Fundamentals of Biology HW Set #2

The following options are all reproductive barriers. Which one is an example of a prezygotic barrier in which the two different species do mate?

Two dragonfly species regularly mate, but their gametes are incompatible.

You are examining a fragment of material from an unknown life-form extracted from a sample taken deep in Earth's crust. Which of the following clues would convince you the sample came from an archaeal cell?

histones associated with DNA and some introns present in genes, but no evidence of membrane-enclosed organelles

Which of the following statements about adaptation is true?

A population that has an increase in frequency of alleles for thicker fur has become adapted to the cold.

Which of the following is radially symmetrical? A.a doughnut B.a spoon C.an automobile D.a submarine sandwich (a.k.a. hoagie, sub, grinder, or bomber)

A. a doughnut

Which correctly pairs a challenge to living on land with the relevant plant adaptation? A.water loss ... cuticle B.reproduction and dispersal ... vascular tissue C.reproduction out of water ... flagellated sperm D.water loss ... apical meristem

A.water loss ... cuticle

Which of the following best expresses the concept of natural selection?

Differential reproductive success based on inherited characteristics

Several groups of protists have variable modes of nutrition: Some species are photoautotrophs, whereas close relatives are heterotrophs. Such diversity even exists within a single species in some cases. Evidence suggests that this pattern is a result of the _____.

B.independent acquisition of green and red algae as endosymbionts by many protist groups, with subsequent evolution producing photosynthetic organelles

Which option provides evidence for the role of endosymbiosis in the origin of eukaryotes?

Chloroplasts and mitochondria have their own DNA and reproduce by binary fission.

Which of the following scenarios would most likely result in the microevolution of a population of humans? A. Excess ultraviolet radiation causes a major increase in mutation rates within the skin cells of adults. B. A plane crashes, killing 212 random individuals out of a total U.S. population exceeding 275 million. C. Only random mating takes place in all the people that reproduce in North America. D. A colony of twelve humans is established on the moon and remains isolated from Earth.

D. A colony of twelve humans is established on the moon and remains isolated from Earth.

Which of the following scenarios would most likely result in the microevolution of a population of humans? A.Excess ultraviolet radiation causes a major increase in mutation rates within the skin cells of adults. B.A plane crashes, killing 212 random individuals out of a total U.S. population exceeding 275 million. C.Only random mating takes place in all the people that reproduce in North America. D.A colony of twelve humans is established on the moon and remains isolated from Earth.

D. A colony of twelve humans is established on the moon and remains isolated from Earth.

Citrus fruit has always been distributed from areas where the fruit is grown to other parts of the country, often by train. In the early 1900s train cars were heated with coal, and it was believed that this heat helped ripen the fruit. Imagine the surprise of growers and suppliers when fruit that arrived in new boxcars heated by steam arrived unripe. Why did the fruit no longer ripen?

Ethylene, a by-product of coal burning, ripened the fruit in the cars with the coal stove but was absent from the steam-powered trains.

The sickle-cell allele produces a serious blood disease in homozygotes. Why doesn't natural selection eliminate this allele from all human populations?

In populations where endemic malaria is present, heterozygotes have an important advantage: They are resistant to malaria and therefore are more likely to survive and produce offspring that carry the allele.

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. Next, 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 lead you to conclude that the island finch population had evolved into a distinct biological species?

Individuals from the different populations sometimes mate with each other, but all of the resulting eggs are sterile.

Comparison of 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 say about this?

Lack of recent change is consistent with the punctuated equilibrium model.

Christmas cactus is a short-day plant that usually blooms in the winter. Which strategy might induce it to bloom for the 4th of July?

Leaving it in a dark closet all night and part of each morning during June.

A graduate student finds an organism in a pond and thinks it is a freshwater sponge. A professor thinks it looks more like an aquatic fungus. How can they decide whether it is an animal or a fungus?

Look for cell walls under a microscope.

Which of the following constitutes the use of a biological weapon?

Members of a commune in Oregon contaminated a salad bar at a local restaurant with Salmonella bacteria to try to manipulate a local election by making people too sick to vote.

During the 1950s, a scientist named Lysenko tried to solve the food shortages in the Soviet Union by breeding wheat that could grow in Siberia. He theorized that if individual wheat plants were exposed to cold, they would develop additional cold tolerance and pass it to their offspring. Based on the ideas of artificial and natural selection, do you think this project worked as planned?

No, because there was no process of selection based on inherited traits. Lysenko assumed that exposure could induce a plant to develop additional cold tolerance and that this tolerance would be passed to the plant's offspring.

Lake Victoria is home to a group of related fishes known as cichlids. Hundreds of forms are present, differing slightly in their color patterns, habitat use, and feeding behavior. What is the best method for scientists to determine conclusively whether the fish are members of a population that has a lot of variation or members of entirely different species?

