Ultimate Quiz - Fall 2018 Sec. 2 Flashcards
get an A bitches
Science can prove a theory is true but cannot prove it is false.
False
Which of the statements below is the worst definition of science?
The application of sophisticated tools and reasoning to explore any type of phenomenon.
A controlled experiment _______.
includes at least two groups, one of which does not receive the experimental treatment
How does a scientific theory differ from a scientific hypothesis?
Theories are usually an explanation for a more general phenomenon; hypotheses typically address more specific issues.
Which of the following best describes the logic of scientific inquiry?
If my hypothesis is correct, I can expect certain test results.
Which of the following emphasizes the community-based or social nature of modern science?
Scientific progress is made via communication and discussion of research findings, publication of scientific findings is subject to peer-review, scientific studies are often conducted by groups of specialized researchers.
Because scientific explanations must be discarded or revised based on new evidence
Scientists must be willing to change their minds in light of new evidence.
The best scientific explanation of a process or observation is determined by:
The quality and strength of the evidence
Which of the following is NOT a falsifiable statement?
Birds and dinosaurs share an evolutionary history.
Because science is a human endeavor,
scientists’ hypotheses can be influenced by their cultures.
Ethical scientific practices include all of the following EXCEPT:
Altering experiments or results so they are more consistent with an important theory.
Science favors the most parsimonious explanation, meaning the explanation that is the
simplest explanation of all of the facts.
The fact that scientists consider their conclusions to be tentative means that scientific conclusions are
durable but not unchanging.
Over the past 25 years, our classification of living things has changed from a two kingdom, to three kingdom, to five kingdom, to three domain model. This change is an example of:
The self-correcting nature of science.
Because scientists cannot exactly replicate the origin of life,
Observations of fossil and living organisms, as well as experiments, can provide evidence for how life arose on earth.
You notice that the majority of the electrons in NaCl spend their time around the chlorine. You also notice that the electrons in H2 are evenly distributed among the two atoms. Which two types of bonds are represented in these molecules?
Ionic bonds in NaCl; covalent bonds in H2
Plasma membranes are a feature of
all cells
The largest molecule of the following is
a polysaccharide
all organic molecules contain
hydrogen and carbon
what structure best represents a polymer?
a protein
The major class of macromolecules that stores energy and makes up the major component of plasma membranes are
lipids
Select which of the following might be a reason that eukaryotic cells are larger in size than prokaryotic cells
Compartments devoted to single functions concentrates the molecules for that function so reactants are more likely to bump in to one another.
The feature of carbon important for producing a diversity of organic molecules is
carbon can form both polar and nonpolar covalent bonds with various elements.
The strongest chemical bonds are
covalent bonds
The LEAST hydrophilic substance is
oil
fats and fatty acids
are insoluble in water
The macromolecule that can accomplish the widest range of biological functions are
proteins
The macromolecule composed of amino acids is a
protein
Eukaryotes such as animal and plants cells differ from prokaryotes in that prokaryotes
lack internal compartmentalization
A molecule of salt will dissociate in water in to the atoms that make up the molecule. A molecule of glucose will not dissociate in water in to the atoms that make up the molecule. This occurs because:
The atoms in NaCl are held together by an ionic bond, while those in glucose are held together by covalent bonds.
The endosymbiotic hypothesis is an attempt to explain…
the origins of certain eukaryotic cell organelles, such as mitochondria and chloroplasts.
Whales and pythons lack external hind limbs, but both have rudimentary internal hind limb bones hidden deep within their bodies. These examples are evidence that
each group evolved from four-legged ancestors that had functional hind limbs.
Changes in ________ represent the predominant component of biological evolution.
the genome
Which of the following is NOT considered an essential characteristic of living organisms?
multicellular
Over long periods of time, many cave-dwelling organisms have lost their eyes, many aquatic mammals have lost their hind limbs, and many large birds have lost functional wings. Which of the following best explains how natural selection accounts for these losses?
Under conditions that persisted for long periods, each of these structures presented greater costs than benefits.
Parasitic species tend to have simple morphologies. Which of the following statements best explains this observation?
Simple morphologies convey some form of advantage to parasites.
