Q1. [2] straightforward exam-ready
Distinguish between cross-pollination and self-pollination on the basis of: (i) the source of pollen, and (ii) the genetic variation produced in offspring.
Generated by claude-sonnet-4-6 · 2026-06-26 01:01 · grounding rag
Model Answer
(i) Source of pollen:
- Self-pollination: Pollen is transferred from the anther to the stigma of the same flower.
- Cross-pollination: Pollen is transferred from the anther of one flower to the stigma of a different flower, carried by agents like wind, water, or animals.
(ii) Genetic variation in offspring:
- Self-pollination: Produces little or no genetic variation; offspring are similar to the parent.
- Cross-pollination: Produces greater genetic variation in offspring, as it combines genetic material from two different plants.
Source: Chapter 7, Section 7.3.2 — Sexual Reproduction in Flowering Plants
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Explanation
- The textbook directly states: "If the transfer of pollen occurs in the same flower, it is referred to as self-pollination. On the other hand, if the pollen is transferred from one flower to another, it is known as cross-pollination."
- For variation, the textbook notes that "modes of sexual reproduction allow for greater variation to be generated." Cross-pollination involves two individuals, hence more variation; self-pollination is more like a single-parent process, producing less variation.
- Each point (i) and (ii) carries 1 mark. Keep each distinction crisp and paired — examiner looks for a clear contrast between the two types.