Observe them together under natural conditions to see if they interbreed to produce fertile offspring.

A student wanted to plant an avocado seed to try to grow an avocado plant, but she could not tell which end of the seed was the bottom and which was the top. She asked her friends what she should do. Which friend's suggestion will have the highest success of growing the avocado plant?

One friend suggested a compromise: Put the seed sideways, since gravity will ensure that the shoots grow up and the roots grow down.

A peanut farmer decides that she can make more money growing cotton and so plants her fields with cotton. The terrific yield of her fields is so encouraging that she continues to plant cotton for several more years, but each year her cotton yield decreases. What advice could you give her to increase her yield?

Plant peanuts in alternate years since this crop rotation will provide extra nitrogen to the soil.

Which of the following is a true similarity between algae and plants?

Plants and algae both are eukaryotic photosynthesizers.

Which properly states the role of bacteria and prokaryotes in general in human life?

Prokaryotes cause half of all infectious human diseases. However, they also play vitally important positive roles as decomposers and even as beneficial partners in our bodies. The sudden disappearance of all prokaryotes would almost certainly doom humans to extinction.

A news article discussing the evolution of domestic dogs from wolves included this statement: "On its way from pack-hunting carnivore to fireside companion, dogs learned to love?or at least live on?wheat, rice, barley, corn, and potatoes." What is a more scientifically accurate way to state what happened with dogs?

Some wolves may have had variants in their digestion that allowed them to eat wheat, rice, barley, corn, and potatoes and so were able to survive with humans.

_____ generated many key crop plant species in the past, and continues to be an important method for plant geneticists today.

Sympatric speciation by polyploidy

A gardener planted large, healthy flower bulbs in her garden. When spring arrived, green shoots emerged from the bulbs, and some of them, but not all, produced flowers. She decided to dig up a few bulbs that flowered and a few that didn't to see if she could see what the difference was. She was stunned to find that none of the bulbs looked healthy; they all appeared much smaller. What had happened?

The bulbs were a sugar source; sugars from them traveled up the phloem to the aboveground sugar sink.

In plant research labs, plants are often grown in light-proof chambers where the hours of light and dark are carefully controlled. A new researcher goes into a chamber and accidentally turns on the light during the "dark" period. How should the researcher respond to get the plants back to their controlled schedule quickly?

The researcher should quickly produce a flash of far-red light and close the door.

Certain bacterial strains have traits that allow them to resist the effects of antibiotic drugs. How do the resistance traits arise in a bacterial population, and under what circumstances will the resistance traits be most common?

The resistance traits are produced by chance mutations and are present to varying degrees in most bacterial populations. Resistance traits will be most prevalent, however, in bacteria that are chronically exposed to antibiotic drugs.

Each biological species is genetically isolated from other species. Why do the species evolve independently?

The two species evolve independently because they do not exchange genes. Reproductive barriers keep them from successfully interbreeding

Often, the morphological species concept is used to define and describe species. Why?

This is the most convenient way of identifying species, and it is one of the few ways to identify fossil or asexual species.

Strolling through the woods, you would be least likely to notice which of the following?

a fern gametophyte

Most of the seeds and spices used for human consumption come from _____.

angiosperms

What is the role of the fungus in a mycorrhizal association?

absorption of water, phosphate, and other minerals

The evolution of numerous ecologically diverse species from a single ancestor in a relatively short time period, as seen in Darwin's finches, is called _____.

adaptive radiation

Two animals are considered members of different biological species if they _____.

are male and female, but cannot interbreed

You have been asked to participate in the cleanup of an old mining site. You build a treatment wetland to clean up a contaminated spring flowing out of the mine area. Before sending the water to the wetland, you pass it through a holding tank where Thiobacillus removes heavy metals. The plants and microbes of the wetland will absorb many of the contaminants that remain in the water. Your method is an example of _____.

bioremediation

Around hydrothermal vents at depths of more than 2,500 m, scientists have found colonies of giant tube-dwelling worms. The worms contain symbiotic prokaryotes that are able to use hydrogen sulfide as an energy source for the synthesis of organic matter from carbon dioxide. The bacteria are _____.

chemoautotrophic

micronutrients function in plants mainly as

cofactors in chemical reactions

Which experiment might be performed by a biologist who is interested in determining which plant organs (stems, buds, leaves, etc.,) are responsible for sensing photoperiod?

cover different plant organs with a foil covering to prevent light exposure

when a nursery worker pinches off the terminal buds on a young plant to make it grow bushy, which plant hormone, when produced, is mainly responsible for growth of side branches

cytokinin

under what conditions would you expect a plant to have the highest concentration of absidic acid? (ABA)

desert after a long drought

Application of herbicides made from plant hormones may have unintended consequences because

different types of plants could respond differently to the same herbicide.

