Exam 2 flash cards

alleles associated with low production of the repressor protein and an increase in the number of fruit compartments

Tomatoes carry a gene called fw2.2 that encodes a protein made during early fruit development?the job of which is to repress cell division. Additionally, researchers have identified a second gene called fas that controls the number of compartments in the mature fruit. Artificial selection leading to the production of very large tomatoes has apparently capitalized on ________. a. alleles associated with low production of the repressor protein and an increase in the number of fruit compartments b. alleles associated with high production of the repressor protein and an increase in the number of fruit compartments c. alleles associated with low production of the repressor protein and a decrease in the number of fruit compartments d. alleles associated with high production of the repressor protein and a decrease in the number of fruit compartments

all of the above

Transposons can be deleterious to a host genome because they can a. disrupt a protein coding sequence. b. disrupt regulatory elements. c. generate mutations. d. cause recombination errors. e. All of the above

True

True or False? Even when a species consists of many populations, gene flow between populations may slow or even inhibit local specializations and so promote continuance and stability of the species.

None of the above

When examining the recombination rate across a chromosome, a researcher detects an area of high recombination rates. What could she infer based on this observation? a. This region is likely the centromere. b. This region is likely a telomere. c. This region is likely an isochore. d. This region is in a protein coding gene. e. None of the above

in linkage disequilibrium

When genotypes at one locus of a chromosome are nonrandomly associated with the genotypes at another locus of the same chromosome, the two loci are ________. a. in linkage equilibrium b. in linkage disequilibrium c. nonrandomly associated d. None of the above.

hotter and there was less oxygen than today.

When life first evolved the oceans were: a. hotter and there was more oxygen than today. b. hotter and there was less oxygen than today. c. cooler and there was more oxygen than today. d. cooler and there was less oxygen than today.

Male gametes are not transferred to the female gametes.

Which of the following is not a postzygotic isolating mechanism? a. Male gametes are not transferred to the female gametes. b. Zygotes die early in embryogenesis. c. Hybrids are inviable. d. Hybrids are sterile. e. Backcross hybrids are inviable.

It is meant to be a single organism.

Which of the following statements about LUCA is not correct? a. The acronym stands for "last universal common ancestor." b. It represents a base to the tree of life. c. It is meant to be a single organism. d. It represents a phylogenetic event horizon.

It can result in instantaneous speciation.

Which of the following statements about changes in ploidy is true? a. It often reduces reproductive isolation. b. It can result in instantaneous speciation. c. It causes coiling in snails. d. It is less common in plants than animals.

The self-replicating ribozymes that had more efficient catalytic activities would soon began to dominate their populations.

Which of the following statements about the Lincoln and Joyce experiment on self-replicating ribozymes is most likely correct? a. The self-replicating ribozymes that had more efficient catalytic activities would soon began to dominate their populations. b. In the self-replicating ribozymes, variation in the rate of replication was not heritable. c. Ribozymes produced true protein-based enzymes. d. all of the above

DNA is more stable and thus is a more efficient transmission system.

Why is DNA favored over RNA as genetic material? a. DNA is more stable and thus is a more efficient transmission system. b. DNA can self-replicate. c. DNA makes chromosomes. d. DNA mutates more readily, with a weaker repair machinery. e. DNA has a more limited information storage capacity.

The RNA produced was not self-replicating.

Why were the first RNA replication experiments insufficient support for the RNA world hypothesis? a. The experiments did not demonstrate natural selection. b. RNA could not adapt to environmental challenges. c. The RNA produced was not self-replicating. d. No mutations occurred in the RNA. e. Mutations occurred, but they were not heritable.

geographical isolation

__________ is the first step in allopatric speciation. a. selective speciation b. sympatric speciation c. geographical isolation

50%

A hypothetical population has two alleles for a gene: A and a. In a random sample of 100 individuals, 20 are homozygous for a, 20 are homozygous for A, and 60 are heterozygous. What is the frequency of A? a. 20% b. 25% c. 50% d. 60% e. 80%

cannot be used in introns

A limitation of examining Ka/Ks ratios is that they a. are sensitive to demographic changes. b. cannot be used in introns. c. can only detect positive selection. d. cannot detect drift. e. None of the above

A and B

A researcher tracks the escape behavior of a population of squirrels on campus across two generations. When she plots the escape behavior of the offspring generation against the parental behavior, she notes that the offspring's behavior exactly matches the parental behavior. Nonetheless, the narrow-sense heritability equals zero. How can the heritability equal zero in this example? a. The additive genetic variance equals zero. b. All the escape behavior alleles are fixed in the population. c. There is no phenotypic variation. d. A and B e. All of the above

the peripheral isolate mode of allopatric speciation

A small population of a species invades an island where the species is not found. The population subsequently diverges from the ancestral population and becomes a new species. This is an example of a. the dumbbell model of allopatric speciation. b. the peripheral isolate mode of allopatric speciation. c. sympatric speciation. d. parapatric speciation.

True

According to modern selectionist theory, even very weak selection can have substantial impact over time. T or F?

