Evolution Quiz
Questions: 16 · 10 minutes
1. A bat wing and a human arm contain a similar arrangement of major bones but perform different functions. What does this similarity most strongly indicate?
Bats developed wings because their ancestors repeatedly exercised their forelimbs.
The structures were inherited from a common ancestor and modified along different lineages.
The structures evolved independently and only happen to share the same internal pattern.
Humans and bats experience identical environmental pressures.
2. Sharks and dolphins have similar streamlined bodies, although sharks are fish and dolphins are mammals. This similarity is best explained by what?
Inheritance of the streamlined shape from a recent shared species
Gene flow between shark and dolphin populations
Convergent evolution under similar environmental pressures
Genetic drift occurring in the same direction in both groups
3. Two populations of the same ancestral species become geographically separated. Much later, they can no longer produce fertile offspring together. What does this outcome most directly demonstrate?
Both populations stopped evolving after their separation.
The populations became genetically identical through gene flow.
Reproductive isolation developed, indicating that speciation occurred.
Natural selection always produces organisms with greater complexity.
4. Two individuals belong to the same species. One produces more offspring that survive and reproduce. In evolutionary biology, this individual has greater what?
Evolutionary fitness
Physical strength
Genetic complexity
Mutation rate
5. Under otherwise similar conditions, in which population is genetic drift generally expected to cause larger random changes in allele frequencies?
A small, isolated population
A very large population with frequent immigration
A large population experiencing stable environmental conditions
A population in which every individual has identical reproductive success and no alleles vary
6. Wind carries pollen from one plant population into another, where it introduces alleles that were previously uncommon. Which evolutionary process is this?
Genetic drift
Gene flow
Reproductive isolation
Natural selection
7. A wildfire randomly leaves only a small fraction of a large animal population alive. The survivors have different allele frequencies from the original population. Which mechanism is most directly involved?
A population bottleneck producing genetic drift
Gene flow caused by migration
Directional selection for traits that caused the fire
Nonrandom mutation triggered by population decline
8. In a population, newborns of intermediate weight have higher survival than newborns at either extreme. If weight is heritable, which pattern of selection is occurring?
Directional selection
Disruptive selection
Sexual selection
Stabilizing selection
9. Which statement best defines biological evolution at the population level?
A change in the frequencies of heritable variants in a population across generations
A change in an individual organism caused by learning or exercise
An increase in the number of organisms living in an ecosystem
A steady progression of every species toward greater complexity
10. In a beetle population, shell color is heritable. Birds catch light beetles more easily than dark beetles, and dark beetles become more common over many generations. What best explains this change?
All beetles gradually changed color at the same rate in response to the environment.
Individual light beetles darkened their shells because they needed better camouflage.
Birds caused specific color mutations to appear in the beetles they hunted.
Dark beetles survived and reproduced at higher rates, increasing the frequency of inherited dark coloration.
11. Researchers find a dated series of fossils in which older specimens have mostly ancestral features and later specimens show a mixture of ancestral and derived features. What does this evidence most directly support?
Organisms change traits because they consciously respond to future conditions.
Every modern species appeared at the same time as the oldest fossils.
Fossil similarity proves that environmental conditions never changed.
Lineages can accumulate evolutionary changes over time, producing transitional combinations of traits.
12. A bacterial population contains a few antibiotic-resistant cells before treatment begins. After antibiotic use, resistant bacteria make up most of the population. What happened?
The antibiotic taught surviving bacteria how to resist it during their lifetimes.
Every bacterium developed the same resistance mutation when exposed to the drug.
Treatment favored bacteria with existing resistance, so their descendants became more common.
The resistant bacteria stopped reproducing, allowing the population to stabilize.
13. Which statement correctly describes the role of mutation in evolution?
Mutations always improve an organism's ability to survive.
Mutations arise only when a population needs a new trait.
Mutations guarantee that natural selection will occur.
Mutations can create new alleles on which evolutionary processes may act.
14. During a drought, birds with deeper beaks obtain more food. However, beak depth in this population is not heritable. What should researchers expect from natural selection on beak depth?
A rapid inherited increase in beak depth, because survival alone makes a trait evolutionary
No consistent inherited increase in beak depth, because offspring do not reliably inherit the advantageous difference
Identical beak mutations in every offspring born during the drought
Permanent deeper beaks in the surviving adults, which will then be genetically transmitted
15. A few randomly selected mainland birds colonize an island. Their allele frequencies differ from those of the large mainland population. Which process best describes this situation?
Stabilizing selection
Artificial selection
The founder effect
Convergent evolution
16. A phylogenetic tree shows that species A and B share a more recent common ancestor with each other than either shares with species C. What is the best conclusion?
Species A evolved directly from species B.
Species A and B are more closely related to each other than either is to species C.
Species C is the unchanged ancestor of both A and B.
Species A and B must look more alike in every observable trait.