Biology 1002 Midterm
The earliest known flowering plants date to the Tertiary (early Cenozoic era). Triassic (early Mesozoic era). Cambrian (early Paleozoic era). Cretaceous (late Mesozoic era).
Cretaceous (late Mesozoic era)
Suppose you have two small plants. You cut the roots off of one and then place both plants in a jar of red dye. After 20 minutes, the roots, stem, and leaves of the plant with roots have turned pink. The plant without roots has not changed color at all. Why has the plant without roots remained a normal, green color? -Cutting the roots has damaged the xylem, so the plant can no longer take up water. -Cutting the roots has damaged the apical meristem, so the plant can no longer take up water. -Cutting the roots has damaged the phloem, so the plant can no longer take up water. -Cutting the roots has damaged the sporangia, so the plant can no longer take up water.
Cutting the roots has damaged the xylem, so the plant can no longer take up water.
Conjugation between a bacterium that lacks an F factor (F -) and a bacterium that has an F factor on its chromosome (F+) could produce which of the following results? The F- bacterium ends up carrying one or more plasmids from the F+ bacterium; the F+ bacterium is unchanged. The F- bacterium ends up with a recombinant chromosome that carries some genes from the F+ bacterium, and the F+ bacterium ends up with an unaltered chromosome. The F+ bacterium ends up with a recombinant chromosome that carries some genes from the F- bacterium, and the F- bacterium ends up with an unaltered chromosome. The F+ bacterium ends up with a recombinant chromosome that carries some genes from the F- bacterium, and the F- bacterium ends up with a chromosome that lacks those genes.
The F- bacterium ends up with a recombinant chromosome that carries some genes from the F+ bacterium, and the F+ bacterium ends up with an unaltered chromosome.
Which of the following statements characterizes the lytic cycle of a viral infection? The virus reproduces outside of the host cell. The cycle typically leads to the lysis of the host cell. The viral genes typically remain inactive once they are inside the host cell. The cycle typically ends when the host bacterium divides.
The cycle typically leads to the lysis of the host cell.
Speciation has become complete when -organisms of one population do not recognize the mating call of another population and so mating does not occur. -two populations of organisms have been separated for a very long time. -a change in allele frequency has occurred. -offspring of mating from members of two different populations are able to mate with members of either population.
organisms of one population do not recognize the mating call of another population and so mating does not occur.
Which highly reactive gas was probably absent from the Earth's primitive atmosphere? water vapor carbon dioxide oxygen methane
oxygen
Which of the following represents the male gametophyte of a conifer? tree pollen cone sperm pollen grain
pollen grain
The fossil record shows that for many plant and animal groups, the time between speciation events varies greatly, but averages 6.5 million years. is usually greater than 40 million years. is equivalent to the length of 100 generations of a species. is usually about 50,000 years.
varies greatly, but averages 6.5 million years.
Which of the following would tend to promote adaptive radiation? -An organism colonizes an isolated area that is habitable but relatively devoid of life. -An organism colonizes an area that already has a high level of existing species diversity. -An organism has a very stable set of features and capabilities over long spans of evolutionary time. -A single species goes extinct, but it has several competitors that quickly expand to assume its ecological roles.
An organism colonizes an isolated area that is habitable but relatively devoid of life.
Which statement about archaea is false? Archaea cannot survive in very hot temperatures. Archaea are abundant in the oceans. Some archaea live in the digestive tracts of cattle.
Archaea cannot survive in very hot temperatures.
Chemoautotrophic bacteria obtain their carbon from ________ and their energy from ________. methane; sunlight CO2; sunlight CO2; reactions involving inorganic chemicals organic molecules; sunlight
CO2; reactions involving inorganic chemicals
Which of the following occurs in the sexual reproduction phase of the fungus life cycle? -Hyphae of two different mating fungi fuse. -Heterokaryotic cells separate to re-create the original haploid hyphae. -Spores germinate and form a haploid mycelium. -Diploid nuclei form, undergo meiosis, and produce haploid spores.
Diploid nuclei form, undergo meiosis, and produce haploid spores.