False

African cichlids are very diverse because they began speciation 30 to 40 million years ago. T of F?

False

African cichlids are very diverse because they began speciation 30 to 40 million years ago. T or F?

there was no selection for any of the variations in length.

All of the following is true regarding Spiegelman's experiment on the origins of life except that: a. the most common size of the RNA strand in the final test tubes was a little over 200 nucleotides long. b. variation in the length of strands occurred at each round of replication. c. there was no selection for any of the variations in length. d. shorter RNA sequences were favored by selection, so long as they were not too short.

False

All viral genomes consist of a single linear chromosome. T or F?

True

Allopatric speciation requires geographical isolation as the initiating process. T or F?

3.2 billion

Among the oldest fossils on Earth are the microfossils from the Agnes gold mine of South Africa, which are __________ years old. a. 4.5 billion b. 3.2 billion c. 3.5 million d. 500,000

True

Anole evolution on Carribean islands is an example of convergent evolution. T or F?

0.8 or 80%

Blue flower color (B allele) is dominant to white (b allele). In a population plants with white flowers (bb) are at a frequency of 0.04. What frequency of the alleles are for blue flower color (B)? Select one: a. 0.04 or 4% b. 0.16 or 16% c. 0.2 or 20% d. 0.8 or 80% e. 0.96 or 96%

True

Compared to North America Tar Weeds, Hawaiian Silver swords show positive selection at regulatory loci. T of F?

a new allele arises by mutation that increases fitness and the environment changes are correct.

Directional selection would be expected to occur if a. a new allele arises by mutation that increases fitness. b. the environment changes. c. the population is large. d. a new allele arises by mutation that increases fitness and the environment changes are correct. e. a new allele arises by mutation that increases fitness, the environment changes and the population is large are correct.

more transcription- and translation-associated genes with archaea and more metabolic genes with bacteria.

Eukaryotes share a. all of their genes with archaea. b. all of their genes with bacteria. c. more transcription- and translation-associated genes with archaea and more metabolic genes with bacteria. d. more transcription- and translation-associated genes with bacteria and more metabolic genes with archaea.

Common functional genes imply the minimal characteristics of early cells.

How does comparative data on genes of extant species help us to make estimates of what happened before the phylogenetic event horizon? a. Common genes must have existed for a long time. b. If the first life-forms consisted of RNA, then current RNA-coding genes must be the ancestral genes. c. Common functional genes imply the minimal characteristics of early cells. d. Because so many small genome bacteria are endosymbionts, the earliest cells must have been endosymbionts.

All of the above

How does mutational bias influence GC content? a. G is more likely to mutate to A. b. C is more likely to mutate to T. c. G is less likely to mutate to C. d. A is less likely to mutate to T. e. All of the above

False

Hybrid sterilizing is a prezygotic isolating mechanism. T or F?

All of the these are possible.

Hybridization between populations upon secondary contact may result in ________. a. reinforcement of the two original species by way of pre- or post-zygotic isolating mechanisms b. the creation of one or more new species as hybrids between the two parental species c. the creation of a hybrid lineage that has higher fitness than either of the parental species d. All of the these are possible. e. None of the these is possible.

True

If one sex is missing in interspecific hybrids, Haldane's rule says that the heterogametic sex. T or F?

50%

If two gene loci are unlinked, what is the expected recombinational frequency between them? a. 100% b. 50% c. 25% d. 33% e. 75%

found some peptide-like structures, but the bonds between the amino acids were weak and unstable.

In 1977 Sidney Fox tried a different approach to testing the prebiotic synthesis of biological molecules. He mixed a number of different amino acids together at a high temperature (120°C) in an environment lacking water. When he subsequently placed the mixture into water to investigate what the amino acids would form, he: a. found some peptide-like structures, but the bonds between the amino acids were weak and unstable. b. found that a mechanism for joining the amino acids together to make proteins was completely absent. c. found ribose in very low supply, d. added CO and had success with creating polypeptides.

False

In a ring species complex, all crosses are equally inviable. T or F?

False

In allopatric speciation, evolution prezygotic isolating mechanisms precede post zygotic isolating mechanisms. T or F?

Splitting into two equal parts is the most energetically efficient method.

In early cell evolution, why would natural selection favor division into equal-sized daughter cells? a. Splitting into two equal parts is the most energetically efficient method. b. Two daughter cells is the most efficient way to reproduce sexually. c. Splitting into two daughter cells is more efficient for horizontal gene transfer. d. Hypercycles can be maintained by splitting into two.

True

In finches,birdsong, a learned trait , can serve as an isolating mechanism. T of F?

Comparative genomics and studies of the bacteria with very small genomes do shed light on a common ancestor and researchers can estimate the minimal characteristics that a cell would need to operate as a living organism.

