Biology 182 Exam 2

Prezygotic isolating mechanisms: A. reduce the fitness of hybrid offspring B. generally prevent individuals of different species from producing zygotes C. are found only in animals D. are found only in plants E. are observed only in organisms that reproduce asexually

B. generally prevent individuals of different species from producing zygotes

A species of seagull migrates into the region in which a crab population lives. This type of seagull has never lived in this particular environment before. The seagulls eat crabs, and begin to prey on the crab population. The smallest of the crabs are able to successfully hide under rocks and avoid being eaten by the seagulls. The largest of the crabs are too big to fit inside of the seagulls' beaks, so the seagulls learn not to try to eat them. Over time, the seagulls prey on the medium sized crabs, and only the smallest and largest members of the initial crab population survive. Which type of selection does the described situation model? A. Disruptive B. Directional C. Divergent D. Random

A. Disruptive

One species of organisms living in the same valley begin to diverge from each other over time and eventually two distinct species emerge that no longer mate with members of the other group. What type of speciation is this? A. Sympatric speciation B. Allopatric speciation

A. Sympatric speciation

In a certain population, disruptive selection is occurring. In this population, which is most likely to survive? A. organisms w/ average traits B. organisms w/ extreme traits C. organisms that sexually select D. organisms that are small

A. organisms with extreme traits

Which of the following is an effect of gene flow? Write ALL that apply. A. Decreased genetic variation B. Increased genetic variation C. Increased extinction D. No speciation

B. Increased genetic variation D. No speciation

Which of the following describes how parapatric speciation differs from peripatric speciation? A. Parapatric speciation and peripatric speciation do not differ B. There can be contact between the two diverging populations in parapatric speciation C. Parapatric speciation is a subgroup of peripatric speciation

B. There can be contact between the two diverging populations in parapatric speciation

Rabbits are important grazers, maintaining some important grassland habitats. If another catastrophe were to reduce rabbit populations what would happen? A. Important grassland butterflies would be lost B. There would be more grass for the surviving rabbits C. The grassland would be invaded by trees and shrubs D. All of the above

B. There would be more grass for the surviving rabbits

Cheetahs nearly became extinct but recovery efforts managed to save them. Now, most cheetahs are genetically identical. This is due to: A. gene flow B. bottleneck effect C. selective migration D. random mating

B. bottleneck effect

In a population of organisms, certain individuals pass on their alleles with more frequency than other individuals. What type of selection would increase or decrease a trait, such as size, in an entire population over generations? A. stabilizing selection B. competition C. directional selection D. speciation E. disruptive selection

C. directional selection

Speciation occurs when: A. two populations become geographically isolated B. one population moves to a different area C. enough differences accumulate between two populations that they can no longer interbreed D. gene mutations accumulate

C. enough differences accumulate between two populations that they can no longer interbreed

Gene Flow Defined

Cause: Immigration Random Increased variation Decreased speciation Ex: Chihuahua breeding w/ Dachshund; dog from one specific population breeding w/ dog from another specific population.

two varieties of monkeys, one dark and one light, lived on an island. The dark ones lived in the trees while the light ones lived on the ground. One day, these big birds swooped down and picked up the dark ones from the trees. The light ones were able to hide on the ground. Eventually, all the dark ones got picked off because they couldn't hide. Is this example of natural selection, genetic drift, or gene flow?

Natural selection

A scientist measures the circumference of acorns in a population of oak trees and discovers that the most common circumference is 2 cm. There are very few acorns with circumferences of 3 cm or circumferences of 1 cm. Only the 2 cm circumference acorns survive. Disruptive, Stabilizing, Directional

Stabilizing

Women often have complications during labor while giving birth to very large babies, whereas very small babies tend to be underveveloped. As a result, medium sized babies are the ones that end up surviving to adulthood. Disruptive, Stabilizing, Directional

Stabilizing

Juvenile baboons spend time babysitting younger baby baboons in their troop. This behavior comes at a cost (lost time foraging or watching out for predators). Which of the following possible explanations describes a byproduct benefit of this cooperative behavior? a) Babysitting improves offspring survival, leading to a larger troop, and all baboons have better survival in large troops b) Baboons only babysit their siblings, nieces, and nephews c) Juveniles are more likely to help babysit for parents who babysat for them when they were younger d) Adult baboons withold food from juveniles who don't babysit

a) Babysitting improves offspring survival, leading to a larger troop, and all baboons have better survival in large troops