Which of the following statements correctly describes the alternation of generations in a plant life cycle? Diploid sporophytes that produce gametes by meiosis alternate with haploid sporophytes that produce gametes by mitosis. Diploid sporophytes that produce spores by meiosis alternate with haploid gametophytes that produce gametes by mitosis. Diploid gametophytes that produce spores by mitosis alternate with haploid sporophytes that produce gametes by meiosis. Diploid gametophytes that produce gametes by meiosis alternate with haploid sporophytes that produce spores by mitosis.
Diploid sporophytes that produce spores by meiosis alternate with haploid gametophytes that produce gametes by mitosis.
Which of the following statements regarding ferns is true? Ferns produce pollen that is dispersed by air. Ferns are most diverse in grassland environments. Ferns have well-developed roots and rigid stems. Ferns produce seeds that are dispersed by water.
Ferns have well-developed roots and rigid stems.
Which of the following statements is true? Gymnosperms have seeds that are not enclosed in a protective casing, while angiosperms have flowers that produce seeds with a protective casing. Gymnosperms lack seeds, while angiosperms have flowers that produce seeds with a protective casing. Gymnosperms lack true roots and leaves, while angiosperms lack lignin cell walls. Gymnosperms have flowers that produce seeds with a protective casing, while angiosperms have seeds that are not enclosed in a protective casing.
Gymnosperms have seeds that are not enclosed in a protective casing, while angiosperms have flowers that produce seeds with a protective casing.
Barry Marshall and his collaborators showed that -Helicobacter pylori bacteria are protective against peptic ulcers. -lab animals are easily infected by Helicobacter pylori. -Helicobacter pylori bacteria cause chronic gastritis and stomach ulcers. -lifestyle factors such as stress, diet, and smoking cause chronic -gastritis and stomach ulcers.
Helicobacter pylori bacteria cause chronic gastritis and stomach ulcers.
Which of the following is an example of exaptation? Human middle ear bones are derived from ancestral gill arch tissue. Mutation rates can increase at higher temperatures. Wings of bats and wings of birds are homologous. Some insects do not develop wings when resources are plentiful.
Human middle ear bones are derived from ancestral gill arch tissue.
The accompanying figure shows the hierarchy of classification of the cow, Bos primigenius. The greatest number of organisms would be found in B. A. E. I.
I.
________ are heterotrophic protists; ________ are photoautotrophic protists. Mixotrophs; protozoans Protozoans; algae Parasites; protozoans Protozoans; plants
Protozoans; algae
The following figure from your text shows a simplified eukaryote phylogeny. From this figure, answer the following question. Which group has the least scientific support for its position in the phylogeny? -SAR, because the phylogeny indicates that stramenopiles, alveolates, and rhizarians have only partial scientific support of evolutionary relationships. -Excavata, because the phylogeny indicates this group is not related to any other group in the phylogeny. -Unikonta, because the phylogeny indicates that fungi and animals are only partially evolutionarily related to one another. -Archaeplastida because the phylogeny indicates that red and green algae have stronger relationships with one another than with land plants.
SAR, because the phylogeny indicates that stramenopiles, alveolates, and rhizarians have only partial scientific support of evolutionary relationships.
Anti-evolutionary thinkers sometimes argue that natural selection could not produce a complex structure like the vertebrate eye. They claim that all of the parts of the eye must have arisen at once, asking why natural selection would favor the development of part of an eye that is not yet capable of forming a focused image. Which of the statements about the molluscan eye rejects the claim of anti-evolutionary thinkers? There are many intermediate stages of eye complexity, such as those in molluscs, that fulfill different adaptive functions. The vertebrate eye is the ancestral form, and other types of organism, such as molluscs, have degenerate eyes that have lost most of their original structure and function. The anti-evolution argument has a great deal of merit. Only full-blown image-forming eyes are present in modern organisms, including in molluscs. The vertebrate eye works in a way that is completely different from the eyes found in molluscs and other invertebrates.
There are many intermediate stages of eye complexity, such as those in molluscs, that fulfill different adaptive functions.
Which of the following statements about treatment or prevention of a prion infection is true? Preventative vaccines have recently been shown to be effective in preventing prion infections. There is no known treatment or cure for prion infections. High doses of anti-inflammatory drugs such as ibuprofen reduce the symptoms of prion infections. Antibiotic therapies such as penicillin are very effective cures.
