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

question 65

Multiple Choice

The peppered moth provides a well-known example of natural selection. The light-coloured form of the moth was predominant in England before the Industrial Revolution. In the mid-19th century, a dark-coloured 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 coloured, whereas light-coloured 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-coloured 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 colouration.
• C) Yes; they are reproductively isolated based on habitat.
• D) No; they still can interbreed.

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Definitions:

Glycolipids

Lipids with a carbohydrate attached, important in cell recognition and membrane structure.

Carbohydrates

Organic compounds composed of carbon, hydrogen, and oxygen, typically found in foods and used as energy sources.

Phospholipids

A class of lipids that are a major component of all cell membranes, as they can form lipid bilayers.

Bilayer

Often refers to the lipid bilayer, a thin polar membrane made of two layers of lipid molecules, forming the basic structure of cell membranes.