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An experiment is performed with peppered moths. The table below shows the populations before and after the trees turned black.

\begin{tabular}{|c|c|c|c|c|}
\cline { 2 - 5 } \multicolumn{1}{c|}{} & \multicolumn{2}{|c|}{ Starting population } & \multicolumn{2}{c|}{ Ending population } \\
\hline Environment & \begin{tabular}{c}
Light-colored \\
moths
\end{tabular} & \begin{tabular}{c}
Dark-colored \\
moths
\end{tabular} & \begin{tabular}{c}
Light-colored \\
moths
\end{tabular} & \begin{tabular}{c}
Dark-colored \\
moths
\end{tabular} \\
\hline \begin{tabular}{c}
Light-colored \\
trees
\end{tabular} & 40 & 40 & 60 & 20 \\
\hline \begin{tabular}{c}
Dark-colored \\
trees
\end{tabular} & 40 & 40 & 30 & 50 \\
\hline
\end{tabular}

Based on this data, which is a reasonable hypothesis for what happened after the trees turned black?

A. The light-colored moths mutated.
B. The light-colored moths developed an adaptation.
C. The dark-colored moths were more fit.
D. The dark-colored moths mutated.



Answer :

GinnyAnswer
To analyze the changes in the populations of light-colored and dark-colored moths in different environmental contexts, let's examine the data provided in the table.

1. Starting Population:
- On light-colored trees:
- Light-colored moths: 40
- Dark-colored moths: 40
- On dark-colored trees:
- Light-colored moths: 40
- Dark-colored moths: 40

2. Ending Population After Trees Turned Black:
- On light-colored trees:
- Light-colored moths: 60
- Dark-colored moths: 20
- On dark-colored trees:
- Light-colored moths: 30
- Dark-colored moths: 50

We can now evaluate each hypothesis based on these observations:

A. The light-colored moths mutated.
- Mutation would result in new traits not related to the color of the environment. The observed data only shows changes in population sizes rather than evidence of new mutations. Therefore, this option doesn’t seem supported by the data.

B. The light-colored moths developed an adaptation.
- Adaptation suggests a change over time that increases the survival rate due to specific environmental pressures. However, if light-colored moths developed an adaptation for darker environments (e.g., turning dark), we would see an increase in their numbers on dark-colored trees. This is not observed since their population decreased on dark trees (from 40 to 30).

C. The dark-colored moths were more fit.
- Fitness refers to an organism’s ability to survive and reproduce in its environment. If we observe the dark-colored trees, the population of dark-colored moths increased from 40 to 50, indicating that dark-colored moths had a survival advantage in this environment. This hypothesis appears consistent with the data.

D. The dark-colored moths mutated.
- Similar to the mutation hypothesis for light-colored moths, this would imply some new traits emerging within the population. The provided data does not show evidence of such mutations; change in population size alone does not suggest mutations.

Given this detailed analysis, the most reasonable hypothesis based on the provided data is:

C. The dark-colored moths were more fit.