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MasteringBio questions from Module 1 of BIOL 1510 at Georgia Tech

In the course of a conversation, you observe that three of your friends like horror movies. Horror movies happen to be your favorite type of movie as well. You also know that all of these friends were born in the same week that you were, even in the same year.

An astrology-loving friend hypothesizes that people born in that week like horror movies more than other genres of movies. You decide to use the scientific method to test this hypothesis.

What should you do next?

Perform experiments to test your hypothesis.

In the course of a conversation, you observe that three of your friends like horror movies. Horror movies happen to be your favorite type of movie as well. You also know that all of these friends were born in the same week that you were, even in the same year.

An astrology-loving friend hypothesizes that people born in that week like horror movies more than other genres of movies. You decide to use the scientific method to test this hypothesis.

Which of the following experiments would best test your hypothesis?

Find other people born in the same week and ask them what their favorite type of movie is.

[You obtain results]

What should you do next?

Refine your hypothesis.

What is a hypothesis?

a tentative explanation that can be tested and is falsifiable

How does a scientific theory differ from a scientific hypothesis?

A theory is an explanation for a very general phenomenon or observation; hypotheses treat more specific observations.

In the experiment on ant navigation summarized in the figure, how would interpretation of the results change if the researchers had used just 1 ant in each group instead of 25?

The results would provide weaker support for the pedometer hypothesis.

Which of the following statements is true about biological studies?

Hypotheses may be tested by a combination of observation, measurement, and experimentation

The role of controls in scientific experiments is to

test for factors other than the one being investigated that might influence the outcome of the experiment

Which of these events occurred earliest in the history of Earth?

-- formation of oxygen
first humans
evolution of land plants, fungi, and land animals
origin of eukaryotes
origin of multicellularity

Which of these events occurred most recently in the history of Earth?

formation of oxygen
-- first humans
evolution of land plants, fungi, and land animals
origin of eukaryotes
origin of multicellularity

Which of these events occurred during the Paleozoic?

origin of Earth
-- colonization of land by plants
origin of eukaryotes
origin of multicellularity
first humans

What species are most likely to fossilize?

Hard-shelled species that die where sediment is actively being deposited are most likely to fossilize, whereas soft-bodied species that die where they cannot be buried are rarely fossilized. Moreover, if a species is not abundant or does not exist for a long time, its fossils will likely be rare. Species that die in an environment with a low oxygen content are more likely to leave fossils because a low oxygen content inhibits decomposition.

What is a fossil?

A fossil is an organism that has turned to stone.
A fossil is an extinct organism.
-- A fossil is physical evidence of an organism that lived in the past.
A fossil is a preserved hard part of an organism, such as shell or bone.

Which statement about fossilization is correct?

-- Rare, local, or ephemeral species leave a poor fossil record.
Recent fossils are more common than ancient fossils because biodiversity has increased over evolutionary time.
Organisms that live aboveground in dry areas are most likely to fossilize.
Only hard parts of organisms can form fossils.

Which sequence of eons, from oldest to youngest, is correct?

Hadean, Archaean, Proterozoic, Phanerozoic

Which measurement would help determine absolute dates by radiometric means?

the loss of parent isotopes
the loss of daughter isotopes
the accumulation of the daughter isotope
all three of these
--Only the accumulation of the daughter isotope and the loss of the parent isotope

How many half-lives should have elapsed if 6.25% of the parent isotope remains in a fossil at the time of analysis?

Four

Which free-living cells were the earliest contributors to the formation of Earth's oxidizing atmosphere?

Cyanobacteria

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:
I. double-stranded DNA
II. a nuclear envelope
III. a nucleoid
IV. a nucleolus
V. nucleic acids

II and IV only

The snowball Earth hypothesis provides a possible explanation for the

diversification of animals during the late Proterozoic.

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)

Fossilized stromatolites

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

Which of the following types of organic compounds was found in the liquid water after the experiment described in the figure [can simple molecules and kinetic energy lead to chemical evolution]?

amino acids

In experiments that successfully simulate chemical evolution, why must at least some small, reduced molecules be present?

They act as electron donors in redox reactions.

Consider the experiment that Stanley Miller did to simulate chemical evolution. Recall that a glass flask held the reduced gases NH3, CH4, and H2 and that the gases were exposed to electrical sparks. What is the null hypothesis in the experiment?

Chemical evolution does not occur.

What prediction does the chemical evolution hypothesis make?

Molecules with carbon-carbon bonds will form.

Suppose that Miller repeated his chemical evolution experiment but without a source of electrical sparks. What would be the purpose?

to test if electrical energy is required for chemical evolution

Which of the following statements about natural selection is true?

