as they undergo adaptive radiation. (Many species will diversify but some species may not be able to compete and will become extinct.)

15.3 Why are elephant tusks unlikely to get much longer, even though the tusks have obvious advantages?

** Stabilizing selection will keep the trait at its current average length. (The advantages of long tusks are balanced by the disadvantages. Longer tusks may help with competition for mates, but they are heavy and make feeding difficult.)

Which postulate of natural selection is deliberately enforced by dog breeders using artificial selection?

** Survival and reproduction are not determined by chance. (In the wild, the ability to survive and reproduce is determined by the traits an organism possesses. A breeder chooses which traits are the very best and only allows individuals who have these traits to reproduce.)

16.3 What could lead members of a single species in a specific geographical area with a variety of habitats to evolve new traits?

** Survival in one habitat or another in a single geographical area will lead to the evolution of different traits in the two groups (Natural selection in species in the two different habitats may lead to the evolution of the two groups.)

16.3 Assume that several members of a particular species of mosquito inadvertently entered an airplane in Asia and were transported to the United States, where they thrived as an isolated colony. What is likely to occur over time?

** The colony could genetically diverge in isolation and a new species could be formed. (Genetic differences that develop between the population in Asia and the one in the United States prevent the two populations from interbreeding and the two become separate species.)

17.4 What was the evolutionary advantage of the modification of scales on reptiles to feathers on ancestral birds?

** The feathers helped retain body heat. (This made ancestral birds more active in cooler habitats and during the night.)

17.3 The evolution of large cells became an advantage by preventing predation, but also presented a major problem. What is it?

** The larger a cell becomes, the less surface membrane is available per unit volume of cytoplasm, making it difficult for the cell to distribute oxygen and nutrients and eliminate metabolic waste products. (Evolution provided multicellular organisms to solve the problem.)

15.1 You see a dog with completely black fur. What can you say about fur color genetics in this dog?

** The phenotype of the dog is black. (We cannot comment on the genotype of a dog with so little information. We can only see the phenotype.)

15.1 In a certain population of mice, the frequency of the brown fur allele is 0.4 and the frequency of the black fur allele is 0.6. In the next generation, the frequency of the brown fur allele drops to 0.3. What has happened in this population?

** The population has evolved. (From this limited information, we can only conclude that the population has evolved. We cannot say why this occurred.)

15.1 Which of the following is a correctly stated condition that must be true for a population to be in Hardy-Weinberg equilibrium?

** The population must be large (A small population could allow genetic drift to occur, which is a form of evolution.)

15 Quiz What condition is necessary for genetic drift to have a significant effect on a population?

** The population needs to be small. (Random changes in allele frequency are rare when a large number of individuals are mating.)

Which of the following correctly describes the evolution of roaches who were resistant to Combat®?

** The roach bait caused the population to evolve by selecting against roaches that preferred the bait. (A population evolved here because a force of natural selection, roach bait, favored one mutation over another.)

What can you conclude by looking at the following sequences from the cytochrome c gene of humans, mice, and an unknown organism? Human - ATGGTCTCTTT Mouse - ACGGTCTGTTC Unknown - ACGGTGTGTTC

** The unknown organism is more closely related to mice than to humans. (The unknown organism shares three changes from the human sequence with mice and has one unique change of its own.)

The human appendix is a tiny vestigial form of the cecum, a long tube in the intestines of many mammals, used for digesting plant matter. Why did this structure shrink in size during human evolution?

** There must have been an advantage to humans in having a smaller cecum. (Traits only change when the change aids in survival and reproduction.)

17 Quiz The earliest cells on Earth were primitive anaerobic bacteria. Why were they anaerobic?

** There was no oxygen gas in the early Earth's atmosphere.

17.6 An anatomical feature that distinguishes us from our closest relative, the apes, is a large, highly developed brain. Why would natural selection have favored an individual with a highly developed brain?

** These individuals would have been much more successful at completing the tasks required to stay alive, such as hunting for food. (Individuals who had a developed brain could learn, reason and act successfully.)

What conclusion can you make from comparing the bones in a bird wing, a bat wing, and a pterodactyl wing?