There is no known treatment or cure for prion infections.
The first organisms on Earth were very small, but now when you look around you see many large organisms. Which is the best explanation for this observation? Evolution tends toward larger and larger organisms. The goal of evolution is to produce the largest organisms possible. Organisms got larger because they needed to use resources more efficiently. There were many steps necessary to go from small cells to large organisms.
There were many steps necessary to go from small cells to large organisms.
How do scientists calibrate a molecular clock for a group of organisms with known nucleotide sequences? They use radioactive isotopes to measure the age of DNA material directly. They analyze fossilized DNA of known age and compare its nucleotide sequences to modern DNA sequences. They graph the number of nucleotide differences against the dates of evolutionary branch points known from the fossil record.
They graph the number of nucleotide differences against the dates of evolutionary branch points known from the fossil record.
Many flower traits are specifically attractive to a certain type of pollinator. For example, the scent of rotting flesh is attractive to certain flies and beetles but not to most other pollinators. What adaptive purpose is served by this kind of "niche marketing" of flowers to specific pollinators? -This targeting is done because the wrong kind of pollinator might eat all the pollen instead of delivering it to another flower. -This adaptation works to reduce pollinator traffic at a flower. Therefore, flowers do not have to produce as much nectar to feed big crowds of pollinators. -This adaptation helps to assure that pollen will be delivered to another flower of the same species. If less specialized pollinators are used, the odds are greater that pollen will wind up on the stigma of a different species. -This adaptation reduces pollinator traffic so that flowers have a chance to develop their pollen fully before it is spread.
This adaptation helps to assure that pollen will be delivered to another flower of the same species. If less specialized pollinators are used, the odds are greater that pollen will wind up on the stigma of a different species.
Which of the following statements regarding viral diseases is false? -AIDS was around for decades before becoming a widespread epidemic. -New viral diseases often emerge when a virus infects a new host species. -Very few new human diseases have originated in other animals because the genetic differences are too great. -RNA viruses tend to have an unusually high rate of mutation because their RNA genomes cannot be corrected by proofreading.
Very few new human diseases have originated in other animals because the genetic differences are too great.
A scientist collects a protist from a rotting log. He grows the protist in a petri dish that contains Escherichia coli bacteria; the protist engulfs the bacteria. For a while the protist multiplies as single cells. When the E. coli are all consumed, the protists aggregate to form a clump that rises up to become a stalked structure with a globular head. What kind of protist does the scientist have? a water mold a cellular slime mold a plasmodial slime mold a free-living amoeba
a cellular slime mold
Which of the following would a biologist describe as microevolution? -the extinction of species -a change in the gene pool of a population from one generation to the next -the formation of new species -dramatic biological changes, such as the origin of flight, within a taxon
a change in the gene pool of a population from one generation to the next
A comet orchid has creamy white-colored flowers and a characteristic "tail" that contains the flower's nectar. This orchid does not emit a scent during daylight hours but is aromatic at night. The comet orchid is most likely pollinated by a nocturnal pollinator. windy nighttime conditions. pollen traveling on animal fur. moisture from cool evenings.
a nocturnal pollinator.
Which of the following types of reproductive barriers separates a pair of moth species that could interbreed but for the fact that the females' mating pheromones are not attractive to the males of the other species? gametic isolation mechanical isolation temporal isolation behavioral isolation
behavioral isolation
A protein coat that enclosed a viral genome is known as a(n) envelope. capsid. prophage. capsule.
capsid.
Someone diagnosed with meningitis has inflamed membranes that cover and protect the brain and spinal cord. Meningitis is a result of pathogenic gram-negative bacteria that cause extreme infections when their bacterial cell wall dies and lipopolysaccharide (a lipid and polysaccharide) is released. The lipopolysaccharide is an example of a/an parasite. endotoxin. stomach microbiota. exotoxin.
endotoxin.
Hallucinations, nervous spasms, and even death can result when humans consume grain infested with corn smut. coccidioidomycosis. chytrids. ergots.
ergots
A new plant species may arise in a single generation by -a sudden geological disruption causing separation of two populations. -mutations in genes for flower color. -changes in the pollinator species. -errors in meiosis leading to polyploidy.
errors in meiosis leading to polyploidy.
