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bio test 2
Terms in this set (337)
Which of the following statements about species, as defined by the biological species concept is (are) correct?
biological species are defined by reproductive isolation; the biological species is the largest unit population in which successful reproduction is possible
What is generally true of two very closely related species that have diverged from each other quite recently?
they shared a common ancestor recently in evolutionary time
Which of the various species concepts distinguishes two species based on the degree of genetic exchange between their gene pools?
Which species concept is currently most popular among most biologists?
There is still some controversy among biologist about whether Neanderthals should be placed within the same species as modern humans, or into a separate species of their own. Most DNA sequence data analyzed so far indicate that there was probably little or no gene flow between Neanderthals and Homo sapiens. Which species concept is most applicable in this example?
A biologist discovers two populations of wolf spiders whose members appear identical. Members of one population are found in the leaf litter deep within the woods. Members of the other population are found in grass at the edge of the woods. The biologist decides to designate the members of the two populations as two separate species. Which species concept is this biologist most closely utilizing?
What was the species concept most used by Linnaeus?
You are confronted with a box of preserved grasshoppers of various species that are new to science and have not been described. Your assignment is to separate them into species. There is no accompanying information as to where or when they were collected. Which species concept will you have to use?
Male of one species sing only when its predators are absent; males of another species sing only when its predators are present.
One species lives only in tree holes; another species lives only in streams
Females of one species choose mates based on song quality; females of another species choose mates on the basis of size
One species mates at the season when daylight is increasing from 13 hours to 13 hours, 15 minutes; another species mates at the season when daylight is increasing from 14 hours to 14 hours, 15 minutes
Males of one species are to small to perform amplexus (an action that stimulates ovulation) with females of all other species
Dog breeders maintain the purity of breeds by keeping dogs by keeping dogs of different breeds apart when they are fertile. This kind of isolation is most similar to which of the following reproductive isolating mechanisms?
rank from most general to most specific
reproductive isolating mechanism; prezyotic isolating mechanism; gametic isolation; pollen- stigma incompatibility
Two species of frogs belonging to the same genus occasionally mate, but the offspring fail to develop and hatch. What is the mechanism for keeping the two frog species separate?
post zygotic barrier called hybrid inviability
Theoretically, the production of sterile mules by interbreeding between female horses and male donkeys should:
strengthen post zygotic barriers between horses and donkeys
The biological species concept is inadequate for grouping:
Which example below will most likely guarantee that two closely related species will persist only as distinct biological species?
reproductive isolation from one another
Races of humans are unlikely to evolve extensive differences in the future for which of the following reasons?
the human races are incompletely isolated
In a hypothetical situation, a certain species of flea feeds only on pronghorn antelopes. In rangelands of the western United States, pronghorns and cattle often associate with one another. If some of these fleas develop a strong preference, instead, for cattle blood and mate only with fleas that, likewise, prefer cattle blood, then over time which of these should occur, if the host mammal can be considered as the fleas' habitat?
reproductive isolation; sympatric speciation; habitat isolation; and prezygotic barriers
A defining characteristic of allopatric speciation is:
A rapid method of speciation that has been important in the history of flowering plants is:
Two closely related populations of mice have been separated for many generations by a river. Climatic change causes the river to dry up, thereby bringing the mice population back into contact in a zone overlap. Which of the following is not a possible outcome when they meet?
they interbreed in the region of overlap, producing an inferior hybrid. Subsequent interbreeding between inferior hybrids produces progressively superior hybrids over several generations
The difference between geographic isolation and habitat differentiation is the
relative location of two populations as speciation occurs
Among known plant species, which of these have been the two most commonly occurring phenomena leading to the origin of new species?
sympatric speciation; and polyploidy
Beetle pollinators of a particular plant are attracted to its flowers' bright orange color. The beetles not only pollinate the flowers, but they mate while inside of the flowers. A mutant version of the plant with red flowers to the orange flowers. Over time, these two beetles variants diverge from each other to such an extent that interbreeding is no longer possible. What kind of speciation has occurred in this example, and what has driven it?
sympatric speciation, habitat differentiation
The origin of a new plant species by hybridization, coupled with accidents during nuclear division, is an example of:
The phenomenon of fusion is likely to occur when, after a period of geographic isolation, two populations meet again and:
an increasing number of viable, fertile hybrids is produced over the course generations
The constantly changing nature of the Appalachian ground crickets (allonemobius fasciatus and allonemobius socius) hybrid zone favors
increased levels of gene flow between the two gene pools
A hybrid zone is properly defined as:
an area where mating occurs between members of two closely related species, producing viable offspring
Which of these should decline in hybrid zones where reinforcement is occurring?
gene flow between distinct gene pools
The most likely explanation for the high rate of sympatric speciation that apparently existed among the cichlids of Lake Victoria in the past is:
The most likely explanation for the recent decline in cichlid diversity in Lake Victoria is:
In such narrow hybrid zone that separates the toad species Bombina bombina and Bombina variegata, what is true of those alleles that those alleles are unique to the parental species?
Alleles' heterozygosity should be higher among the hybrid toads there
Which of these reduces gene flow between the gene pools of the two species on Sao Tome, despite the existence of hybrid?
The observation that island D. yakuba are more closely related to mainland D. yakuba that island D. yakuba are to D. santomea is best explained by proposing that D. santomea:
descended from an original colony of
D. yakuba, of which there are no surviving members. The current island D. yakuba represent a second colonization event from elsewhere
If a speciation event occurred on Sao Tome, producing D. santomea from a parent colony of D. yakuba, then which terms apply?
macroevolution and sympatric speciation
Using only the information provided in the paragraph, which of these is the best initial hypothesis for how D. santomea descended from D. yakuba?
Which of these evolutionary trees represents the situation described in the paragraph above NOTE: yakuba (I) represents the island population, and yakuba (M) represents the mainland population
If the low number of hybrid flies in the hybrid zone, relative to the number of D. santomea flies there, is due to the fact that hybrids are poorly adapted to conditions in the hybrid zone, and if fewer hybrid flies are produced with the passage of time, this is most likely to lead to:
The data in the graphs above indicate that
2-way migration of squirrels occurred across the bridge, but without hybridization
The results depicted in the graphs above are best accounted for by which of the following facts?
