A Punnett square predicts probabilities but not exact outcomes. Why?
Punnett square gives probabilities because fertilization is a random process, not a fixed outcome.
Key Idea
| Term | Meaning |
|---|---|
| Probability | Chance of an event occurring |
| Random Fertilization | Any gamete can combine with any other |
Why Not Exact
| Reason | Explanation |
|---|---|
| Random Gamete Fusion | No fixed pairing |
| Large Sample Needed | Ratios appear over many offspring |
| Chance Variation | Small samples may differ |
Example
| Expected Ratio | Actual Outcome |
|---|---|
| 3 Tall : 1 Short | May not be exact in small number |
Stepwise Understanding
Parents produce different types of gametes
Gamete fusion happens randomly
Each combination has certain probability
Punnett square shows all possible outcomes
Actual result may vary due to chance
Important Concept
Genetic ratios are theoretical expectations, not guaranteed results.
Real Insight
If only 2–3 offspring are observed, results may look completely different from expected ratio, but with large numbers it becomes closer.
So Punnett square predicts chances, not exact results every time.