** These organisms share a common ancestor with each other. (The similarity of bone structure shows that the organisms have a common ancestor that had fore-limbs with particular bones.)

16.3 Cross-mating may occur between two different species but the resulting offspring survive poorly and are sterile. Why is this particularly important to endangered species that cross-mate?

** This can lead to extinction of particular species. (The formation of hybrids can cause declines in species numbers.)

Which postulate of natural selection is best supported by the work of Gregor Mendel?

** Traits are passed from parent to offspring. (Mendel detailed the mechanisms by which children inherit traits from their parents.)

Which of the following is necessary for evolution to occur?

** Variation must exist. (Without variation in a population, survival and reproduction would be random.)

16.2 Assume that you have found two squirrels that look very much alike. One was found on the north rim of the Grand Canyon and the other on the south rim. How could you prove that they are members of the same species?

** You would have to determine if they can interbreed and produce viable offspring. (They may not interbreed freely because they are geographically isolated from one another.)

17 Quiz What is the definition of a ribozyme?

** a catalytic RNA molecule

16.1 Which of the following best describes a "species"?

** a group of populations that evolved independently

16.3 Each branch of an evolutionary tree represents _____.

** a speciation event

16 Quiz What would be the result of cross-species fertilization between a male lion and a female tiger that produced a "liger"?

** a sterile hybrid (Hybrid infertility prevents hybrids from passing their genetic information to offspring, which blocks genetic flow between the two parent populations.)

16 Quiz Which of the following is speciation resulting from two populations becoming isolated from one another?

** allopatric speciation (The two species become geographically separated from one another and evolution occurs.)

15 Quiz Which of the following alleles is most likely to decrease in frequency in a population?

** an allele causing infertility (Infertile individuals cannot pass alleles on to the next generation, so the allele that results in infertility has heavy selection against it.)

Compare a bird wing to a butterfly wing. What kind of structure does this pair represent?

** analogous structure (Structures that are used for the same purpose, but share no evolutionary history, are analogous structures.)

16.1 A species is often defined as a group of interbreeding individuals within a natural population. What would be an exception to this definition?

** bacteria (Bacteria are defined as asexually reproducing organisms so they are unable to interbreed.)

15 Quiz Which of the following is represented by a wolf that hunts rabbits?

** biotic predator (The wolf is preying on the rabbits and is a biotic component of the rabbit's habitat.)

15.2 A forest fire kills off 90% of a rabbit population. What has occurred in this population?

** bottleneck (This population has been bottlenecked, a specific type of genetic drift.)

16.2 In what way could marine invertebrates that scatter gametes in the water prevent the sperm from one species from fertilizing the eggs of another species?

** by preventing the sperm from binding to or entering the egg of another species (Some sperm have a binding protein for attachment to specific eggs whereas others use an enzyme to penetrate a membrane surrounding the appropriate egg.)

16 Quiz Shark skeletons are mostly made of what?

** cartilage

The evolution of different beak sizes on finches in the Galapagos Islands is most similar to which of the following evolutionary events?

** change in leg length of transplanted Anole lizards (Lizards on the original island maintain their current leg length, but lizards on the new islands adapt to the different conditions there.)

16.1 A difficult task for the biologist trying to determine if a group of organisms is a separate species is __________.

** determining whether group members breed with organisms outside the group (The biological species concept is based on the observation that a member of a species is unable to breed successfully outside the group.)

17.6 A learned skill that accompanied early hominin evolution was their ability to _____.

** develop tools (One of the first uses of stone tools was to help prepare food for eating.)

Which of the following did Darwin observe during his time in the Galapagos Islands?

** different finch populations that appeared closely related (Each island had a population of finches with a slightly different lifestyle that was specific to the environment of that island.)

16 Quiz Which of the following is considered to be the most immediate cause of extinction?

** environmental change (Change can be in either the nonliving or the living parts of the environment.)

17.2 What evolutionary event followed metabolic release of oxygen into the atmosphere and gave cells a significant selective advantage?

** evolution of aerobic respiration mechanisms (The oxygen in the atmosphere was used to help metabolize food molecules more efficiently.)

The wing of a bat is homologous to the _____ of a whale.