All the nonliving parts of an ecosystem are referred to as: a. the community b. biotic factors c. abiotic factors d. biomes

c. abiotic factors; water, temp, nutrients, salinity

Peripatric speciation is a subgroup of which of the following types of speciation? A. Parapatric B. Peripatric C. Allopatric D. Sympatric

C. Allopatric; peripatric: a small portion of the population becomes genetically isolated from the main population; ex, founder effect

A 'habitat' is: A. A place to buy furniture and furnishings B. The same as an ecosystem C. A particular area inhabited by plants and animals D. The number of different organisms living in a specific area

C. A particular area inhabited by plants and animals

In order for evolution to take place, there must be variation between A. populations B. species C. kingdoms D. individuals

D. individuals

Female guppies tend to choose brightly colored mates. Over time, the populaton of guppies becomes more colorful. This is an example of: A. kin selection B. natural selection C. gamete compatibility D. sexual selection

D. sexual selection

A population of Madagascar hissing cockroaches lives in a woodpile. The cockroaches are eaten by lizards. Because the lizards have small heads, the lizards are unable to eat the very largest adult cockroaches, and instead prey upon small and medium sized adults. Over time, only the large headed lizards survive. Disruptive, Stabilizing, Directional

Directional

A population of birds with various size beaks eats seeds. Small seeds can be eaten by birds with small beaks. Larger, thicker seeds can only be eaten by birds with larger, thicker beaks. During a drought, only large thick seeds exist so only the large, thick-beaked birds survive. Disruptive, Stabilizing, Directional

Directional

Which of the following is false of sympatric populations? A. Sympatric populations are geographically overlapping B. Sympatric populations diverge due to behavioral isolation C. Sympatric populations show differences in body structure D. Sympatric populations may form hybrids E. Sympatric populations diverge due to geographic isolation

E. Sympatric populations diverge due to geographic isolation

Freshwater habitats are independent of terrestrial habitats. T/F

False

A fisherman who caught a red-colored fish decided to release it, but did not return it into its original lake and put it into one with only green-colored fish. Both varieties end up interbreeding with each other. Is this example of natural selection, genetic drift, or gene flow?

Gene flow

Pre-zygotic: Habitat isolation

Location: forest; mountains

Mutation is often said to be "undirected". What does this mean?

Mutation is not directed toward the adaptive needs of the organism

Pre-zygotic: temporal Isolation

Not all organisms mate at the same time; day/night; spring/winter

convergent evolution

Process by which unrelated organisms independently evolve similarities when adapting to similar environments (birds & bats)

Small lizards have difficulty defending territories so they end up dying out. Large lizards are more likely to be preyed upon by owls. Over time, only medium sized lizards end up surviving. Disruptive, Stabilizing, Directional

Stabilizing

An ecosystem consists of biotic and abiotic factors. T/F

True

An organism's niche includes its habitat. T/F

True

Clearing a forest would reduce the amount of energy available to the consumers. T/F

True

Cutting down trees in a forest alters the habitat of the organisms living in the forest. T/F

True

While an understanding of the interactions between organisms and their environment was very important to early hunter and gatherer humans, it is even more important today because humans are having significant effects on the environment. T/F

True

sympatric speciation

Two groups of identical species lives in identical geographical areas, they evolve where they can no longer interbreed, so they're considered to be different species.

Which of the following are adaptations for avoiding unfavorable conditions? a. migration b. dormancy c. body temperature regulation d. all of the above

d. all of the above

Which of the following would not be included in a description of an organism's niche? a. its trophic level b. the humidity and temperature it prefers c. when it reproduces d. its number of chromosomes

d. its number of chromosomes

Founder events may lead to rapid speciation because of a. differences in natural selection on the new population versus the original population. b. genetic differences due to genetic drift. c. enhanced gene flow between the new population and the original population. d. all of the above. e. a and b only

e. a and b only

Which of the following would be considered an example of a postzygotic isolating mechanism? a. incompatible genitalia b. different mating seasons c. incompatible gametes d.mountain range separating two populations e. fertilized egg fails to develop normally

e. fertilized egg fails to develop normally

mutation

generates differences in alleles that then translates to differences in proteins

Species

interbreed and produce fertile offspring

What causes new genetic variation at a particular site in the DNA sequence? A. Recombination B. Sexual reproduction C. mutational changes in DNA

mutational changes in DNA

When the giant Metroid hit the earth 65.5 million years ago, the land reptiles were wiped out because of lack of food, whereas marine reptiles survived because they were able to get food from water. Is this example of natural selection, genetic drift, or gene flow?

