Question 1

What is natural selection?

Accepted Answer

Natural selection is the process by which organisms with favorable traits survive and reproduce more successfully than those without.

Question 2

Who proposed the theory of evolution by natural selection?

Accepted Answer

Charles Darwin proposed the theory of evolution by natural selection.

Question 3

What is a mutation?

Accepted Answer

A mutation is a change in the DNA sequence that can introduce new traits into a population.

Question 4

What is variation in a population?

Accepted Answer

Variation refers to differences in traits among individuals of the same species. Variation arises from genetic differences and is essential for natural selection to act upon.

Question 5

What does "survival of the fittest" mean?

Accepted Answer

"Survival of the fittest" means that organisms best adapted to their environment are more likely to survive and pass on their genes.

Question 6

How does camouflage help an organism survive?

Accepted Answer

Camouflage helps organisms blend into their environment, making them harder for predators to spot.

Question 7

What are the four key components of natural selection?

Accepted Answer

Variation (individuals differ), Inheritance (traits are passed to offspring), Selection (some traits improve survival/reproduction), Time (populations change over many generations).

Question 8

Give an example of natural selection in action.

Accepted Answer

The peppered moth in England: before industrialization, light-colored moths survived better on light tree bark. After pollution darkened the bark, dark moths became more common because they were better camouflaged from predators.

Question 9

What is the difference between natural selection and artificial selection?

Accepted Answer

Natural selection is driven by environmental pressures; artificial selection is driven by humans who selectively breed organisms for desired traits (e.g., dog breeds, crop plants).

Question 10

What is an adaptation?

Accepted Answer

An adaptation is a heritable trait that increases an organism's ability to survive and reproduce in its environment.

Question 11

What is the difference between structural, behavioral, and physiological adaptations?

Accepted Answer

Structural adaptations are physical features (e.g., thick fur). Behavioral adaptations are actions (e.g., migration). Physiological adaptations are internal body processes (e.g., hibernation, antifreeze proteins).

Question 12

How does antibiotic resistance in bacteria demonstrate natural selection?

Accepted Answer

When antibiotics are applied, most bacteria die but a few with resistance mutations survive. These reproduce rapidly, passing on the resistance gene. Over time, the population becomes resistant — a real-world example of natural selection.

Question 13

What is convergent evolution?

Accepted Answer

Convergent evolution occurs when unrelated species independently evolve similar traits due to similar environmental pressures (e.g., dolphins and sharks both have streamlined bodies for swimming).

Question 14

What types of evidence support the theory of evolution?

Accepted Answer

Evidence includes: the fossil record (showing gradual change over time), homologous structures (similar anatomy in different species), DNA comparisons, embryology (similar embryo development), and direct observation of natural selection.

Question 15

What are homologous structures and what do they indicate?

Accepted Answer

Homologous structures are anatomically similar structures in different species that suggest common ancestry (e.g., the arm bones of humans, whales, and bats share the same basic structure despite different functions).

Question 16

How does the fossil record provide evidence for evolution?

Accepted Answer

The fossil record shows a chronological sequence of organisms from simple to complex over millions of years, including transitional fossils that show intermediate forms between ancestral and descendant species.

Question 17

What is speciation?

Accepted Answer

Speciation is the process by which one species splits into two or more distinct species, typically when populations become isolated and evolve separately over long periods.

Question 18

A population of beetles lives on green leaves. Most are green, but some are brown. Predict what happens after a bird predator is introduced.

Accepted Answer

Brown beetles are more visible on green leaves and will be eaten more often. Green beetles survive and reproduce more. Over generations, the population will shift to mostly green beetles — natural selection favoring camouflage.

Question 19

Why does natural selection act on phenotypes rather than genotypes directly?

Accepted Answer

Natural selection acts on observable traits (phenotype) — what predators see, what helps the organism find food, etc. The underlying genotype is only selected indirectly through its effect on the phenotype.

Question 20

Can one individual organism evolve during its lifetime? Explain.

Accepted Answer

No — evolution occurs at the population level across generations. An individual cannot change its genes through experience. A person lifting weights becomes stronger, but that change is not inherited by their children.

Natural Selection Answer Key

Prior Knowledge Questions

Activity A – Survival of the Fittest

Activity B – Adaptation

Activity C – Evidence for Evolution

Assessment Questions

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