In 1942 a scientist testing part of a radar system discovered that a candy bar in his pocket had melted. Intrigued, he tried placing an egg near the system he was working on; it exploded and splattered him with hot egg. In this way it was discovered that part of the radar system could be used to cook foods, which led to the development of the microwave oven. When this kind of repurposing occurs in biological systems, it is called -adaptive radiation. -paedomorphosis. -mutation. -exaptation.
exaptation
Feathers are an example of a(n) ________; they originally evolved ________. exaptation; in anticipation of future use in the development of flight exaptation; for some other function and only later became adapted for flight homology; for flight in an entire lineage of dinosaurs
exaptation; for some other function and only later became adapted for flight
A patient visits her doctor complaining of stomach cramps, vomiting, and nausea. When he takes a bacterial sample, he determines that Escherichia coli bacteria have used their ________ to attach to the cells lining her gastrointestinal tract. fimbriae flagella cilia peptidoglycan
fimbriae
Which of the following options lists major events in the history of life on Earth in the proper order, from earliest to most recent? -first prokaryotes, photosynthesis, colonization of land by plants and fungi, first eukaryotes -first prokaryotes, photosynthesis, first eukaryotes, colonization of land by plants and fungi -first prokaryotes, first eukaryotes, photosynthesis, colonization of land by plants and fungi -first eukaryotes, photosynthesis, colonization of land by plants and fungi, first prokaryotes
first prokaryotes, photosynthesis, first eukaryotes, colonization of land by plants and fungi
Which two groups of protists produce hard, mineralized skeletal structures or cell walls that contribute to marine sediments and form fossils? dinoflagellates and diatoms green algae and brown algae foraminiferans and radiolarians cellular slime molds and water molds
foraminiferans and radiolarians
According to the accompanying figure, during what time frame was there an adaptive radiation of eutherians? from 140 to 100 million years ago from 100 million years ago to the present about 170 million years ago about 200 million years ago
from 100 million years ago to the present
Which structure is found in angiosperms but not gymnosperms? fruit seeds ovule spores
fruit
For speciation to occur there must be isolation. genetic variation. sexual reproduction. natural selection.
genetic variation
About 80% of plants have mycorrhizae linking them to -glomeromycetes. -basidiomycetes. -chytrids. -ascomycetes.
glomeromycetes.
Which of the following types of reproductive barriers separates a pair of insect species that could interbreed but for the fact that one lives on goldenrod plants and the other on autumn daisies in the same general area? temporal isolation gametic isolation habitat isolation behavioral isolation
habitat isolation
Which of the following human activities has contributed to an increase in the number of bacteria having R plasmids? -heavy use of antibiotics in medicine and in agriculture -increased carcinogen exposure from excessive fossil fuel burning -nitrogen fixation by genetically engineered plants -improper use of restriction enzymes in research and medical facilities
heavy use of antibiotics in medicine and in agriculture
The envelope of a mumps virus -is coded by host genes. -accounts for viral resistance to antibiotics. -helps the virus insert its DNA into the host cell genome. -helps the virus enter the cell.
helps the virus enter the cell.
A cocklebur is dispersed by ________, whereas most fleshy, edible fruits are eaten by animals that ________. hitching rides on animals; defecate the intact seeds water currents; defecate the intact seeds hitching rides on animals; fully digest the fruits, including the seeds, which are killed wind; fully digest the fruits, including the seeds, which are killed
hitching rides on animals; defecate the intact seeds
Two species interbreed occasionally and produce vigorous, fertile hybrids. When the hybrids breed with each other or with either parent species, however, the offspring are feeble or sterile. These species are affected by gametic isolation. reduced hybrid fertility. reduced hybrid viability. hybrid breakdown.
hybrid breakdown.
Conjugation, transformation, and transduction are all ways that bacteria alter their oxygen requirements. increase their genetic diversity. reduce their DNA content. increase the amount of RNA in the cytoplasm.
increase their genetic diversity.
