GEN BIO 1307 2 TEST 2

Which Anolis lizard ecomorph has long legs? -Crown -Trunk/crown -Trunk/ground -Twig

Trunk/ground

Radiometric dating __________. -allows us to determine an absolute, errorless date -allows us to indirectly date fossils up to billions of years old based on minerals in surrounding volcanic strata -only works on rocks younger than 75,000 years -relies on the fact that the daughter isotope decays to the parent isotope at a constant rate Submit

allows us to indirectly date fossils up to billions of years old based on minerals in surrounding volcanic strata

A hybrid zone is properly defined as -an area where members of two closely related species intermingle, but experience no gene flow. -a zone that features a gradual change in species composition where two neighboring ecosystems border each other. -an area where two closely related species' ranges overlap. -a zone that includes the intermediate portion of a cline. -an area where mating occurs between members of two closely related species, producing viable offspring.

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

The oldest fossils usually __________. -are found above younger fossils -are found in the deepest strata -are found in sediments formed during the Cenozoic era -contain more radioactive isotopes than younger fossils -have the longest half-lives

are found in the deepest strata

phylogenetic

based on evolutionary history

behavioral isolation example:

beetle mating displays show different spot patterns

Males of different species of the fruit fly Drosophila that live in the same parts of the Hawaiian Islands have different elaborate courtship rituals. These rituals involve fighting other males and making stylized movements that attract females. What type of reproductive isolation does this represent? -temporal isolation -habitat isolation -behavioral isolation -gametic isolation

behavioral isolation

temporal isolation example:

birds are active during different times of the day

Which effect of continental drift would allow scientists to track the history of life on the planet? -change in distribution of extinct animals -alteration of habitat -allopatric speciation -climate change

change in distribution of extinct animals

Radiometric dating is based on the -ratio of carbon-14 to carbon-12. -decay of radioactive isotopes. -amount of carbon-12 in an organism at time of death. -temperature and pressure of the environment.

decay of radioactive isotopes.

habitat isolation definition:

differences in habitat occupied

behavioral isolation definition:

differences in mating rituals or displays

temporal isolation definition:

differences in the timing of mating

Mesozoic era -the Cambrian explosion, first tetrapods and insects appear -oldest fossils of cells (prok) appear -dinosaurs evolve and radiate, origin of mammals -origin of Earth -oldest fossils of eukaryotic cells appear -humans appear. major radiation of pollinating insects

dinosaurs evolve and radiate, origin of mammals

Black-bellied seedcrackers have either small beaks (better for eating soft seeds) or large beaks (better for hard seeds). There are no seeds of intermediate hardness; therefore, which kind of selection acts on beak size in seedcrackers? -Directional selection -Disruptive selection -Stabilizing selection

disruptive selection

Which type of selection tends to increase genetic variation? -Directional selection -Disruptive selection -Stabilizing selection

disruptive selection

A swim bladder is a gas-filled sac that helps fish maintain buoyancy. The evolution of the swim bladder from the air-breathing organ (a simple lung) of an ancestral fish is an example of __________. -exaptation -changes in Hox gene expression -paedomorphosis -adaptive radiation

exaptation

mechanical isolation example:

flowers accommodate different insect pollinators

The ease with which humans travel across the globe is likely to increase _____. -mutation -natural selection -genetic drift -gene flow -all of these

gene flow

What prevents speciation from occurring in sympatric populations? -Geographical isolation -Gene flow -Natural selection -Genetic drift

gene flow

Which of these should decline in hybrid zones where reinforcement is occurring? -mutation rate -speciation -the genetic distinctness of two gene pools -gene flow between distinct gene pools -hybrid sterility

gene flow between distinct gene pools

Adaptive radiations can be a direct consequence of three of the following four factors. Select the exception. -vacant ecological niches -evolutionary innovation -colonization of an isolated region that contains suitable habitat and few competitor species -genetic drift

genetic drift

Allele frequencies in a gene pool may shift randomly and by chance. What is this random shift called? -genetic drift -directional selection -gene flow

genetic drift

Modern travel along with migration reduces the probability of _____ having an effect on the evolution of humans. -natural selection -gene flow -genetic drift -disease -mutation

