Question 1
Multiple choiceHard1 markIn an insect population, wing length varies and is inherited. Across generations, individuals with shorter wings leave more offspring, and short wings become more common. Darwin’s contemporaries already accepted that species change; Lamarckism attributed change to traits acquired during an individual’s life and passed to offspring. Which account identifies both Darwin’s mechanism and why his theory was a paradigm shift?
Show answer and explanation
Answer: D. Natural selection acts on existing inherited variation: individuals that leave more offspring contribute more to later generations, so their trait becomes more common in the population. Darwin’s paradigm shift was not the acceptance that species change, which was already widespread; it was providing natural selection as a convincing mechanism in place of Lamarckism. A: uses inheritance of acquired traits and treats acceptance of species change as Darwin’s new contribution. B: gives the selection mechanism correctly but mistakes the already accepted idea of species change for the paradigm shift. C: identifies the historical shift but explains the population change through inheritance of acquired traits rather than differential reproduction. Remember: natural selection changes populations over generations; it does not make individuals acquire adaptive traits.