The Colorado River has been an effective geographic barrier to these two types of squirrels for several million years
According to the concept of punctuated equilibrium, the "sudden" appearance of a new species in the fossil record means that
speciation occurred rapidly in geologic time
According to the concept of punctuated equilibrium,
new species accumulates most of its unique features as it comes into existence
Which of the following would be a position held by an adherent of the punctuated equilibrium theory?
a new species forms most of its unique features as it comes into existence and then charges little for the duration of its existence
can involve changes involving a single gene
Which of the following statements about speciation is correct?
speciation is a basis for understanding macroevolution
Upon undergoing change, which of these genes is most likely to result in speciation while a geographic barrier separates two populations of a flowering-plant species?
one that affects the compatibility of male pollen and female reproductive parts
In order for speciation to occur, what is true?
at least one gene, affecting at least one phenotypic trait must change
Which of these five species (V-Z) in the evolutionary tree would likely have fossil record indicating that punctuated equilibrium was an important part of their evolutionary history?
V and W
Which of these five species originated earliest and appeared suddenly in the fossil record?
Which conclusion can be drawn from this evolutionary tree?
A single clade can exhibit both gradualism and punctuated equilibrium
Which of these five species is the extant species that is most closely related to species X, and why is this so?
V; shared a common ancestor with X most recently
The largest unit within which gene flow can readily occur is a
Bird guides once listed the myrtle warbler and Audubon's warbler as distinct species. Recently, these birds have been classified as eastern and western forms of a single species, the yellow-rumped warbler. Which of the following pieces of evidence, if true, would be cause for this reclassification
two forms interbreed often in nature, and their offspring have good survival and reproduction
Males of different species of the fruit fly Drosophila that live in the same parts of the Hawaiian islands have different elaborate courtship rituals that involve fighting other males and stylized movements that attract females. What type of reproductive isolation does this represent?
Which of the following factors would not contribute to allopatric speciation?
gene flow between the two population is extensive
Plant species A has a diploid number of 12. Plant species B has a diploid number of 16. A new species, C, arises as an allopolyploid from A and B. The diploid number for species C would probably be
According to the punctuated equilibria model
most new species accumulate their unique features relatively rapidly as they come into existence, then change little for the rest of their duration as a species
When gene flow between two populations ceases, the potential for _______ exist
Bird guides once listed the myrtle warbler and Audubon's warbler as distinct species. However, recent books show them as eastern and western forms of a single species, the yellow-rumped warbler. Apparently, the myrtle warbler and Audubon's warbler ______.
successfully interbred and produce fertile offspring
Imagine that part of a population of South American finches is blown by a storm onto an island far offshore and manages to survive and reproduce there for a period of 10,000 years. After that period, a climate change results in lower sea levels and the reconnection of the island with the mainland. Members of the formerly isolated island finch population can now interact freely with members of the original mainland population. Which of the following observations would, by itself, lead you to conclude unequivocally that the island finch population had evolved into a distinct species, according to the biological species concept?
Individuals from the different populations sometimes mate with each other, but all of the resulting eggs are sterile
Which of the following conditions is necessary for speciation to occur?
At which point in the adaptation of a population is it clear that speciation has occurred?
gene pool changes establish reproductive barriers between two populations
prevent fertilization of gametes from members of closely related species
Three species of frogs, Rana pipiens, Rana clamitans, and Rana sylvatica, all mate in the same ponds, but they pair off correctly because they have different calls. This is a specific example of a _____ barrier, called ______.
prezygotic ... behavioral isolation
Which of the following reproductive barriers actually prevents individuals of closely related species from copulating successfully?
Two species of water lilies in the same pond do not interbreed because one blooms at night and the other drug during the day. The reproductive barrier between them is an example of ______
Which of the following is an example of a post zygotic reproductive barrier?
two fruit flies of different species produce sterile offspring
There are two groups of pine trees that appear to be very similar phenotypically and genotypically. However, one releases pollen in January, when the female structure of that group are receptive and one in March. What kind of reproductive barrier is this?
The phylogenetic species concept emphasizes _______
Lake Victoria, in Africa, is home to a group of related fishes known as cichlids. Many of these fishes are similar in appearance but have different conclusively whether the fish are members of a population that has a lot of variation or members of entirely different species?
Observe the fish in their natural environment for possible instances of interbreeding leading to several generations of fertile offspring
In practice, how do scientists distinguish most species?
by using the morphological species concept
Which species concept defines a species as a set of organisms with a unique genetic history
phylogenetic species concept
Sometimes two phenotypically different populations interbreed to a limited extent, so that it is difficult to determine whether they are clearly separate species. This is not a concern to scientists because this _____.
may indicate that the formation of a new species is in progress
Which of the following organisms is most likely to be subject to allopatric speciation?
pine trees in Alaska and pine trees on the island of Madagascar
According to the experiment of Diane Dodd, can adaptive divergence of allopatric fruit fly populations lead to reproductive isolation?
no, after several generations, the formation of a reproductive barrier was evident, but not absolute
Which of the following evolutionary mechanisms does NOT contribute to the process of allopatric speciation?
In which of the following groups has sympatric speciation been most important?
If a new species of plants is to be produced by means of allopolyploidy from two parental species that are 2n= 4 and 2n=8, how many chromosomes whould you expect in the somatic cells of the new species?
A new species can arise in a single generation ________.
if a change in chromosome number creates a reproductive barrier
The Galapagos finches collected by Darwin are thought to have descended from a very small parent population. Different species of finches that are confined to only one or two island most likely arose by ______
In the case of the Lake Victoria cichlids sympatric speciation has been shown to be driven by _____
In a hybrid zone, which of the following would tend to lead to reinforcement?
all of the listed responses are correct
In the Lake Victoria cichlids, what appears to be contributing to fusion of different species?
females have a difficult time visually selecting males of the same species in the murky, polluted water
According to the punctuated equilibrium model of evolution ______
the tempo of evolution consists of abrupt episodes of speciation among long periods of equilibrium
Comparison of human fossils with living humans seems to show that there have been no significant physical changes in Homo sapiens in 30,000 to 50,000 years. What might an advocate of punctuated equilibrium model
lack of change is consistent with the punctuated equilibrium model
What is the first thing that must happen in order for speciation to occur?
gene flow between populations must be interrupted
How many genes must change in order to form a new species?
there is no set number of genes or loci that produces a new species. Genetic and environmental factors interact.