genetic drift

There are 25 individuals in population 1, all with genotype AA, and there are 40 individuals in population 2, all with genotype aa. Assume that these populations are located far from each other and that their environmental conditions are very similar. Based on the information given here, the observed genetic variation most likely resulted from_______. -nonrandom mating -genetic drift -gene flow -directional selection

genetic drift

Cenozoic era -the Cambrian explosion, first tetrapods and insects appear -oldest fossils of cells (prok) appear -dinosaurs evolve and radiate, origin of mammals -origin of Earth -oldest fossils of eukaryotic cells appear -humans appear. major radiation of pollinating insects

humans appear, major radiation of pollinating insects

reduced hybrid viability definition:

hybrid offspring are produced but are feeble or unable to compete for mates

reduced hybrid fertility definition

hybrid offspring are produced but are sterile

Natural selection changes the alleles frequencies because some_________survive and reproduce better than others. -loci -alleles -species -individuals

individuals

reduced hybrid viability example:

lion-tiger hybrids don't reach maturity

Homologous pairs of chromosomes are lined up independently of other such pairs during _____. -telophase II -anaphase I -prophase II -metaphase II -metaphase I

metaphase 1

Generation-to-generation change in the allele frequencies in a population is _____. -microevolution -mutation -genetic drift -natural selection -macroevolution

microevolution

Crossing over, resulting in an increase in genetic variation, occurs between _____. -sister chromatids of homologous chromosomes -nonsister chromatids of nonhomologous chromosomes -sister chromatids of nonhomologous chromosomes -sex cells and somatic cells -nonsister chromatids of homologous chromosomes

nonsister chromatids of homologous chromosomes

biological

not applicable for extinct species

reduced hybrid fertility example:

offspring of 2 newts are sterile

Archaean eon -the Cambrian explosion, first tetrapods and insects appear -oldest fossils of cells (prok) appear -dinosaurs evolve and radiate, origin of mammals -origin of Earth -oldest fossils of eukaryotic cells appear -humans appear. major radiation of pollinating insects

oldest fossils of cells (prok) appear

Proterozoic eon -the Cambrian explosion, first tetrapods and insects appear -oldest fossils of cells (prok) appear -dinosaurs evolve and radiate, origin of mammals -origin of Earth -oldest fossils of eukaryotic cells appear -humans appear. major radiation of pollinating insects

oldest fossils of eukaryotic cells appear

Hadean eon -the Cambrian explosion, first tetrapods and insects appear -oldest fossils of cells (prok) appear -dinosaurs evolve and radiate, origin of mammals -origin of Earth -oldest fossils of eukaryotic cells appear -humans appear. major radiation of pollinating insects

origin of Earth

morphological

relies on similarities in structure

mechanical isolation definition:

reproductive structure incompatibility

A mutation occurs when _____. -there is a change in the DNA sequence of a gene -some individuals leave more offspring than other individuals -population sizes are small -individuals enter a population -individuals leave a population

there is a change in the DNA sequence of a gene

morphological, phylogenetic, and biological

used by scientists in classification

No 2 people are genetically identical, except for identical twins. The main source of genetic variation among humans is_____? -the reshuffling of alleles in sexual reproduction -genetic drift -new mutations that occurred in the preceding generation -environmental effects

the reshuffling of alleles in sexual reproduction

What is the frequency of the A1A2 genotype in a population composed of 20 A1A1 individuals, 80 A1A2 individuals, and 100 A2A2 individuals? - 0.5 - 80 - 0.1 - 0.4

0.4

How does continental drift affect living organisms? -It may cause an increase or decrease in competition among different species. -All but one of the listed responses are correct. -It causes changes in habitats, such as when large amounts of shallow marine habitat were lost in the formation of Pangaea. -It happens so slowly that it does not affect living organisms. -It causes climate change, which puts selective pressure on organisms.

All but one of the listed responses are correct.

