AP Biology : Understanding Other Theorists

Study concepts, example questions & explanations for AP Biology

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Example Questions

Example Question #1 : Understanding Other Theorists

The sum of all genetic alleles in a population is the __________.

Possible Answers:

gene supply

gene stock

gene frequency

gene resources

gene pool

Correct answer:

gene pool

Explanation:

A population is composed of numerous individuals, each carrying a common set of genes with a unique combination of genetic alleles. The gene pool is the sum of all of these alleles.

Example Question #2 : Understanding Other Theorists

Which term refers to the relative proportions of a specific allele in relation to all alleles for the given gene in a population?

Possible Answers:

Allele concentration

Allele amount

Allele frequency

Allele coefficient

Allele population

Correct answer:

Allele frequency

Explanation:

The allele frequency for any given gene is the relative proportion of each allele of that gene in a population. This value can be found by dividing the number of a specific allele by the total number of alleles in a population.

Example Question #3 : Understanding Other Theorists

Mutation, gene flow, nonrandom mating, and natural selection combine to cause which of the following?

Possible Answers:

Genetic drift

Mutations

Reproduction

Segregation

Evolution

Correct answer:

Evolution

Explanation:

Evolution is any change in the proportions of different genotypes in a population from one generation to the next. Mutation, geneflow, nonrandom mating, and natural selection all contribute toward favoring certain alleles over others within a population. This leads to changes in allele frequency, and subsequent evolution.

Example Question #4 : Understanding Other Theorists

The requirements for Hardy-Weinberg equilibrium are designed to create which scenario for the given population?

Possible Answers:

Nonrandom mating will flourish

Evolution will not occur

Mutations will be common

Divergency will occur

Extinction is eminent

Correct answer:

Evolution will not occur

Explanation:

The Hardy-Weinberg principle is a mathematical model that states that, under certain conditions, the allele frequencies and genotype frequencies in a sexually reproducing population will remain constant over generations. This consistency means that evolution is not occurring, as evolution (by definition) requires a change in allele frequency.

Requirements for Hardy-Weinberg equilibrium include: large population size, no mutation, no migration, random mating, and no natural selection.

Example Question #5 : Understanding Other Theorists

A process in which chance events are likely to change allele frequencies in a small population is known as __________.

Possible Answers:

natural selection

evolution

genetic drift

allele fluctuation

bottleneck effect

Correct answer:

genetic drift

Explanation:

Genetic drift is a change in the allele frequencies of a small population purely by chance.

The bottleneck effect occurs when allele frequencies are affected by a cataclysmic event. Evolution refers to a change in allele frequency, but is not limited to small populations or random chance. Natural selection refers to changes in allele frequency due to specific conditions, as opposed to random chance.

Example Question #6 : Understanding Other Theorists

Which of the following are characteristics that help an individual survive and reproduce in an environment?

Possible Answers:

Traits

Mutations

Skills

Habits

Adaptations

Correct answer:

Adaptations

Explanation:

An adaptation is a characteristic of an organism that helps it survive and reproduce in a particular environment. Adaptations are the result of random mutations that have favorable outcomes. The favorability of these traits enables offspring that inherit them to thrive, thus increasing their prevalence in the population.

Example Question #7 : Understanding Other Theorists

Scientific discoveries and advances are the result of many scientists uncovering small mysteries, each new piece of information contributing to a bigger picture. Our understanding of DNA today can be attributed to several scientists and their experiments. Which of the following scientists was able to show the diversity of DNA (and therefore the diversity of species) through patterns of base pairs?

Possible Answers:

Watson and Crick

Hershey and Chase

Darwin

Chargaff

Franklin 

Correct answer:

Chargaff

Explanation:

Chargaff was able to show the diversity of DNA through patterns within base pairs. While studying DNA, he noticed that the concentration of adenine was equal to the concentration of thymine, and the concentration of cytosine was equal to that of guanine. This led him to establish Chargaff’s rules, which state that the base composition of DNA varies between species, and for each species the percentages of adenine and thymine bases are roughly equal and the percentages of cytosine and guanine are also roughly equal.

Example Question #8 : Understanding Other Theorists

Which theorist believed that the human population would grow and deplete the Earth’s limited resources?

Possible Answers:

Charles Darwin

Jean-Baptiste Lamarck

Thomas Malthus

Pierre Louis Maupertuis

Correct answer:

Thomas Malthus

Explanation:

Thomas Malthus was a political/economic theorist who observed that the human population would eventually overpopulate the world, overwhelming food and natural resources. 

Example Question #9 : Understanding Other Theorists

Mitochondria and chloroplasts are believed to have evolved from __________ cells and replicate via __________

Possible Answers:

eukaryotic . . . binary fission

prokaryotic . . . mitosis

eukaryotic cells . . . mitosis

prokaryotic . . . meiosis

prokaryotic . . . binary fission

Correct answer:

prokaryotic . . . binary fission

Explanation:

Mitochondria and chloroplasts are believed to have evolved from prokaryotic cells over 1.5 million years ago. This is known as the endosymbiotic hypothesis. Mitochondria, chloroplasts, and prokaryotes all contain circular DNA and reproduce via binary fission. Mitosis involves the separation of chromosomes during the cell cycle, which is only seen in the somatic cells of eukaryotes. Meiosis is not seen in prokaryotes. 

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