The time interval between speciation events is typically _____
times between speciation events vary widely and depend on generation times, causes of speciation, environmental factors, and chance
Which gas was least abundant in Earth's early atmosphere, prior to 2 billion years ago?
In their laboratory stimulations of the early Earth, Miller and Urey observed the abiotic synthesis of
Which of the factors below weaken the hypothesis of abiotic synthesis of organic monomers in early Earth's atmosphere?
the relatively short time between intense meteor bombardment and appearance of the first life forms and uncertainty about which gases comprised early Earth's atmosphere
Which of the following has not yet been synthesized in laboratory experiments studying the origin of life?
protobionts that use DNA to program protein synthesis
In what way were conditions on the early Earth of more than 3 billion years ago differently from those on today's Earth?
only early Earth was intensely bombarded by large space debris
What is true of the amino acids that might have been delivered to Earth within carbonaceous chondrites?
the proportion of the amino acids was similar to those produced in the Miller-Urey experiment
Which of the following is the correct sequence of these events in the origin of life?
synthesis of organic monomers; synthesis of organic polymers; formation of protobionts; formation of DNA based genetic system
Which is defining characteristic that all protobionts had in common?
a surrounding membrane or membrane like structure
Although absolute distinctions between the "most evolved" protobiont and the first living cell are unclear, biologist generally agree that one major difference is that the typical protobiont could not
perform controlled, precise reproduction
The first genes on Earth were probably
auto-catalytic RNA molecules
RNA molecules can both carry genetic information and be catalytic. This supports the proposal that
RNA was the first hereditary information
What probably accounts for the switch to DNA-based genetic systems during the evolution of life on Earth?
DNA is chemically more stable and replicates with fewer errors (mutations) than RNA
The synthesis of new DNA requires the prior existence of oligonucleotides to serve as primers. On Earth, these primers are small RNA molecules. This latter observation is evidence in support of the hypothesized existence of
earlier genetic system than those based on DNA
Several scientific laboratories across the globe are involved in research concerning the origin of life on Earth. Which of these questions is currently the most problematic and would have the greatest impact on our understanding if we were able to answer it?
How did RNA sequences come to carry the code for amino acid sequences?
Several scientific laboratories across the globe are involved in research concerning the origin of life on Earth. Which graph below, if the result were producing abiotically, would have the greatest promise for revealing important information about the origin or Earth's first genetic system
the one with spike in RNA amino acid
If natural selection in a particular environment favored genetic systems that permitted the production of daughter "cells" that were genetically dissimilar from the mother "cells" then one should expect selection for
polynucleotide polymerases without proofreading capability and polynucleotide polymerases with high mismatch error rates
If relatively small carbonaceous chondrites from space were a significant sources of Earth's original amino acids, then which two of these would have been most important in permitting their organic materials to survive impact with Earth?
Earth's early atmosphere must have had little free oxygen and Earth's atmosphere must have been dense enough to dramatically slow the chondrites before they impacted
If the half-life of carbon 14 is about 5,730 years, then a fossil that has one- sixteenth the normal proportion of carbon 14 to carbon 12 should be about how many years old
Which measurement would help determine absolute dates by radiometric means?
the accumulation of the daughter isotope and the loss of parent isotopes
How many half-lives should have elapsed if 6.25% of the parent isotope remains in a fossil at the time of analysis?
Approximately how far back in time does the fossil record extend?
Assuming that the rate of sea-floor spreading was constant during the 1 million year period depicted above, Earth's magnetic field has undergone reversal at an average rate of once every
If a particular marine organism is fossilized in the sediments immediately overlaying the igneous rock at the arrow labeled "II" at which other location, labeled A-E, would a search be most likely to find more fossils of this organism?
Earth's current magnetic field is the same as it had been when which sea-floor areas solidified?
Area C and E
Assuming that the rate of sea-floor spreading was constant during the 1 million year period depicted above, what should be the approximate age of marine fossils found in undisturbed sedimentary rock immediately overlaying the igneous rock at the arrow labeled "II"
Argon-40 the daughter isotope of potassium-40, is a gas. Elemental potassium has an atomic mass of about 39. If the submersible robot (which is equipped with a drill that is long enough to get to the igneous rock) ascends from depth too quickly, gases trapped within igneous rock may rapidly expand, fracture the rock, and escape from the sample before it can be dated aboard the floating research vessel. Rock samples can also absorb argon gas. Which of these techniques has the highest chance of providing inaccurate dates of igneous rocks distant from the rift valley, and what type of inaccuracy would it cause?
if the submersible robot keeps the sample in a chamber of pure argon at high pressure, overestimation of age
What is true of the fossil record of mammalian origins?
it includes transitional forms with progressively specialized teeth
If a fossil is incased in a stratum of sedimentary rock without any strata of igneous rock (e.g. lava, volcanic ash) nearby, then it should be
difficult to determine the absolute age of the fossil, because radiometric dating of sedimentary rock is less accurate than that of igneous rock
Lets say that a hypothetical submersible robot was used to collect samples of sedimentary rock from the sea floor along the section illustrated. The robot moved back and forth along the transect, collecting first from site A and then site III, then site B, then site II and lastly site D. Assuming that sedimentation has occurred at a constant rate along the transect over the past million years, rearrange the sites mentioned above the basis of the thickness of the sediments overlaying the igneous rock, from thickest to thinnest.
III, D, II, B, A
An early consequence of the release of oxygen gas by plant and bacterial photosynthesis was to
cause iron in ocean water and terrestrial rocks to rust (oxidize)
Arrange these events from earliest to most recent
emission of lava that solidified at the same time as rusted iron precipitated from seawater; emission of lava in what is now Siberia at time of Permian extinctions; emission of lava in what is now India at time of Cretaceous extinctions; emission of lava that solidified at the same time as iron bearing terrestrial rocks began to rust
Which free-living cells were the earliest contributions to the formation of Earth's oxidizing atmosphere?
