British Land Snails Are an Example of Disruptive Selection

question 40

Multiple Choice

British land snails are an example of disruptive selection. In the grassy fields, the light-banded snails escape bird predators. In the darker forest, the dark snails survive and the light-banded snails are eaten. The different colored snails have the opportunity to interact and breed across the British landscape. Why doesn't this "disruptive selection" eventually lead to two separate species?

• A) There is no reproductive isolation to prevent gene flow.
• B) They are already two separate species, and the intermediate forms are hybrids.
• C) The color forms are probably not genetically determined.
• D) There must be some unknown factor producing an equal stabilizing selection "to hold the species together."
• E) This will result in the formation of two species if given long enough time.

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Definitions:

Overallocation

The process of distributing or assigning more resources or rights than are available, often leading to shortages or conflicts.

Underallocation

A situation in which resources are not distributed efficiently, often leading to a failure to meet demand for certain goods or services.

Farm Subsidies

Government aid provided to farmers to boost their income, regulate the production of farm products, and affect the price and availability of these commodities.

Agribusiness

The portion of the agricultural and food product industries that is dominated by large corporations.