** flipper

Which of the following can be used to show the gradual evolution of aquatic mammals from land-dwelling mammals?

** fossils (Fossils exist of many animals connecting land-dwelling mammals to whales and dolphins. The gradual loss of hind legs can be observed at many stages.)

What event has caused a shift in the developmental cycle of the mosquito?

** global warming (As temperatures have warmed, mosquitoes are now waiting later in the fall to go dormant.)

What is the relationship between the structures that form the gill pouches on human and fish embryos?

** homologous structures (Some homologous structures are only present in embryos. In fully formed organisms they have disappeared completely.)

16.2 Which of the following is an example of a postmating mechanism that limits formation of a hybrid offspring?

** hybrid inviability (Mating may occur, but the hybrid is not able to survive.)

15 Quiz Which of the following is a result of nonrandom mating within a population?

** inbreeding (If the members of the population mate only with the closest individual, the population can quickly become inbred. This can happen in a predator pack or in pockets of plants in a larger population.)

16 Quiz New evidence suggests that great white sharks evolved from a relative of what?

** mako sharks

15.3 Generation-to-generation change in the allele frequencies in a population is _____.

** microevolution

15 Quiz What is another word for gene flow in animal populations?

** migration

17 Quiz Which of the following are members of the class Mammalia and are known as primates?

** monkeys

16.2 Which one of the following is an important evolution concept that helps prevent organisms from mating across species boundaries?

** natural selection

When predatory snakes eat songbirds with the loudest songs, they are acting as agents of what?

** natural selection (Agents of natural selection often act by killing off individuals with a particularly extreme trait.)

15.3 Approximately 65 million years ago, a mass extinction occurred on planet Earth. Layers of soil dating back to this time contain large amounts of the radioactive element iridium. This indicates that a large asteroid or comet struck Earth, throwing up huge clouds of debris, which would block much of the sunlight. Food became very scarce. Half of the marine species and nearly all of the dinosaur species went extinct during this time. Soon after the cloud settled, the surviving species of mammals rapidly diversified and filled the niches left empty by the dinosaurs. What evolutionary event was represented by this asteroid collision and the resulting cloud?

** natural selection (Natural selection favored individuals with a phenotype that could survive and reproduce in this new, harsh environment. Entire species did not have a favorable phenotype and thus failed to reproduce.)

15.2 A patient has an infection of Streptococcus bacteria. She takes azithromycin, which kills off 99% of a bacterial population. All surviving bacteria are resistant to azithromycin. What has occurred in this bacterial population?

** natural selection (The antibiotic selected against any individual bacterium that didn't have resistance alleles.)

15.1 A biologist studying evolution starts with a single cell of E. coli and grows a population of one billion bacteria from it. Which rule of Hardy-Weinberg must be broken first before evolution will occur in this population?

** no new mutations (All of the bacteria are identical, so all allele frequencies are currently identical. To change allele frequencies, individuals must carry different alleles. Gene flow could also result in a difference in alleles, but this is somewhat difficult to accomplish because bacteria do not mate.)

15.2 Which term from the Hardy-Weinberg equilibrium represents the frequency of the homozygous dominant genotype?

** p 2 (Because p is the frequency of the dominant allele, the frequency of having two dominant alleles is p x p.)

15.3 On which of the following is natural selection based?

** phenotype (Natural selection cannot measure which alleles are present in an individual, only the phenotype they create.)

15 Quiz Which of the following is the smallest group that can evolve?

** population (Evolution is a change in the frequency of alleles in a population.)

17.4 A major reason reptiles were adapted to life on land was their ability to _____.

** produce shelled, waterproof eggs containing a supply of water (Reptiles were much more adapted to land than were early amphibians, which required a watery environment for their sperm and eggs.)

15.2 A dam is built on a river upstream of a population of trout. The trout experience a dramatic reduction in their habitat. What evolutionary event has likely occurred to this population?

** reduction in diversity due to a bottleneck

15 Quiz In the common phrase, "survival of the fittest," what determines how fit an individual is?

** reproductive success (Biology determines fitness by an individual's contribution to the next generation, not by physical strength or speed.)

