Evolution and Adaptation Quiz

Grade 7 · Science · Quiz

Test your understanding of natural selection, adaptations, and the evidence that supports the theory of evolution.

Questions

Which of the following is NOT evidence for evolution?
1. Fossil record showing gradual changes over time
2. Similar DNA sequences in different species
3. Observations made during a single organism's lifetime
4. Homologous structures in different species
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Answer: Observations made during a single organism's lifetime
Observations made during a single organism's lifetime describe individual development, not evolutionary change. Evolution occurs over many generations in populations, not in individual organisms.
Whales have small remnant leg bones inside their bodies even though they do not use them. These are called:
1. Analogous structures
2. Vestigial structures
3. Adaptive structures
4. Homologous structures
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Answer: Vestigial structures
Vestigial structures are remnants of features that were functional in ancestors but have reduced or lost their original function. Whale leg bones are a classic example, suggesting whales evolved from land-dwelling ancestors.
Which scenario is the best example of natural selection?
1. A giraffe stretches its neck and passes the longer neck to its offspring
2. Bacteria that survive an antibiotic become more common in a population
3. A student practices running and becomes faster over time
4. A dog is trained to sit on command
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Answer: Bacteria that survive an antibiotic become more common in a population
Antibiotic resistance is a real-world example of natural selection. Bacteria with a natural mutation that makes them resistant survive the antibiotic, reproduce, and pass on the resistance gene.
Speciation occurs most often when a population is geographically isolated from others of its species.
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Answer: True
Geographic isolation prevents gene flow between populations. Separated populations adapt to different environments and accumulate different genetic changes over time, eventually becoming distinct species.
A cactus stores water in its thick stem and has spines instead of leaves. These are best described as:
1. Behavioral adaptations
2. Structural adaptations
3. Physiological adaptations
4. Vestigial structures
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Answer: Structural adaptations
Thick stems and spines are physical (structural) features of the cactus body — these are structural adaptations suited to hot, dry desert environments.
If two species have very similar DNA sequences, scientists would most likely conclude that they:
1. Live in the same habitat
2. Are the same species
3. Share a relatively recent common ancestor
4. Have identical adaptations
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Answer: Share a relatively recent common ancestor
Similar DNA indicates a more recent common ancestor. The more DNA sequences match between species, the more closely related they are evolutionarily.
The process by which organisms with favorable traits are more likely to survive and reproduce is called natural ______.
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Answer: selection
Natural selection is the cornerstone of Darwin's theory of evolution — nature 'selects' for traits that improve survival and reproduction in a given environment.
Over many generations, a population of beetles in a dark soil environment becomes mostly dark-colored. Which best explains this change?
1. Dark beetles chose to become darker over time
2. All beetles changed their color within their lifetimes
3. Dark beetles survived better and passed their color to more offspring
4. Light beetles migrated away to other environments
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Answer: Dark beetles survived better and passed their color to more offspring
Dark beetles had a survival advantage (better camouflage from predators) in dark soil, so they survived and reproduced more. Over generations, this shifted the population toward darker coloring — classic natural selection.

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