Science (086) — AI-generated practice question

Variations arise due to errors in DNA copying during reproduction. While most variations are neutral or harmful to individual organisms (e.g., a bacterium with an unusual enzyme may be less competitive in normal conditions), some rare variants may prove advantageous when the environment changes.

Example: In a population of bacteria living in temperate water, if global warming raises the water temperature, most bacteria die. However, a few individuals with a heat-resistant variation survive and reproduce. Thus, variation is beneficial for the species (ensuring survival) but not necessarily for every individual organism, which may not possess the useful variant and could perish.

Source: Chapter 7, Section 7.1.1 – The Importance of Variation

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• The examiner expects two distinct ideas: (1) why variation is useful for species, and (2) why it may be harmful/neutral to individuals.
• The bacteria + global warming example is directly from the textbook — always use it; it scores full marks.
• Key contrast to highlight: species survival (long-term, population level) vs. individual disadvantage (individual may not have the favourable variant or may carry a harmful one).
• At 3 marks: one line of concept + example with explanation is sufficient. Do not write more.