Which of the following statements provides the strongest evidence that prokaryotes evolved before eukaryotes?
the oldest fossilized cells resemble prokaryotes
What is thought to be the correct sequence of these events, from earliest to most recent, in the evolution of life on Earth?
origin of cyanobacteria; origin of mitochondria; origin of chloroplasts; origin of multicellular eukaryotes; origin of fungal-plant symbioses
If it were possible to conduct sophisticated microscopic and chemical analyses of microfossils found in 3.2 billion year old stromatolites, then within such microfossils, one should be surprised to observe evidence of:
nuclear envelope; nucleolus
Recent evidence indicates that the first major diversification of multicellular eukaryotes may have coincided in time with the
melting that ended the "snowball Earth" period
Which of these observations fails to support the endosymbiotic theory for the origin of eukaryotic cells?
existence of structural and molecular differences between the plasma membranes of prokaryotes and the internal membrane of mitochondria and chloroplasts
Which event is nearest in time to the end of the period known as snowball Earth?
The snowball Earth hypothesis provides a possible explanation for the
diversification of animals during the late Proterozic
If two continental land masses converge and are united, then the collision should cause
a net loss of intertidal zone and coastal habitat
A major evolutionary episode that corresponds in time most closely with the formation of Pangaea was the
On the basis of their morphologies, how might Linnaeus have been classified the Hawaiian silverswords?
He would have placed them in more species than modern botanists do
Anatomically, what was true of Lystrosaurus?
it was a tetrapod
Which of Lystrosaurus features help explain why these organisms fossilized so abundantly?
the presence of hard parts, such as tusks; persistence across at least two geological eras; its widespread geographic distribution
Which of these is the most likely explanation for the modern-day distribution of dicynodont fossils?
the dicynodonts were distributed more abundantly throughout Gondwanaland than throughout any other land mass
The observation that tusks were limited to males in several species, and were apparently not used in food-gathering is evidence that the tusks probably
were maintained as the result of sexual selection
Which of these is most likely explanation for the existence of dicynodont fossils on modern-day Antarctica?
The landmass that is now the Antarctic continent was formerly located at a more-northerly position, and was also united to other landmasses
dicynodonts survived the Permian extinction and, therefore, existed during both the
Paleozoic and Mesozoic eras
There are at least a dozen known species in the extinct genus Lystrosaurus. If each species was suited to a quite different environment, then this relatively large number of species is likely due to
The dicynodonts survived the mass extinction that was most closely correlated in time, if not in cause, with
the formation of Pangaea and lava flows that covered large portions of Pangaea
The dicynodonts that survived the Permian extinction would initially have had to endure (or escape from) the physical effects of _____, and subsequently, the biological effects of ______
volcanic ash in the atmosphere, increased predation
If an increase in dicynodont species diversity (i.e. number of species) occurred soon after the Permian extinction, and if it occurred for the same general reason usually given for the increase in mammalian diversity following the Cretaceous extinction, then it should be attributed to
the availability of previously occupied niches
An organism has a relatively large number of Hox genes in its genome. Which of the following is not true of this organism?
it must have multiple paired appendages along the length of its body
Bagworm moth caterpillars feed on evergreens and carry a silken case or bag around with them in which eventually pupate. adult female bagworm moths are larval in appearance; they lack the wings and other structures of the adult male and instead retain the appearance of a caterpillar even though they are sexually mature and can lay eggs within the bag. This is a good example of
The loss of ventral spines by modern freshwater sticklebacks is due to natural selection operating on the phenotypic affects of Pitx1 gene
silencing (loss of expression)
If these fly species lost the ability to fly independently of each other as a result separate mutation events in each lineage, then the flightless condition in these species could be an example of
In each fly species, the entire body segment that gave rise to the original flight wings is missing. The mutation(S) that led to the flightless condition could have
either altered the nucleotide sequence within a Hox gene or altered the expression of a Hox gene
If the foods preferred by each species are found on different parts of the island, and if the flies mate and lay eggs on their food sources, regardless of the food source, and then the speciation events involving these fly species may have been driven, at least in part, by which of the following?
If the males halteres have species- specific size, shape, color, and use in courtship displays, and if the species ranges overlap, then the speciation events may have been driven, at least in part, by which of the following?
Fly species W. found in a certain part of the island, produces fertile offspring with species Y. Species W does not produce fertile offspring with species X or Z. If no other species can hybridize, then species W and Y
have genomes that are still similar enough for successful meiosis to occur in hybrid flies; have more genetic similarity with each other than either did with the other two species; may fuse into a single species if their hybrids remain fertile over the course of many generations
Which of these fly organs, as they exist in current fly population, best fits the description of an exaptation?
The existence of the phenomenon of exaptation is most closely associated with which of the following reasons that natural selection cannot fashion perfect organisms?
evolution is limited by historical constraints
If the complex protein assemblage of the prokaryotic flagellum arose by the same general processes as those the complex eyes of mollusks (such as squids and octopi), then
ancestral versions of this protein assemblage were either less functional, or had different functions, than modern prokaryotic flagella
If the prokaryotic flagellum developed from assemblages of proteins that originally were not involved with cell motility but with some other function instead, then the modern prokaryotic flagellum is a(n)
In certain motile prokaryotes, dozens of different proteins comprise the motor that powers the prokaryotic flagellum. The motor has a complicated structure, and its various proteins interact to carry out its function. Based on Darwin's explanation for the existence of human eyes, how would he probably have explained the existence of such motors?
he would have proposed that these motors were the products of aliens, and had been delivered to Earth by extraterrestrial visitors
It has been found that certain proteins of the complex motor that drives bacterial flagella are modified versions of proteins that had previously belonged to plasma membrane pumps. This is evidence in support of the claim that
natural selection can produce new structures by cobbling together parts of other structures
The explanation for the evolution of insect wings suggest that wings began as lateral extensions of the body that were used as heat dissipaters for thermoregulation. When they become sufficiently large, these extensions became useful for gliding through the air, and selection later refined them as flight-producing wings. If this hypothesis is correct, insect wings could best be described as
If one organ is an exaptation of another organ, then what must be true of these two organs?
they are homologous organs
Many species of snakes lay eggs, but in the forest of northern Minnesota where growing seasons are short, only live-bearing snake species are present. This trend toward species that perform live birth in an example of
In the 5-7 million years that the hominid lineage has been diverging from its common ancestor with the great apes, dozens of hominid species have arisen, often with several coexisting in time and space. As recently as 30,000 years ago, Homo sapiens coexisted with Homo neanderthalensis. Both species had large brains and advanced intellects. The fact that these traits were common to both species is most easily explained by which of the following?
