bio test 1 (hw)
Evolution works by _____.
"tinkering" with existing structures
The distinct beaks and the musculature that each of the finch species has determines what food they are able to eat. Small-beaked birds eat smaller seeds, and larger-beaked birds eat larger seeds. Is this a product of evolution? - Based on the video and what you know about natural selection, which of the following must be true if evolution is the explanation for what the Grants have observed over time on Daphne? Select all that apply.
- Beak depth and length must be heritable. - Beak depth and length must show variation among individuals of a single species. - Beak depth and length must affect survival and/or reproduction of birds.
Darwin and Wallace independently arrived at the same conclusion that species change over time. Which observations supported their conclusions?
- Birdwing butterflies were found throughout the Malay archipelago, but species differed slightly from island to island. - The fossilized remains of giant sloths were similar to the smaller, living sloths Darwin encountered. - The bony shells of armadillos resembled fossilized shells from the extinct Glyptodon. - Tortoises from different Galapagos islands have distinct shells. - Bird families clustered geographically: cockatoos in the Malay Archipelago and Australia, macaws and hummingbirds in the Americas. - Mockingbirds from different Galapagos islands had subtle, consistent differences.
Darwin and Wallace made independent observations in different parts of the world. Which statements are true?
- Both witnessed nature up close and realized it was a battlefield with massive casualties. - Both collected huge numbers of specimens and realized that individuals vary within species. - Both observed slightly different species on nearby islands and concluded that species could change over time.
In the lab, Nachman examined dark mice from two different populations living hundreds of miles apart. The mice looked nearly identical. Their dark color was caused by two different genes. What does this tell you?
- Dark fur color evolved independently on each lava flow. - There are at least two genes involved in creating dark mouse fur. - Under very similar conditions, natural selection can favor very similar adaptations. - Two completely different mutations in two separate genes can generate the same phenotype.
No two species of anoles lizards living in the same geographical location have dewlaps of the same size, shape or color. Why?
- Differences in dewlaps keep different anole species reproductively isolated, even when they live together. -Dewlap color is under strong selection. Dewlaps that contrast with a lizard's environment are more effective for communication. - Male anole lizards use dewlaps to court females. - Female anole lizards distinguish males of their own species from males of other species by their dewlaps.
The branching pattern of a phylogenetic tree indicates whether taxa are closely or distantly related relative to other taxa in the tree. Use this phylogenetic tree to determine whether each statement is true or false.
- Fishes and chimps have no common ancestors. *False* - In this tree, lizards are the sister taxon of the lineage that includes humans and chimps. *True* - The taxon that shares the most recent common ancestor with frogs is fishes. *False* - Frogs and humans are more distantly related than are lizards and humans. *True*
How do multiple lines of evidence (from the field, the fossil record, and molecular genetics) work together to illustrate stickleback evolution?
- Genetic evidence reveals the precise molecular mechanism responsible for the change in pelvic structures in stickleback populations. - If the same morphological changes occur in the fossil record as in living populations, we might deduce that the genetic mechanism discovered in the living populations might be responsible for the changes observed in fossils. - Data obtained by analyzing living fish in lakes show the selective pressures present in different environments. - The fossil data show a pattern of evolution over long stretches of time.
Some monkey flowers (Mimulus guttatus) living near the sites of copper mines can grow in soil containing high concentrations of copper, which is toxic to most plants. Copper tolerance is a heritable trait. - Use the map to determine which of the statements below are true.
- If you were to test monkey flowers growing on the shore of the lake, you would expect nearly 100% of them to be copper tolerant. - Nearly 100% of monkey flowers growing in copper-contaminated soil are copper tolerant. - The population that existed before mining must have included both copper-tolerant and copper-intolerant plants.
During the rainy season, and just as the dry season starts, food is abundant for all finches. However, as the dry season wears on, the seeds they eat become harder to find and competition becomes an important factor in survival. When a serious drought lasting 2.5 years hit Daphne, the only finches that survived were the ones that could find enough food; seeds that they could not split open did not contribute to survival. Heavy mortality in a population means there is strong selection for heritable traits that help individuals survive and reproduce. For example, G. magnirostris eat large seeds, and G. magnirostris can outcompete all other finches. The Big Birds and G. fortis fight over smaller seeds and water holes, but the Big Birds are dominant to G. fortis because they are almost twice the size of G. fortis. - Given what you know about G. fortis, G. magnirostris, and the Big Bird lineage, what do you predict will happen as the drought continues?
- Immediate effects (top to bottom): individuals with large breaks die, most individuals thrive, many individuals outcompete smaller birds for large seeds - Long-term effects (top to bottom): beaks become smaller in the population, beaks remain large in the population, beaks remain the same size, and the population fills a larger niche, eating a greater variety of seeds
Why do some stickleback populations lack pelvic spines?
- In lakes with dragonfly larvae, pelvic spines can be disadvantageous, allowing the predatory larvae to grab the fish. - In lakes where there are no large predatory fish, there is no advantage to having pelvic spines.
What did researchers discover about the genetic mutation causing the loss of pelvic spines?
- It is found in a regulatory region (a "switch") upstream of the coding region of the Pitx1 gene. - It occurred in a similar DNA region in freshwater stickleback populations all over the world.
What does Dr. Carroll mean when he says, "while mutation is random, natural selection is not"?
- Mutations for advantageous traits are more likely to be passed on to the next generation. - Natural selection acts on traits. - Natural selection favors some mutations.
What observations and evidence have Jonathan Losos and his colleagues gathered to support the theory of natural selection?
- On each of the four large Caribbean islands, Losos observed the same distribution of anole lizard body types. - DNA evidence suggests that the different lizard body types (twig, grass, etc.) evolved independently on each of the four large Caribbean islands. - When Losos and colleagues transplanted tree-dwelling anoles to small, hurricane-scrubbed islands without trees, the lizards evolved to have shorter legs after only a few generations.
group of researchers gathered data on the number of cliff swallow road kills they observed while driving between nest sites in Nebraska. The data cover a period of about 30 years and date back to the time when cliff swallows first started to nest under highway overpasses.As the graph shows, the number of road kills observed declined sharply over time. The data led the researchers to ask themselves this question: What caused this decline? - Which of the following are testable hypotheses that could explain the researchers' data? Select all that apply.
