Rough-skinned newts produce a strong toxin called TTX as a defense mechanism against predators. Garter snakes
1 answer:
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Complete question:
1. The graph below depicts the frequency of expression of the coloration of beetles on an island:
Graph is the 1st Pic --> Attached files
Birds are the main predators of these beetles; they hunt the beetles by sight and pick them up off of the tree bark where they feed. A logging company clears the trees off of the island and plants younger trees as a replacement. Trees with light bark are planted on one side of the island and trees with dark bark are planted on the other side of the island. What do you predict would happen to the range of coloration in the populations of beetles on each side of the island?
Select TWO answers, one to represent the beetles living on the light colored trees and one to represent the beetles living on the dark colored trees. (2 points)
A. graph 2 below
B. graph 3 below
C. graph 4 below
D. graph 5 below
Answer:
B. graph 3 below
D. graph 5 below
Explanation:
The original population of beetles (Graph 1) shows that most individuals had an intermediate phenotype between dark and light color. The graph expresses its highest point in the middle of the phenotypic ax, while the curve´s tails coincide with light and dark colors.
Probably, most of the trees inhabiting the whole island had some darkish color tone, which beetles used to camouflage and avoid predation.
When the company cleared the area and reforested, they planted light trees on one half and dark trees on the other half of the island. This change in the environment modeled the beetled phenotype, together with predation pressure.
<em>If we consider the whole original population, we should say that it went under a disruptive selection.</em> But if we think about the sides of the island separately, we could say that the population living on each side went under directional selection. We are not thinking about the whole population of beetled inhabiting the whole island, but two groups inhabiting each side of the island.
- Graph 3 represents the beetles inhabiting the part of the land with dark trees. The population went under directional selection, and most of them turned into dark-colored to camouflage with the substrate in which they live.
- Graph 5 represents the beetles inhabiting the other part of the land with light trees. The population went under directional selection, and most of them became light-colored to camouflage with the substrate in which they live.