"Carnivory" in plants is an adaptation to...

discouraging herbivorous insects

Unlike humans and other animals, plants have _____.

distinct multicellular haploid and diploid stages

in many grocery stores, fresh fruits are sold in plastic bags dotted with holes so that they will not over-ripen. The main function of the holes is to...

facilitate diffusion of ethylene away from the fruit

After reading the paragraph, answer the question(s) that follow. In the 1930s, the Navajo Nation treated sheep and cattle for ticks and other parasites by using concrete "dip tanks." Animals were herded through one end of the tank and out the other. Each day, the tanks were filled with 200,000 gallons of insecticide and any remaining chemicals were emptied onto the ground. The pesticide solution seeped into the ground, ditches, and pits around the tanks. This was a common practice in the United States during that period. The EPA Emergency Response Team (ERT) was called to the Navajo Nation during the 1990s to investigate the problem. They concluded that bioremediation procedures were the best for this site. Certain types of bacteria are able to feed on and digest toxic organic substances, such as pesticides, and use them as fuel for cell respiration. The ERT distributed the pesticide-eating microorganisms through the contaminated soil to remove the chemical residues. Once the contaminants are degraded, these microorganism populations die off because they've used all of their food supply. Based on the scenario, the pesticide-eating bacteria probably evolved from species that

fed on molecules with a chemical structure similar to pesticides.

Ferns have vascular tissue, an adaptation to life on land, but they have an ancestral reproductive trait that tends to limit them to moist habitats. What is it?

flagellated sperm

Humans share several features with salamanders. Certain genes and proteins are nearly identical between the two species; both species have four limbs with a similar skeletal structure; the species' early embryos are very similar; and where the salamander has a functional tail, humans have a vestigial tailbone. In evolutionary terms, these are examples of

homology

What is one adaptive advantage for deciduous plants that lose their leaves during the winter?

it prevents water loss from leaves when soil water is unavailable due to freezing

During the Carboniferous period, forests consisting mainly of _____ produced vast quantities of organic matter, which was buried and later became coal.

lycophytes and ferns

Which of the following is a member of the domain Archaea?

methanogens

commercial inorganic fertilizers have greatly increased agricultural productivity. What is an advantage of using inorganic rather than organic fertilizers?

nutrients are released faster from inorganic fertilizers.

Imagine that part of a population of flies is blown from the California coast to an offshore island. The island flies have no contact with the mainland flies for 10,000 years. Then an earthquake rearranges the landscape and the island is rejoined to the mainland. The former island flies can now mingle freely with the mainland flies. If attempts at mating between flies from the two groups are successful and the resulting offspring grow up strong and healthy and have offspring of their own, you could conclude that _____.

over the past 10,000 years, no speciation occurred in these flies

Unlike most angiosperms, grasses are pollinated by wind. As a consequence, some unnecessary parts of grass flowers have almost disappeared. Which of the following parts would you expect to be most reduced in a grass flower?

petals

A major difference between angiosperms and gymnosperms involves the _____.

presence or absence of the ovary

According to the _____ model, evolution occurs in spurts: Species evolve relatively rapidly and then remain unchanged for long periods.

punctuated equilibrium

mimosa plants spread their leaflets during the day and fold them at night. you design an experiment to test whether Mimosa's leaf movements are controlled by a biological clock. Which experiment would be the best test of your hypothesis

putting the plant in a dark closet at nightfall. Check on the plant at noon the next day, while the plant is still in the closet. If the leaves are open, a biological clock is indicated.

Which of the following is thought to be most closely related to humans?

sea stars

fruit that forms on an unpollinated plant in response to a hormone will lack

seeds

The key factor that made possible the colonization of dry environments by conifers and other gymnosperms was most likely the evolution of _____.

seeds and pollen

You are given an unknown animal to study in the laboratory. It is long and ribbonlike and appears to be segmented. You find it has three tissue layers, it does not have a digestive tract, and it has male and female reproductive structures in the same individual. This animal probably is a(n) _____.

tapeworm

In arthropods, molting is necessary because _____.

the chitinous exoskeleton cannot grow

Legumes are frequently grown in rotation with primary field crops. What is the benefit in this?

the legumes' symbiotic nitrogen-fixing bacteria add nitrogen to the soil

Which best describes how an organism's Darwinian fitness is measured?

the organism's reproductive success relative to other individuals in the same population

On a trip to the Southwest, you and a friend collect some seeds from a piñon, which is a type of pine tree. Your friend also gathers a small bagful of soil from under the piñon tree. Back home, both of you plant your seeds in commercial sterilized potting soil, but your friend adds a spoonful of the collected dirt to each of her pots. Her seedlings do better than yours. Which of the following is the likeliest reason?

the soil from the Southwest probably contained fungi able to establish a mycorrhizal association with the seedlings' roots