natural selection

Which of the following would be a biotic (living organism that shapes its environment) factor in an ecosystem? a. bacteria b. soil c. temperature d. rainfall

a. bacteria

In which of the following is variation reduced in the population: a.Stabilizing Selection b.Disruptive Selection c.Directional Selection d.None of the above

a.Stabilizing Selection

Which of the following reasons could explain why sympatric speciation is more common in plants than in animals? A. Plants are less prone to chromosomal abnormalities B. Animal populations move around too much C. Plants are more likely to be able to self-fertilize D. Plants can become geographically isolated more easily

C. Plants are more likely to be able to self-fertilize; b/c sympatric speciation means speciation within the same geographical region

What model of evolution suggests that species stay the same for a long period of time, then change abruptly due to mutations in key genes? A. good genes hypothesis B. phyletic speciation C. punctuated equilibrium D. marginal fossilization

C. punctuated equilibrium

If two species of holly flower different months, their gene pools may be kept separate by: A. mechanical isolation B. ecological isolation C. temporal isolation D. behavioral isolation E. postzygotic isolation

C. temporal isolation; different breeding times either during diff times of day or diff time of year.

Which of the following can lead to genetic divergence? Select All that apply. Founder effect Gene Flow Natural selection Mutation Genetic Drift

Founder effect Natural selection Mutation Genetic Drift

Homology

Similarity in characteristics resulting from a shared ancestry.

What is the definition of a species?

A population of animals that can interbreed and produce fertile offspring.

Wha t is a vestigial trait? Give an example.

A trait that is no longer needed/used but was inherited from a common ancestor. Examples: wisdom teeth, appendix, facial hair, ear muscles, etc.

The wing structures of bats and birds are examples of which of the following? A. Convergent evolution B. Divergent evolution C. Allopatric evolution D. Genetic drift E. Homology

A. Convergent evolution; Bird wings and bat wings arose independently of one another, as they do not share a common ancestor with wings

Which of the following best defines sympatric speciation? A. Formation of two distinct species within the same geographic location B. Populations diverge due to geographic location C. A population divides into two adjacent niches with contact and minimal genetic exchange D. Isolated peripheral populations cease genetic exchange

A. Formation of two distinct species within the same geographic location

Which of the following best describes the initial speciation event in allopatric speciation? A. Geographic isolation B. Isolated niche population C. Partially isolated population D. Genetic polymorphism

A. Geographic isolation

Which of the following would be considered an example of conditions leading to allopatric speciation? A. Separation of a population of lake fish by a drought resulting in a sand bar dividing the lake B. A differentiation in preferred food source by members of a population within a given habitat C. Females selecting mates based on courtship displays D. Combat amongst males to show superiority for mating with females

A. Separation of a population of lake fish by a drought resulting in a sand bar dividing the lake

Prezygotic isolating mechanisms ensure that: A. hybrids are never conceived or born B. hybrids are not fertile C. hybrids are more likely to survive D. genes do not mutate and affect the entire population

A. hybrids are never conceived or born

Which of the following is NOT necessary for evolution to occur? A. nonrandom mating B. variation w/in the species C. inheritance of characteristics D. all of these are necessary

A. nonrandom mating

Asexual vs Sexual Reproduction Fitness

Asexual Fitness > Sexual b/c 2x more offspring through asexual reproduction; sexual organisms must produce twice as many offspring to receive same fitness as asexual organism receives

Which of the following is an example of sympatric speciation? A. Two populations of mice compete for the same resources in a forrest. After several years, the two populations of mice begin mating with one another. B. A population of bears prefers red berries. At some point, part of the population develops a preference for blue berries. Eventually, the two groups no longer interact to the point that they no longer breed. C. A population of butterflies is split when a housing development is built, splitting their habitat in two. Butterflies from each group rarely go to the opposite side of the development, so opportunities for breeding between the groups are very limited. D. None of these

B. A population of bears prefers red berries. At some point, part of the population develops a preference for blue berries. Eventually, the two groups no longer interact to the point that they no longer breed.

