Biology Review

The three components of biodiversity include: ________________, ______________, and _______________.

Genetic, species, ecosystem

Q15. What are the major sources of CO2, N2O, and CH4?

Livestock and landfills are responsible for the methane gas. Carbon dioxide and nitrous oxide come from the burning of fossil fuels.

Which of the following describes the type of speciation event that is occurring in these whales? (1 pt) a) sympatric speciation b) allopatric speciation c) geographic speciation d) polyploidy speciation

answer = A

Cave-dwelling catfish and cave-dwelling salamanders share striking similarities: Both organisms lack pigmentation, and their eyes are reduced or absent. The most recent common ancestor to these organisms had normal pigmentation and fully developed eyes. The similarities between cave catfish and cave salamanders are an example of a) convergent homology b) analogy (convergent evolution) c) homology d) exaptation

answer = B

Global warming is the result of a) rising ocean levels b) rising concentrations of greenhouse gases c) increased solar activity d) habitat loss

answer = B

List three key points about evolution by natural selection

(1) Individuals do not evolve; populations do. (2) Natural selection works only on heritable traits. (3) There is no overall directed goal of natural selection.

Ecosystems vary in their energy efficiency, but as a general rule, ____________% of the energy available at one level is transferred to the next trophic level.

10%

Q27. There is a large "dead zone" in the Gulf of Mexico. What does this mean, how does it form, and what is the cause?

A "dead zone" is an anoxic body of water, i.e. low water O2 levels. It forms because decomposers (bacteria) become overactive metabolizing dead organic matter, a process that consumes O2. It's typically caused by nutrient (nitrogen or phosphorus) runoff from fertilizer used on agricultural landscapes to boost production. The added nutrients cause an algal bloom in the water (where N and P were limiting population growth) and as they die the decomposer activity increases.

2) Suppose that a bacterial infection swept across a sea otter population and killed most sea otters before they could reproduce. How would the marine community be affected? (1 pt) a) For a period of time, there would be overpopulations of sea urchins and therefore a decline in kelp populations. b) For a period of time, there would be an overpopulation of kelp and therefore a decline in sea urchins. c) Sea otters would continue to decline until they reached extinction. d) Kelp would become a primary predator of sea urchins.

Answer = A

Consider the following marine community: Sea otters prey on sea urchins and therefore help maintain a healthy sea urchin population. Sea urchins prey on kelp. By helping to maintain viable sea urchin populations, the sea otters are also allowing enough kelp to grow and act as a habitat for other organisms. 1) In this marine community, the sea otter is a) A primary consumer b) A producer c) A keystone species d) A scavenger

Answer = C

The Yellowstone to Yukon Conservation Initiative is a plan to (1 pt) a) connect all of the national parks in the western United States. b) connect all of the national parks in the United States. c) connect parks in the United States and Canada with protected corridors where wildlife can travel safely. d) create a giant, fenced private land area between the national parks in the United States to create a protected zone for wildlife.

Answer = C

In the North Pacific Ocean, two groups of the same species of killer whales (Orcinus orca) appear to be forming two different species based on what they eat. One group eats fish and the other eats mammals such as seals. Scientists can tell what they eat based on their teeth, because whales that feed on fish have significantly different wear patterns. 1) Which of the following would not be a useful procedure to perform in determining whether or not this speciation has occurred? (1 pt) a) Compare teeth of whales alive today to teeth of whales in ancient samples. b) Compare DNA samples from fish-eaters and mammal-eaters. c) Compare stomach contents of whales from each to the two populations. d) Compare body shape of whales from each population.

Answer = D

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? (1 pt)A) Yes; the wheat probably evolved better cold tolerance over time through inheritance of acquired characteristics. B) No, because Lysenko took his wheat seeds straight to Siberia instead of exposing them incrementally to cold. C) 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. D) Yes, because this is generally the method used by plant breeders to develop new crops.

Answer=C

List three components of sexual reproduction that account for genetic variation. (3 pts, 1 pt each)

Crossing over of genes between homologous chromosomes, independent assortment of chromosomes, random fertilization

An argument against evolution by natural selection is that it is not observable on a human time scale. However, this is not exactly true. List two examples of evolution by natural selection that have been documented

Evolution by natural selection can be observed in insects after repeated exposure to pesticides and in bacteria after repeated exposure to antibiotics.

Briefly contrast extirpation and extinction

Extirpation refers to the loss of one population of a species, whereas extinction refers to the loss of all individuals of a species.

