Biology Exam III 109
Mass extinctions create conditions that promote _____.
adaptive radiation
The appearance of an evolutionary novelty promotes _____.
adaptive radiation
Consider a population of birds living on an island. Suppose several individuals of the same species from a different population migrate to the island. Due to the arrivial of the new birds, the allele frequencies in the original population change.
gene flow
A change in the gene pool due to chance results in ________.
genetic drift
The evolution of populations due to chance is
genetic drift.
The tailbone of a human ________ to the tail of a monkey.
is homologous to
A process in which organisms with certain inherited characteristics are more likely to survive and reproduce than individuals with other characteristics is called __________.
natural selection
Animals that possess homologous structures probably __________.
shared a common ancestor
Darwin thought that significant evolution was much too slow to be witnessed in a human lifetime. Recent experiments by biologists have _____.
shown that some populations can evolve quite rapidly, with important changes occurring over several generations in the laboratory
The process of speciation starts with a single species. It often involves the following steps: (1) two populations become physically separated from one another by a barrier to dispersal and stop exchanging genes; (2) the populations experienceindependent evolutionary changes; (3) changes in one or both populations result in development of reproductive isolating mechanisms that prevent interbreeding; further changes in geography may bring the groups back into contact. When do you officiallyhave two separate species?
step 3
The naming and classifying of organisms is called _____.
taxonomy
The science of naming, identifying, and classifying organisms is called ________.
taxonomy
Eastern and western spotted skunks breed at different times of the year. Therefore, they are prevented from interbreeding by _____ isolation.
temporal
Sympatric speciation is __________.
the appearance of a new species in the same area as the parent population
The population of American bison used to number in the millions. Hunting and other problems greatly decreased the number of bison to about 1,000. Today, the numbers are recovering to estimates of more than 200,000 bison. This crash in the population of bison and recent recovery is an example of __________.
the bottleneck effect
Which anatomical features are homologous?
the forelimb of a dog and the forelimb of a cat
Imagine that a new population of humans is established on a previously uninhabited planet from ten randomly selected people in your biology class. Over thousands of years, the descendants of those ten people reproduce and prosper, but they do not reflect well the diversity of humans on Earth. This reduction in genetic diversity in the establishment of the population is an example of __________.
the founder effect
_____ is rapid speciation under conditions in which there is little competition.
Adaptive radiation
In a species of snail, dark-shelled individuals are better hidden from bird predators in the shady forest, while light-shelled individuals are better hidden in well-lit brushy edge areas. If there were no areas of intermediate brightness in this habitat,which type of selection would act on shell color in these snails?
Disruptive selection
Which is a phenomenon that can result from directional selection?
There is an increase in the number of giraffes with long necks in areas of Africa where low-growing trees have died.
Natural selection is best described as _____.
a filtering process that fine-tunes the traits of populations by sorting among existing, randomly produced variations
Natural selection can be defined as ________.
a process in which organisms with certain inherited traits are more likely to survive and reproduce than individuals with other traits
The different finch species found on the Galápagos Islands probably arose as a result of _____.
adaptive radiation
Feathers either play a role, or may have played a role, in _____.
all of these
HIV has become an important source of mortality for humans. If AIDS persists as a major factor for humans for many generations in the future, natural selection theory predicts that _____.
any heritable traits that help humans survive and reproduce in the presence of AIDS should become more frequent over time
Which of the following is not a kingdom included in the domain Eukarya?
bacteria
Homology is evidence of ________.
common ancestry
In evolutionary terms, an organism's fitness is measured by its __________.
contribution to the gene pool of the next generation
Analogous structures are evidence of ________.
convergent evolution
Which mechanism for evolution was proposed by Lamarck?
evolution by inheritance of acquired characteristics
A period of mass extinction is often followed by ________.
explosive diversification
Which explanation is most likely for a particular human population with a higher incidence of polydactyly (extra fingers/toes) than the human population as a whole?
founder effect
Which of the following are causes of evolutionary change? Select all that apply.
gene flow genetic drift mutation natural selection
In a population with brown and green alleles for color, genetic drift
has more effect on the evolution of a small population.
Similarity resulting from common ancestry is known as ________.
homology
The founder effect differs from a population bottleneck in that the founder effect ________.
involves the isolation of a small colony of individuals from a larger population
In _____ isolation, it is physically impossible for two species to mate with each other, often because their genitalia do not fit together properly.
mechanical
Generation-to-generation change in the allele frequencies in a population is _____.
microevolution
Color is an inherited trait in beetles. If brown beetles move into a population from a nearby island, which of the following statements is correct?
Gene flow causes the frequency of the brown allele to increase.
Biological species consist of groups of ________.
populations
Remember that color is an inherited trait in beetles. Which of the following is an example of natural selection?
Green beetles leave more offspring than brown beetles because they are better at finding food.
Natural selection __________.
relies on variation among individuals in a population
________ introduced a system for grouping species into a hierarchy of categories.
Linnaeus
The common house mouse species, Mus musculus, has the following taxonomic classification: Mus, Muridae, Rodentia, Mammalia, Chordata, Animalia, Eukarya. Which part of the name is the Family?
Muridae
Why is natural selection considered to be the most important mechanism of microevolution?
Natural selection is the only mechanism that consistently leads to adaptive changes in populations.
Which statement is TRUE?
Natural selection works on variation already present in a population.
A biologist spends her summer break collecting frogs from a remote jungle in Peru. She discovers two distinct color forms that could be variants of a single species or two different species. What would be the most direct test of their species statusunder the biological species concept?
Observe mating in the natural environment of the two groups. If the two forms do not mate with each other, they are different species.
Small lizards have difficulty defending their territory, but large lizards are more likely to be preyed upon by owls. Which type of selection would act on body size in these lizards under these conditions?
Stabilizing selection
The human immune system cannot effectively suppress the HIV virus on its own. What key feature of HIV makes it so hard to beat?
The HIV virus has an extremely high rate of mutation.
Plate tectonics has been responsible for instances of all of the following EXCEPT ________.
sympatric speciation
If color is an inherited trait in beetles, and birds are more likely to eat brown beetles than green beetles,
the frequency of the green allele will increase.
Which of the following is a true statement?
Species with nucleotide sequences that match closely share a recent common ancestor.
Imagine that four people are infected with HIV from a common source (an infected blood sample). Initially, the patients' HIV populations are genetically identical. By the time they develop full-blown AIDS, how would the viral populations of the fourpatients compare?
Each patient's viral population would be unique, specifically adapted to deal with—and overcome—his or her unique immune system responses.
Consider a population of snowshoe hares in Montana. Their fur color changes in response to changes in day length. During the long summer days, they have brown fur, but as the days shorten in the fall, their fur turns white in preparation for winter. Then as the days get longer in the spring, their fur turns brown again. Their fur coloration acts as camouflage from predators. As climate change brings warmer fall temperatures to Montana, colder temperatures with snowfall are coming later in the year, and there may be less snowfall overall. As a result, the hares' fur color may be mismatched to the color of their surroundings, making them more visible to predators.
Hares with a mutation that causes them to change color in response to temperature rather than day length
As proposed by Darwin, what sorts of traits are favored by natural selection?
Heritable traits that help individuals survive and reproduce more successfully than others in the same population.
According to current evolutionary theory, which of the following is true?
Populations are the units of evolution.