Q1. [1] medium exam-ready
In a population of bacteria reproducing asexually, a particular variation is found in 60% of individuals while another variation is found in only 5%. Which variation most likely arose earlier, and why?
((A)) The 5% variation; rare traits are always newer
((B)) The 60% variation; a higher frequency suggests the variation has had more time to accumulate through successive generations
((C)) Both arose at the same time; frequency does not reflect age
((D)) The 60% variation; common traits are always more beneficial
- A The trait present in 10%, because rare traits are older
- B Both traits arose at the same time
- C The trait present in 60%, because it has had more time to accumulate in the population
- D Neither trait can be compared this way
Generated by claude-sonnet-4-6 · 2026-06-26 01:02 · grounding rag
Model Answer
(C) The trait present in 60%, because it has had more time to accumulate in the population through successive generations of asexual reproduction.
Explanation
The textbook (Ch. 8, Q1 under Section 8.1) directly asks this: "If a trait A exists in 10% … and trait B in 60% … which arose earlier?" The expected reasoning is that in asexual reproduction, variations accumulate over generations; a higher frequency means more time has passed for it to spread — not that it is necessarily more beneficial. Avoid option D's reasoning ("always more beneficial") as the textbook does not say frequency equals benefit.