Answer :
To determine the best explanation for the observed and expected frequencies of the phenotypes in the population of four o'clock plants, let's go through a step-by-step analysis of the data provided:
1. Analyze the Given Data:
- We have three phenotypes and their respective expected and observed counts in the population of 1,000 plants.
- The data are summarized as:
| Phenotype | Number expected | Number observed |
|---------------|-----------------|-----------------|
| Red flowers | 105 | 173 |
| Pink flowers | 484 | 343 |
| White flowers | 411 | 484 |
2. Sum of Expected and Observed Numbers:
- Calculate the total number of plants for expected and observed counts to compare the overall totals.
- Expected total = 105 (Red) + 484 (Pink) + 411 (White) = 1000
- Observed total = 173 (Red) + 343 (Pink) + 484 (White) = 1000
3. Interpret the Totals:
- Both the expected and observed totals are the same (1000). This means we have the same total number of plants in the population, but the distribution among the phenotypes differs.
4. Compare Expected vs. Observed Frequencies:
- Red flowers: Expected = 105, Observed = 173 (greater than expected)
- Pink flowers: Expected = 484, Observed = 343 (less than expected)
- White flowers: Expected = 411, Observed = 484 (greater than expected)
5. Conclude the Difference:
- Since the observed frequencies differ significantly from the expected frequencies for each phenotype, this discrepancy cannot be explained simply by random chance or equilibrium.
6. Reason for Discrepancy:
- Given that the expected and observed totals are the same, but individual categories show major differences, one primary explanation is that some genetic changes, such as allele mutation, have occurred, leading to changes in phenotype distributions.
7. Best Explanation:
- The statement "The observed frequency of the phenotypes is different from the expected frequency because some alleles mutated," best explains the observed results. This suggests that some alleles have changed (mutated), resulting in different distributions of the phenotypes from what was initially expected.
Therefore, the correct statement is:
The observed frequency of the phenotypes is different from the expected frequency because some alleles mutated.
1. Analyze the Given Data:
- We have three phenotypes and their respective expected and observed counts in the population of 1,000 plants.
- The data are summarized as:
| Phenotype | Number expected | Number observed |
|---------------|-----------------|-----------------|
| Red flowers | 105 | 173 |
| Pink flowers | 484 | 343 |
| White flowers | 411 | 484 |
2. Sum of Expected and Observed Numbers:
- Calculate the total number of plants for expected and observed counts to compare the overall totals.
- Expected total = 105 (Red) + 484 (Pink) + 411 (White) = 1000
- Observed total = 173 (Red) + 343 (Pink) + 484 (White) = 1000
3. Interpret the Totals:
- Both the expected and observed totals are the same (1000). This means we have the same total number of plants in the population, but the distribution among the phenotypes differs.
4. Compare Expected vs. Observed Frequencies:
- Red flowers: Expected = 105, Observed = 173 (greater than expected)
- Pink flowers: Expected = 484, Observed = 343 (less than expected)
- White flowers: Expected = 411, Observed = 484 (greater than expected)
5. Conclude the Difference:
- Since the observed frequencies differ significantly from the expected frequencies for each phenotype, this discrepancy cannot be explained simply by random chance or equilibrium.
6. Reason for Discrepancy:
- Given that the expected and observed totals are the same, but individual categories show major differences, one primary explanation is that some genetic changes, such as allele mutation, have occurred, leading to changes in phenotype distributions.
7. Best Explanation:
- The statement "The observed frequency of the phenotypes is different from the expected frequency because some alleles mutated," best explains the observed results. This suggests that some alleles have changed (mutated), resulting in different distributions of the phenotypes from what was initially expected.
Therefore, the correct statement is:
The observed frequency of the phenotypes is different from the expected frequency because some alleles mutated.