Old cemeteries (pre-1900) often have gravestones that often host many types of lichens. However, it is not impossible to find old cemeteries where lichens are entirely absent. Given what is known about lichens, an old cemetery without lichens probably -is close to a source of air pollution. -gets a great deal of rain, which favors the growth of competing bacteria. -has an unusually dry climate. -is subject to extremely cold winter temperatures.
is close to a source of air pollution.
Conjugation -is the direct transfer of DNA from one bacterium to another. -occurs when a phage transfers bacterial DNA from one bacterium to another. -occurs when a bacterium acquires DNA from the surrounding environment. -is the result of cell division.
is the direct transfer of DNA from one bacterium to another.
The findings of Pasteur and others have established that -living organisms regularly self-assemble (arise spontaneously) from nonliving matter. -living organisms do not arise from nonliving matter today, nor did they arise from nonlife in the past. -advanced organisms cannot arise from nonliving matter, but simple microbial life often does arise from nonlife today. -life does not arise from nonliving matter today, but in the conditions of early Earth, such an event could have occurred.
life does not arise from nonliving matter today, but in the conditions of early Earth, such an event could have occurred.
One of the factors that helps animal-pollinated flowering plants transfer pollen to plants of the same species is that -pollinators are able to rapidly extract nectar from any species of flower, regardless of the pollinators' past or recent experience with a given flower type. -pollinators only visit flowers that produce massive amounts of pollen. -many pollinators have limited learning capacities and are most successful at obtaining food if they continue to visit the same type of flower after learning how to extract its nectar. -most pollinators broadly use many different types of flowers.
many pollinators have limited learning capacities and are most successful at obtaining food if they continue to visit the same type of flower after learning how to extract its nectar.
Traditional microbial genomics and cultivation methods have given scientists access to approximately 1% of microbial genetic diversity. This is because most microbes cannot be grown up, or cultured, on petri dishes. Which scientific field would allow scientists to have a much greater access to an environment's genetic resources? bioremediation agriculture metagenomics forestry
metagenomics
If you place an organism classified as a photoautotroph at the bottom of a lake and later see that it is able to acquire nutrients from dead plant material, you can conclude the photoautotroph is actually a mixotroph. chemoautotroph. chemoheterotroph. photoheterotroph.
mixotroph.
Individual prokaryote cells are ________ eukaryote cells; collectively, all prokaryote cells on Earth ________. the same size as; weigh about one-tenth the total mass of eukaryote cells much smaller than; weigh about 10 times as much as the total mass of eukaryote cells much smaller than; weigh about one-tenth the total mass of eukaryote cells much larger than; weigh about 10 times as much as the total mass of eukaryote cells
much smaller than; weigh about 10 times as much as the total mass of eukaryote cells
Protists include two clades of eukaryotes: one is related to animals and fungi, and the other is related to plants. a single clade of eukaryotes that are distantly related to animals. two clades of eukaryotes: algae and protozoans. multiple clades of eukaryotes.
multiple clades of eukaryotes.
The intimate, mutually beneficial association formed between a fungus and the root of a plant is called a sporophyte. hypha. mycorrhiza. mycelium.
mycorrhiza.
Transduction -requires DNA polymerase. -occurs when a bacterium acquires DNA from the surrounding environment. -is the direct transfer of DNA from one bacterium to another. -occurs when a phage transfers bacterial DNA from one bacterium to another.
occurs when a phage transfers bacterial DNA from one bacterium to another.
The trickling filter at a sewage treatment plant works by: -passing wastewater through fine sand and then mechanically removing fine pollution particles. -passing wastewater through a thick bed of rocks where biofilms of bacteria and fungi on the rocks remove much of the organic material dissolved in the wastewater. -adding fertilizer to wastewater and then passing it through a culture medium that is rich in oil-eating prokaryotes. -passing wastewater through a thick bed of rocks that contains chemicals that sterilize the water and neutralize chemical pollutants.
passing wastewater through a thick bed of rocks where biofilms of bacteria and fungi on the rocks remove much of the organic material dissolved in the wastewater.