Which of the following are causes of evolutionary change? -natural selection -genetic drift -gene flow -mutation

All of them

Every few years a giant axe chops off the head of every person who is over 6 feet tall. How will this affect the human population? -The mutation rate will increase. -Gene flow will increase. -Genetic drift will play less of a role in the evolution of humans. -It will increase in number since shorter people use fewer resources than taller people. -Alleles that promote "tallness" will decrease in frequency.

Alleles that promote "tallness" will decrease in frequency.

_____ were the dominant vertebrate life form during the Paleozoic era. -Amphibians -Reptiles -Sponges -Dinosaurs -Mammals

Amphibians

We are living during the _____era. -Neogene -Cenozoic -Paleozoic -Paleogene -Mesozoic

Cenozoic

_____ were the dominant vertebrate life form during the Mesozoic era. -Dinosaurs -Mammals -Fish -Birds -Amphibians

Dinosaurs

Long necks make it easier for giraffes to reach leaves high on trees, while also making them better fighters in "neck wrestling" contests. In both cases, which kind of selection appears to have made giraffes the long-necked creatures they are today? -Disruptive selection -Stabilizing selection -Directional selection

Directional selection

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

False

True or false? Heterozygote advantage refers to the tendency for heterozygous individuals to have better fitness than homozygous individuals. This higher fitness results in less genetic variation in the population.

False

True or false? The evolution of different ecomorphs on the Caribbean islands is an example of stabilizing selection.

False

True or false? The last ice age produced many different species mainly because populations dispersed and colonized new habitats.

False

Which of the following are basic components of the Hardy-Weinberg model? -Allele frequencies, phenotype frequencies -Allele frequencies, number of individuals in the population -Allele frequencies in a subset of the population -Frequencies of two alleles in a gene pool before and after many random matings

Frequencies of two alleles in a gene pool before and after many random matings

Which of the following statements about adaptive radiation is correct? -Adaptive radiation occurs very slowly over time. -Adaptive radiation occurs in species that live in one habitat. -Adaptive radiation occurs in the presence of competitors. -Adaptive radiation occurs within a single lineage.

Adaptive radiation occurs within a single lineage

Why are the large finches now living on the Galápagos Islands different from the original source population from a nearby island? -All three answers are correct. -Genetic drift occurred in the two populations. -Natural selection favored individuals that were more fit in the new environment. -The separation of habitats reduced gene flow between the populations.

All 3 answers are correct

Which of the following evolutionary forces could create new genetic information in a population? -Nonrandom mating -Selection -Mutation -Genetic drift

Mutation

Seed plants first appeared during the _____. -Paleozoic -Triassic -Mesozoic -Cenozoic -Jurassic

Paleozoic

Why don't similar genotypes always produce the same phenotype? -Animals display different phenotypes dependent on diet, not genotype. -Parents alter their phenotypes and pass on this phenotype to progeny. -Phenotype is the product of genotype and many environmental influences. -Genetic variants of ADH enzyme produce the same phenotype.

Phenotype is the product of genotype and many environmental influences.

Animals first appeared during the _____. -Mesozoic -Paleozoic -Precambrian -Silurian -Cenozoic

Precambrian

Life arose during the _____. -Precambrian -Cenozoic -Triassic -Paleozoic -Mesozoic

Precambrian

The first prokaryotic cells appeared during the _____. -Jurassic -Cretaceous -Paleozoic -Triassic -Precambrian

Precambrian

Which of the following statements about reinforcement is true? -Reinforcement increases the number of intermediate phenotypes. -Reinforcement is a type of natural selection. -Reinforcement is also called dispersive selection. -Reinforcement decreases the morphological difference between two incipient species. Submit

Reinforcement is a type of natural selection.

Which of the following evolutionary forces consistently results in adaptive changes in allele frequencies? -Mutation -Inbreeding -Selection -There is no evolutionary force that results in adaptive changes in allele frequencies.

Selection

A paleontologist finds a new tyrannosaur in a site she is excavating, and wishes to date the fossil. What is the most likely method she will use? -She will determine the fossil's age by measuring the ratio of carbon-14 to carbon-12 in the fossil. -She will measure the amount of the radioisotope uranium-238 in the stratum where she found the tyrannosaur. -She will infer the age of the fossil by dating layers of volcanic rock above and below the stratum containing the fossil.