A major limitation of the fossil record is that…
it is incomplete
One hypothesis for the origin of life emphasizes that Earth’s early atmosphere was __________, which could have facilitated the accumulation of complex, organic molecules. However, today’s ___________ atmosphere prevents the spontaneous and abiotic creation of long, complex molecules like those found in living organisms. The blanks should be filled, respectively, with:
reducing, oxidizing
Similar gill pouches in embryos of a chicken, human, and cat are an example of _____.
developmental homology
Which of the following is NOT a basic assumption underlying Darwin’s mechanism for natural selection?
Individuals will strive to survive, thus evolving and adapting to their environment over their lifetime.
A proficient engineer can easily design skeletal structures that are more functional than those currently found in the forelimbs of such diverse mammals as horses, whales, and bats. The actual forelimbs of these mammals do not seem to be optimally arranged because _____.
natural selection is limited to modifying structures that were present in previous generations
Order the following events in the history of life on Earth from earliest to latest:
1 - evolution of multicellular organisms
2- evolution of bilateral symmetry
3- evolution of vertebrates
4- evolution of the prokaryotic cell
5- evolution of the eukaryotic cell
4, 5, 1, 2, 3
Chemical evolution occurs when…
a molecule becomes more common in a population of molecules due to a favored property.
RNA was likely to have been a key macromolecule in the early evolution of life because it has the ability to store information and can self-replicate. Importantly, RNA can also…
be a biological catalyst
Which of the following is likely NOT an example of convergent evolution?
presence of hair in mice and apes
Consider a diploid organism whose karyotype shows it to have a total of 50 chromosomes. How many chromosomes would be contained in each germ cell (gamete) of this organism?
25
If we describe a cell as 2n, with n = 8, we know that this cell is __________ and has __________ chromosomes in total. The blanks should be filled, respectively, with
diploid; 16
In a tetraploid species (4n), a euploid individual would have __ sets of chromosomes.
4
Place the following events of mitosis in the correct order:
I. Sister chromatids align on the metaphase plate.
II. The cleavage furrow forms.
III. The mitotic spindle forms.
IV. Sister chromatids condense.
V. Sister chromatids separate.
IV, III, I, V, II
As discussed in the article by Morran et al., The Red Queen hypothesis proposes that sexual reproduction (or outcrossing) is beneficial and will be maintained long-term when organisms are forced to adapt to…
an ever-changing environment
Why must the life cycle of sexually reproducing species alternate between haploid and diploid stages?
The haploid stage must occur at some point in the life cycle to prevent a doubling of chromosomes in each generation.
Which of the following statements regarding the G1 (first gap) phase of the eukaryotic cell cycle is NOT true?
If DNA is heavily damaged, G1 checkpoint proteins will repair the damage and allow the cell cycle to proceed.
what is trisonomy?
2n+1
Crossing over during meiosis typically…
can be expected to increase the genetic variety of gametes produced.
During DNA replication preceding meiosis two mutations arise, each within the newly synthesized DNA strands of different homologous chromosome pairs. When this diploid cell then undergoes meiosis, how many daughter cells will contain at least ONE mutation?
either or 1 or 2 cells
Consider an organism with a karyotype of 2n, where n = 4. The cell below shows 4 pairs of sister chromatids lined up along the metaphase plate during metaphase of ________.
meiosis II
The process by which haploid cells are produced from diploid cells is called…
gametogenesis
Which of the following DOES NOT occur during mitosis but DOES occur during meiosis?
separation of homologous chromosome into two different cells
According to the article by Morran et al., one of the costs of sexual reproduction (or outcrossing) is…
fewer total offspring per individual
During DNA replication, all of the following proteins are important for separating the DNA strands and allowing movement of the replication fork EXCEPT
DNA polymerase
The following statements are false
One chromosome is made up of many DNA molecules,
During the DNA replication process, which of the following organisms would have the fewest origins of replication per cell?
a Streptococcus bacterium.
A DNA specimen that contains 30% guanine has ________ thymine.
20%
Type S Streptococcus pneumoniae bacterium is lethal and will kill its host. If heat inactivated the S strain dies and becomes nonlethal. Type R Streptococcus pneumoniae is a nonvirulent strain of bacteria. What would occur if one were to inject both the R strain and heat-killed S strains into a host organism such as the mouse?
