Bio 182 - Unit 18

If two species eat a different diet but one of the food sources is eliminated and both species are forced to eat the same foods, what change in the hybrid zone is most likely to occur?

Fusion is most likely to occur because the two species will interact more and similar traits in food acquisition will be selected.

When a population becomes separated by a geographic barrier, ______is disrupted, which makes it possible for the two populations to have different allelic frequencies at numerous genetic loci.

Gene flow

Which example would allow natural selection to take place?

In a mouse population, several alleles exist that produce differences in coat color.

Hybrid zone

area where two closely related species continue to interact and reproduce, forming hybrids

Which description is an example of a phenotype? a. A certain duck has a blue beak. b. A mutation occurred to a flower. c. Most cheetahs live solitary lives. d. both a and c

b. A mutation occurred to a flower.

What is the main difference between dispersal and vicariance? a. One leads to allopatric speciation, whereas the other leads to sympatric speciation. b. One involves the movement of the organism, and the other involves a change in the environment. c. One depends on a genetic mutation occurring, and the other does not. d. One involves closely related organisms, and the other involves only individuals of the same species.

b. One involves the movement of the organism, and the other involves a change in the environment.

Which of the following statements is false? a. Punctuated equilibrium is most likely to occur in a small population that experiences a rapid change in its environment. b. Punctuated equilibrium is most likely to occur in a large population that lives in a stable climate. c. Gradual speciation is most likely to occur in species that live in a stable climate. d. Gradual speciation and punctuated equilibrium both result in the divergence of species.

b. Punctuated equilibrium is most likely to occur in a large population that lives in a stable climate.

Which variable increases the likelihood of allopatric speciation taking place more quickly? a. lower rate of mutation b. longer distance between divided groups c. increased instances of hybrid formation d. equivalent numbers of individuals in each population

b. longer distance between divided groups

Which scientific concept did Charles Darwin and Alfred Wallace independently discover? a. mutation b. natural selection c. overbreeding d. sexual reproduction

b. natural selection

What is the main difference between autopolyploid and allopolyploid? a. the number of chromosomes b. the functionality of the chromosomes c. the source of the extra chromosomes d. the number of mutations in the extra chromosomes

b. the functionality of the chromosomes

Which of the following situations will lead to natural selection? a. The seeds of two plants land near each other and one grows larger than the other. b. Two types of fish eat the same kind of food, and one is better able to gather food than the other. c. Male lions compete for the right to mate with females, with only one possible winner. d. all of the above

c. Male lions compete for the right to mate with females, with only one possible winner.

Aneuploidy

condition of a cell having an extra chromosome or missing a chromosome for its species

Reinforcement

continued speciation divergence between two related species due to low fitness of hybrids between them

Dolphins and sharks have the same body shape even though they do not share a direct common ancestor. This is an example of

convergent evolution

Habitat isolation

reproductive isolation resulting when populations of a species move or are moved to a new habitat, taking up residence in a place that no longer overlaps with the other populations of the same species

Reproductive isolation

situation that occurs when a species is reproductively independent from other species; this may be brought about by behavior, location, or reproductive barriers

Sympatric speciation

speciation that occurs in the same geographic space

allopatric speciation

speciation that occurs via geographic separation

adaptive radiation

speciation when one species radiates out to form several other species

An error in meiosis occurs in a self-pollinating plant, giving rise to polyploid offspring. The offspring can self-pollinate to produce additional polyploid plants, but cannot interbreed with members of the parent population. This is an example of

sympatric speciation

In any species, every individual varies slightly from another individual Individuals that are 'most fit' in the context of natural selection are

the individuals that leave the most offspring.

Both Lamarck and Darwin proposed that species evolved, however their ideas differed with regard to

the mechanism for evolutionary change.

Behavioral isolation

type of reproductive isolation that occurs when a specific behavior or lack of one prevents reproduction from taking place

The first bird that evolved the ability to fly now had habitats never before available and soon branched out into many different species utilizing different resources, which is an example of

Adaptive radiation

In Australia, there are a number of species of marsupials that look very different from their ancestors. This diversification is where speciation occurs due to geographical separation.

Allopatric speciation

Two species of birds have different mating songs and so do not interbreed. This is an example of .

Behavioral isolation

Darwin argued that natural selection was the inevitable outcome, given the basic principles that operate in nature. What are these principles? Select all that apply.

Characteristics are passed from parent to offspring. More offspring are produced than are able to survive. Resources for survival and reproduction are limited

Although flowers have a common ancestor, they vary quite differently due to the environment and their specific pollinators. This is an example of

Divergent evolution

Which of the following fields of study provide evidence to support the theory of evolution? Select all that apply.

Embryology Anatomy Paleontology Biogeography Molecular biology

In a process called 'reinforcement', the hybrids produced between species are —— fit than the parents, which promotes the —— of the two species over time.