Which of the following options correctly lists the varieties of life in the order that they appear in the geologic record, from earliest to most recent? -land arthropods, plants and fungi on land, flowering plants, reptiles -reptiles, land arthropods, plants and fungi on land, flowering plants -plants and fungi on land, land arthropods, flowering plants, reptiles -plants and fungi on land, land arthropods, reptiles, flowering plants
plants and fungi on land, land arthropods, reptiles, flowering plants
When plants undergo allopatric speciation, an initial reproductive barrier is often polyploidy. pollinator choice. temporal isolation. gametic isolation.
pollinator choice.
Which of the following characteristics tends to limit bryophytes and seedless vascular plants to habitats that are relatively moist? absence of cuticle presence of free-living, independent zygotes and early embryos presence of flagellated sperm absence of lignified vascular tissues
presence of flagellated sperm
Viral DNA incorporated into host cell DNA is known as a(n) prophage. capsid. envelope. phage.
prophage.
Some white blood cells are able to surround and ingest bacteria. Which of the following would you expect to see as part of the blood cell structure? cilia flagella secondary cell walls pseudopodia
pseudopodia
Two species that occasionally mate and produce zygotes, but that have incompatible genes that prevent the resulting embryo from developing, are affected by reduced hybrid fertility. behavioral isolation. reduced hybrid viability. gametic isolation.
reduced hybrid viability.
Mass extinctions -remove well-adapted species and groups from the Earth, so that it may take millions of years for species diversity to recover. -remove many species, but they are usually replaced within a million years or less by an even greater diversity of life. -are caused by human activity and did not occur prior to the expansion of the Earth's human population. -mainly serve to "weed out" poorly adapted organisms and make room for new, better adapted specie
remove well-adapted species and groups from the Earth, so that it may take millions of years for species diversity to recover.
Speciation, or the formation of new species, is -responsible for the diversity of life. -a form of microevolution. -an event that has occurred only a few times in the history of the planet. -necessary for natural selection and adaptation.
responsible for the diversity of life.
Which of the following enzymes does HIV use to synthesize DNA on an RNA template? reverse transcriptase DNA ligase RNA polymerase DNA polymerase
reverse transcriptase
RNA molecules that can function like enzymes are called ribozymes. mRNA. ribosomes.
ribozymes
If the divergence illustrated here is based on some female insects preferring large males and others preferring small males, then this would be an example of temporal isolation. allopatric speciation. hybrid inviability. sexual selection.
sexual selection.
The biological species concept is -easy to apply to all present sexually reproducing organisms but harder to apply to asexual organisms and fossils. -sometimes difficult to put into practice even for present sexual organisms and useless for asexual organisms and fossils. -applicable to all forms of life, past and present. -applicable to all present life-forms but not to fossil organisms whose reproductive behavior cannot be observed.
sometimes difficult to put into practice even for present sexual organisms and useless for asexual organisms and fossils.
Which of the following would be the best evidence to demonstrate that mushrooms are living, reproducing organisms? flagellated sperm spore production and dispersal lignin pollen
spore production and dispersal
In ferns, the ________ produces spores by ________ in ________. gametophyte; mitosis; sporangia male gametangium; meiosis; sperm sporophyte; meiosis; sporangia female gametangium; mitosis; eggs
sporophyte; meiosis; sporangia
Speciation without geographic isolation is called ________ speciation. sympatric incomplete diversifying allopatric
sympatric
A friend accidentally sends an email to you that contains a computer virus from his computer. Without knowing it, you infect your computer with the virus when you open the email. This process of spreading the computer virus via email is most like which of the following processes? binary fission conjugation transformation transduction
transduction
Multicellular organisms evolved from three different ancestral lineages: stramenopiles, unikonts, and archaeplastids. Of these, fungi and animals evolved from two different lineages of ________, and land plants are ________. archaeplastids; unikonts unikonts; archaeplastids alveolates; unikonts alveolates; archaeplastids
unikonts; archaeplastids
One of the key contributions of the punctuated equilibrium model is that it helps explain -why large, widespread populations tend to be the ones that evolve most rapidly and unpredictably. -how new species arise from hybridization events. -why transitional fossils are more common than Darwin would have predicted. -why transitional fossils tend to be rare and certain common fossil species remain unchanged for long time spans.
why transitional fossils tend to be rare and certain common fossil species remain unchanged for long time spans.
