Which of the following provides evidence for evolution?
direct observation of genetic changes in populations
sharing of characteristics between organisms
the fossil record
all of the above
In natural selection,
the genetic composition of the population changes randomly over time
new mutations are generated over time
all individuals in a population are equally likely to contribute offspring to the next generation
individuals that possess particular inherited characteristics consistently survive and reproduce at a higher rate than other individuals
Adaptive traits
are features of an organism that hinder its performance in its environment
are rare in most natural populations
are favored by natural selection
result from genetic drift
The fossil record shows that the first mammals evolved 220 million years ago. The supercontinent Pangea began to break apart 200 million years ago. Therefore, fossils of the first mammals should be found
on most if not all of the current continents
only in Antartica
on only one or a few continents
only in Africa
The fact that the flipper of a whale and the arm of a human both have five digits and the same set of bones can be used to illustrate that
genetic drift can cause the evolution of populations
organisms can share characteristics simply because the share a common ancestor
whales evolved from humans
humans evolved from whales
The Galapagos Islands provide examples of
microevolution only
macroevolution only
both micro- and macroevolutionary change
none of the above
Differences in survival and reproduction caused by chance events can cause the genetic makeup of a population to change randomly over time. This process is called
mutation
natural selection
macroevolution
genetic drift
The splitting of one species into two or more species is called
speciation
common descent
adaptation
Features of organisms that are related to one another through common descent are
convergent
homologous
divergent
analogous
Artificial selection is the process by which
Natural selection fails to act in wild populations
humans prevent natural selection
humans allow only organisms with specific characteristics to breed
humans cause genetic drift in domesticated populations
A population of 1,500 individuals has 375 individuals of genotype AA, 750 individuals of genotype Aa, and 375 individuals of genotype aa. The genotype frequencies for genotypes AA, Aa, and aa are
0.33, 0.33, 0.33
0.25, 0.50, 0.25
0.375, 0.75, 0.375
0.125, 0.25, 0.125
A population of toads has 280 individuals of genotype AA, 80 individuals of genotype Aa, and 60 individuals of genotype aa. What is the frequency of the a allele?
0.24
0.33
0.14
0.07
A study of a population of the goldenrod Solidago altissima finds that large individuals consistently survive at a higher rate than small individuals. Assuming size is and inherited trait, the lost likely evolutionary mechanism at work here is
disruptive selection
directional selection
stabilizing selection
natural selection, but it is not possible to tell whether it is disruptive, directional, or stabilizing
Use the Hardy-Weinberg equation (p^2 + 2pq + q^2 = 1) to solve the following problem: If the frequency of the A allele is 0.7 and the frequency of the a allele is 0.3, what is the expected frequency of the genotype Aa in a population that is not evolving?
Over time, a population of birds ranges in size from 10 to 20 individuals. If allele frequencies were observed to change in a random way from year to year, which of the following would be the most likely cause of the observed changes in gene frequency?
Two large populations of a species found in neighboring locations with different environments are observed to become genetically more similar over time. Which evolutionary mechanism is the most likely cause of this trend?
gene flow
Assume that individuals of genotype Aa are intermediate in size and they leave more offspring than either AA or aa individuals do. This situation is an example of.
sexual selection
The process by which differences in inherited characteristics of individuals cause them to differ in their ability to get mates is most accurately called
reproductive success
mate choice
The splitting of one species to form two or more species most commonly occurs
by sympatric speciation
by genetic drift
by allopatric speciation
suddenly
The time required for populations to diverge to form new species
varies from a single generation to millions of years
is always greater in plants than in animals
is never less than 100,000 years
is never more than 1,000 years
Adaptations
match organisms closely to their environment
are often complex
help the organism accomplish important functions
Prezygotic and postzygotic barriers to reproduction have the effect of
reducing genetic differences between populations
increasing the chance of hybridization
preventing speciation
reducing or preventing gene flow between species
Evidence urges that sympatric speciation may have occurred or may be in progress in all of the following except
the apple maggot fly
squirrel on opposite sides of the Grand Canyon
cichlid fishes
polyploid plants (or their ancestors)
The diploid number of chromosomes in plant species A is 8; the diploid number in plants species B is 16. If plant species C originated when a hybrid between A and B spontaneously doubled its chromosome number, what is the most likely number of diploid chromosomes in C?
8
12
24
48
The biological species concept
can be applied to organisms that reproduce asexually
can be applied to fossil life forms
would classify two natural populations, A and B, as separate species if A and B are separated by a geographical barrier
would classify two natural populations, A and B, as separate species if A and B are unable to exchange genes even if they co-occur
Lake Victoria cichlids
exhibit low rates of speciation compared to most other fishes
exhibit high rates of speciation because of polyploidy
have evolved into many species in part because females choose mates by specific color patterns that males display
have diverged into many species because females have different feeding behaviors than males