The R strain would be transformed into the virulent S strain and kill the host.
Which of the following is the highest (or most complex) level of structure for genetic material?
chromosome
Without data from the base composition studies of Chargaff, what might Watson and Crick’s modeling studies have erroneously concluded?
Any purine could pair with any pyrimidine
Which molecule catalyzes covalent bond formation between fragments of DNA.
ligase
Bacteria are grown in 15N (heavy) medium and then transferred to 14N (light) medium and are allowed to replicate for 1 generation. The DNA is subsequently isolated and centrifuged in a CsCl2 gradient to yield what type of gradient band(s)?
one half-heavy (intermediate to heavy and light) band
How many replication forks are there at an origin of replication?
2
The nucleotides within DNA are composed of a
phosphate group, deoxyribose sugar, and nitrogenous base.
Which of the following diseases is associated with faulty DNA repair mechanisms?
xeroderma pigmentosum
What is the complementary DNA strand to 5′-ATTCGGTGA-3′?
3′-TAAGCCACT-5′.
The function(s) of DNA polymerase includes which of the following?
DNA synthesis, DNA proofreading, and removal of RNA primers and filling in the gaps.
After a fragment of DNA containing the gene of interest has been inserted into a vector, how are the gaps between the two pieces of DNA sealed together?
DNA ligase catalyzes the formation of covalent bonds in the DNA backbone.
Which of the following statements is TRUE of restriction enzymes?
they protect bacterial cells from invasion by foreign DNA.
A researcher runs a BLAST program comparing turkey phenylalanine hydroxylase, which functions in the metabolism of phenylalanine, with known database sequences. Which of the following should provide the closest match?
chicken
A DNA library is
a collection of recombinant vectors containing DNA fragments of a given organism.
If a plasmid lacks an origin of replication what will happen when it is transformed into bacteria?
As the bacteria divide they will lose the plasmid
The lacZ gene encodes
β-galactosidase.
You cut some sheep DNA and some plasmid DNA with the same restriction enzyme. The plasmid contains an AmpR gene and a lacZ gene. You mix together the fragments of sheep DNA and the linearized plasmid. You transform bacteria with your mixture, and plate the bacterial cells on growth media containing the antibiotic ampicillin and X-gal (the substrate of beta-galactosidase). You need to pick some bacterial colonies that contain recombinant plasmids (plasmids containing inserted DNA). Which colonies do you choose?
the white colonies; only cells that contain a recombinant plasmid will be white.
Which of the following statements about genomic libraries and cDNA libraries is TRUE?
a cDNA library is derived from mRNA and is made using reverse transcriptase.
You cut a plasmid with a restriction enzyme that cuts it into three pieces — one fragment is 240 base pairs, one fragment is 600 base pairs, and one fragment is 1200 base pairs. You carry out electrophoresis of the digested sample. Which of the fragments will be closer to the top of the gel where the sample was inserted?
the 1200 base pair fragment
Primers are used in both PCR and in DNA sequencing. What is the purpose of the primers?
to provide a 3’- OH for DNA polymerase to build a new DNA strand.
Dideoxy nucleotides are used in which of the following processes?
DNA sequencing
You grow a culture of bacteria and split it into two culture tubes. One sample of bacteria you treat with calcium and the other is not treated. When you transform both samples with a plasmid, only the samples treated with calcium take up the plasmid. Which of the following best explains your results?
The calcium makes the bacterial membrane more porous to DNA.
A small amount of DNA is collected from a crime scene. However, the amount of DNA collected is insufficient to perform the necessary experiments to link a suspect to the crime. Which method could be utilized to increase the amount of DNA?
PCR
You insert a fragment of sheep DNA into a plasmid containing an AmpR gene. You transform bacteria with the recombinant plasmid, and plate the cells on growth media containing the antibiotic ampicillin. Each colony on the plate arose from ________ that ________ to ampicillin.
a single bacterium; is resistant
Why is Taq polymerase used in a polymerase chain reaction (PCR)?
Unlike other DNA polymerases, Taq polymerase is heat stable and survives the 94 degree denaturation step in PCR.