Q25. True or false: Harmful bacteria far outnumber beneficial bacteria. If false, make it a correct statement. (1 pt)

False, beneficial bacteria are more numerous.

True or false: A protist is a prokaryotic organism that is not a plant, animal, or fungus. If false, make it a correct statement.

False, it is a eukaryote

True or false: The current greatest threat to biodiversity is pollution from human activities. If false, make it a correct statement.

False, the single greatest threat is from habitat loss

The frequency of alleles in a population should remain constant unless there are other factors at work. This principle is known as the

Hardy-Weinberg Principle

The similarities seen in certain species that result from common ancestry is known as ____________.

Homology

. Briefly explain how two organisms that live in different areas of the world can have similar adaptations and even resemble one another. Provide an example of such an occurrence. (2 pts)

In convergent evolution, organisms come to share characteristics because of the similarity of their environments. Examples are the Australian and North American moles.

Would a top-level predator be expected to have more or less of a pollutant in its body? Briefly explain your answer

It would be expected to have more of a pollutant in its body as a result of biological magnification.

The five conditions required for a population to be at Hardy-Weinberg equilibrium are given. Fill in the descriptions for why each is critical for H-W allele frequencies. (5 pts, 1 pt each)

Large population -A large population limits chance fluctuation. No gene flow -Individuals moving into or out of populations add or remove alleles from the gene pool. No mutation -Mutations modify the gene pool by changing alleles or removing them. Random mating -Random mating ensures mixing of the alleles. No natural selection -This can alter allele frequencies through the unequal reproductive success created by natural selection

Q23. Examine the phylogenetic tree in Figure 15.16B on page 311 of your textbook and identify the outgroup. (1 pt)

Lizards and snakes

A recent study in the peer-reviewed journal, Science, revealed that the ~1 degree Celsius (~1.8 degrees F) warming that the Earth has experienced in the past 100 years has already caused physiological and morphological changes to large numbers of species. (3 pts, 1 pt each) Is this an example of micro- or macro-evolution? What's the mechanism driving these changes? (circle one) Genetic drift, mutation, founder effect, natural selection, artificial selection Would you expect climate change to cause the formation of new species (speciation) during the 21st century? Why or why not?

Microevolution, changing allele frequencies within populations over Natural selection Unlikely, but if it did it would most likely be among a fast reproducing organism such as a protest.

List four reasons why natural selection does not create perfect organisms. (4 pts, 1 pt each)

Natural selection only works on alleles that are present; evolution is limited by historical constraints; adaptations are usually a trade-off; chance, natural selection, and the environment interact.

Why do ecosystems tend to have very few tertiary and quaternary predators while having an abundance of different producers and primary consumers?

Only a fraction of the energy in biomass is available to consumers in subsequent trophic levels (~10% per level). For example, it takes a lot of mice to maintain a population of owls. As such, the population of tertiary and quaternary consumers is limited.

A scientist discovers a new prokaryote that lives in the thermal ponds in Yellowstone National Park. Initial observations indicate that the organism contains a chlorophyll-like pigment, and an enzyme similar to what plants use to fix atmospheric CO2. What mode of nutrition does this organism likely use?

Photoautotroph

Isle Royale National Park consists of a series of islands located in Lake Superior. Initially, there were no wolves on any of the islands since they were in the middle of Lake Superior. However, in 1949, an unusually long and cold winter produced an ice bridge between Canada and the islands of the National Park. During this winter, a pair of wolves used the ice bridge to travel inadvertently to Isle Royale. Today there continues to be a wolf population on the main island descended from that original pair. Has allopatric speciation occurred yet? If not, could it?

Probably not because not enough time has passed. In theory, it could as long as enough time passes to allow the wolves on Isle Royale to be subjected to the selective pressures specific to Isle Royale

Q12. A geographic barrier to ____________ can give rise to ____________ speciation. (2 pts)

Reproduction, allopatric

What key event marks the boundaries between eras in the geological record? (2 pts)

The boundaries are marked by mass extinctions.

What happened to the ecosystem as wolves were reintroduced to the Yellowstone National Park region in 1995?

The ecosystem began to stabilize and return to a natural balance. Plant diversity along river edges began to recover, primarily because elk changed their browsing behavior to avoid predation.

Q20. A structure that evolves for one use and, over time, begins to be used for a different function is an example of a(n) _____________. Provide two examples

The feathers of birds and the flippers of penguins

What would be true regarding any fossils found in strata at the top versus fossils found in lower strata? Refer to Figure 13.2C on page 258 of your textbook.