A population of sloths lives in a forest. New trees start to take over the forest, and these new trees make it easier for sloths with longer arms to climb them. The sloths with longer arms survive longer and produce more offspring than their shorter-armed counterparts. The sloths with the shortest arms die quickly and do not produce many offspring. Over time, the average arm length of the sloth population increased. Which type of natural selection is modeled in the described scenario? A. Stabilizing B. Directional C. Disruptive D. Divergent E. Convergent

B. Directional

What is required for sympatric speciation to occur? A. A limited separation of members of a population, followed by reintroduction back into the parent population B. Emergence of a reproductive barrier C. Geographic separation of a population D. Continuous gene flow between populations

B. Emergence of a reproductive barrier

In a population of woolybeasts, individuals with long snouts tend to survive better on an island that has burrowing termites. Over time, the woolybeast population consists of individuals with extremely long snouts. This is an example of: A. stabilizing selection B. directional selection C. disruptional selection D. allopatric speciation

B. directional selection

A gene pool consists of all the A. genetic variations of a species B. genetic variations in a population C. adaptations within a species D. different organisms in a population E. adaptations within an environment

B. genetic variations in a population

Two populations of a species of squirrel are geographically isolated from each other. Although they have the same population density, one population is significantly larger in number than the other. A new bacterial disease, which is easily spread and extremely virulent, affects both populations at the same time. Which if the following is the best prediction of how the new disease will affect the two populations? A. The two populations will be equally affected, because the ability to trigger the immune response is randomly distributed among all squirrels of that species. B. The larger population will be less affected by the disease than the smaller population, because the mutation rate of the larger population is higher than the mutation rate of the smaller population. C. The smaller population will be more affected than the larger population, because the smaller population has less genetic variation that the larger population. D. The smaller population will be less affected than will the larger population, because the smaller population exhibits more genetic drift than the larger population exhibits.

C. The smaller population will be more affected than the larger population, because the smaller population has less genetic variation that the larger population.

Any characteristic that can help an organism survive and/or reproduce can be called a(n): A. gene B. species C. adaptation D. specialization

C. adaptation

In Amish populations, the incidence of a certain type of dwarfism is much higher than those of other populations. What principle explains this? A. founder effect B. genetic drift C. both of these D. neither of these

C. both of these

An animal breeder, attempting to cross a llama with an alpaca for finer wool, found that the hybrid offspring rarely lived more than a few weeks. This outcome probably resulted from: A. genetic drift B. prezygotic reproductive isolation C. postzygotic reproductive isolation D. sympatric speciation E. genetic recombination

C. postzygotic reproductive isolation

Genetic Drift Defined

Cause: Random Event Random Event Decreased Variation Increased Extinction Ex: short tailed vs long tailed monkeys

Endotherms (Humans) Thermoregulation Cost Constraint

Cost: Have to burn up more energy, eat more for metabolism; always thermoregulating, even when cost outweighs benefit Constraint: Starvation, not enough resources to supply their energy stores.

Ectotherms (reptiles and amphibians) Cost Constraint

Cost: Risk because of predators Constraint: not being able to relocate...what if there are predators in new location Have to do mini cost benefit analysis--relocate so their cells don't die/freeze and RISK getting eaten. Potential cost they would pay to stay warm (cost in form of risk)

A population of rabbits lives in a forest in the Southeastern United States. A large group of rabbits is cut off from the population when a six-lane highway is built through the forest. Over many generations, the large group of rabbits begins to develop darker fur in response to the dominant foliage on one side of the highway. When rabbits from the two populations are brought together, they no longer reproduce with each other. What kind of speciation does this represent? A. Sympatric B. Founder effect C. Temporal D. Allopatric

D. Allopatric

behavior that maximizes fitness-gets what you need in the shortest time possible A. Optimality Modeling B. Rate Maximization C. Game Theory D. Optimal Behavior

D. Optimal Behavior

If the gametes of two organisms are not combining, which of the following is most likely occurring? A. Extinction B. Mutation C. Hybridization D. Reproductive Isolation

D. Reproductive Isolation

Members of different species do not normally produce offspring due to: A. differing courtship rituals B. varying breeding times C. gamete incompatibility D. all of these

D. all of these

If a cow develops a preference for eating white four o'clock flowers and ignoring pink and red four o'clock flowers, what type of selection is being demonstrated?

Directional-One extreme is favored, the other is selected against-white eaten, red are not.

post-zygotic zygote mortality

Egg is fertilized, but zygote does not develop

Post-zygotic Hybrid Sterility

Grows into Sterile mature adult

pre-zygotic: mechanical isolation

Morphological differences can prevent successful mating; elephant /mouse

male birds that could build prettier and stronger nests were preferred over one's that couldn't. Is this example of natural selection, genetic drift, or gene flow?