A mushroom is -specialized to obtain most of the nutrients for the fungal mycelium. -an aboveground reproductive structure connected to a mycelium. -an independent stage in the alternation of generations of the fungal life cycle. -composed of many threadlike filaments called mycorrhizae.
an aboveground reproductive structure connected to a mycelium.
The similarities in function of hummingbird wings and the wings of a butterfly reflect -analogy but not homology. -homology through convergent evolution. -homology but not analogy. -analogy and homology.
analogy but not homology
A growth-producing region of cell division, known as a/an ________, is found near the tips of stems and roots. sporangium apical meristem lignin cuticle
apical meristem
Diatoms are heterotrophic protists that decompose dead plants and animals in freshwater habitats. are autotrophs with a glassy cell wall that contains silica. include the malaria parasite. are mixotrophs.
are autotrophs with a glassy cell wall that contains silica.
The data in this graph indicate: there were fewer total tough seeds in 1976 than in 1977. available seeds were generally tougher in 1977 than in 1976. seed abundance in 1977 was severely reduced by finch feeding. plants that produced soft seeds in 1976 produced tougher seeds in 1977.
available seeds were generally tougher in 1977 than in 1976.
After reading the paragraphs below, answer the questions that follow. Exposure to the HIV virus doesn't necessarily mean that a person will develop AIDS. Some people have genetic resistance to infection by HIV. Dr. Stephen O'Brien from the U.S. National Cancer Institute has recently identified a mutant form of a gene, called CCR5, that can protect against HIV infection. The mutation probably originated in Europe and became more prevalent among survivors of the bubonic plague. The mutated gene prevents the plague bacteria from attaching to cell membranes and, therefore, from entering and infecting body cells. Although the HIV virus is very different from the bacteria that causes the plague, both diseases affect the exact same cells and use the same method of infection. The presence of the mutated gene in descendants of plague survivors helps prevent them from contracting AIDS. Pharmaceutical companies are using this information as the basis for a new approach to AIDS prevention. This could be very important in areas of the world where the mutation is scarce or absent, such as Africa. Which of the following shows the steps of a viral infection in the proper order? -virus locates host cell > forms hydrogen bonds > changes DNA to RNA > host cell produces copies of virus -virus locates host cell > penetrates cell membrane > enters nucleus > alters host cell DNA > host cell produces copies of virus -virus locates host cell > enters nucleus > alters host cell DNA > destroys cell membrane -virus locates host cell > alters host cell DNA > host cell produces copies of virus > copies enter host cell nucleus > nucleus leaves cell
virus locates host cell > penetrates cell membrane > enters nucleus > alters host cell DNA > host cell produces copies of virus
Potassium-40 can be used to date ________ that are ________ old. volcanic rocks and associated fossils; thousands of years volcanic rocks and associated fossils; hundreds of millions of years potassium-rich fossils; millions of years carbon-containing rocks and fossils; up to 75,000 years
volcanic rocks and associated fossils; hundreds of millions of years
After reading the paragraphs below, answer the questions that follow. Exposure to the HIV virus doesn't necessarily mean that a person will develop AIDS. Some people have genetic resistance to infection by HIV. Dr. Stephen O'Brien from the U.S. National Cancer Institute has recently identified a mutant form of a gene, called CCR5, that can protect against HIV infection. The mutation probably originated in Europe and became more prevalent among survivors of the bubonic plague. The mutated gene prevents the plague bacteria from attaching to cell membranes and, therefore, from entering and infecting body cells. Although the HIV virus is very different from the bacteria that causes the plague, both diseases affect the exact same cells and use the same method of infection. The presence of the mutated gene in descendants of plague survivors helps prevent them from contracting AIDS. Pharmaceutical companies are using this information as the basis for a new approach to AIDS prevention. This could be very important in areas of the world where the mutation is scarce or absent, such as Africa. Imagine that a pharmaceutical company was successful at producing a drug based on the CCR5 gene product that is effective at preventing the contraction of AIDS. However, shortly after the drug has been in use, patients and doctors report that the drug is not as effective as it once was. What is the most likely explanation for this result? -The HIV virus gained mutations in its DNA genome in order to become resistant to the actions of the drug. -The DNA of white blood cells of the people taking the drug has mutated to become resistant to the drug. -Some HIV viruses have genetic variations in the RNA genome that provide resistance to the actions of the drug. -The people taking the drug have built up a tolerance to the drug.