The fossils found closer to the surface are expected to be younger.

Briefly explain how a heterozygous individual "protects" the recessive allele from elimination within the population.

The heterozygous individual will carry the recessive allele while displaying the dominant phenotype, which keeps the recessive allele in the gene pool.

How did the loss of wolves in the Yellowstone National Park region have a cascading effect on the landscape?

The loss of wolves led to an increase in the populations of herbivores and changed their behavior. This increased the grazing done by these animals, especially along river and stream banks. This in turn led to a loss of lush riparian areas along river banks due to overgrazing.

In 150 years, an earthquake strikes along the San Andreas fault causing a small chunk of California to break off and move off the coast. Briefly explain how this event could trigger macroevolution given enough time.

The organisms found in each environment would begin to be subjected to different selective forces. Given enough time, these forces could lead to organisms that are no longer able to interbreed.

A population of dogs has two different coat colors coded for by two different alleles. The character of coat color follows Mendel's rules. The frequency of one of the alleles for coat color is 250/1150. What is the frequency of both alleles in the population of dogs? What is the population of dogs? (2 pts)

The population of dogs is 575 because there are a total of 1150 alleles. The frequency of the two alleles is .22 and .78.

Briefly explain the roles of cellular respiration and photosynthesis in the carbon cycle

They are chemical opposites of each other: photosynthesis removes carbon from the abiotic reservoir and incorporates it into organic matter, and cellular respiration removes carbon from the biotic reservoir and returns it to the abiotic reservoir.

What are some ways in which the earlier arrival of spring, as a result of climate change, has negatively affected ecosystems?

This can affect the precise timing that certain organisms rely on for specific events. One example is the pollination of plants by insects. Other phenological mismatches can occur such as between emergence of an animal from hibernation and appearance of its primary food source.

Evidence suggests that we might be at the beginning of a sixth mass extinction. The difference between the previous five and this possible one is that this one is a result of what?

This extinction would be caused predominantly by human activities

A few persons go boating in the boundary waters of Minnesota. They pulled their own boat to and from their campsite. Without their knowledge, a small population of aquatic organisms is in/on the boat. As soon as they get home, they put their boat back in the pond behind the house. There are no other members of this species in the pond. Which mechanism is this?

This is an example of the founder effect, which is a type of genetic drift.

Q13. True or false: A new plant species can occur in one generation resulting from the creation of a tetraploid plant. If false, make it a correct statement.

True

True or false: Even though the open ocean has a low net primary productivity, it still accounts for the majority of Earth's total net primary productivity because of its sheer size. If false, make it a correct statement

True

True or false: Plants cannot absorb atmospheric nitrogen gas. As such, plants require bacteria to convert atmospheric nitrogen to a form they can readily uptake. If false, make it a correct statement.

True

True or false: Radiometric dating is based on the decay of radioactive isotopes over time. If false, make it a correct statement.

True

True or false: The more recently two species branched away from each other, then the more similar their sequences of DNA should be. If false, make it a correct statement. (1 pt)

True

Humans can learn something about our own sustainability from the fact that available energy decreases as you go up in trophic levels. What is a simple solution (that would require no new technology) for how humans could feed more of our species?

We could eat at a lower trophic level (vegetarianism) and have more energy available to us.

Would clear cutting massive expanses of forests affect the carbon cycle? If so, what aspect of the carbon cycle would be altered? Refer to Figure 37.19 on page 753 of your textbook

Yes, because the ability to remove carbon from the abiotic reservoir would be hindered now that the trees are gone and they are no longer performing photosynthesis

Could an organism like the red-tailed hawk be both a quaternary consumer and a tertiary con- sumer? Briefly explain your answer either way

Yes, because the red-tailed hawk can eat organisms at the secondary level or tertiary level. If the owl consumed a kangaroo rat, then it would be considered a tertiary consumer; if the hawk ate a diamondback snake, then it would be a quaternary consumer.

Would you expect a fungal pathogen to have more or less of a negative effect on a population of genetically modified corn plants where there was very little genetic diversity? Briefly explain your answer.

You would expect the fungal pathogen to have more of a negative effect. With reduced genetic diversity, the plants will have less variability in their traits to resist the fungus.

