The Peppered Moth Provides a Well-Known Example of Natural Selection

question 1

Multiple Choice

The peppered moth provides a well-known example of natural selection. The light-colored form of the moth was predominant in England before the Industrial Revolution. In the mid-19th century, a dark-colored form appeared. The difference is produced by a dominant allele of one gene. By about 1900, approximately 90% of the moths around industrial areas were dark colored, whereas light-colored moths were still abundant elsewhere. Apparently, birds could readily find the light moths against the soot-darkened background in industrial areas and, therefore, were eating more light moths. Recently, use of cleaner fuels has greatly reduced soot in the landscape, and the dark-colored moths have been disappearing. Should the two forms of moths be considered separate species?

• A) Yes; natural selection has affected the frequency of the two different forms.
• B) Yes; they have completely different coloration.
• C) Yes; they are reproductively isolated based on habitat.
• D) No; they still can interbreed.

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Definitions:

Chemical Synapses

Specialized junctions through which neurons signal to each other and to non-neuronal cells, allowing the transmission of chemical messengers (neurotransmitters).

Electrical Synapses

Direct connections between neural cells allowing for rapid transmission of electrical signals through gap junctions.

Presynaptic Activation

The process by which an action potential in a neuron stimulates the release of neurotransmitters from the presynaptic terminal.

Electrical Synapses

A type of synapse in which electrical signals are directly passed from one neuron to another through gap junctions, allowing for rapid communication.