16.3 The underlying factor that allows an organism to become a separate species is _____.

** sufficiently large genetic differences (The genetic differences must be large enough to prevent the organisms from interbreeding and producing vigorous, fertile offspring.)

16 Quiz Which of the following is the best definition of polyploidy?

** the acquisition of multiple copies of each chromosome (Acquisition of multiple copies of each chromosome has been a frequent cause of sympatric speciation.)

17.3 What was an important factor leading to early diversification of animals?

** the emergence of predatory lifestyles favoring those individuals with improved mobility and senses (The resulting individuals were better able to survive than their evolutionary predecessors.)

16.2 What is an example of temporal isolation?

** the male and female reproductive structures of different plant species maturing at different times, thus preventing pollination (This is aka time-related isolation.)

16.3 What is the best definition of speciation?

** the process by which new species form (Isolation and genetic divergence are critical for speciation to occur.)

What type of structure is the human tailbone?

** vestigial structure (The tailbone is a reduced, useless version of the tail.)

17.2 The evolution of photosynthetic organisms required a source of hydrogen for the synthesis of complex, high-energy molecules. What is the source of hydrogen for today's photosynthetic organisms?

** water (As water is broken down, the hydrogen is captured and oxygen is released as a by-product.)

17.2 What process evolved around 2.3 billion years ago that introduced significant amounts of free oxygen to the atmosphere?

** water-based photosynthesis (This process converts water and carbon dioxide to energetic molecules of sugar, releasing oxygen to the atmosphere as a by-product.)

16.3 What mutational event can cause a new species to arise nearly instantaneously?

**development of polyploidy (Polyploidy is a frequent cause of sympatric speciation.)

17.5 Part A: What are the chances of a woman giving birth to craniopagus twins? Part B: Which of the following is true concerning conjoined twins? Part C: You are a neurologist. A patient visits you, describing his symptoms as having two feet that are doing different things. What part of the brain do you focus on? Part D: Which of the following is currently problematic for the Hogan twins? Part E: Which of the following is true regarding surgery to separate craniopagus twins?

Part A: ** 1 in 2.5 million Part B: ** They are always identical. Part C: ** corpus callosum Part D: ** sight Part E: ** It has been successful only on young twins.

15.3 Part A: In a species of snail, dark-shelled individuals are better hidden from bird predators in the shady forest, while light-shelled individuals are better hidden in well-lit brushy edge areas. If there were no areas of intermediate brightness in this habitat, which type of selection would act on shell color in these snails? Part B: Small lizards have difficulty defending their territory, but large lizards are more likely to be preyed upon by owls. Which type of selection would act on body size in these lizards under these conditions?

Part A: ** Disruptive selection (Disruptive selection causes both extreme phenotypes (light and dark shells) to be favored over the intermediate phenotype.) Part B: ** Stabilizing selection (Stabilizing selection does not change the mean of the population; only the extreme phenotypes (large and small lizards) become less common)

Part A: Which of the following is currently thought to be true? Part B: You find a stray dog while out walking. Which of the following would convince you that it is a Carolina dog? Part C: You are a reproductive biologist interested in the mating behavior of dogs. How many times a year can you study the Carolina dog? Part D: You are interested in adopting a dog and want it to be an ancient breed. Which of the following should you pick? Part E: You are a zoologist studying hunting behavior of predators in the wild. What should you expect when observing Carolina dogs?

Part A: ** Dogs arrived in North America before European colonization. Part B: **It has a fishhook tail and it digs snout pits. Part C: ** 1 Part D: ** Basenji Part E: ** Hunting as a pack

15 Quiz Part A: You are a cattle rancher and will abide by the new legislation. Which of the following will you be allowed to do? Part B: What does the FDA think drug companies will do regarding voluntary label changes on antibiotics for livestock? Part C: Which of the following people is most likely to be against the new antibiotics legislation? Part D: Which of the following prompted the passing of the new legislation regarding antibiotic use in livestock? Part E: Which of the following is true?

Part A: ** Give antibiotics to an animal in your herd that is ill. Part B: ** They will comply with the new recommendations. Part C: ** The CEO of the National Pork Producers Council. Part D: ** The decreasing effectiveness of antibiotics in humans. Part E: ** Countries besides the U.S. have legislation in place regarding the use of antibiotics in livestock.