An organism with genotype AaBb can produce a variety of different sperm genotypes equaling:
4
Eyelash length is an inherited trait. In the human population, there is an eyelash length gene. There are two possible variants of this gene - an allele for long eyelashes (> 1cm) and an allele for short eyelashes (1 cm or less). How many eyelash length alleles does an individual have in one of her/his somatic cells?
2
Human males produce
sperm, half contain an X chromosome, half contain a Y chromosome.
An organism that is heterozygous for two traits can produce a maximum of ________ different gametes for these traits.
4
In dogs, there is a hereditary deafness caused by a recessive allele, d. A kennel owner has a male dog that she wants to use for breeding purposes if possible. The dog can hear, but the owner is unsure of the genotype. She does a testcross (crosses it to a homozygous recessive dog), and two of the five offspring are deaf. This means that the male dog
has the genotype Dd
Tay Sachs is a lysosomal storage disease that is inherited in an autosomal recessive manner. Individuals with Tay Sachs have a defect in the gene encoding hexosaminidase A, a lysosomal enzyme that breaks down cell membrane components called gangliosides. The inability to break down gangliosides causes harmful quantities of this lipid to accumulate in nerve cells of the brain, eventually leading to premature death of affected cells. There is no known cure for the disease, and death usually occurs by age 4. Jack and Jill have a child who has Tay-Sachs. What do you know about the genotypes of Jack and Jill? (T= dominant allele; t = recessive allele)offspring?
Both are Tt
In wolves, gray coat color (G) is dominant to black (g) and brown eyes (B) are dominant to blue (b). The genes that control these traits are located on different chromosomes. The alpha male of the pack has the dominant phenotype for both traits and is heterozygous for both traits. The alpha female has brown eyes and a black coat; she is heterozygous for eye color. Which option represents gametes that would be made by the alpha female?
Bg and bg
The inheritance pattern where two or more genes do not assort independently because they are close together on the same chromosome is called
linkage
In rabbits, spotted coat (S) is dominant to solid color (s) and black (B) is dominant to brown (b). A true-breeding black spotted rabbit is mated to a true-breeding brown solid rabbit to produce a heterozygous F1 generation. Two F1 individuals are mated, and you do not see a 9:3:3:1 (black spotted: black solid: brown spotted: brown solid) ratio of offspring, but instead see that almost all offspring are a non-recombinant phenotype. This tells you that
that the genes for fur pattern (spotted vs. non-spotted) and fur color are on the same chromosomes.
What is a dominant allele?
In a heterozygous individual, the allele that determines the phenotype
P, D, and Q are three genes found on a single chromosome in greyhounds. The recombination frequencies between the three genes are shown below. In which order are these genes found on the greyhound chromosome? P - D = 50%; P - Q = 20%; D - Q = 30%
P-D-Q
If organisms of type BbSs and type bbSs are crossed, what is the probability that the offspring will be BbSs?
1/4
A couple has five sons. What is the probability that their next child will be a girl?
50%
When nonrandom mating occurs in a population so that individuals prefer to mate with genetically similar individuals, allele frequencies should…
remain the same, but homozygotes will be overrepresented in the population.
Most Swiss starlings produce four to five eggs in each clutch (the set of eggs laid at a given time). Starlings producing fewer or more than this have reduced fitness. Which of the following terms best describes this situation?
stabilizing selection
In the Hardy-Weinberg equation, p and q represent __________ frequencies, while p2, 2pq, and q2 represent __________ frequencies. The blanks should be filled, respectively, with:
allele; genotype
If allele frequencies are changing within a population over time, this indicates that ______________ is definitely occurring.
evolution
Fitness is a measure of relative reproductive success. If an individual with genotype BB produces 6 offspring, and a heterozygous individual (Bb) produces 10 offspring, and a third individual with genotype bb produces 5 offspring, what is the fitness value for the individual with BB genotype?
0.6
One of the assumptions necessary for the Hardy-Weinberg equation to accurately predict the genotype frequencies within a population is often worded as “large population size.” Which of the following evolutionary forces is most strongly and directly affected by population size?
genetic drift
Which of the following is the ultimate source of genetic diversity in a population?
mutation
Consider a gene with two alleles (F and f) with initial frequencies of p = q = 0.5 in a large, closed population with random mating patterns. If the relative fitness values are WFF = 1.0, WFf = 1.0, Wff = 0.5, we can predict that
the f allele should decrease in frequency
In a small population of alpine foxes, you observe increased ear length over a ten-year period. Can you conclude that increase in ear length is advantageous in this population?
