EVOLUTION EXAM

Which of the following is an example of a vestigial structure in humans?

• The skin

• The lungs

• The heart

• The appendix

The hypothesis that evolution of a species occurs in periods of rapid change separated by periods of little or no change is called

• Divergence.

• Gradualism.

• Punctuated equilibrium

• Isolation.

Answer explanation

The correct answer is 'Punctuated equilibrium', which describes the pattern of evolution as periods of rapid change followed by long periods of stability, contrasting with gradualism that suggests slow, continuous change.

Comparing human hemoglobin of chimpanzees, horses, kangaroos, and chickens, reveal that humans have the fewest amino acid differences with

• Kangaroos

• Horses

• chickens

• chimpanzees

Answer explanation

Humans share a closer evolutionary relationship with chimpanzees than with horses, kangaroos, or chickens, resulting in fewer amino acid differences in hemoglobin. Thus, the correct answer is chimpanzees.

The fossil record provides evidence that

• Fossils cannot be dated.

• All species were formed during Earth's formation and have changed little since then.

• The fossilized species have no connection to today's species.

• Older species gave rise to more-recent species.

Answer explanation

The fossil record shows a progression of species over time, indicating that older species evolved into more-recent species, supporting the theory of evolution. This contradicts the other options, which are inaccurate.

All of the following are examples of Natural Selection EXCEPT

• skin color

• dog breeds

• antibiotic resistance

• colorful feathers in male birds

Answer explanation

Dog breeds are a result of artificial selection by humans, not natural selection. The other options, like skin color and antibiotic resistance, are examples of traits shaped by natural selection in response to environmental pressures.

Starting in 1954, commercial fishers in the northwest Pacific were paid by how dark the shells of the oyetsers they caught were. Darker oysters have a more delicious taste while light colored oysters have a botter taste. The fishers began to throw light colored oysters back into the water if they caught them. Which of the following effects did this change in fishing technique most likely have on the oyster population over the next 20 years?

• The average color of the oysters became darker.

• The average color of the oysters became lighter,

• None of the above.

Answer explanation

By discarding light-colored oysters, fishers reduced their numbers in the population. Over time, this selective pressure likely led to a decrease in lighter-colored oysters, resulting in an overall darker average color for the remaining oysters.

The process in which organisms with traits well suited to an environment are more likely to survive and to produce offspring is

• Natural selection.

• Origin of species.

• Genetic principles.

• Trait mechanism.

Answer explanation

Natural selection is the process where organisms with advantageous traits are more likely to survive and reproduce, leading to the prevalence of those traits in future generations.

Which of the following best describes the role of mutations in the process of evolution?

• Mutations always decrease an organism's chance of survival.

• Mutations introduce genetic variation, which can lead to evolutionary change.

• Mutations prevent natural selection from occurring.

• Mutations only occur in response to environmental changes.

Structures with no function that are remnants of an organism’s evolutionary past are

• Not visible organisms.

• Vestigial.

• Young in origin.

• Useful to the organism.

Answer explanation

Structures that no longer serve a function and are remnants of evolutionary history are called vestigial. This term specifically refers to these non-functional traits, making 'Vestigial' the correct answer.

Some willow trees alter the chemical composition of their leaves when attacked by caterpillars. Compared to normal leaves, the chemically altered leaves are less nutritious and more difficult for caterpillars to digest. Which of the following is a likely effect of this ability to alter leaf composition?

• Willow trees with this ability will attract more caterpillars than other willow trees.

• Willow trees with this ability have a survival advantage over other willow trees.

• More butterflies will lay their eggs on willow trees with this ability than other willow trees.

• None of the above.

Answer explanation

The ability to alter leaf composition makes leaves less nutritious and harder to digest for caterpillars, reducing caterpillar damage. This gives willow trees a survival advantage over others that cannot defend themselves as effectively.