- Scavenger population sizes have increased, and more road-killed swallows get eaten before they can be found. - Traits that help individuals avoid being hit by cars have evolved through natural selection in the cliff swallow population. - The population size of cliff swallows living near roads has decreased over time.
Identify the four postulates of natural selection.
- Some trait differences are heritable. - Individuals in a population vary in the traits they possess. - Individuals with certain traits are more likely to survive and reproduce. - Survival and reproductive success are variable among individuals in a population.
After his journey on the HMS Beagle, Darwin made this now-famous sketch in his notebook. Which ideas does it represent?
- Species descend from other species just as naturally as children come from parents. - All species are linked to one another by common ancestry. - All species are connected to one another in a "family tree."
Use the same diagram to determine whether each statement is true or false.
- Taxa D and E arose from a common ancestor and are sister taxa. *True* - Branch point 2 is the common ancestor shared uniquely by Taxa A, B, and C. *False* - Branch point 1 represents the common ancestor of Taxa A-F. *True* - Rotating the tree at branch point 2 would change the relationship between Taxa D and A. *False*
Select the statements about the K-T boundary that are true.
- The K-T boundary in Zumaia, Spain is sharp--representing an abrupt change in the marine ecosystem. - The K-T boundary separates rock layers of the Cretaceous period from those of the Tertiary period. - The K-T boundary dates to 65 million years ago (when the dinosaurs disappeared).
Gametes from two plant species combine and produce a haploid zygote, and that zygote develops into a haploid, hybrid plant. Why is the hybrid plant sterile?
- The cells do not contain homologous chromosomes. - Meiosis cannot occur.
Which observations led Darwin to establish a relationship between extinct and living animals?
- The fossilized remains of giant sloths were found in places where smaller sloths now live. - The bony shells of armadillos resembled the shells of ancient Glyptodon fossils.
How could an asteroid impact kill off such a large number of different species all over the planet?
- The impact was so extreme that life at ground zero was vaporized. - Debris from the impact orbiting around the Earth shielded sunlight, halting photosynthesis. - Tsunamis, landslides, earthquakes, and heat caused by the impact killed organisms near the site of impact.
The evolutionary history of a group of organisms can be represented in a branching diagram called a phylogenetic tree. Phylogenetic trees are visual representations of evolutionary relationships between organisms.
- The point at which two or more lineages diverge from their common ancestor is called a(n) *branch point* or node. - The horizontal line indicating a branch on a phylogenetic tree represents ancestral forms of the named taxon, thereby illustrating the *evolutionary lineage* leading to that taxon. - *Sister taxa* are groups of organisms that share a unique common ancestor not shared by any other groups. - Each branch tip on a phylogenetic tree represents a specific group of organisms known as a(n) *taxon*.
Based on these data alone, which of the following conclusions is consistent with the observed changes in genotypic frequency for A. gambiae and A. coluzzii?
- The r allele was present in A. gambiae before 2006 and increased over time because individuals with the r allele are resistant to insecticides and pass their resistant genes to new generations. - The r allele was not present in A. coluzzii before 2006, but was present in A. coluzzii populations after hybrid individuals carrying the r allele were observed in 2006. This suggests that A. gambiae ×× A. coluzzii hybrids mated with A. coluzzii individuals, leading to the transfer of the adaptive allele r into A. coluzzii populations.
Jonathan Losos and colleagues conducted experiments on small, hurricane-swept islands as "natural laboratories." Which of the following statements is true?
- There are many small islands with similar environments, meaning that researchers can repeat their experiments and observations in several locations. - Natural selection can lead to rapid changes. The average leg length of lizard populations decreased within a few generations. - Islands scrubbed by hurricanes allow researchers to introduce new lizard populations and observe their evolution.
The phylogenetic tree below shows the evolutionary relationships between the island fox subspecies and the gray fox. Drag the labels to their appropriate locations on the tree. - First, drag the labels of Group 1 to identify the common ancestors at the branch points. - Next, drag one label of Group 2 to identify the homologous characteristic. - Then, drag one label of Group 3 to identify the relationship between the two species.
- a: ancestor of gray foxes and island foxes - b: ancestor of santa rosa and san miguel foxes - c: dwarfism - d: ancestor of northern channel island foxes - e: most closely related - f: ancestor of southern channel island foxes - g: ancestor of island foxes - h: ancestor of santa catalina and san clemente foxes
Three of the most prominent definitions of species are the biological species concept, the phylogenetic species concept, and the morphological species (morphospecies) concept. Drag each characteristic to the appropriate bin based on the species concept(s) to which it applies.
- biological -- not applicable for extinct species - morphological -- relies on similarities in structure - phylogenetic -- based on evolutionary history - morphological and phylogenetic -- accommodates asexual reproduction -- species acceptance criteria can be subjective - morphological, phylogenetic, and biological -- used by scientists in
An amnion is a shared homologous characteristic for which of the following lineages?
- crocodiles - mammals
(Scientific evidence documents the pattern of evolution. The evidence exists in a variety of categories, including direct observation of evolutionary change, the fossil record, homology, and biogeography. Sort the following examples into the correct categories.) - fossil record
- discovery of transitional forms of horses - discovery of shellsof extinct species
Classify each event in the history of life into the appropriate eon or era. Drag each phrase to the appropriate bin.
- hadean eon -- orgin of earth - archaean eon -- oldest fossils of cells(prokaryotes) appear - Proterozoic eon -- oldest fossils ofeukaryotic cells appear - Paleozoic era -- first tetrapods and -- insects appear the Cambrian explosion - Mesozoic era -- origin of mammals -- dinosaurs evolve and radiate - Cenozoic era -- humans appear -- major radiation of pollinating insects
Use the data provided in the table to calculate the percent frequency of the +/+ genotype in A. gambiae over time (from pre-2006 to post-2006). Note that "frequency" refers to the proportional representation of an allele or genotype in a population. Indicate the percent frequency of the +/+ genotype in A. gambiae during the periods specified. For help with the calculations, see Hint 1.
- pre-2006: 30.0% - 2006: 34.8% - post-2006: 4.8%
Can you match these prefixes, suffixes, and word roots with their definitions?
- same: homo- (or homeo-) - behind: post- (or postero-) - food: -pod - first: prim- - joint: arthr- - chromosomes: ploid - both, double, two: amphi-
Can you match these prefixes, suffixes, and word roots with their definitions?