The existence of evolutionary trends, such as increasing body sizes among horse species, is evidence that
in particular environments, similar adaptations can be beneficial in more than one species
Fossil evidence indicates that several kinds of flightless dinosaurs possessed feathers. If some these feather-bearing dinosaurs incubated clutches of eggs in carefully constructed nests, this might be evidence supporting the claim that
their feathers originally served as insulation, and only later became flight surfaces
The appearance of Pax-6 in all animals with eyes can be explained in multiple ways. Which explanation is most likely?
The Pax-6 gene was an innovation of an ancestral animal of the early Cambrian. Animals with eyes or eyespots are descendants of this ancestor
Fruit fly eyes are of the compound type, structurally very different from the camera-type eyes of mammals. Even the camera-type eyes of mollusks, such as octopi, are structurally quite different from those of mammals. Yet, fruit flies, octopi and mammals possess very different types of eyes is most likely due to
independent evolution of this gene at many different times during animal evolution
Pax-6 usually causes the production of a type of light-receptor pigments. In vertebrate eyes, though, a different gene is responsible for the light-receptor pigments of the retina. The rh gene, like Pax-6, is ancient. In the marine ragworm, for example, the rh gene causes production of c-opsin, which helps regulate the worm's biological clock. Which of these most likely accounts for vertebrate vision?
During vertebrate evolution, the rh gene for biological clock opsin was co-opted as a gene for visual receptor pigments
resemble structures formed by bacterial communities that are found today in some warm, shallow, salty bays
The oxygen revolution changed Earth's environment dramatically. Which of the following adaptations took advantage of the presence of free oxygen in the oceans and atmosphere?
the evolution of cellular respiration, which used oxygen to help harvest energy from organic molecules
Select the factor most likely to have caused the animals and plants of India to differ greatly from species in nearby Southeast Asia
India was a separate continent until 55 million years ago
Adaptive radiations can be a direct consequence of four of the following five factors. Select the exception.
A genetic change that caused a certain Hox gene to be expressed along the tip of vertebrate limb bud instead of farther back helped to make possible the evolution of the tetrapod limb. This type of change is illustrative of
a change in a developmental gene or in its regulation that altered the spatial organization of body parts
Which of the following steps has not yet been accomplished by scientists studying the origin of life?
formation of protobionts that use DNA to direct the polymerization of amino acids
A swim bladder is a gas-filled sac that helps fish maintain buoyancy. The evolution of the swim bladder from lungs of an ancestral fish is an example of
Why is the four-stage hypothesis for the abiotic origin of life useful?
it leads to prediction that can be tested
The early atmosphere on Earth is thought to have lacked which of the following gases?
Currently scientists think the early atmosphere probably consisted of
N2, H2O, CO2, NH3, CH4, H2, and H2S
Miller and Urey abiotic synthesis experiment showed that
simple organic molecules can form spontaneously under conditions like those thought to prevail early in Earth's history
The early atmosphere may not have been as reducing as originally postulated by Haldane, Oparin, Miller, and Urey. In light of current thinking about the composition of the early atmosphere, what is regarded as a likely place for the abiotic synthesis of organic molecules to have occurred?
Abiotically produced vesicles display which of the following rudimentary qualities necessary for life?
the ability to perform simple reproduction and metabolism
Cech and Altman suggested that the first self-replicating molecules were______
Which of the following organisms is most closely related to the ancestor of modern amphibians?
A radioactive isotope has half of 1.2 billion years. As measured by the presence of the isotope and its stable decay product, a rock originally contained 10 grams of the radioactive isotope, and now contains 1.25 grams. Approximately how many years old is the rock
3.6 billion years
You are watching a movie in which one of the characters excitedly claims to have found human remains in Asia dated at 10 million years old. The date was obtained by carbon 14 dating. What is your reaction?
This can't possibly be true because carbon 14 dating can only be used back to about 75,000 years
Single-celled prokaryotes had the Earth to themselves for approximately
1.5 billion years
The correct order of the geologic eras, from most ancient to most recent is
Paleozoic, Mesozoic, Cenozoic
Ancient cyanobacteria were very important in the history of life because they
produced atmospheric oxygen
What prokaryotic adaptation occurred during the oxygen revolution and opened up the possibility for energy-demanding multicellular life forms
What evidence supports the hypothesis that mitochondria and plastids evolved from prokaryotic endosymbionts
mitochondria and plastids have chromosomes and ribosomes that are very similar to those found in prokaryotes
Prior to the Cambrian explosion, most animals were small and soft bodied. What development appears to have spurred adaptations such as sharp spines, claws, and body armor (shells)?
What were the two major problems that had to be solved before, plants, animals, and fungi could move into terrestrial habitats?
reproduction and prevention of dehydration
What does the snowball Earth hypothesis propose?
Larger multicellular eukaryotes are scarce in the fossil record until the late Proterozoic because an ice age limited life to deep-sea vents and hot springs
Plants colonized land in the company of _____; their symbiotic relationships still exist today.
What evidence most strongly suggests that an impact by an asteroid or meteorite may have caused the extinction of the dinosaurs?
Sedimentary rock contains a layer of iridium, a mineral uncommon on Earth
Which of the following best describe how the break up of Pangaea affected evolution?
the geographic isolation of populations that had previously coexisted led to speciation
The fauna and flora of Australia are very different from those of the rest of the world. Why might this be true?
