Objectives Students will have the opportunities to:
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1. Define mutation and explain how mutations can affect the physical appearance of an organism and/or its genetic makeup.
2. List ways in which mutations can be harmful and beneficial.
Approximate time one-half week.
In 1886, Hugo de Vries, an American botanist, studied the growth of primroses and discovered that every so often a new variety of primrose would grow that could not be accounted for by genetic laws. He called these changes in characteristics ‘mutations’.
Errors are being made throughout our lives in one form or another whether intentionally or unintentionaLly. However, these mistakes are sometimes detected at an early stage and ways to correct these errors can be implemented instantaneously without causing great damage. An alteration, change, mistake in the transcription of one base in the DNA molecule of a gene can have severe consequences. This is sometimes the case with a gene mutation. A slight change in the DNA of a cell may not be detected in the early stages of life for correction, until it has manifested itself after a period of growth and development. This applies to other living things including plants.
If a mutation occurs in one of the early cells that start off the life of a new baby, the plans of development may be terribly upset. In some major ways babies are born deformed and it is believed that some of these deformities result from mutation in the DNA. Mutation is responsible for the diversity of the alleles necessary to produce genetic variation. Virtually any trait is the result of the combined action of genetic and environmental factors.
Most mutations either are so slight that they do not seem to have much effect on an organism’s chance to survive or they harm it in some way. For example, a fruit fly that have orange eyes instead of the normal red eyes, would probably be able to get along just as well as if it had not had the mutation. But if a mutation caused it to be born without eyes may cause its life span to be curtailed. However, a mutation can actually help an organism to survive. Perhaps it can run or fly faster than the other of its kind. Or it may have skin or fur that matches the background of its environment as to escape or hide from its prey. Even today, farmers and animal breeders watch for and use them to breed stronger and better plants and animals. e.g. breeding strains of corn with more nourishing protein and perhaps rice that gives a much higher yield per acre.
1. Students will visit the Agriculture Garden Center and observe heredity traits of at least ten similar plants. Students will note common and uncommon traits among the plants, such as the shape of the leaves or the color of the petals.
Students will not only make observations, but will be applying concepts, comparing, identifying, relating and classifying the plants according to their observable traits.
2. Students will investigate topics including how some insects develop resistance to insecticides; the prolonged use of certain antibiotics and how radiation can cause mutations. A discussion of these topics will be held next lesson.