- same: sym- - first: proto- - true, good: eu- - with or together with: co- - equal: equi- - many: poly- - father: pater (or patr-) - other: allo-
(Scientific evidence documents the pattern of evolution. The evidence exists in a variety of categories, including direct observation of evolutionary change, the fossil record, homology, and biogeography. Sort the following examples into the correct categories.) - homology
- similarities in mammalian forelimbs - same genetic code in fireflies and tobacco plants - vestigial pelvis in right whales
(Scientific evidence documents the pattern of evolution. The evidence exists in a variety of categories, including direct observation of evolutionary change, the fossil record, homology, and biogeography. Sort the following examples into the correct categories.) - biogeography
- similarity of endemic island species to nearby mainland species - the high concentration of marsupial species in Australia
The researchers discovered that the 12 populations could be organized into 3 distinct species. Populations A, B, and C each belong to a different species. Use the data in the grid to sort each population to the species to which it belongs.
- species 1 (includes population A) -- K, D, F, H, I - species 2 (includes population B) -- L, E - species 3 (includes population C) -- G, J
Which evidence is consistent with the asteroid impact hypothesis?
- tektites, a type of melted rock - shocked quartz in the K-T boundary layer - spherules, glass-like beads in the K-T boundary layer - iridium
Each finch species has a distinct beak morphology (shape); that is, they have a distinct length and depth. Together, these two beak dimensions can determine what foods the birds will be able to eat. All finches eat seeds (among other things), but during the dry season, seeds are encased in dry, hard shells. The bigger, stronger muscles associated with larger beaks mean that large-beaked birds can crack open much harder shells to get to the nutritious seeds. The Grants collected the data represented in the graph. Each oval shows the distribution of bird beaks they measured in the population. F represents G. fortis, BB represents the Big Bird lineage, and M represents G. magnirostris. Use the graph to answer the following questions. - Drag the numbers and terms on the left to the sentences on the right. Not all numbers and terms will be used.
1. 8, 12 2. 18 3. G. magnirostris 4. G. fortis, G. magnirostris 5. lower right quadrant
The researchers decided to take a closer look at the data they had collected on the shape and length of the cliff swallows' wings. This graph compares the wing length data collected from cliff swallows that were killed on the roads (blue bars) and from cliff swallows in the general population (maroon bars). - Drag the terms on the left to the appropriate blanks on the right to complete the sentences. Not all terms will be used.
1. decreased 2. increased 3. longer 4. shorter 5. natural selection 6. adaptation, already present
The age of fossils can sometimes be determined by radiometric dating, which is based on the constant rate of decay of radioactive isotopes. The time required for half of a radioactive isotope to decay is called the half-life of that isotope. For example, the isotope carbon-14 has a half-life of 5,730 years. Suppose it is determined that a fossilized leaf contains 12.5% of the carbon-14 that was present when the fossil formed. How old is the fossil? Express your answer numerically.
1.72e4 years
Plant species F has a diploid number of 8. Plant species G has a diploid number of 10. What would be the diploid number of an allopolyploid hybrid of species F and species G?
18
Which of the numbers in this tree represents the most recent common ancestor of amphibians and lizards?
2
The Mesozoic era began approximately _____ million years ago.
251
The Precambrian time began at least _____ million years ago.
4,600
Which of the cells shown in the figure are eukaryotic cells?
5, 6, and 7
The Cenozoic era began approximately _____ million years ago.
65
A farmer wishes to develop a strain of high-yield corn that is also resistant to drought. He has the following individuals from the current year's crop: Individual A—Yield: 179 bushels/acre; drought resistance: highIndividual B—Yield: 220 bushels/acre; drought resistance: lowIndividual C—Yield: 185 bushels/acre; drought resistance: mediumIndividual D—Yield: 140 bushels/acre; drought resistance: highIndividual E—Yield: 200 bushels/acre; drought resistance: medium - Which of the following crosses would produce the highest corn yield with the highest resistance to drought?
A and E
What is genetic drift?
A change in allele frequencies caused by random events
Which of the following organisms could be produced by artificial selection?
A cow that produces a large quantity of milk.
In the projected video showing the growth of bacteria, why did the bacteria grow up to the edge of the area with antibiotics, pause, then continue to grow across the area with antibiotics?
A few bacteria experienced random mutations in their DNA, which allowed some of them to grow even though antibiotics were present.
What does it mean that organisms have a nearly universal genetic code?
A specific DNA sequence encodes the same information in one species as it would in nearly any other.
Which of the following statements about vestigial structures is accurate?
A vestigial structure in species A can be homologous to a functional structure in species B.
Which term describes a trait that increases an individual's ability to survive in a particular environment?
Adaptation
_____ is rapid speciation under conditions in which there is little competition.
Adaptive radiation
The theory of evolution through natural selection is considered a scientific theory because __________.
All of the listed answers are correct. - it is supported by a massive body of evidence from many discipline - sit is broad enough in scope to explain many observations - it is general enough to provide many testable hypotheses
Which of the following observations most strongly supports the common origin of all life on Earth?
All organisms use essentially the same genetic code.
Why are the large finches now living on the Galápagos Islands different from the original source population from a nearby island?
All three answers are correct. - Genetic drift occurred in the two populations. - The separation of habitats reduced gene flow between the populations. - Natural selection favored individuals that were more fit in the new environment.
_____ were the dominant vertebrate life form during the Paleozoic era.
Amphibians
Which of the following correctly describes what the video referred to as a "microbial cure"?
Antibiotics are used to kill all of the infectious bacteria in a person.
Which of the following statements best defines artificial selection?
Artificial selection is a process in which humans decide which plants and/or animals will and will not breed.
The cow Bos primigenius (which is farmed for meat and milk) has a smaller brain and larger eyes than closely related species of wild ungulates. Which of the following statements best describes the process that led to differences between domesticated/farmed cows and their wild relatives?
Artificial selection resulted in changes in the lineage leading to domesticated cows because humans wanted animals with high milk output and high muscle content.
The scientific community was slow to accept the asteroid impact hypothesis. Why?
At the time, most geologists thought that the Earth changed slowly and gradually, and not by major catastrophes.