Natural selection

Several species of fireflies are active on the same summer nights in the same fields. Males and females recognize one another by their distinctive flashing patterns. This is an example of what kind of reproductive isolation?

Pre-zygotic, Behavioral Isolation

Asexual vs Sexual Reproduction Cost

Sexual Cost> Asexual b/c cost of courting and looking for mate; time and energy

Asexual vs Sexual Reproduction Variation

Sexual Variation> Asexual b/c alleles coming from each parent; allows for species to adapt to new environments due to variation, gives them survival advantage; diseases less likely to affect all individuals in population. Asexual variation only occurs if random mutation occurs in organism's DNA that is passed on to offspring.

phyletic speciation

Speciation occurs through the gradual accumulation of changes in a lineage over time until the descendants are sufficiently distinct from the original ancestor to be considered a new species.

Pre-zygotic gametic isolation

Sperm of one species may not be able to fertilize eggs of another species

Female birds that lay close to the optimum number of eggs have the most surviving offspring. Those that lay fewer or more eggs have lower relative fitness. Disruptive, Stabilizing, Directional

Stabilizing

Starlings produce an average of five eggs in each clutch. If there are more than five, the parents cannot adequately feed the young. If there are fewer than five, predators may destroy the entire clutch. As a result, five eggs becomes the most common clutch size. Disruptive, Stabilizing, Directional

Stabilizing

Heritability

The proportion of variation among individuals that we can attribute to genes. The heritability of a trait may vary, depending on the range of populations and environments studied.

Most common way speciation occurs:

Through allopatric ("other" "homeland") speciation: geographic separation

The types and numbers of species in a given area is most greatly determined by the area's: a. biotic factors b. precipitation c. climate d. biodiversity

a. biotic factors

Which of the following would not be included in a description of an organism's niche? a. its trophic level b. its color c. the humidity it prefers d. when it reproduces

b. its color

Abiotic factors affect an ecosystem and include all of these except the a. quantity and quality of water b. nitrogen-fixing bacteria c. amount of light available d. quantity of minerals

b. nitrogen-fixing bacteria

A major mechanism of speciation in plants but not animals is a. anagenesis. b. polyploidy. c. hybrid breakdown. d. genetic changes that alter the o rganism's niche. e. both a and d.

b. polyploidy.

Which of these statements correctly describes the role of searching time in optimal diet theory? Assume the foraging predator can choose from a highvalue prey A and low-value prey B. A and B occur at different frequencies in the environment, so it may take different average times to find the next A or B item. a) Predators will only feed on A regardless of search time. b) If it takes too long to search for A, predators may switch to eating only B instead. c) If it takes too long to search for A, predators may eat B as well, if B is more abundant than A. d) If it takes too long to search for A, predators may eat both A and B whenever either is encountered.

d) If it takes too long to search for A, predators may eat both A and B whenever either is encountered.

Hybrid breakdown occurs when species hybrids a.do not develop past the early embryonic stages. b. have a reduced life span. c. are infertile. d. are fertile but produce offspring with reduced viability and fertility. e. produce offspring that only express the traits of one of the original species

d. are fertile but produce offspring with reduced viability and fertility.

The concept of punctuated equilibrium su ggests that a. the rate of evolution is constant,with short time periods of no evolutionary change. b. evolution occurs gradually over time. c. small genetic changes accumulate over time to allow for phenotypic change and speciation. d. long periods of little evolutionary change are interrupted by short periods of major evolutionary change. e. both b and c

d. long periods of little evolutionary change are interrupted by short periods of major evolutionary change.

sympatric

geographically overlapping

allopatric

geographically separate

Define "niche" and "competition". Give examples of each.

A "niche" is the role or function of an organism in its environment. "Competition" is a negative interaction between organisms where they are competing for the same limited resource (ie food or shelter). Examples: a predator's "niche" is often to control prey populations. "Competition" occurs between tigers who occupy and hunt in overlapping territories.

Genetic Drift

A change in the allele frequency of a population as a result of chance events rather than natural selection.