She will infer the age of the fossil by dating layers of volcanic rock above and below the stratum containing the fossil.

Compare sickle cell disease and malaria. -Sickle cell disease and malaria are both infectious diseases. -Sickle cell disease and malaria are both genetic diseases. -Sickle cell disease and malaria are both inherited diseases. -Sickle cell disease and malaria are both potentially lethal diseases.

Sickle cell disease and malaria are both potentially lethal diseases.

Which of the following statements supports the hypothesis of "an RNA world" on early Earth? -Some RNA molecules are important catalysts in modern cells. -The oldest known fossils contain traces of RNA molecules. -Single-stranded RNA molecules are linear and cannot form three-dimensional shapes.

Some RNA molecules are important catalysts in modern cells.

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

Tetraploid

What was the "oxygen revolution," which took place 2.3 billion years ago? -The "oxygen revolution" was the rapid increase in atmospheric oxygen that took place 2.3 billion years ago, dooming many prokaryotic groups. -The "oxygen revolution" was the rapid increase in atmospheric oxygen that took place 2.3 billion years ago, with the origin of plants. -The "oxygen revolution" was the rapid increase in atmospheric oxygen that took place 2.3 billion years ago, immediately preceding the origin of animals.

The "oxygen revolution" was the rapid increase in atmospheric oxygen that took place 2.3 billion years ago, dooming many prokaryotic groups.

A genetic change that caused a certain Hox gene to be expressed along the tip of a vertebrate limb bud instead of farther back helped make possible the evolution of the tetrapod limb. This type of change is illustrative of __________. -the influence of environment on development -heterochrony -paedomorphosis -a change in a developmental gene or in its regulation that altered the spatial organization of body parts

a change in a developmental gene or in its regulation that altered the spatial organization of body parts

gametic isolation example:

a coral's sperm can't fertilize another's eggs

Most modern animal phyla evolved during the _____ era. -Paleozoic -Cenozoic -Mesozoic -Precambrian

Paleozoic

Reptiles first appeared during the _____ era. -Paleozoic -Triassic -Mesozoic -Cenozoic -Jurassic

Paleozoic

Evolution works by __________. -converging on a particular phenotype -predicting the future -"tinkering" with existing structures -constantly increasing complexity -molding the environment to conform to the organisms living in it

"tinkering" with existing structures

How did Dr. Allison test his hypothesis that sickle cell disease was connected to malaria? Can be multiple answers. -He expanded his study area beyond Kenya to the rest of East Africa to see if malaria and sickle disease were connected. -He looked for the underlying genetic mechanism causing sickle cell disease. -He evaluated blood samples for malaria parasites and the presence of sickle cells. -He studied the way that the malaria parasite interacts with sickle cells. Submit

-He expanded his study area beyond Kenya to the rest of East Africa to see if malaria and sickle disease were connected. -He evaluated blood samples for malaria parasites and the presence of sickle cells.

How does Dr. Allison's work provide an example of natural selection in humans? Can be more than one answer. -Natural selection caused the sickle cell allele to appear in east African populations. -In areas without malaria, individuals with two sickle cell alleles reproduced at lower rates than those without sickle cell disease. -In areas with malaria, natural selection causes individuals to acquire the sickle cell allele as protection against malaria. -In areas with malaria, individuals with one sickle cell allele reproduced at higher rates than those with no sickle cell alleles.

-In areas without malaria, individuals with two sickle cell alleles reproduced at lower rates than those without sickle cell disease. -In areas with malaria, individuals with one sickle cell allele reproduced at higher rates than those with no sickle cell alleles.

If a person has two normal copies of the hemoglobin allele, which statements are true? Can be more than one answer. -The person is heterozygous at the hemoglobin locus. -The person is homozygous at the hemoglobin locus. -The person is protected against malaria. -The person is susceptible to malaria.

-The person is homozygous at the hemoglobin locus. -The person is susceptible to malaria.