Over time, bacteria have become increasingly resistant to antibiotics. Which of the following best explains this in terms of natural selection?
Bacteria that happen to have natural resistance to antibiotics survived and reproduced.
What happened in the soapberry bug population in central Florida when the bugs began to feed on seeds from the goldenrain tree fruits which are much closer to the fruit surface?
Bugs with shorter beaks had more access to food, allowing them to produce more offspring.
If x indicates the location of fossils of two closely related species, then fossils of their most-recent common ancestor are most likely to occur in which stratum?
C
The figure shows an outcrop of sedimentary rock whose strata are labeled A-D. - If x indicates the location of fossils of two closely related species, then fossils of their most-recent common ancestor are most likely to occur in which stratum?
C
What question did the researchers ask?
Can predation result in selection for color patterns in guppies?
Cotton-topped tamarins are small primates with tufts of long white hair on their heads. While studying these creatures, a scientist noticed that males with longer hair get more opportunities to mate and that they father more offspring than males with shorter hair. Which of the following possible studies would be the best design for testing if longer hair is an adaptive trait? Assume that hair length is a trait that is inherited.
Capture a group of males with long hair at random, and cut the hair very short in half of the males; then, compare the number of matings of males with their hair left unchanged vs. males with shortened hair. Submit
We are living during the _____ era.
Cenozoic
Suppose that a phylogenetic tree were constructed using the data shown in this table. Mosses represent the outgroup.
Cherries and peas are each other's closest relatives.
Which of the following conclusions is most consistent with the information in the evolutionary tree shown above?
Crocodiles are more closely related to hawks than to lizards.
Why do researchers use rRNA in investigations of relationships between taxa that diverged hundreds of millions of years ago?
DNA coding for rRNA changes relatively slowly.
Which of the following statements best describes Darwin's theory of evolution by natural selection?
Darwin's theory emphasized that populations vary and change over time.
What is the meaning of Darwin's expression "descent with modification"?
Descent with modification refers to evolutionary change over time.
DNA evidence suggests that anole lizard species from the four largest Caribbean islands are related as shown in the figure. Which statement is true?
Different body types evolved repeatedly and independently on each island.
What is the most important characteristic of anole lizard species that keeps members of one species from mating with members of another species?
Different species living in the same habitat have different dewlaps.
_____ were the dominant vertebrate life form during the Mesozoic era.
Dinosaurs
Which of the following statements about evolutionary trees is accurate?
Evolutionary trees are considered evolutionary hypotheses.
How do foraminifera found in rock layers above the K-T boundary compare to those in rock layers below?
Foraminifera above the boundary are smaller and less diverse than those below.
Which of the following best describes the change in kdr genotype frequencies over time in A. coluzzii?
From pre-2006 to post-2006, the frequencies of the r/r and +/r genotypes increased dramatically while the frequency of +/+ decreased dramatically.
Which of the following best describes the change in kdr genotype frequencies over time in A. gambiae?
From pre-2006 to post-2006, the frequency of the r/r genotype increased dramatically while the frequencies of +/+ and +/r genotypes decreased dramatically.
Daphne can be a hard place to live. Because the island is small, resources can be limited. Shifts in population numbers and morphology occurred when G. magnirostris colonized the island, and again when the Big Bird colonized Daphne and bred. - What would happen if another species came to the island? - Given what you know about the birds on Daphne, predict what would happen to the native species with each type of colonizing finch. Assume that the colonizing bird is superior to the native birds at foraging.
From top to bottom: - Immediate consequences: small native birds starve so only the larger natives pass on their genes, native birds with genes for larger beaks starve, native birds starve - Native population responds by: getting larger over generations, getting smaller over generations, population numbers drop - long-term outcome: the native species begins to overlap somewhat with big birds in morphological space, the native species begins to overlap somewhat with big birds in morphological space, the native species goes extinct on the island
To test their hypotheses, the researchers examined the data they collected during the period of study. Using the information available to them, they assessed whether the population sizes of cliff swallows and potential scavengers living near highways had changed over time. They determined how traffic patterns on these roads had changed over time. They also measured the bodies of cliff swallows that had been killed on the roads and compared their features to the features of cliff swallows in the general population. The table below summarizes the researchers' findings. - Drag the Group 1 labels onto the table to identify the data that is relevant to each hypothesis. Then use the Group 2 labels to indicate whether each hypothesis is supported or not supported by the data.
From top to bottom: - data collected: the wing shapes of swallows killed on roads differ from those of the general population, the total number of cliff swallow nests near roads increased during this time, avian scavengers did not increase during this time, and terrestrial scavengers probably did not increase, car traffic stayed the same or increased during this time - hypothesis supported?: yes, no, no, no
Iridium is a component of cosmic dust that rains down upon the earth at a constant rate. Why did Luis Alvarez suggest measuring iridium levels in the K-T boundary?
He was looking for a way to determine how quickly the layer had been deposited.
Fossil evidence indicates that modern whales and other cetaceans (dolphins and porpoises) are closely related to even-toed ungulates (hippopotamuses, pigs, deer, and cows). Which of the following predictions would you make if you wanted to test this idea using the amino acid sequence of hemoglobin?
Hemoglobin sequences of whales will be more similar to hippopotamuses than to horses.
Which term describes the ability of a trait to be passed on to offspring?
Heritability
Which of the following statements is an accurate combination of postulates 1 and 2 of natural selection?
Heritable variation exists for traits among individuals in a population.
When dark-colored fur gives mice a 1% competitive advantage and 1% of the population begins with dark fur, in about 1000 years, 95% of the population will have dark fur. Which of the following statements is true?
If dark-colored rock pocket mice had a competitive advantage of 0.1%, it would take longer for 95% of the population to have dark fur.
A population of birds colonizes an area in which the insects upon which they feed live inside trees. Which of the following events accounts for an observed increase in average beak size in the bird population over time?
Increased fitness of large-beaked birds, leading to natural selection
Which of the following statements is an accurate combination of postulates 3 and 4 of natural selection?
Individuals experience differential success in their ability to survive or reproduce due to differences in certain traits.
Which of these conditions do NOT occur in populations evolving due to natural selection?
Individuals pass on most traits that they acquire during their lifetime.
It has been observed that organisms on many islands are different from, but closely related to, similar forms found on the nearest continent. Which of the following possible conclusions is best derived from this observation?