Some HIV viruses have genetic variations in the RNA genome that provide resistance to the actions of the drug.
Which of the following statements regarding the definition of species is false? -The morphological species concept relies upon comparing the DNA sequences of organisms. -The phylogenetic species concept defines a species as a set of organisms that shares a common ancestor and forms one branch on the tree of life. -Under the biological species concept, the gap between species is maintained by reproductive isolation. -The ecological species concept identifies species in terms of their ecological niches.
The morphological species concept relies upon comparing the DNA sequences of organisms.
A group of ants escaped from a picnic basket carried to the top of a mountain and thrived in this area where there were no other ants. Many years later descendants of these ants crawled into a picnic basket on the mountain and traveled back to the valley from which their ancestors had come. Which of these observations would cause you to conclude that the ants on top of the mountain had become a different species from those in the valley? The mountain ants and valley ants were different colors. The mountain ants and valley ants were different sizes. The mountain ants ate different food than the valley ants. The mountain ants could not mate with the valley ants.
The mountain ants could not mate with the valley ants.
Which organisms are common soil decomposers that grow in colonies of branched chains of cells that superficially resemble a fungus? cyanobacteria proteobacteria cocci actinomycetes
actinomycetes
The geographic isolation of a population from other members of the species and the subsequent evolution of reproductive barriers between it and the parent species describes ________ speciation. allopatric sympatric punctuated biogeographic
allopatric
After reading the paragraphs below, answer the questions that follow. Exposure to the HIV virus doesn't necessarily mean that a person will develop AIDS. Some people have genetic resistance to infection by HIV. Dr. Stephen O'Brien from the U.S. National Cancer Institute has recently identified a mutant form of a gene, called CCR5, that can protect against HIV infection. The mutation probably originated in Europe and became more prevalent among survivors of the bubonic plague. The mutated gene prevents the plague bacteria from attaching to cell membranes and, therefore, from entering and infecting body cells. Although the HIV virus is very different from the bacteria that causes the plague, both diseases affect the exact same cells and use the same method of infection. The presence of the mutated gene in descendants of plague survivors helps prevent them from contracting AIDS. Pharmaceutical companies are using this information as the basis for a new approach to AIDS prevention. This could be very important in areas of the world where the mutation is scarce or absent, such as Africa. The most likely method by which the mutated CCR5 gene prevents AIDS is by -rupturing the nuclear membrane. -coding for a protective protein in the cell membrane. -attacking and destroying the HIV virus particles. -covering the cell membrane.
coding for a protective protein in the cell membrane.
In the chiclid populations in Lake Victoria, what trait in females acted as a selection factor on which males they mated with? -preferred water depth -body color -ability to hear sounds made by the male -color vision
color vision
In 1865, a biologist, St. George Jackson Mivart, constructed an evolutionary tree of existing primate species with many branches based on analysis of spinal columns. But to his dismay, another tree based on limb comparison was quite different. Which of the following analyses would be best to include today to determine which tree is more accurate? examination of evolutionary trees constructed by others comparison of DNA sequences of primates comparison of genes that control development comparison of eyes of primates
comparison of DNA sequences of primates
Which of the following would violate the assumptions of the molecular clock? -assuming that organisms in competitive environments have the same rate of mutation as those in noncompetitive environments -comparison of genes of a species that lives deep in the ocean with relatives that live on the surface and are exposed to strong mutation-inducing ultraviolet radiation -comparison of genes for homologous structures across many species -comparison of many genes in many species of insects that undergo metamorphosis
comparison of genes of a species that lives deep in the ocean with relatives that live on the surface and are exposed to strong mutation-inducing ultraviolet radiation
Plasmodial slime molds: are marine decomposers. are photoautotrophic. are primitive fungi. contain many nuclei in one mass of cytoplasm.
contain many nuclei in one mass of cytoplasm.
Earth's continents and seafloors together form a thin outer layer of the planet called the biosphere. crust. mantle. strata.
crust.