Which of the following converts inorganic components of the ecosystem into organic substances? (1 pt) a. Producers b. Decomposers c. Consumers d. None of the above

a. Producers

Which of the following type of interspecific interaction benefits both organisms? (1 pt) a. Mutualism b. Parasitism c. Predation d. Herbivory

a. mutualism

Q22. The simplest explanation for a set of observations is known as ______________. (1 pt) a. parsimony b. ingroup c. cladistics d. shared ancestral characters

a. parsimony

. In 2012, scientists discovered that colonies of single-celled organisms can be found in high numbers in the human gut. Scientists are particularly concerned with the colonies that produce methane, as methane in the human gut can be linked to constipation and irritable bowel syndrome (IBS). The scientists can classify these colonies as belonging to the domain (1 pt) a) Archaea b) Bacteria c) Eukarya d) Protista

answer = A

Compost piles create an intense heat source and would therefore be suitable environments for ________. (1 pt) a) extreme thermophiles b) extreme halophiles c) methanogens d) proteobacteria

answer = A

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 (1 pt) a) endotoxin b) exotoxin c) stomach microbiota d) parasite

answer = A

Textile mills often release dye color and toxic by-products into rivers and streams, which may then taint groundwater. Fungi associated with mangrove trees have been shown to reduce both colors and toxicity in tainted groundwater. The fungi are being used as a form of (1 pt) a) bioremediation b) endosymbiosis c) phagocytosis d) mixotrophy

answer = A

. You find the frozen remains of a woolly mammoth in an Alaskan glacier. You analyze a bit of the tusk and find that its 14C:12C ratio is about one-fourth (25%) of the baseline level typically found in living organisms. Given that the half-life of 14C is 5,730 years, when did the mammoth die? (1 pt) a) 5730 years old b) almost 12,000 years ago c) at least 25,000 years ago d) approximately 75,000 years ago

answer = B

Currently, the single greatest threat to biodiversity is a) global warming b) habitat destruction due to human activity c) the introduction of exotic species d) overexploitation of populations for food

answer = B

The earliest discovered fossils are of ___________ dating back to ___________ years ago. (1 pt) a) single-celled eukaryotes; 4.5 billion b) prokaryotes; 3.5 billion c) algae; 1 billion d) fish; 600 million

answer = B

Another difference between the two groups is in how they hunt. Whales that hunt fish tend to travel in large pods (groups of whales) and vocalize often. Whales that hunt seals, however, tend to travel in very small groups and vocalize very little, likely because of the excellent hearing ability of seals. If these differences brought about speciation, the separation would be considered (1 pt) a) habitat isolation b) temporal isolation c) behavioral isolation d) mechanical isolation

answer = C

In your backyard you overturn a large rock. In the damp soil underneath the rock, you see various insects scurrying for cover: one black spider, five black ants, two brown beetles, and three gray pillbugs. In this community of organisms, species richness is represented by (1 pt) a) the ants, since there are more of them than any other organism. b) eleven total organisms c) four different species of organisms d) the ants and the spider equally, since they have the greates number or organisms of the same color

answer = C

You culture the dried soup from a 4,000-year-old cooking pot found in an Egyptian tomb and obtain a distinctive species of prokaryote. You immerse a test tube of these bacteria in boiling water for several hours, but the colony grows back. This species is probably (1 pt) a) halophilic b) a spirochete c) endospore-forming d) a cyanobacteria

answer = C

Which species of wheat shown is polyploidy?

c) T. turgidum

Q11. Which of the following represents a post-zygotic barrier? (1 pt) a. Temporal b. Habitat c. Reduced hybrid viability d. Gametic

c. Reduced hybrid viability

Q10. Which of the following best describes relative fitness? (1 pt) a. The creation of new gene combinations b. Individuals migrating into and out of an area c. The ability to produce healthy offspring d. The change in a population's gene pool over generations

c. The ability to produce healthy offspring

The first photosynthetic bacteria were important to the development of life on Earth because they (1 pt) a. removed O2 from the atmosphere. b. produced water vapor. c. added O2 to the atmosphere. d. converted methane gas into sugar.

c. added O2 to the atmosphere

Q5. Which of the following can be passed on to offspring from their parents? (1 pt) a. Muscles from body building b. A tattoo c. A deep tan from constant tanning d. Blonde hair

d. Blond hair

If 40% of a population expresses the recessive phenotype, what percentage of the population are heterozygous carriers of the recessive allele? Assume Hardy-Weinberg equilibrium. (1 pt)

q2=0.4, q=0.63, p=1-q=0.37, 2pq=2(0.63)(0.37)= 0.47 or 47%