No
Which of the following can be expected to consistently result in adaptation?
natural selection
Some non-poisonous species of snakes have coloration that mimics that of a poisonous snake. This mimicry is only advantageous as long as the mimics are relatively rare, compared to the prevalence of the truly poisonous snake. This is an example of…
frequency-dependent selection
In a population of 500 fruit flies, 50 are genotype RR, 300 are genotype Rr and 150 are genotype rr. The frequencies of the R and r alleles, respectively, in this population are:
0.40 and 0.60
If a population is in Hardy-Weinberg equilibrium with respect to a given allele, it is predicted that the genotype frequencies in a population will…
remain the same throughout subsequent generations
If a DNA template strand has a sequence of 3′ TACAATGTAGCC 5′, the RNA produced from it will be which sequence?
5′AUGUUACAUCGG3’
Wild type bread mold can grow in a minimal medium without supplements, while certain mutated strains can only grow in a minimal medium that is supplemented with specific intermediates found in the following metabolic pathway for arginine synthesis. See the figure below for an overview of the arginine biosynthetic pathway.
A strain that can grow in minimal medium containing ornithine, citrulline, or arginine, but not in minimal medium alone would have a mutation in the gene that encodes for
Precursor (enzyme 1)->ornithine(enzyme 2)->citrulline(enzyme 3)->arginine
enzyme 1
What basic features of transcription is NOT shared by both prokaryotes and eukaryotes?
The initiation of transcription in both prokaryotes and eukaryotes involves the interactions of more than one protein.
Intervening sequences that are transcribed, but not translated into protein are called
introns
What is the function of the poly A tail?
The poly A tail increases mRNA stability in eukaryotes.
What factors are utilized by the cell in order to recognize the stop codon and disassemble the translation machinery?
release factors
The amino acids of a growing polypeptide chain are held together by what kind of bond during the elongation stage of translation?
peptide
How many nucleotides are contained in a single codon?
3
What process enables a single gene to encode two or more polypeptides that are different in their amino acid sequence?
alternative splicing
Which sequence of events CORRECTLY describes the initiation and elongation steps of translation in prokaryotic cells?
(1) initiator tRNA binds start codon on mRNA
(2) small ribosomal subunit binds to mRNA
(3) large ribosomal subunit binds
(4) tRNA entry and peptidyl transfer reaction
(5) translocation of ribosome and release of tRNA
2, 1, 3, 4, 5
If a cell’s splicesomes were mutated so they no longer functioned normally, what consequences would result?
Introns would remain in the mature mRNA.
The following mRNA transcript would result in which polypeptide sequence?
5′-ACU UUC ACU AUG UUU UUA UCC UCC ACU CCU UGA-3′
Use the following codons and the amino acids they encode. AUG = Met; UUU, UUC = Phe; UUA, UUG = Leu; UCU, UCC = Ser; CCU, CCC = Pro; ACU, ACC = Thr; UGA = Stop.
Met-Phe-Leu-Ser-Ser-Thr-Pro
The transcription process in a eukaryotic gene directly produces ________.
pre-mRNA
________ is to transcription as ________ are to translation.
RNA polymerase; ribosomes
The processes of transcription and translation are collectively known as
gene expression
An mRNA that contains the coding sequence for two or more structural genes is called a
polyextronic mRNA
A cell’s ability to control their level of gene expression is called
gene regulation
In E. coli cells when lactose is absent from the environment,
trace amounts of b-galactosidase, lactose permease, and galactosidetransacetylase are made.
An activator is to an enhancer as a ________ is to a silencer.
repressor
Why would bacteria evolve so that the presence of tryptophan inhibits its own production?
Producing the enzymes that synthesize tryptophan is metabolically expensive, so it is wasteful to make them when tryptophan levels are high and its synthesis is not necessary.
Jacob, Monod, and Pardee constructed a mutant strain of E. coli that carried a lacI-gene mutation (encodes the lac repressor). Which is TRUE of this mutant strain?
