IDNLearn.com provides a collaborative environment for finding and sharing answers. Find reliable solutions to your questions quickly and accurately with help from our dedicated community of experts.

In four o'clock plants, there are three phenotypes for flower color, but only two alleles. The table shows both the expected and observed numbers of plants of each flower color in a population of 1,000.

| Phenotype | Number expected | Number observed |
|---------------|------------------|-----------------|
| Red flowers | 105 | 173 |
| Pink flowers | 484 | 343 |
| White flowers | 411 | 484 |

Which statement best explains the results in the table?

A. The population is in equilibrium because the total number of plants expected and observed was about the same.
B. The population evolved because the frequency of the alleles and the genotypes changed.
C. The frequency of the alleles and genotypes in the population changed because of gene flow.
D. The observed frequency of the phenotypes is different from the expected frequency because some alleles mutated.


Sagot :

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.