Darwin surmised that a few finches migrated to the Galapagos from the mainland. These finches gave rise to the many species of finches on the islands today. This is an example of: A. adaptive radiation B. phyletic speciation C. founder effect D. industrial melanism

A. adaptive radiation

A population of birds is blown by a storm to an island off the mainland. The island has very few trees, and the bird population on the island develops new nesting behaviors. Mainland birds nest in trees, island birds nest on the ground. After a long period of time, the island birds are reunited with the mainland birds, it is observed that the two populations can no longer interbreed. This is an example of: A. sympatric speciation B. allopatric speciation C. nonrandom mating D. all of these

B. allopatric speciation

Which scenario is an example of allopatric speciation? A. Hawks with thin, sharp beaks primarily eat fish and small rodents, while hawks with larger beaks tend to eat reptiles and larger birds B. Certain members of a human population have more offspring than others C. A river separates members of a squirrel population that used to occupy the same geographical area D. A disease ravages a large fox population, killing all members that did not have a genetic resistance to the disease E. Houseflies from a certain region migrate and interbreed with a different housefly population in a neighboring area

C. A river separates members of a squirrel population that used to occupy the same geographical area

There was once a population on planet M311, called the Freg, who lived on a planet not unlike Earth. At the height of the Fregs technology and evolution, a collection of asteroids bombarded the planet and the devastation was so great that the planet was split in two, as was the Freg population. Much of the Freg population died, but many still survived on both pieces of M311. As time progressed following the catastrophe, the genetic structure of the Freg populations began to differ from each other since they were no longer reproducing with each other. What is this process called? A. None of these B. Evolutionary segregation C. Allopatric speciation D. Sympatric speciation E. Genetic conversion

C. Allopatric speciation

Which of these animals would be least likely to undergo allopatric speciation? A. Snake B. Raccoon C. Bird D. E. coli E. Prehistoric human

C. Bird

There was a population of winged and non-winged creatures. One day, a volcano erupted and non-winged died because they could not fly away. This is: A. Gene flow B. Genetic Flow C. Natural Selection D. Geographic Isolation

C. Natural Selection

What is the most likely cause that a green haired individual is born in a brown haired population? A. natural selection B. genetic drift C. mutation D. reproductive isolation

C. mutation

Speciation through Meiosis Error

Diploid Plant (2n) through meiosis error makes a tetraploid plant (4n) that can only reproduce w/ other tetraploid plants. If tetraploid plant reproduces w/ diploid plant, they will produce a non-viable or infertile triploid plant.

Black rabbits (BB) and white rabbits (bb) are both able to survive because they can camouflage into the white and black rocks in their environment. However, the intermediate gray rabbits (Bb) do not survive. This results in only white and black rabbits. Disruptive, Stabilizing, Directional

Disruptive

Seed cracker birds have either large beaks or small beaks. They do not have medium sized beaks because medium sized beaks do not allow for adequate cracking of seeds. Disruptive, Stabilizing, Directional

Disruptive

How does studying embryos give us clues to which organisms are most closely related? Give an example.

Embryos that have the most similarities throughout gestation are most likely more closely related. For example, the rabbit and the human are almost identical up until the third trimester.

a lake once had white fish in it separated into 2 lakes when water levels went down between then. There were some genetic mutations in each smaller lake, and when the water levels went up and the 2 lakes became one again, both variations could still interbreed. Is this example of natural selection, genetic drift, or gene flow?

Gene Flow

pre-zygotic, behavioral isolation

Mate selection; birds sing; rabbits dance

adaptive radiation

the diversification of a group of organisms into forms filling different ecological niches (Darwin's finches)

A physical barrier separates a single species, causing two separate populations to form. Over time these two populations adapt to their environments. Eventually, these two populations are no longer able to successfully reproduce with each other. This is known as __________. A. allopatric speciation B. peripatetic speciation C. sympatric speciation D. parapatric speciation

A. allopatric speciation

Mt. Vesuvius erupted and wiped out the Italians who lived in the area, but there were Italians in other cities that were not affected and survived. Is this example of natural selection, genetic drift, or gene flow?

Genetic Drift

Post-zygotic Hybrid Inviability

Hybrid embryo dies before birth; sometimes, offspring develops fully w/ mixed traits, forming a frail, often infertile adult

allopatric speciation

When a new species evolves in geographic isolation from its ancestor; there would now be two species where there was formerly one

In which of the following are individuals of intermediate phenotypes are lost from the population? a.Stabilizing Selection b.Disruptive Selection c.Directional Selection d.None of the above

b.Disruptive Selection

Divergent Evolution

evolution of one or more closely related species into different species; resulting from adaptations to different environmental conditions

heterozygote advantage

individuals who are heterozygous at a particular locus have greater fitness than do both kinds of homozygotes