The lac operon is constitutively expressed
Genes organized into an operon are beneficial to certain bacteria because the operon allows for
coordinated regulation of a group of genes that encode proteins with a common function.
Both eukaryotes and prokaryotes require a promoter region for gene transcription.
True
Eukaryotic genes are almost always organized in groups, similar to operons in prokaryotes.
False
The likely outcome from a deletion mutation in the lacO site (lac Operator) of the lac operon would be
binding of a repressor protein could be hindered.
The core promoter in eukaryotes is usually composed of which two features?
transcriptional start site and TATA box
Liver cells, mammary cells, and skin cells all contain the same genome; however, their respective proteomes vary drastically. This observation is best explained by what phenomenon?
cell differentiation
Histone deacetylase inhibitors are a class of drugs used as mood stabilizers and anti-epileptics that are also being researched for their efficacy as anti-cancer agents. Histone deacetylase inhibitors block the action of histone deacetylases, which remove acetyl groups from lysine residues in histone tails making chromatin more open. How will blocking histone deacetylases affect gene expression in the cell?
gene expression will be increased
Events that occur during transcriptional regulation in eukaryotes include
RNA processing and export from the nucleus
The introduction of cloned genes into living cells to try and cure disease is known as what?
gene therapy
Short tandem repeat sequences (STRs) can be used for DNA fingerprinting because ________.
the number of repeats varies between individuals.
Shown below are steps in making a transgenic plant.
- Expose plant cells to Agrobacterium tumefaciens
- Place plant cells on selective medium
- Transform the recombinant plasmid into Agrobacterium tumefaciens
- Insert gene of interest into Ti plasmid
- Place plant cells on growth medium with plant hormones
Which of the following represents the correct order?
4 - 3 - 1 - 2 - 5.
Human growth hormone (HGH) is a peptide hormone that stimulates growth, cell division and regeneration. HGH is made in the anterior pituitary gland. A researcher wants to introduce the gene encoding human growth hormone into E. coli so she can produce large quantities of the peptide hormone for medical treatments. What strategy should the researcher take?
Obtain the HGH gene from a human anterior pituitary gland cDNA library.
A bacteria contains two copies of the lac operon; one on the bacterial chromosome and one on a plasmid. The lacO site on the chromosomal lac operon is mutated and non-functional whereas the lacO site on the plasmid is functional. What is the most likely outcome for the bacterial cell when glucose is declining and lactose is present?
Expression of lac structural genes on the chromosome and plasmid will increase because the lacO site does not affect the CAP protein that activates the operon.
Which of the following is an example of a clone on the organism level?
identical twins
The bacterium Agrobacterium tumefaciens is used
to produce transgenic plants
The milk of goats has been genetically modified to produce human antithrombin, a protein with anticoagulant properties. How did the recombinant plasmid containing the human antithrombin gene get into the goats?
The recombinant plasmid was put into a goat oocyte, which was in turn fertilized and implanted into a surrogate goat mother.
Which of the following is an advantage of molecular pharming compared to expression of mammalian proteins in bacteria?
Proteins are more likely to function properly when expressed in mammals.
Which of the following accurately describes the process used to make Dolly the sheep?
A mammary cell of one sheep was fused with an enucleated egg of another sheep. The resulting diploid embryo was placed in a surrogate sheep mother.
Which of the following is defined as the use of living organisms or the products of living organisms to benefit humans?
biotechnology
A cloned gene that inactivated a gene’s normal function in the homozygote is called which of the following
knockout
A researcher wants to introduce the human gene encoding tissue plasminogen activator (used to dissolve blood clots) into a mammal so that the protein will be secreted into the milk of the mammary gland. What is required for the researcher’s success?
The gene should be placed next to the promoter of a gene that is expressed in mammary cells.
The first human gene therapy was approved for patients suffering ADA (adenosine deaminase) deficiency. In this therapy, lymphocytes were removed from the patient, the normal ADA gene was put into the cells, and the cells were returned to the bloodstream. How was the normal ADA put into the lymphocytes?
via a viral vector
________ occurs when a cloned gene recombines with the normal gene on a chromosome to create a genetically modified organism (GMO).
gene replacement
A higher taxon (e.g., family) that is monophyletic is comprised of…
a common ancestral species and all of its descendant species.
