Margaret M. Loos
I. Objectives:
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1. To develop appreciation of scientists as human beings and the “timing” of developments in science.
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2. To begin a vocabulary in genetics.
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3. To urge students to examine their own potential as scientists.
II. Read the paragraph and use it to analyze these articles that follow in less than one page.
When an idea is “alive” in the minds of people called scientists many things can happen. Some scientists can make experiments and never realize the significance of their outcomes because the information for their interpretation is not available. Some scientists can look at results and misunderstand them. Some scientists understand the possibilities and really don’t know what to do with them. All of these have happened in the field we call genetics.
III. Genetics: In the beginning . . .
Human genetics, based on Mendelian Laws and ratios began with the “rediscovery” of Mendel’s studies in 1900, but it was preceded by observations of peculiarities in families as far back as the 1700’s. In order for a characteristic to be considered as carried from one generation to the following ones, the peculiarity had to be inborn, not acquired and it had to be free of rules of chance or coincidence. A mathematician (they’re the ones who give validity to genetics) named P.L.M. De Mauperius in 1752 found a family where extra fingers and toes occurred in four generations and since extra digits only occurred as one per 20,000 in that population (Berlin), he established a strong possibility that inheritance was responsible. Families who realized that color vision varied among them brought about pedigrees for color blindness. The natural division between those who were color blind and those who weren’t exhibited the law of segregation later explained by Mendel.
In 1883 Francis Galton, another British mathematician, completely unaware of Mendel’s work, but a compulsive measurer, started measuring what he termed “eugenics”. There was no recognition of separate packaging of positive or negative traits, but a general concept of “good blood” or “bad blood” passing the traits on. From 1870 to the 1930’s societies for “positive genetics” to encourage the “scientific” breeding of children for good traits arose.
One community in Oneida, N. Y. actually chose matings by the decision of a committee but the spiritual leader of the group seemed to be chosen more often for that heavy duty and the community disbanded in 1881.
On the other hand “negative genetics” also led to abuses Enthusiasts proposed that it might eliminate disease, producing supermen and a superior society. In America Social Darwinists were convinced that all mental retardation and unacceptable behavior (such as getting angry) were controlled genetically (post Mendel). They even urged the United States to avoid “pollution” of their genetics by restricting “undesirable” ethnic groups in immigration laws. They urged the passing of sterilization laws for the retarded or “socially-inadequate” persons. Pre-war and wartime Nazis in Germany carried this to the highest stage, the killing of the “socially unfit” and the control of mating and marriage. These practices were seen to be abominations and eugenics became an ugly word.
IV. Assignment: Outside research
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A Contracts
Read Mendel’s original publication and research one of the following for a short report
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1. Karl Pearson
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2. Francis Galton
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3. Correns
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4. DeVries
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5. Tschermak
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6. Morgan, Thomas A.
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B Contracts
Copy the three laws as presented in text and learn them. Research one of the above.
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Prepare a pedigree.
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C Contracts
Do one or the other of above.
(figure available in print form)