Natural selection favors individuals that reproduce more than others

Which term describes a trait that increases an individual's ability to survive in a particular environment?

Adaptation

Which term describes the ability of a trait to be passed on to offspring?

Heritability

Which of the following organisms could be produced by artificial selection?

A chimpanzee that communicates through sign language.
A rabbit that is housebroken.
A dog that serves as the "eyes" for a blind individual.
-- A cow that produces a large quantity of milk.

Which pair of chickens should a farmer breed to produce larger chickens?

Large hen, large rooster

A farmer wishes to develop a strain of high-yield corn that is also resistant to drought. He has the following individuals from the current year's crop:

Individual A—Yield: 179 bushels/acre; drought resistance: high
Individual B—Yield: 220 bushels/acre; drought resistance: low
Individual C—Yield: 185 bushels/acre; drought resistance: medium
Individual D—Yield: 140 bushels/acre; drought resistance: high
Individual E—Yield: 200 bushels/acre; drought resistance: medium

A and E -This cross would result in an average corn yield of 189.5 bushels/acre and have a medium-high drought resistance, which is the best you can get for both traits.

During a study session about evolution, one of your fellow students remarks, "The giraffe stretched its neck while reaching for higher leaves; its offspring inherited longer necks as a result." Which statement is most likely to be helpful in correcting this student's misconception?

Characteristics acquired during an organism's life are generally not passed on through genes

Given a population that contains genetic variation, what is the correct sequence of the following events, under the influence of natural selection?
1. Well-adapted individuals leave more offspring than do poorly adapted individuals.
2. A change occurs in the environment.
3. Genetic frequencies within the population change.
4. Poorly adapted individuals have decreased survivorship.

2,4,1,3

It has been observed that organisms on islands are different from, but closely related to, similar forms found on the nearest continent. This is taken as evidence that

island forms and mainland forms descended from common ancestors

What is exceptional about the Burgess Shale, Doushantuo, and Ediacaran faunas?

Soft-bodied animals are well-represented in these faunas

Which is the best definition of adaptive radiation?

An adaptive radiation occurs when a single lineage produces many ecologically diverse descendant species in a relatively short period of time

Why do mass extinctions wipe out species more or less randomly?

They are caused by exceptionally harsh, short-term conditions.

How would vestigial traits be explained if evolution occurred via inheritance of acquired characters as proposed by Lamarck?

as a change in an individual's phenotype in response to an environmental challenge

Which of the following statements is correct?

Most fossils formed during a few catastrophic events.
-- Fossils form in sedimentary rocks.
Fossils from rocks under other rocks are younger than the fossils found above them.
Fossils form only from the hard parts of extinct organisms.

Why do related species share homologous traits?

Related species have inherited homologous traits from a common ancestor.

How is biological fitness measured?

Biological fitness measures the relative reproductive success of an individual relative to others in the population.

Which aspect of Galapagos finches is the best example of heritable variation?

Body size varies among individuals and large parents tend to have large offspring.

Which of Darwin's postulates about evolution by natural selection is most directly related to differential reproductive success?

In each generation, many more offspring are produced than can possibly survive

Do individuals change when natural selection occurs? Why or why not?

No. Individuals do not change but the population does.

Natural selection usually produces adaptations that are far from perfect. Why?

Adaptive traits are constrained by historical and genetic factors

Which statement is correct?

Only populations can evolve.

Which statement about adaptation is correct?

The adaptive value of a trait varies as the environment changes.

In biology, fitness is defined as

the ability of an individual to produce surviving offspring

What is gene flow?

Gene flow is the migration of individuals or gametes.

What is natural selection?

environmental conditions dictate which individuals are more likely to reproduce

Generation-to-generation change in the allele frequencies in a population is

microevolution

For a gene suspected of causing hypertension in humans, you observe the following genotype frequencies: A1A1 0.574; A1A2 0.339; A2A2 0.087. Is this gene in Hardy-Weinberg equilibrium? Why or why not? (Assume that a difference of 3% or more in any of the observed versus expected frequencies indicates a statistically significant difference.)

No. The expected genotype frequencies are A1A1 0.553; A1A2 0.381; A2A2 0.066

If a population is NOT in Hardy-Weinberg equilibrium for a specific gene, which statement is correct?

At least one mechanism that alters allele frequencies is acting on this gene

Which statement about balancing selection is correct?

When balancing selection occurs, no single allele has a distinct advantage and increases in frequency

How do stabilizing and disruptive selection differ?

Stabilizing selection reduces the amount of variation in a trait. Disruptive selection increases the amount of variation in a trait.