Island forms are descended from mainland forms.
The sequence of events illustrated in this figure results in a fertile hybrid plant called an allopolyploid. Which of the following statements is the most complete description of an allopolyploid?
It contains more than two sets of chromosomes, which are derived from two species.
What role does nondisjunction play in the formation of a fertile allopolyploid hybrid?
It doubles the chromosome number in the hybrid.
Which of the following statements is accurate about an organ described as vestigial?
It must be homologous to some feature in an ancestor.
Which pair of chickens should a farmer breed to produce larger chickens?
Large hen, large rooster
Which of the following statements best describes Linnaeus' method of classifying organisms?
Linnaeus grouped organisms into increasingly more inclusive categories.
Fossils of Thrinaxodon, a species that lived during the Triassic period, have been found in both South Africa and Antarctica. Thrinaxodon had a reptile-like skeleton and laid eggs, but small depressions on the front of its skull suggest it had whiskers and, therefore, fur. Thrinaxodon may have been endothermic (able to generate its own internal heat). Which of the following statements is likely most accurate about Thrinaxodon?
Mammals evolved from a relative of Thrinaxodon.
What did Wallace conclude from observing that the bones in manatee flippers look similar to the bones in a human arm and hand?
Manatees' arm and finger bones are evidence that manatees share a common ancestor with land mammals.
Identify the pair of homologous structures.
Maple leaf and oak leaf
Dinosaurs went extinct during the _____.
Mesozoic
Flowering plants first appeared during the _____.
Mesozoic
When Charles Darwin set sail on the HMS Beagle, what did he and most of his contemporary scientists think about the origin of species?
Most scientists, including Darwin, thought each species was specially created by God in its present form and did not change over time.
Which of the following statements best represents a conclusion that Cuvier made when he considered the fossils found in the vicinity of Paris?
Multiple catastrophes caused extinctions and then species from other areas repopulated emptied areas.
Which of the following statements about natural selection is true?
Natural selection favors individuals that reproduce more than others.
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?
Natural selection in an aquatic environment resulted in significant changes to whale forelimb anatomy.
Does the ability of a Mycobacterium tuberculosis cell to infect a new host depend on its drug-resistant phenotype?
No, drug-susceptible cells and drug-resistant cells are equally likely to infect a new host.
Which of the following statements is most consistent with data obtained from the fossil record?
Older strata carry fossils that differ greatly from living organisms.
A particular antibiotic kills 99% of a bacterial population. What will be the result of the continued application of this antibiotic?
Over time, the antibiotic will become less effective at killing the bacteria.
Bony fish first evolved during the _____ .
Paleozoic
Most modern animal phyla evolved during the _____ era.
Paleozoic
Reptiles first appeared during the _____ era.
Paleozoic
Seed plants first appeared during the _____.
Paleozoic
Which of the following statements best describes evolution?
Populations change genetically from one generation to the next.
Animals first appeared during the _____.
Precambrian
Life arose during the _____.
Precambrian
The first prokaryotic cells appeared during the _____.
Precambrian
What was the researchers' main hypothesis?
Predation results in selection for more drab color patterns in guppies.
What conclusion would you draw from the data presented?
Predation results in selection for more drab coloration in pike-cichlid pools.
Why do some scientists believe that RNA, rather than DNA, was the first genetic material?
RNA has both information storage and catalytic properties.
Which of the following statements about reinforcement is true?
Reinforcement is a type of natural selection.
Which of the following statements is most accurate in comparing scientific theories and scientific hypotheses?
Scientific theories are supported by, and make sense of, many observations, whereas scientific hypotheses are narrow, testable ideas.
Based on the character table in Part B, which of the following statements about shared derived characters in plants is correct?
Seeds are a shared derived character of pines, cherries, and peas.
Within six months of effectively using methicillin to treat S. aureus infections in a community, all new S. aureus infections were caused by a resistant strain (MRSA). How can this best be explained?
Some drug-resistant bacteria were present at the start of treatment, and natural selection increased their frequency.
How did some stickleback populations come to live exclusively in fresh water?
Some stickleback populations became trapped in lakes that formed at the end of the last ice age.
Which of the following observations helped Darwin shape his concept of descent with modification?
South American temperate plants are more similar to South American tropical plants than to European temperate ones.
Currently, two living elephant species (X and Y) are classified in the genus Loxodonta, and a third species (Z) is placed in the genus Elephas. Thus, which of the following statements would be accurate?
Species X and Y share a greater number of homologies with each other than either does with species Z.
Which of the following is an observation or inference on which natural selection is based?
Species produce more offspring than the environment can support.
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?
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.
Based on this tree, select the correct statement.
Taxon A is the sister taxon of the lineage that includes Taxa B and C.
Soapberry bugs use needlelike "beaks" to feed on seeds within the fruits of various plants. Bugs feed most successfully when their beak length matches the size of the fruit on which they are feeding. For 25 years, populations of soapberry bugs in central Florida have been feeding on small goldenrain tree fruits that were introduced to the area, rather than on the larger native balloon vine fruits that serve as food for other soapberry bug populations. Beak lengths of soapberry bugs are variable, but the average beak length is shorter in soapberry bug populations that feed on goldenrain tree fruits than in populations that feed on balloon vine fruits, as shown in the graph. How does natural selection act on beak length in soapberry bug populations?
The action of natural selection on beak length in soapberry bug populations varies with the environment.
Which of the following conclusions is consistent with the information in the evolutionary tree?
The amnion occurs in mammals, birds, and lizards.
In the United States today, about half of the corn crop is genetically engineered with a protein that is toxic to corn borers, an insect pest of corn. Which of the following conditions would be necessary for evolution of resistance to the toxic protein to occur in the corn borer?
The corn borer must have or generate (by mutation) heritable variation in resistance to the toxic protein. The resistant corn borers must survive better or reproduce more than nonresistant corn borers. Submit
Which of the following statements describes the evolution by natural selection of Mycobacterium tuberculosis bacteria in their new environment?
The drug-resistance trait is an adaptation to the environment in which human hosts are medicated with the antibiotic rifampin.
Members of two different species possess a similar-looking structure that they use in a similar way to perform about the same function. Which of the following observations would suggest that the relationship more likely represents homology than convergent evolution?
The embryological development of the two structures are similar.