Gene Flow

-a result of the movement of fertile individuals of their gametes -can introduce new alleles into a population's gene pool

morphological and phylogenetic

-accommodates asexual reproduction -species acceptance criteria can be subjective

prezygotic barriers include:

-behavioral isolation -mechanical isolation -habitat isolation -temporal isolation -gametic isolation

Natural Selection

-consistently causes a population to become better adapted to its environment -a result of differential success in reproduction -cannot cause a harmful allele to become more common

postzygotic barriers include:

-reduced hybrid fertility -reduced hybrid viability

Genetic Drift

-responsible for the bottleneck effect -responsible for the founder effect -causes the allele frequencies to fluctuate randomly

habitat isolation example:

2 fish species spawn at different depths

One out of 10,000 babies born in North America is affected by cystic fibrosis, a recessive condition. Assuming that the North American human population is in Hardy-Weinberg equilibrium for this trait, what percentage of the population is heterozygous for this trait? (Remember the equation for a population in Hardy-Weinberg equilibrium: p2 + 2pq + q2 = 1.) - 0.01% - 2% - 1%

2%

In human gamete production there is an average of _____ crossover events per chromosome pair. -10+ -9-10 -2-3 -5-6 -0-1

2-3

The Mesozoic era began approximately _____ million years ago. -4,600 -570 -251 -65 -25

251

The Precambrian time began at least _____ million years ago. -4,600 -570 -245 -65 -25

4,600

The Cenozoic era began approximately _____ million years ago. -4,600 -570 -245 -65 -25

65

Hoe many years ago did dinosaurs become extinct?

65.5 million years ao

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 -Diploid number of 12 -Diploid number of 6 -Haploid number of 12

Haploid number of 6

In 1949, Dr. Tony Allison observed a high frequency of Kenyans carrying the sickle cell allele in coastal areas and near Lake Victoria, but a lower frequency in the highlands. What did he hypothesize? -He hypothesized that malaria is a genetic disease. -He hypothesized that sickle cell disease was an environmental, not a genetic disease. -He hypothesized that malaria causes sickle cell disease. -He hypothesized that there was a connection between malaria and sickle cell disease.

He hypothesized that there was a connection between malaria and sickle cell disease.

A population of birds colonizes an area in which the insects upon which they feed live inside trees. Which of the following events accounts for an observed increase in average beak size in the bird population over time? -Increased fitness of large-beaked birds, leading to natural selection -Decreased fitness of small-beaked birds, creating a new species -Decreased fitness of the insects, allowing the birds to catch them more easily -Increased fitness of the large-beaked birds, creating a new species

Increased fitness of large-beaked birds, leading to natural selection

Which factor most likely caused animals and plants in India to differ greatly from species in nearby southeast Asia? -The species became separated by convergent evolution. -The climates of the two regions are similar. -India was a separate continent until 45 million years ago. -India is in the process of separating from the rest of Asia.

India was a separate continent until 45 million years ago.

In some populations, 1 in 500 people have sickle cell disease. What reason does the film give for why a potentially deadly, inherited disease is found at such high frequencies? -Individuals with two normal hemoglobin alleles get both sickle cell disease and are susceptible to malaria, so these alleles are eliminated from the population. -Individuals with two sickle cell alleles have an evolutionary advantage because they do not get sickle cell disease or get infected with malaria. -Individuals with one sickle cell allele are protected from malaria and do not have sickle cell disease, thus keeping the allele in the population. -Sickle cell alleles are new mutations and not enough time has gone by for these alleles to be eliminated from the population by natural selection.

Individuals with one sickle cell allele are protected from malaria and do not have sickle cell disease, thus keeping the allele in the population.

Which organisms are not examples of an adaptive radiation? -Horses and deer in the post-dinosaur age -Mammals and reptiles in the post-dinosaur age -Honeycreeper songbirds of the Hawaiian islands -Anolis lizards of the Caribbean

Mammals and reptiles in the post-dinosaur age

Workers from a nearby greenhouse accidentally introduce white flower seeds into the population's habitat. Mechanism: -natural selection -genetic drift -gene flow Effect on allele frequencies: -white allele increases -purple allele increases -change but not predictably

Mechanism: gene flow Allele Frequencies: white allele increases

A storm kills many plants at random. Mechanism: -natural selection -genetic drift -gene flow Effect on allele frequencies: -white allele increases -purple allele increases -change but not predictably