Genetic drift

produces changes in allele frequencies that are not adaptive

Two frog populations (same species) living in two neighboring lakes sing slightly different courtship songs. Increased irrigation makes the land between the two lakes wetter, allowing frogs to expand their ranges to the area between the lakes. Females in both populations prefer loud frogs to quieter frogs, but do not distinguish between the two slightly different songs. Assuming that courtship song differences have a genetic basis, predict what will likely happen to the songs of the two frog populations.

The songs become more similar to each other.

Which evolutionary mechanism increases genetic variation in a population?

mutation

When inbreeding is occurring, how should observed genotype frequencies compare to those expected under the Hardy-Weinberg principle?

For homozygotes, observed frequencies should be higher than expected.

For the elephant seal population shown in the figure, consider an allele that increases reproductive success in males versus a similar allele in females. Which allele will increase in frequency faster via sexual selection and why?

the male allele, because variation in reproductive success is much higher in males than in females - Because a few males father most of the offspring, an allele that increases reproductive success in males should be present in a greater fraction of offspring in each generation than a similar allele in females, where variation in reproductive success is much lower.

Why are males usually the sex with exaggerated traits used in courtship?

In most species, females protect their larger investment in offspring by being choosy about their mates.

Which type of natural selection is most likely to be involved in the formation of new species?

disruptive selection

Feathers either play a role, or may have played a role, in

extended hops
courtship
gliding
flight
-- all of these

____is rapid speciation under conditions in which there is little competition.

Adaptive radiation

Mass extinctions create conditions that promote

adaptive radiation

The appearance of an evolutionary novelty promotes

adaptive radiation

The different finch species found on the Galápagos Islands probably arose as a result of

adaptive radiation

Which term is used to describe populations that live close enough to interbreed?

Sympatry

What prevents speciation from occurring in sympatric populations?

Gene flow

True or false? A mating between a tetraploid individual and a diploid individual produces biologically fit offspring.

False

Which of the following statements about autopolyploid individuals is true?

They contain more than two haploid sets of chromosomes.

What would be the ploidy of the viable gametes produced by a tetraploid individual if nondisjunction of all chromosomes occurred in meiosis I?

Tetraploid

How can an allopolyploid plant become a biologically fit new species?

Nondisjunction event during mitosis

How many chromosomes would be found in an allopolyploid plant if its parents had diploid numbers of 2 and 10, respectively?

Haploid number of 6

Which of the following statements about species, as defined by the biological species concept, is (are) correct?
I. Biological species are defined by reproductive isolation.
II. Biological species are the model used for grouping extinct forms of life.
III. The biological species is the largest unit of population in which successful reproduction is possible.

I and III

Several closely related frog species of the genus Rana are found in the forests of the southeastern United States. The species boundaries are maintained by reproductive barriers. In each case, match the various descriptions of frogs below with the appropriate reproductive barrier listed.


Females of one species choose mates based on song quality; females of another species choose mates on the basis of size.

Behavioral

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?
I. The environment is unlikely to change.
II. Human evolution is complete.
III. The human races are incompletely isolated.

III

Among known plant species, which of these have been the two most commonly occurring phenomena leading to the origin of new species?
1. allopatric speciation
2. sympatric speciation
3. sexual selection
4. polyploidy

2 and 4

On the volcanic, equatorial West African island of Sao Tomé, two species of fruit fly exist. Drosophila yakuba inhabits the island's lowlands, and is also found on the African mainland, located about 200 miles away. At higher elevations, and found only on Sao Tomé, is found the very closely related Drosophila santomea. The two species can hybridize, though male hybrids are sterile. A hybrid zone exists at middle elevations, though hybrids there are greatly outnumbered by D. santomea. Studies of the two species' nuclear genomes reveal that D. yakuba on the island is more closely related to mainland D. yakuba than to D. santomea (2n=4 in both species). Sao Tomé rose from the Atlantic Ocean about 14 million years ago.


Using only the information provided in the paragraph, which of these is the best initial hypothesis for how D. santomea descended from D. yakuba?

habitat differentiation

A hybrid zone is properly defined as

an area where mating occurs between members of two closely related species, producing viable offspring.

Which of the following statements about speciation is correct?

Speciation is a basis for understanding macroevolution.

The largest unit within which gene flow can readily occur is a

species.

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?

behavioral isolation

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

28

Two populations of birds with somewhat different coloration live on opposite sides of a peninsula. The habitat between the populations is not suitable for these birds. When birds from the two populations are brought together, they produce young whose appearance is intermediate between the two parents. These offspring will breed with each other or with birds from either parent population, and all offspring of these pairings appear intermediate to various degrees.


The two populations are ___

different subspecies, under the morphospecies concept

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