In light of recent achievements in the field of genomics, would it be reasonable to expect that the use of comparative genomics might shed light on the extinct genomes of early life? a. Simple prokaryotes today have very different genomes than early life and we could not learn very much from the comparative genomics of the extant species. b. Despite efforts in molecular prokaryotic genetics, we cannot predict what kinds of genes may have been present in pre-LUCA genomes. c. Comparative genomics and studies of the bacteria with very small genomes do shed light on a common ancestor and researchers can estimate the minimal characteristics that a cell would need to operate as a living organism. d. none of the above

all of the above

In order to understand the origin of life on Earth, evolutionary biologists collaborate with: a. chemists. b. geologists. c. atmospheric scientists. d. all of the above

True

In plants, polyploidy in vegetatively propagating hybrid might give rise to functional gametes. T of F?

genotypic value and environmental deviation

In quantitative genetic terms, a phenotypic value can be expressed as a. dominance and recessiveness. b. epistasis and pleiotropy. c. genotypic value and environmental deviation. d. A and B e. All of the above

True

Most prokaryotic genomes are between 0.6 and 10 Mb. T or F?

True

Polyploidy is more important in plant speciation than in animals. T or F?

True

Purifying Selection removes deleterious mutations at a locus. T or F?

True

QTL loci can produce a bell curve. T or F?

True

Rates of speciation are quite variable among many varied taxa. T or F?

when different habitat preferences result in different diets.

Resource partitioning occurs a. when the same plants produce different seed types. b. infrequently in sympatric speciation. c. only in lakes. d. when different habitat preferences result in different diets.

sympatric

Sexual isolation should be strongest among ________________ populations. a. allopatric b. peripatric c. sympatric d. parapatric

True

Sexual isolation should be the weakest among allopatric populations. T or F?

False

Speciation by hybridization is more common in animals than in plants. T of F?

True

Speciation by hybridization is more common in plants than in animals. T or F?

True

Speciation can proceed quite rapidly under circumstances in which a peripheral population is genetically isolated from its parent. T or F?

False

Speciation of cichlids in an African crater lake is an example of allopatric speciation. T or F?

True

Structural genes between humans and chimpanzees show evidence of purifying selection. T of F?

population within and among which individuals actually or potentially interbreed and outside of which they do not interbreed

The biological species concept, formalized by Ernst Mayr in 1942, defined a species as a ________. a. group of individuals that inhabit the same location b. group of individuals with similar morphological characteristics c. population within and among which individuals actually or potentially interbreed and outside of which they do not interbreed d. group of individuals who share similar allelic frequencies e. population of individuals within and among which reproduction takes place frequently

False

The bulk of Multicelluar Eukaryotic Genomes are mostly coding DNA. T or F?

All of the choices are correct.

The effect of inbreeding is: a. an increase of homozygotes in succeeding generations. b. a decrease of heterozygotes in succeeding generations. c. decreasing the mean fitness of a population. d. All of the choices are correct.

many current genes arose through the rearrangement of exons.

The exon theory of genes states that a. genes consist solely of exons. b. introns are deleterious and are purged from the genome. c. introns lead to recombination errors. d. many current genes arose through the rearrangement of exons. e. introns disrupt protein structure.

True

The fact that an ichytosaur resembles a porpoise in form is an example of convergent evolution. T or F?

By studying such genomes, researchers try to discover the basic and essential cellular functions of early life.

The human parasite Mycoplasma genitalium, withone of the smallest genomes of any organism that can be grown, as well as Chlamydia trachomatis, an obligate intracellular parasite, are examples of the types of organisms that functional genomics researchers have focused on. What is the main purpose of the study of such genomes? a. These and other obligate parasites or symbiontes are very easy to study. b. They are very ancient prokaryotes with original small genomes. c. By studying such genomes, researchers try to discover the basic and essential cellular functions of early life. d. all of the above

the G-value paradox.

The nematode, C. elegans, and humans have nearly identical numbers of protein coding genes, yet humans have much more complex organismal features. This is an example of a. the C-value paradox. b. the G-value paradox. c. cell size paradox. d. linkage disequilibrium. e. None of the above

C and D

The observation of an offspring phenotype outside of the range of parental phenotypes is most likely due to a. additive genetic effects. b. mutation. c. selection. d. latent variation. e. C and D

small efficient cells

The origin of multicelluarity provides several advantages. Which of the following is NOT an advantage? a. increase size beyond the surface-to-volume ratio of single cells b. enhanced dispersal c. distinct cell types give an increase in efficiency d. small efficient cells

adaptive radiation

The rapid evolution of one or a few forms into many different species occupying a variety of habitats within a new geographical area is referred to as ______________. a. adaptive radiation b. genetic mutation c. genetic drift d. migration

discrete characters

The rediscovery of Mendelian inheritance caused increased scrutiny of Darwin's theory of natural selection because of an apparent conflict in the two concepts. This conflict was based on the observation that Darwin focused on continuous traits, whereas Mendelian genetics deals with a. discrete characters. b. alleles. c. flowers. d. genotypes. e. All of the above

prokaryotes and eukaryotes.

The two major cell types are a. archaea and bacteria. b. archaea and prokaryotes. c. prokaryotes and eukaryotes. d. eukaryotes and archaea. e. eukaryotes and bacteria.

True

There are many plant species that have much more DNA than humans. T or F?