Mechanism: genetic drift Allele Frequencies: change but not predictably

A person uproots the 5 closest plants, which all happen to have white flowers. Mechanism: -natural selection -genetic drift -gene flow Effect on allele frequencies: -white allele increases -purple allele increases -change but not predictably

Mechanism: genetic drift Allele Frequencies: purple allele increases

Plants with purple flowers attract more insects, which pollinate the plants. Mechanism: -natural selection -genetic drift -gene flow Effect on allele frequencies: -white allele increases -purple allele increases -change but not predictably

Mechanism: natural selection Allele Frequencies: purple alleles increases

During an extreme heat wave, plants with white flowers survive better. Mechanism: -natural selection -genetic drift -gene flow Effect on allele frequencies: -white allele increases -purple allele increases -change but not predictably

Mechanism: natural selection Allele Frequencies: white allele increases

Dinosaurs went extinct during the _____. -Devonian -Precambrian -Mesozoic -Cenozoic -Carboniferous

Mesozoic

Flowering plants first appeared during the _____. -Devonian -Precambrian -Mesozoic -Cenozoic -Carboniferous

Mesozoic

Bony fish first evolved during the _____ . -Mesozoic -Paleozoic -Cenozoic -Precambrian -Cretaceous

Paleozoic

How can an allopolyploid plant become a biologically fit new species? -Nondisjunction event during mitosis -Nondisjunction event during meiosis -Allopolyploid plants cannot become biologically fit new species; they are always sterile. -Synapsis of homologous chromosomes

Nondisjunction event during mitosis

The fruit fly Drosophila melanogaster has an allele that confers resistance to DDT and similar insecticides. Laboratory strains of D. melanogaster have been established from flies collected in the wild in the 1930s (before the widespread use of insecticides) and the 1960s (after 20 years of DDT use). Lab strains established in the 1930s have no alleles for DDT resistance. In lab strains established in the 1960s, the frequency of the DDT-resistance allele is 37%. Which statement is correct? -The evolutionary fitness associated with the heritable trait of DDT resistance changed once DDT use became widespread. -Alleles for DDT resistance arose by mutation during the period of DDT use because of selection for pesticide resistance. -Resistance to DDT evolved in some fruit flies in order to allow them to survive.

The evolutionary fitness associated with the heritable trait of DDT resistance changed once DDT use became widespread.

What genotype frequencies are expected under Hardy-Weinberg equilibrium for a population with allele frequencies of p = 0.8 and q = 0.2 for a particular gene? -The expected genotype frequencies are 0.33, 0.33, and 0.33 for A1A1, A1A2 , and A2A2 , respectively. -The expected genotype frequencies are 0.25, 0.5, and 0.25 for A1A1, A1A2 , and A2A2 , respectively. -The expected genotype frequencies are 0.32, 0.64, and 0.04 for A1A1, A1A2 , and A2A2 , respectively. -The expected genotype frequencies are 0.64, 0.32, and 0.04 for A1A1, A1A2 , and A2A2 , respectively.

The expected genotype frequencies are 0.64, 0.32, and 0.04 for A1A1, A1A2 , and A2A2 , respectively.

What is the frequency of the A1 allele in a population composed of 20 A1A1 individuals, 80 A1A2 individuals, and 100 A2A2 individuals? -The frequency of the A1 allele is 0.3. -The frequency of the A1 allele is 0.5. -The frequency of the A1 allele is 0.7. -The frequency of the A1 allele is 0.1.

The frequency of the A1 allele is 0.3.

Which of the following statements is not a part of the Hardy-Weinberg principle? -If allele frequencies in a population are given by p and q, then genotype frequencies will be given by p 2, 2pq, and q 2 for generation after generation. -When alleles are transmitted according to the rules of Mendelian inheritance, their frequencies do not change over time. -The genotype frequencies in the offspring generation must add up to two. -Even if allele A1 is dominant to allele A2 , it does not increase in frequency.

The genotype frequencies in the offspring generation must add up to two.