Which of the following observations led to Darwin's major inferences?
The first and fourth answers are correct.
There are a group of 13 related species of birds on a group of about 20 isolated oceanic islands. These species are grouped into four subgroups, with subgroup 1 evolving first (3 species), subgroup 2 evolving second (1 species), subgroup 3 evolving third (5 species), and subgroup 4 evolving last (6 species). If subgroup 4 evolved most recently, then which of the following statements is the most logical prediction?
The genomes of subgroup 4 should be more similar to each other than to the genomes of subgroup 3.
What can you conclude about the lungfish lineage based on this tree?
The most recent common ancestor of lungfishes and amphibians did not have an amnion.
Continental drift (plate tectonics) has moved continents around the globe. Which of the following predictions would be most likely?
The most recently separated continents will have the most closely related species.
Which observation supports the position of eukaryotes at the convergence of the "ring of life"?
The nuclear genome of eukaryotes contains genes from archaeans and from bacteria. Submit
Based on these observations, do you think that the number of malaria cases will increase, decrease, or stay the same in the future?
The number of malaria cases will increase.
Claytonia virginica is a plant with flowers that vary from white, to pale pink, to bright pink. Slugs prefer to eat pink-flowering over white-flowering plants (due to chemical differences between the two), and plants experiencing severe herbivory are more likely to die. The bees that pollinate this plant also prefer pink over white flowers, so that Claytonia with pink flowers produce more seeds than Claytonia with white flowers. A researcher observes that the percentage of different flower colors remains stable in the study population from year to year. Given no other information, if the researcher removes all slugs from the study population, what do you predict will most likely happen to the percentage of flower colors in the population over time?
The percentage of pink flowers will increase over time.
Bell and collaborators painstakingly documented a population of fossil sticklebacks from an ancient freshwater lake over a 20,000-year period. The prevalence of sticklebacks with full and reduced pelvises changed over time. Which is true?
The population of fish with pelvic spines that arrived in the lake at time B evolved a reduced pelvis over time (beginning at time C).
A subset of a population of birds leaves its habitat on the mainland and colonizes a nearby island. The birds, after a period of time, become reproductively isolated. The island sinks and the population of birds that lived on the island returns to its original habitat. Which of the following statements about these bird populations is true?
The populations will not be able to interbreed because they are different species.
Look at this character table. Rattlesnakes (like turtles) are reptiles, yet they do not have four limbs. In fact, they have no apparent limbs.
The presence or absence of four limbs, on its own, could be misleading when considering the evolutionary relationships of rattlesnakes.
A group of small fish live in a lake with a uniformly light-brown sandy bottom. Most of the fish are light brown, but about 10 are mottled. This fish species is often prey for large birds that live on the shore. A construction company dumps a load of gravel in the bottom of the lake, giving it a mottled appearance. Which of these statements presents the most accurate prediction of what will happen to this fish population?The proportion of mottled fish will increase over time.
The proportion of mottled fish will increase over time.
Varieties of Staphylococcus aureus that are resistant to the drug methicillin __________.
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
DDT was once considered a "silver bullet" that would permanently eradicate insect pests. Instead, DDT is now largely ineffective against many insects. Which of the following possible actions would have had the best chance of preventing this evolution of DDT resistance?
The use of DDT should have been interspersed with the use of other pesticides that have a different mode of action.
What is the concern about using antibacterial and antimicrobial soaps?
The use of any chemical that kills bacteria can eventually lead to resistance to that chemical in the population of bacteria.
As Wallace traveled the Malay Archipelago, he noticed that western islands had placental mammals, like monkeys. Eastern islands had marsupial mammals, like kangaroos. How did Wallace explain this distribution?
The western islands were once connected to Asia and the eastern islands had been connected to Australia. The islands had never been connected to each other.
Starting from the wild mustard Brassica oleracea, plant breeders have created the strains known as Brussels sprouts, broccoli, kale, and cabbage. Which of the following statements is correct with regard to the wild mustard?
There is enough heritable variation in the wild mustard to permit these different varieties.
Why do dark-colored rock pocket mice on dark lava flows have white bellies?
There is no selection for dark bellies by visual predators.
A species of mouse that is preyed on by owls (which can see color) at dawn and dusk varies in coat color between dark and light brown. Under which of the following conditions will NO evolution occur if climate change results in the soil color becoming darker?
There is no variability in the genes that control coat color.
The diagram shows two sets of islands. Group A is located 2,500 kilometers from the nearest mainland, whereas Group B is located about 25 kilometers from the mainland. Which of the following statements is most likely accurate in comparing the number of unique species (that is, that had evolved in that place) in Island Groups A and B?
There will be more unique species in Island Group A.
If the bacterium Staphylococcus aureus experiences a cost for maintaining one or more antibiotic-resistance genes, what would be most likely to happen in environments that lack antibiotics?
These bacteria would be outcompeted and replaced by bacteria that have lost the antibiotic resistance genes.
Why did dark-colored rock pocket mice first appear in a population of light-colored rock pocket mice?
They have a genetic mutation that affects their fur color.
Suppose that after 22 months, guppies from the transplanted population were returned to the source pool. What would most likely happen to those guppies?
They would experience a higher rate of predation than the native population, and over time they would evolve and resemble the original source population.
The tree includes the most recent common ancestor of all living species of bears (branch point 1). What does this tell you about this phylogenetic tree?
This phylogenetic tree is rooted.
Why did Kingsley and his team cross marine and freshwater sticklebacks?
To find the location of the gene(s) causing the difference between stickleback populations with and without spines.
Which of the following statements is accurate if we view evolution both as a pattern and a process?
To study evolution as a pattern we draw on information from many other scientific fields, while to study evolution as a process we study factors that cause changes in populations.
How did the types of data the researchers collected enable them to test their prediction?
Tracking the number and area of colored spots provided a quantitative way to compare the brightness of different populations.
A farmer uses triazine herbicide to control pigweed in his field. For the first few years, the triazine works well and almost all the pigweed dies; however, after several years, the farmer sees more and more pigweed growing once again in the fields. Which of the following statements best explains the return of pigweed to the farmer's fields?
Triazine-resistant weeds were more likely to survive and reproduce than were non-resistant individuals.
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?