Australia has been isolated for about 50 million years
Lake Malawi, in the African Rift Valley, is home to more than a hundred species of cichlid fishes, each with slightly different diets and habitats. All these species probably evolved from a common ancestor, making them an example of
Although they originated around 180 million years ago, mammals underwent an adaptive radiation starting approximately 65 million years ago. Why?
Between 180 and 65 million years ago, mammals were outcompeted by the well-established dinosaurs
Mutations in what class of genes have probably been responsible for many of the changes leading to the great diversity of life existing today?
The products of Hox genes
provide positional information in animal embryos
If the wings of extant flying birds originally arose as thermoregulatory devices in ancestral reptiles, then the bird wings could be accurately described as
In the species selection model, ____ is to macroevolution as _____ is to microevolution
differential speciation success... differential reproductive success
offspring that results from the mating of individuals from two different species or from two true-breeding varieties of the same species
the supercontinent that formed near the end of the Paleozoic era, when plate movements brought all the landmasses of Earth together
a method for determining the absolute age of rocks and fossils, based on the half-life of radioactive isotopes
the division of Earth's history into time periods, grouped into three eons - Archaean, Proterozoic, and Phanerozoic; and further subdivided into eras, periods and epochs
period of evolutionary change in which groups of organisms form many new species whose adaptations allow them to fill different ecological roles in their communities
relatively brief time in geologic history when many present day phyla on animals first appeared in the fossil record. This burst of evolutionary change occurred about 535-525 million years ago and saw the emergence of the first large, hard-bodied animals
the retention in an adult organism of the juvenile features of its evolutionary ancestors
population or group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring, but do not produce viable, fertile offspring with members of other such groups
the existence of biological factors (barriers) that impede members of two species from producing viable fertile offspring
formation of new species in populations that live in the same geographic area
evolutionary change above the species level
chromosomal alteration in which the organism possesses more than two complete chromosome sets- accident of cell division
evolutionary change in the timing or rate of an organism's development
post zygotic barrier
reproductive barrier that prevent hybrid zygotes produced by two different species from developing into viable, fertile adults
abiotic precursor of a living cell that had a membrane-like structure and that maintained an internal chemistry different from that of its surroundings
amount of time it takes for 50% of a sample of a radioactive isotope to decay
morphological species concept
definition of species in terms of measurable anatomical criteria
evolutionary change below the species level; change in the allele frequencies in a population over generations
elimination of a large number of species throughout Earth, the result of global environmental changes
process in which a process in which natural selection strengths prezygotic barriers to reproduction, thus reducing the chances of hybrid formation
geographic region in which members of different species meet and mate, producing at least some offspring of mixed ancestry
fertile individual that has more than two chromosome sets as a result of two different species interbreeding and combining their chromosomes
formation of new species in population that are geographically isolated from one another
individual that has more than two chromosome sets that are all derived from a single species
long periods of apparent stasis, in which a species undergoes little or no morphological change, interrupted by relatively brief periods of sudden change
reproductive barrier that impedes mating between species or hinders fertilization if interspecific mating is attempted
an evolutionary process in which one species splits into two or more species
theory that the continents are part of great plates of Earth's crust that float on the hot, underlying portion of the mantle- cause continents to move slowly over time
theory that mitochondria and plastids, including chloroplasts, originated as prokaryotic cells engulfed by an ancestral eukaryotic cell- engulfed cell and its host cell then evolved into a single organism
any of the master regulatory genes that control placement and spatial organization of body parts in the animals, plants, and fungi by controlling the developmental fate of groups of cells
Phylogenetic species concept
species as the smallest group of individuals that share a common ancestor, forming one branch on the tree of life
biological species concept
species as a group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring, but do not produce viable, fertile offspring with members of other such groups
ecological species concept
species in terms of ecological niche, the sum of how member of the species interact with the nonliving and living parts of their environment
layered rock that results from the activities of prokaryotes that bind thin films of sediment together
RNA molecule that functions as an enzyme such as an intron that catalyzes its own removal during RNA splicing
Mycoplasmas are bacteria that lack cell walls. On the basis of this structural feature, which statement concerning mycoplasmas should be true?
they are subject to lysis in hypotonic conditions
Though plants, fungi, and prokaryotes all have cell walls, we place them in different taxa. Which of these observations comes closest to explaining the basis for placing these organisms in different taxa, well before relevant data from molecular systematics became available?
their cell walls are composed of very different biochemicals
Which is the bacterial structure that acts as a selective barrier, allowing nutrients to enter the cell and wastes to leave the cell?
Which statement about bacterial cell walls is false?
Cell walls prevent cells from dying in hypertonic conditions
Which of these is the most common compound in the cell walls of gram-positive bacteria?
Penicillin is an antibiotic that inhibits enzymes from catalyzing the synthesis of peptidoglycan, so which prokaryotes should be most vulnerable to inhibition by penicillin?
The predatory bacteria, Bdellovibrio bacteriophorous, drills into a prey bacterium and that has a slimy cell covering which can inhibit phagocytosis, what is the correct sequence of structures penetrated by B. bacteriophorous on its way to the prey's cytoplasm?
capsule--> membrane composed mostly of lipopolysaccharide--> peptidoglycan --> membrane composed mostly of phospholipids
Jams, jellies, preserves, honey and other foodstuffs with a high sugar content hardly ever become contaminated by bacteria, even when the food containers are left open at room temperature. This is because bacteria that encounters such an environment
undergo death by plasmolysis
In a hypothetical situation, the genes for sex pilus construction and for tetracycline resistance are located together on the same plasmid within a particular bacterium. If this bacterium readily performs conjugation involving a copy of this plasmid, then the result should be
a rapid spread of tetracycline resistance to other bacteria in that habitat
In a bacterium that possesses antibiotic resistance and the potential to persist through very adverse conditions, such as freezing, drying, or high temperatures, DNA should be located within, or be part of, which structures?
nucleoid region; endospore; and plasmids
Which two structures play direct roles in permitting bacteria to adhere to each other, or to other surfaces?
capsules and fimbriae
The typical prokaryotic flagellum features
complex "motor" embedded in the cell wall and plasma membrane
Prokaryotic ribosomes differ from those present in eukaryotic cytosol. Because of this, which of the following is correct?
some selective antibiotics can block protein synthesis of bacteria without effects on protein synthesis in eukaryotic host
Which statement about the genomes of prokaryotes is correct?
the prokaryotic chromosome is not contained within a nucleus but, rather, is found at the nucleoid region
If a bacterium regenerates from endospore that did not possess any of the plasmids that were contained in its original parent cell, the regenerated bacterium will probably
lack antibiotic-resistant genes
Which of the following is composed almost entirely of peptidoglycan in gram positive prokaryotic cell?