15.2 Part A: Which of the following events could NOT be caused by a population bottleneck? Part B: Which of the following statements about the amoeba population described at the end of the tutorial is true? Part C: True or False. In the example described in the tutorial, the red amoebas survived the catastrophic event, and all future generations of amoebas were red because the red amoebas had a higher reproductive rate than the blue ones.

Part A: ** Increased population size (By definition, a population bottleneck dramatically reduces the size of a population.) Part B: ** It is more vulnerable to extinction due to lack of genetic variation. (The amoebas might not have the variation necessary to adapt to future changes in the environment.) Part C: ** false (After the catastrophic event, all future generations of amoebas were red because all blue amoebas died during the catastrophe.)

16 Quiz Part A: Which of the following statements about reinforcement is true? Part B: A subset of a population of birds leaves its habitat and colonizes a nearby island. After many generations, the island sinks and the population of birds living on the island returns to its original habitat. Which of the following statements most accurately describes the two bird populations?

Part A: ** Reinforcement is a type of natural selection. Part B: ** The birds were separated by dispersal, meaning that one population migrated to an isolated location.

17.4 Part A: Which of these events occurred earliest in the history of Earth? Part B: Which of these events occurred most recently in the history of Earth? Part C: Which of these events occurred during the Paleozoic?

Part A: ** formation of oxygen Part B: ** first humans Part C: ** colonization of land by plants

15 Quiz Part A: The evolution of populations due to chance is? Part B: If color is an inherited trait in beetles, and birds are more likely to eat brown beetles than green beetles, Part C: In a population with brown and green alleles for color, genetic drift Part D: Color is an inherited trait in beetles. If brown beetles move into a population from a nearby island, which of the following statements is correct? Part E: Remember that color is an inherited trait in beetles. Which of the following is an example of natural selection?

Part A: ** genetic drift Part B: ** the frequency of the green allele will increase. Part C: ** has more effect on the evolution of a small population. Part D: **Gene flow causes the frequency of the brown allele to increase. Part E: ** Green beetles leave more offspring than brown beetles because they are better at finding food.

17 Quiz Part A: Based on the chemical make-up of the first self-replicating molecule, it most closely resembles the structure of certain types of: Part B: Self-replicating molecules are thought to have appeared about: Part C: The most likely location of where ribozymes developed is:

Part A: ** viruses Part B: ** 4 bil years ago Part C: ** in hot-springs

17 Quiz Part A: Except for modern ethnic groups in ______, the majority of humans appear to have traces of Neanderthal DNA in their genome. Part B: Research confirms that Neanderthal DNA makes up about ____ of the modern human genome. Part C: DNA was isolated from Neanderthal ____ and sequenced so that it could be compared to modern human DNA. Part D: Mating is believed to have taken place between modern humans and Neanderthals in ____ about 70,000 years ago. Part E: The Neanderthal DNA discovered in Homo sapiens is best explained by ____.

Part A: **Africa Part B:** 4% Part C: ** bone fragments Part D: ** the Middle East Part E: ** gene flow

16.1 Part A: According to most paleoanthropologists, which of the following is true? Part B: If your pituitary gland isn't functioning properly, which of the following will be affected? Part C: You are a paleoanthropologist studying Neanderthals. Where should you look for their fossils? Part D: What do paleoanthropologists generally believe about genetic findings? Part E: How do genomes of species change?

Part A: **When modern humans arose, archaic humans disappeared in Africa. Part B: **reproduction and growth Part C: ** Europe Part D: **Genetic findings need corresponding fossil evidence to be true. Part E: ** By mutations in DNA

17 Quiz Part A: After a long period of coevolution, the photosynthetic bacterium consumed by the predatory cell became the cellular organelle known as the: Part B: After a long period of coevolution, the aerobic bacterium consumed by the predatory cell became the cellular organelle known as the: Part C: The bacteria initially persist in the predatory cell because:

Part A:** chloroplast. Part B: ** mitochondrion. Part C: ** the predatory cell is unable to digest the bacteria.