Under particular circumstances that persisted for long periods, natural selection reduced each of these structures because they presented greater costs than benefits.
Which one of the following researchers developed a theory of evolution that was very similar to Charles Darwin's?
Wallace
Researchers further hypothesized that if predation pressure is reduced, drab coloration would become less beneficial (since females prefer brightly colored mates). Based on this hypothesis, what prediction did the researchers test in this experiment?
When guppies with drab colors are transferred to a pool with only killifish, the transplanted population will evolve brighter colors than the original source population.
Do these observations indicate that hybridization can lead to the transfer of adaptive alleles?
Yes; the r allele was not present in A. coluzzii before 2006, but was present in A. coluzzii populations once hybrid individuals carrying the r allele were observed in 2006.
Mutations are always _________.
a change in an individual's DNA
Which of the following observations would provide evidence supporting Lamarck's proposed evolutionary mechanism of "inheritance of acquired characteristics"?
a decrease in tail length in dogs after 20 generations of dogs that had their tails docked (cut off) as puppies
Based on the revised branch of the tree, what kind of group do brown bears plus ancestral species 7 represent?
a paraphyletic group
An adaptation is __________.
a trait that gives an organism a reproductive advantage in the current environment
According to the biological species concept, individuals belong to the same species if they can interbreed in nature and produce viable, fertile offspring. Prezygotic and postzygotic barriers ensure that members of different species do not reproduce with one another. This diagram shows some of these barriers along with examples of the barriers at work.
a. prezygotic barriers b. postzygotic barriers c. behavioral isolation d. mechanical isolation e. temporal isolation f. gametic isolatiom g. reduced hybrid fertility h. two fish species spawn at different depths I. a coral's sperm can't fertilize another's eggs j. offspring of two newts are sterile k. lion-tiger hybrids don't reach maturity
If we assume the alien with a tail stalk is an outgroup, what is the most likely phylogenetic tree based on these shared derived characters? When did these characters appear during the aliens' evolutionary history? Drag the aliens and shared derived characters to their appropriate locations on this phylogenetic tree.
a. spring tail b. fourth eye c. second tail d. grasping hand e. straight tail f. yellow coil tail g. blue coil tail h. purple 2 coil tail i. green 2 coil tail
Based on the results of the 2000 study, how should the portion of the tree extending from branch point 7 be altered?
abc brown bear and polar bear closest related, and then mainland brown bear
Mass extinctions create conditions that promote _____.
adaptive radiation
The appearance of an evolutionary novelty promotes _____.
adaptive radiation
The different finch species found on the Galápagos Islands probably arose as a result of _____.
adaptive radiation
Feathers either play a role, or may have played a role, in _____.
all of these - gliding - courtship - extended hops - flight
Which of the following lineages are not nested within the reptiles?
amphibians
Which of the following factors would most likely cause an increase in population size of a prey animal?
an improvement in eyesight
Given what we know about evolutionary biology, which of the following places would be the most likely to have the highest number of species that are unique to the area (that is, that had evolved in that place). Assume that the conditions have existed for at least a few million years.
an isolated group of ocean islands
Of the following anatomical structures, which is most homologous to the bones in the wings of a bird?
bones in the flippers of a whale
Darwin used the phrase "descent with modification" to explain which of the following ideas?
both the unity and diversity of life
Which branch point represents the most recent common ancestor of all bears?
branch point 1
Which branch point represents the most recent common ancestor of the sloth bear and the spectacled bear?
branch point 2
Which branch point represents the most recent common ancestor of the Asian black bear and the brown bear?
branch point 4
Which of the following characteristics is most likely an adaptation?
bright colors of prairie flowers
Two animals are considered members of different species if they _____.
cannot mate and produce viable, fertile offspring
(Scientific evidence documents the pattern of evolution. The evidence exists in a variety of categories, including direct observation of evolutionary change, the fossil record, homology, and biogeography. Sort the following examples into the correct categories.) - direct observation of evolutionary change
development of drugresistance in bacteria
During the origin of the eukaryotic cell, it is thought that engulfed bacteria
did not initially have a mutually beneficial relationship with their hosts, but later evolved one.
Emerald ash borers are beetles whose larvae eat the leaves of ash trees. Without treatment of the trees, the beetles usually kill all ash trees in an area within 10 years. Which of the following events would provide the best possible avenue for saving the ash trees?
discovery of a gene in ash trees that prevents feeding by emerald ash borers and subsequent breeding of more ash trees with this chemical
A challenge to traditional (pre-1860) ideas about species came from embryology, when it was discovered that _____. See Concept 22.3 (Page)
embryos of dissimilar organisms, such as sharks and humans, resemble each other
In the video, what does the UK's Chief Medical Officer suggest for promoting the development of new antibiotics?
encouraging big pharmaceutical companies to start investing again in new drug research and development
Animals that possess homologous structures probably _____.
evolved from the same ancestor
Which of the following observations helped Darwin agree with Lyell that Earth was more than a few thousand years old?
experiencing an earthquake and seeing fossils of ocean organisms high in the Andes
True or false? The last ice age produced many different species mainly because populations dispersed and colonized new habitats.
false
The wing of a bat is homologous to the _____ of a whale.
flipper
A certain species of salamander was split into two populations by a wide, dry valley, and the populations began to diverge from each other. After a period of time, some members of the two populations began to interbreed in a hybrid zone at the southern end of the valley. Only weak reproductive barriers existed by this time, so the two populations could freely interbreed and re-establish gene flow. This outcome in a hybrid zone is known as _____.
fusion
What is the most important factor that holds a gene pool of a species together and prevents speciation?
gene flow
Based on this tree, which of the following groups of organisms is most closely related to crocodiles?
hawks
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 ________.
homology
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.