Which of the following requires ATP to function, and permits some species to respond to taxes
Not present in all bacteria, this cell covering enables cells that possess it to resist the defenses of host organisms
Not present in all bacteria, this structure enables those that possess it to germinate after exposure to harsh conditions, such as boiling
Which of the following is a structure that permits conjugation to occur?
Which of the following is an important source of endotoxin in gram-negative species?
If this structure connects the cytoplasm of two bacteria, one of these cells may gain new genetic material:
Which of the following contains a copy of the chromosome, along with a small amount of dehydrated cytoplasm, within a tough wall?
Regarding prokaryotic reproduction, which statement is correct?
mutation is a primary source of variation in prokaryote populations
Which of these statements about prokaryotes is correct?
they divide by binary fission, without mitosis or meiosis
Which term best describes what has occurred among experimental populations of cells over this 8 year period?
If it occurs in the absence of any other type of adaptation listed here, which of these is lease reasonable in terms of promoting bacterial survival over evolutionary time in a low- glucose environment?
increased reliance on glycolytic enzymes
If new genetic variation in the experimental populations arose solely be spontaneous mutations, then the most effective process for subsequently increasing the prevalence of the beneficial mutations in the population over the course of generations is
E. coli cells typically make most of their ATP by metabolizing glucose. Under the conditions of this experiment, what should be true of E. coli's generation time?
generation time should be slower than in the typical environment
If the experimental population of E. coli lacks an F factor or F plasmid, and if bacteriophage are excluded from the bacterial cultures, then which of these is a means by which beneficial mutations might be transmitted horizontally to other E. coli cells.
Which term is least closely associated with the others?
recombination involving a bacteriophage
an organism that obtains its energy from chemicals
a prokaryote that obtains both energy and carbon as it decomposes dead organisms
heterotroph and chemotroph
an organism that obtains both carbon and energy by ingesting prey
heterotroph and chemotroph
an organism that relies on photons to excite electrons within its membranes
Which of the following are responsible for many human diseases?
Which of the following use light energy to synthesize organic compounds from CO2?
Which of the following obtain energy by oxidizing inorganic substances; energy that is used, in part, to fix CO2?
Which of the following use light energy to generate ATP, but do not release oxygen?
Which of the following are responsible for high levels of O2 in Earth's atmosphere?
Modes of obtaining nutrients, used by at least some bacteria, include all of the following except
Only certain prokaryotes can perform nitrogen fixation, but nitrogen-fixing prokaryotes are not known to live inside animals. Thus, how do animals gain access to fixed nitrogen?
May ingest nitrogen fixers, may ingest plants that harbor nitrogen fixers, or plants that absorbed fixed nitrogen from the soil, they may ingest other animals that had done either of the other two
Given that the enzymes that catalyze nitrogen fixation are inhibited by oxygen, what are two "strategies" that nitrogen-fixing prokaryotes might use to protect these enzymes from oxygen?
obligate anaerobes and package these enzymes in specialized cells or compartments that inhibit oxygen entry
Nitrogenase, the enzyme that catalyzes nitrogen fixation, is inhibited whenever free O2 reaches a critical concentration. Consequently nitrogen fixation cannot occur in cells wherein photosynthesis produces free O2.
Consider the colonial aquatic cyanobactreium, Anabaena, whose heterocytes are described as having "... a thickened cell wall that restricts entry of O2 produced by neighboring cells in exchange for carbohydrates." Which two questions arise from a careful reading of this quotation, and are most important for understanding how N2 enters heterocytes, and how O2 is kept out of heterocytes?
If carbohydrates can enter the heterocytes from neighboring cells via the "intracellular connections" how is it that O2 doesn't enter via this route? and If the thick cell walls of the heterocytes exclude entry of oxygen gas, how is it that they don't also exclude the entry of nitrogen gas?
Mitochondria are thought to be the descendants of certain alpha-proteobacteria. They are, however, no longer able to lead independent lives because most genes originally present on their chromosomes have moved to the nuclear genome. Which phenomenon accounts for the movements of these genes?
Carl Woese and collaborators identified two major branches of prokaryotic evolution. What was the basis for dividing prokaryotes into two domains?
genetic characteristics such as ribosomal RNA sequences
Which statement about the domain Archaea is false?
genomes of archaeans are unique, containing no genes that originated within bacteria
If archaeans are most closely related to eukaryotes than to bacteria, then which of the following is a reasonable prediction?
Archaean ribosomes should be larger than typical prokaryotic ribosomes
Which of the following traits do archaeans and bacteria share?
presence of plasma membrane, and lack of a nuclear envelope
Assuming that each of these possesses a cell wall, which prokaryotes should be expected to be most strongly resistant to plasmolysis in hypertonic environments?