Less, divergence

Genetic diversity comes from which of the following sources? Select all that apply.

Mutations Sexual reproduction

Which of the following are examples of pre-zygotic barriers? Select all that apply.

Physical incompatibility for sexual intercourse between species Eggs can only be fertilized by sperm of the same species Two populations that reproduce at different times of the year Two populations that live in different habitats

What mechanism prevents fertilization when organisms attempt reproduction?

Prezygotic barrier

What are the mechanistic causes of genetic diversity in a population? Select all that apply.

Randoom mutation Sexual reproduction

In a population of fruit files, gene flow would be greatly if the flies find mates by hanging out on preferred foods in the same habitat of closely related species.

Reduced

In the gradual speciation model, speciation occurs ——. In the punctuated equilibrium model, speciation occurs —— and —— for long periods of time afterwards.

Slowly, quickly, remains unchanged

How does time after separation of a population affect speciation?

Speciation is directly proportional to time.

Some animals are referred to as "living fossils" because they have had a nearly unchanged appearance for tens or hundreds of millions of years. What does this suggest about these species?

They are well-adapted to a stable environment.

Which reproductive combination produces hybrids?

When members of closely related species reproduce.

Polyploidy

a condition in which a cell or organism has an extra set, or sets, of chromosomes.

An adaptation is

a trait that promotes the individual's survival and reproduction.

Which situation would most likely lead to allopatric speciation? a. flood causes the formation of a new lake. b. A storm causes several large trees to fall down. c. A mutation causes a new trait to develop. d. An injury causes an organism to seek out a new food source.

a. flood causes the formation of a new lake.

Dispersal

allopatric speciation that occurs when a few members of a species move to a new geographical area

Vicariance

allopatric speciation that occurs when something in the environment separates organisms of the same species into separate groups

Several birds are blown off course during a migration and begin a new population hundreds of miles from the parent population. Over time, the new population becomes reproductively isolated from the parent population. This is an example of

allopatric speciation.

Which convergent evolution? situation is most likely an example of convergent evolution? a. Squid and humans have eyes similar in structure. b. Worms and snakes both move without legs. c. Some bats and birds have wings that allow them to fly d. all of the above

d. all of the above

Temporal isolation

differences in breeding schedules that can act as a form of prezygotic barrier leading to reproductive isolation

A population of lizards was divided into two subpopulations by a river, and was beginning to form separate species. The river has now dried up. What type of trait variation could still maintain the groups as separate species even when they can intermingle?

elaborate courtship ritual

Speciation

formation of a new species

Even after speciation has occurred, the reproductive barriers between species could weaken in the 'hybrid zone' until the two species become a single species again. This process is called

fusion

Variation

genetic differences among individuals in a population

Charles Lyell, a geologist and friend of Charles Darwin, influenced Darwin's thinking with which idea?

geological forces shaping the earth happen over long periods of time with predictable uniformity

Species

group of populations that interbreed and produce fertile offspring

Adaptation

heritable trait or behavior in an organism that aids in its survival and reproduction in its present environment

Scientists observe that the specific shapes and sizes of the hand and arm bones differ between humans, dogs, and whales, but the overall construction of the hand and arm bones is similar between these species. Therefore, scientists can hypothesize that these bones are

homologous structures

Speciation is said to occur when

individuals from two recently branched populations cannot interbreed.

The biological definition of a species is a group of individuals that

interbreed and produce viable offspring

Adaptive radiation occurs when

members of a population occupy different habitats, leading to multiple speciation events

Punctuated equilibrium

model for rapid speciation that can occur when an event causes a small portion of a population to be cut off from the rest of the population

Gradual speciation model

model that shows how species diverge gradually over time in small steps

Hybrid

offspring of two closely related individuals, not of the same species

Which is most likely to survive, offspring with 2n+1 chromosomes or offspring with 2n-1 chromosomes?

offspring with 2n+1 chromosomes

Homologous structures

parallel structures in diverse organisms that have a common ancestor

Vestigial structure

physical structure present in an organism but that has no apparent function and appears to be from a functional structure in a distant ancestor

Allopolyploid

polyploidy formed between two related, but separate species

Autopolyploid

polyploidy formed within a single species

Gametic barrier

prezygoticbarrieroccurringwhencloselyrelatedindividualsofdifferentspeciesmate,butdifferencesin their gamete cells (eggs and sperm) prevent fertilization from taking place

Divergent evolution

process by which groups of organisms evolve in diverse directions from a common point

convergent evolution

process by which groups of organisms independently evolve to similar forms

Natural selection

reproduction of individuals with favorable genetic traits that survive environmental change because of those traits, leading to evolutionary change

Postzygotic barrier

reproductive isolation mechanism that occurs after zygote formation

Prezygotic barrier

reproductive isolation mechanism that occurs before zygote formation