Table of Contents
What is the story of the peppered moth?
Back in the early 1800s, a small black moth was found in Manchester for the first time. It wasn’t a new species, but an unusual black variety of the Peppered Moth, a fairly common insect that is usually pale grey with black speckles. The new black variety was named ‘carbonaria’.
What was the purpose of the experiments that Dr Kettlewell ran?
During the 1950’s, Henry Bernard Davis Kettlewell ran a series of experiments and field studies to find out if natural selection had actually caused the rise of the dark peppered moth. Dr. Kettlewell was an entomologist, a scientist who studies insects.
What caused the existence of the dark colored peppered moths?
Genetic Changes Moths passed their color to the next generation. Eggs from light moths developed into light moths and dark moth eggs turned to dark adults. The dark color was caused by a mutation in the DNA of a single moth, and the mutated gene had been passed to all its offspring.
How is the peppered moth story an example of natural selection?
Wing-color changes in peppered moths are a common example of what scientists refer to as natural selection. In it, organisms develop random mutations. Some of the gene changes will leave individuals better suited — or adapted — to their environment. These individuals will tend to survive more often.
What type of change does the peppered moth show?
The evolution of the peppered moth is an evolutionary instance of directional colour change in the moth population as a consequence of air pollution during the Industrial Revolution. The frequency of dark-coloured moths increased at that time, an example of industrial melanism.
What was Kettlewell’s conclusion?
He concluded that “for the time being we must discard Biston as a well-understood example of natural selection in action, although it is clearly a case of evolution. There are many studies more appropriate for use in the classroom” and that further studies of the animal’s habits were needed.
What did Kettlewell actually test when he conducted this study?
Kettlewell’s experiment was a test of whether a particular example of natural selection could be accounted for with reference to a specific mechanism or agent, namely, bird predation. If it had failed, biologists would not have rejected the theory of natural selection.
What type of selection does the peppered moth represent?
How did the peppered moths environment change and what caused this change?
How does Kettlewell’s experiment relate to the idea of natural selection?
What was Dr Kettlewell conclusion?
Based on his experiments between 1965 and 1969, he concluded that it was not possible to reproduce Kettlewell’s results, and said that birds showed no preference on moth on either black or white tree trunks. He suggested that Kettlewell had trained the birds to pick moths on tree trunks to obtain desired results.
Why is the peppered moth an example of directional selection?
The peppered moth case study described above is an example of directional selection: the frequency of color varieties changes dramatically in one direction or another (lighter or darker) in response to the predominating habitat conditions.
What type of natural selection is the peppered moth?
evolution through directional selection
The case of the peppered moth (Biston betularia) is a classic example of evolution through directional selection (selection favoring extreme phenotypes). Prior to the industrial revolution in England (pre-1740), the peppered moth was found almost entirely in its light form (light body colored with black spots).
What did Kettlewell find when he recaptured the marked moths?
Kettlewell analyzed the percent recaptured and concluded that twice as many dark moths were recaptured in a polluted forest so twice as many white moths were eaten by birds. In an unpolluted forest he found the opposite results. Twice as many white moths were recaptured.
Is the peppered moth an example of disruptive selection?
Peppered moths are a well-studied disruptive selection example. During England in the Industrial Revolution factories were beginning to produce pollution that changed the industrial areas in the city, covering them in soot.
Are peppered moths disruptive selection?
The case of the peppered moth (Biston betularia) is a classic example of evolution through directional selection (selection favoring extreme phenotypes). Prior to the industrial revolution in England (pre-1740), the peppered moth was found almost entirely in its light form (light body colored with black spots).
What did Kettlewell conclude?
Kettlewell concluded that in an unpolluted forest the birds ate twice as may dark moths as white moths. As scientists you need to analyze both Kettlewell’s experiment and his conclusions.
What type of selection are peppered moths?
through directional selection
What conclusions did Dr Kettlewell make regarding natural selection in peppered moths?
How are peppered moths an example of directional selection?
An example of directional selection is the increase in darker forms of the peppered moth (Biston betularia) that occurred in industrial areas, where the moths with darker wing coloration are better camouflaged than those with lighter wings against polluted tree trunks (see industrial melanism).