The thermoacidophile, Sulfolobus acidocaldarius lacks peptidoglycan. What is likely to be true of this species?
it is in Archaean, optimal pH of enzymes will lie below pH 7, and it could inhabit certain hydrothermal springs
A fish that had been salt-cured subsequently develops a reddish color. You suspect that the fish has been contaminated by the extreme halophile, Halobacterium. Which of these features of cells removed from the surface of the fish, if confirmed would support your suspicion?
cell walls that lack peptidoglycan; cell walls that are isotonic to conditions on the surface of the fish; its cells contain bacteriohodiopsin; and the presence of very large numbers of ion pumps in its plasma membrane
The termite gut protist, Mixotricha paradoxa, has at least two kinds of bacteria attached to its outer surface. One kind is a spirochete that propels its hosts through the termite gut. A second type of bacteria synthesize ATP, some of which is used by spirochetes. The locomotion provided by the spirochetes introduces the ATP-producing bacteria to new food sources. Which term(s) is (are) applicable to the relationship between the two kinds of bacteria?
mutualism, symbiosis, and metabolic cooperation
What is the primary ecological role of prokaryotes?
breaking down organic matter
If all prokaryotes on Earth suddenly vanished, which of the following would be the most likely and most direct result?
the recycling of nutrients would be greatly reduced, at least initially
In a hypothetical situation, a bacterium lives on the surface of a leaf, where it obtains nutrition from the leaf's nonliving, waxy covering, while inhibiting the growth of other microbes that are plant pathogens. If this bacterium gains access to the inside of a leaf, it causes a fatal disease in the plant. Once the plant dies, the bacterium and its offspring decompose the plant. What is the correct sequence of ecological roles played by the bacterium in the situation described here?
mutualist, parasite, nutrient recycler
How can prokaryotes be considered to be more successful on Earth than humans?
prokaryotes are much more numerous and have more biomass; prokaryotes occupy more diverse habitats; prokaryotes are more diverse in metabolism
Foods can be preserved in many ways by slowing or preventing bacterial growth. Which of these methods would not generally inhibit bacterial growth?
closing previously opened containers: prevents more bacteria from entering, and excludes O2
Many physicians administer antibiotics to patients at the first sign of any disease symptoms. Why can this practice cause more problems for these patients, and for others not yet infected?
overuse of antibiotics can select for antibiotic resistant strains of bacteria
Broad-spectrum antibiotics inhibit the growth of most intestinal bacteria. Consequently assuming that noting is done to counter the reduction of intestinal bacterial, a hospital patient who is receiving broad-spectrum antibiotics is most likely to become
deficient in certain vitamins
Which statement about gram-negative bacteria is correct?
they often possess an outer membrane containing toxic lipopolysaccharides.
Genetic variation in bacterial populations cannot result from
light as an energy source and CO2 as a carbon source
Which of the following statements is not true?
only bacteria have histones associated with DNA
Which of the following features of prokaryotic biology involves metabolic cooperation among cells
Which prokaryotic group is mismatched with its members?
Gram-positive bacteria- symbionts in legume root nodules
Plant-like photosynthesis that releases O2 occurs in
Why is salt a good preservative to use for food such as pork and fish?
Prokaryotic cells living in the food will shrink from their cell walls, impacting their ability to reproduce
Gram-negative bacteria have_____ peptidoglycan than gram-positive cells, and their cell walls are ______ complex structurally.
A gram-negative cell wall consists of
a thin layer of peptidoglycan surrounded by an outer membrane containing lipopolysaccharides
Bacteria that ____ tend to have abundant internal membranes
Bacterial cells, but not eukaryotic cells, possess
nucleoid with a circular chromosome
Bacterial flagella have very complex structure composed of 42 distinct proteins. What is the most likely explanation for the evolution of these complex structures?
The bacteria that cause tetanus can be killed by prolonged heating at temperatures considerably above boiling. This suggests that these bacteria
all of the answers are correct
How is it possible that as many as 9 million mutations can arise each day in the E. coli inhabiting one human?
mathematics of large population and size and rapid reproduction rate combine to produce many mutations without a particularly high mutation rate
In the absence of meiosis and sexual reproduction, what general process allows genetic recombination among prokaryotes?
horizontal gene transfer
Which statement about transformation is true?
it can be facilitated by cell-surface proteins that recognize compatible DNA
An F+ bacterial cell
acts as a donor during conjugation
Bacteria that use light for their energy source and CO2 for their carbon source are called
In an experiment, a microbiologist put equal numbers of each of the following organisms into a flask of sterile broth, consisting mostly of sugar and a few amino acids. She then placed the flask in the dark. Which of the organisms would be most likely to survive?
The Desulfovibro bacterium breaks down organic matter and uses sulfate as an electron acceptor. As a result, it produces hydrogen sulfide accounting for the rotten egg smell of swamp muck. Oxygen is a deadly poison to Desulfovibrio. We would call it
obligately anaerobic chemoheterotrophic
Choose the list below contains the substance required by typical nitrogen-fixing cyanobacteria
carbon dioxide, nitrogen, water, light and some minerals
What is the role of heterocysts in a cyanobacteria filament?
carry out only nitrogen fixation
Biofilms are an example of
metabolic cooperation among prokaryotic species
Portions of the genomes of certain prokaryotic species are very similar to portions of the genomes of distantly related prokaryotes. The process that most likely accounts for this genetic similarity is
horizontal gene transfer
Which subgroup of proteobacteria contains many species that are closely associated with eukaryotic hosts in mutualistic or parasitic relationships?
Which subgroup of proteobacteria contains many species that are predators of other bacteria?
Which group of bacteria is unusual in that they lack peptidoglycan in their cell walls?
Which of the following is a difference between bacteria and Archaea?
they have different chemicals in their cell membranes and cell walls
Prokaryotes found inhabiting the Great Salt Lake would be
Which of the following groups of prokaryotes is classified as a member of the domain Archaea?
Which clade of Archaea includes most of the extreme thermophiles?
Prokaryotes are completely indispensable to which chemical cycle?
A type of ecological relationship called ______ involves one organism living at the expense of another organism
Which example below is a correct statement about bacteriodes thetaiotaomicron, a bacterium that lives in the human intestines?
bacteria have a mutualistic relationship with the human body
Ticks that live on deer and field mice are responsible for spreading the bacterium ______, which causes ____
Borrelia burgdoferi.... Lyme disease
Which statement is true regarding cholera?
its symptoms are caused by an exotoxin that stimulates intestinal cells to release chlorine ions into the gut
Scientists hypothesize that theh O157:h7 strain of E.coli is so different from the k-12 strain because of
horizontal gene transfer over many years, most likely through the action of bacteriophages
Which statement about prokaryotes is true?
prokaryotes are widely used for bioremediation
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