The study of biological diversity and evolutionary relationships among organisms is ____________.
systematics
Which statement represents the best explanation for the observation that the nuclear DNA sequence of wolves and domestic dogs is highly similar? Dogs and wolves ___________________________.
share a very recent common ancestor
Linnaeus began naming organisms that were alike using Latin names. He gave each organism two names; for example, the pigmy rattlesnake is called Sistrurus miliarius by scientists. What type of naming system is this and what group does “miliarius” designate?
binomial nomenclature; species
The presence of hair would be a/an _____________ among a group of mammal species, but would be a/an _______________ among those same mammal species when compared to a reptile species. The blanks should be filled, respectively, with:
shared primitive character; shared derived character
The science of describing, naming, and classifying extant and extinct organisms is _______________.
taxonomy
Consider the following DNA sequences for four different species:
Species 1: AATCG
Species 2: TAATG
Species 3: ATAGG
Species 4: ATACC
Based on the principle of parsimony, which species shares a most recent common ancestor with a species having the sequence TTACC?
species 4
Your professor wants you to construct a phylogenetic tree of orchid plants. She gives you tissue from seven orchid species (all within one family Orchidaceae) and one lily species (family Liliaceae). What is the most likely reason she gave you the lily?
to serve as an outgroup
Molecular clocks are based primarily on rates of __________________________.
neutral mutations
A liger is an offspring produced from a mating between a male lion and a female tiger. Male ligers cannot produce offspring. This is an example of
hybrid sterility
Male frogs give calls that attract female frogs to approach and mate. Researchers examined mating calls of two closely related tree frogs in South America. If behavioral isolation is occurring where the two species overlap geographically, what would you expect if you compare the calls of the two species in zones of sympatry versus zones of allopatry?
Calls would be more different in areas of sympatry.
When a species arrives in a new location it may undergo relatively rapid adaptive radiation, diversifying and filling a new set of available ecological niches. Such an event may help to explain the phenomenon of:
punctuated equilibrium
Polyploidy…
involves an increase in the number of chromosomes.
In a hypothetical situation, a certain species of flea feeds primarily on pronghorn antelopes. In the western United States, pronghorns and cattle often associate with one another in the same open rangeland. Suppose that some of these fleas develop a strong preference for cattle blood and tend to mate with other fleas that prefer cattle blood. If this situation persists, and new species evolve, differentiated by food preference, this would be an example of ____ and ____.
sympatric speciation and diversifying selection
At some time within the last 10,000 years, a population of the white lily, Erythronium albidum, gave rise to a new species, Erythronium propullans. Both species are still living and the geographic range of propullans is, and always was, entirely within the geographic range of the widespread E. albidum. This appears to be an example of
sympatric speciation
When cross-pollination is attempted between two closely related species of violets, it is found that the pollen of species A cannot reach the egg of species B because it lacks the proper enzyme to travel down to the location of the egg. Likewise, the pollen of species B cannot reach the egg of species A. This phenomenon is an example of
a pre-zygotic isolating mechanism
What does the biological species concept use as the primary criterion for determining species boundaries?
reproductive isolation
American sycamore (Platanus occidentalis) and European sycamore (Platanus orientalis) are tree species that will interbreed if planted nearby but will not normally interbreed because they occur on different continents. This is an example of
habitat isolation
Development of an animal is connected to the genes that are expressed during development. What roles have been proposed for Hox genes in the evolution and morphology of animal species?
Variation in the number of Hox genes is associated with the evolution of animal diversity.
The general lineage species concept emphasizes
evolutionary independence
Which of the following does NOT tend to promote speciation?
increased gene flow
If two populations are geographically restricted groups of the same species, but display one or more traits that are somewhat different, the two groups are sometimes classified as
subspecies
Dandelions (Taraxacum officinale) are plants that asexually produce fruitlike propagules. Sexual reproduction is very rare in this organism. Which species concept would be least useful in defining dandelions as a species?
biological species concept
Approximately 3.5 million years ago the Isthmus of Panama formed. This new landmass severed the connection between the Pacific Ocean and the Caribbean Sea. An ancestral fish population (porkfish) was split in two by this event; the two populations no longer interbreed and are two distinct species. This type of speciation is called:
allopatric speciation