Turtles are not shown on this tree. Turtles are evolutionarily more closely related to lizards than they are to frogs.
humans and chimps closes related to turtles and lizards and fishes is furthest from the other
Which of the following would help strengthen the researchers' conclusion?
if no other characteristics differed significantly between the source and transplanted populations
Which of the following is(are) homologous to the bones in this image? (looks like four fingers with the middle two super long)
image thats a brown ankle looking thing
Which of the following statements best describes the effect of natural selection on a population?
improved match between a population and its environment
Which of the following factors contribute to limiting the capacity of organisms to overreproduce?
inability of individuals to tolerate the physical conditions, lack of food, and mortality from predators
Antibiotic resistance in bacteria is an increasingly dangerous public health problem. Which of the following strategies would be most likely to reduce public health problems?
increased funding for research into finding new antibiotics with new mechanisms of action
After a drought in 1977, researchers hypothesized that on the Galapagos Island Daphne Major, medium ground finches with large, deep beaks survived better than those with smaller beaks because they could more easily crack and eat the tough Tribulus cistoides fruits. A tourist company sets up reliable feeding stations with a variety of bird seeds (different types and sizes) so that tourists can get a better look at the finches. Which of the following events is now most likely to occur to finch beaks on this island?
increased variation in beak size and shape over time
A heritable trait is one that
is determined at least in part by genes passed from parents to offspring.
Which characteristic was NOT advantageous for organisms in the million years after the catastrophic asteroid impact?
large body size
Which of the following is an example of an adaptation in anole lizards?
long legs in the anole lizards that live primarily on the ground and tree trunks
Evolution of shorter legs in anole lizards placed on small, hurricane-scrubbed islands is an example of which type of evolution?
microevolution
Rank the species from most closely related to horseflies to most distantly related to horseflies. If two species are equally close in their relatedness to horseflies, overlap them.
most closely related - flea - katydid, human body louse - dragonfly, mayfly -silverfish
Only a very small percentage of organisms actually fossilize. Based on the information in the table below, rank the likely abundance of fossils of organisms A-E. - Rank the fossils of organisms A-E from most common to least common. If two fossils have the same commonness, overlap them.
most common fossil - organism e - organism a - organism b - organism c - organism d least common fossil
In the origin of the eukaryotes, endosymbiosis
most likely began with a heterotrophic endosymbiont entering the cell as undigested prey or as an internal parasite.
Imagine that you are an explorer who has discovered an isolated land mass in the middle of the Pacific Ocean. You find a predator that resembles a North American wolf except that it lays eggs. You name it the "mid-ocean wolf." The physical similarity between the mid-ocean wolf and the North American wolf is most likely due to which of the following factors?
natural selection that favors similar traits for organisms with similar ecological roles
Molecular clocks are based on the idea that _____.
on average neutral mutations arise at a constant rate
From his observations of organisms in the Galapagos Islands, Darwin reasoned that __________.
organisms had adapted to new environments, giving rise to new species
The diagram is reminiscent of Darwin's sketch showing the branching of evolution. The horizontal axis of the diagram is a timeline that extends from 100,000 years ago to the present; the vertical axis represents nothing in particular. - Which combination of ideas is represented in the diagram?
origin of new species and extinction
Based on this genetic information, which phylogenetic tree is most parsimonious? Select the most parsimonious tree. If there is a tie, select both trees.
phylogenetic tree III
What data should you collect in order to test your prediction?
predation rate on transplanted versus original source guppies, and color patterns of the population over time
In a hypothetical environment, fishes called pike-cichlids locate their prey by sight and eat small, immature algae-eating fish. Thus, the population of algae-eaters experiences predatory pressure from pike-cichlids. Which of the following possible changes is LEAST likely to occur in the algae-eater population in future generations?
production of fewer offspring by algae-eaters
Charles Darwin __________.
proposed natural selection as the mechanism of evolution
According to the _____ model, evolution occurs in spurts; species evolve relatively rapidly then remain unchanged for long periods.
punctuated equilibrium
A biologist observes that a particular plant species is found in a forest but not in a nearby meadow. She hypothesizes that the plants could grow in the meadow but are not found there because their seeds have yet to land in the meadow. Which of the following would be the most appropriate way to scientifically evaluate this hypothesis?
scattering seeds in several areas of the meadow and observing whether they start to grow
Which of the following sequences is the one that most likely occurred in evolution of whales?
shortening of femur, reduction in foot, loss of tibia
If x indicates the earliest appearance of fossils of two closely related species, neither of which is extinct, then their remains may be found in which of these strata?
strata A and B only
The figure shows an outcrop of sedimentary rock whose strata are labeled A-D. - If x indicates the earliest appearance of fossils of two closely related species, neither of which is extinct, then their remains may be found in which of these strata?
strata A and B only
Which of the following groups of species is a monophyletic group, or clade?
sun bear, Asian black bear, American black bear, ancestral species 5, ancestral species 6
Which of the following contributes the LEAST to the problem of antibiotic resistance?
taking the entire course of antibiotics as prescribed by the doctor
What was the critical piece of evidence that supported the hypothesis that an asteroid struck Earth 65 million years ago?
the Chicxulub crater in Mexico
Which of the following ideas of Charles Darwin was most derived from his reading of Malthus's essay on human population growth?
the ability of all species to over reproduce
Identify the sister taxon to the polar bear.
the brown bear
Hybrid zones provide an opportunity to investigate _____.
the evolution of reproductive isolation
Which of the following is an example of the pattern of evolution?
the fossil record of the evolution of modern cetaceans
Which species is the basal taxon in this tree?
the giant panda
In this diagram, each fork represents which of the following ideas?
the most recent common ancestor of the subsequent species
According to this tree, is the sun bear more closely related to the sloth bear or the polar bear?
the polar bear
What was the control group in this study?
the source population in the pike-cichlid pools
James Hutton and Charles Lyell provided which of the following ideas that paved the way for Darwin's thinking?
the surface features of Earth were formed slowly and gradually and the geological processes are still at work
What was the experimental group in this study?
the transplanted population in the killifish pools
Hox genes are thought to play an important role in the development of different morphologies because _____.
they provide positional information in the embryo
Miller and Urey's experiments that attempted to recreate conditions on early Earth were significant because _____.
they showed that organic molecules such as amino acids could be produced from inorganic molecules
True or false? A flood that separates a population of frogs onto opposite sides of a lake is an example of a vicariance event that may result in allopatric speciation.
true
True or false? It would be difficult to assess whether the drug-susceptible or drug-resistant phenotype in a population of Mycobacterium tuberculosis was more fit in an environment without antibiotics.
true
Currently, two of the living elephant species (X and Y) are placed in the genus Loxodonta, and a third surviving species (Z) is placed in the genus Elephas. Assuming this classification reflects evolutionary relatedness, which of the following is the most accurate evolutionary tree?
z,x,y with x & y connected