Which of the following statements about the evolution of Anolis lizards in the Caribbean islands is true? -A crown ecomorph living on one island is always the same species as a crown ecomorph living on a neighboring island. -The genetic relatedness of ecomorphs was determined by comparing their nuclear DNA sequences. -The phylogeny of ecomorphs on a given island reveals that adaptive radiation has taken place. -Twig ecomorphs can jump very well

The phylogeny of ecomorphs on a given island reveals that adaptive radiation has taken place.

A subset of a population of birds leaves its habitat on the mainland and colonizes a nearby island. The birds, after a period of time, become reproductively isolated. The island sinks and the population of birds that lived on the island returns to its original habitat. Which of the following statements about these bird populations is true? -The birds were separated by a vicariance event. -The populations were sympatric while they diverged. -The populations will be able to interbreed even though they are different species. -The populations will not be able to interbreed because they are different species.

The populations will not be able to interbreed because they are different species.

Predict what will happen to the frequency of the sickle cell allele in areas where malaria has been eradicated. -The sickle cell allele frequency will not be affected. -The sickle cell allele will decrease in frequency. -The sickle cell allele will increase in frequency. Submit

The sickle cell allele will decrease in frequency.

Which statement correctly describes the role of chance in evolution? -An allele that increases evolutionary fitness cannot be lost from a population by chance events. -Evolution by natural selection proceeds by an accumulation of changes that occur by chance. -The ultimate source of new alleles is mutation, random changes in the nucleotide sequences of an organism's DNA.

The ultimate source of new alleles is mutation, random changes in the nucleotide sequences of an organism's DNA.

In a bell-shaped curve, the x-axis (horizontal direction) of the graph represents which of the following? -The number of individuals -The value of a particular characteristic; characteristics of an organism can include such traits as size and color. -Time

The value of a particular characteristic; characteristics of an organism can include such traits as size and color

Which of the following statements about autopolyploid individuals is true? -They can always produce fertile offspring. -They can never produce viable offspring. -They result from matings between individuals of different species. -They contain more than two haploid sets of chromosomes.

They contain more than two haploid sets of chromosomes.

True or false? A flood that separates a population of frogs onto opposite sides of a lake is an example of a vicariance event that may result in allopatric speciation.

True

True or false? Convergent evolution is said to have occurred if the mouse species on two islands with similar habitats are found to have similar characteristics even though they originated from different species that did not have these characteristics.

True

True or false? The Hardy-Weinberg model makes the following assumptions: no selection at the gene in question; no genetic drift; no gene flow; no mutation; random mating.

True

The largest unit within which gene flow can readily occur is a __________. -genus -hybrid -population -species

species

What was the main selective pressure behind the evolution of different Anolis lizard species in the -Caribbean? -Competitors -Conspecifics -Phylogeny -Specific ecological niches

specific ecological niches

gametic isolation definition:

sperm and egg are incompatible

Small Aristelliger lizards have difficulty defending territories, but large lizards are more likely to be preyed upon by owls. Which kind of selection acts on the adult body size of these lizards? -Directional selection -Stabilizing selection -Disruptive selection

stabilizing selection

Women often have complications during labor while giving birth to very large babies, whereas very small babies tend to be underdeveloped. Which kind of selection is most likely at work regarding the birth weight of babies? -Disruptive selection -Directional selection -Stabilizing selection

stabilizing selection

Which term is used to describe populations that live close enough to interbreed? -Allopatry -Speciation -Sympatry -Polyploidy

sympatry

Paleozoic era -the Cambrian explosion, first tetrapods and insects appear -oldest fossils of cells (prok) appear -dinosaurs evolve and radiate, origin of mammals -origin of Earth -oldest fossils of eukaryotic cells appear -humans appear. major radiation of pollinating insects

the Cambrian explosion, first tetrapods and insects appear

A researcher discovers a fossil of what appears to be one of the oldest-known multicellular organisms. The researcher could estimate the age of this fossil based on __________. -the amount of carbon-14 in the fossil -the amount of carbon-14 in volcanic layers surrounding the fossil -the amount of uranium-238 in volcanic layers surrounding the fossil -the amount of uranium-238 in the fossil

the amount of uranium-238 in volcanic layers surrounding the fossil