THE BLUEPRINT OF LIFE
Problem. What controls heredity ? What makes you grow up to look like you and not someone else? The answer to this question is the key to life.
Background. For centuries men have wondered why men look like men. Some people thought that the blood of a mother and father mixed and the characteristics carried in the blood of the parents were passed on to the children.This theory was proven false in 1902, when Walter Sutton discovered the chromosomes. The chromosomes are tiny threadlike structures in the nucleus of a cell that contain the heredity of the cell.
Each human cell has forty-six chromosomes, which are split into forty-six identical pairs whenever the cells divide. Each of the daughter cells receives one-half of the chromosomes. But scientists did not know why or how the chromosomes split into two identical groups.
Explanation. The key discovery in the study of heredity was made by molecular biologists who discovered the chemical make-up of the chromosomes. They found that the chromosomes are made of a certain nucleic acid, called deoxyribonucleic acid. Biologists usually refer to this by its abbreviation, DNA.
In 1953 Doctors Francis Crick and James Watson perfected a three-dimensional model that explained all the characteristics of DNA. The model showed that the molecule was shaped like a spiral staircase. The sides of the stair treads were made of two chemicals and the "treads" were made of four other chemicals.
Many experiments proved that it is the arrangement of these four kinds of "treads" that determines a person’s characteristics.
The cells of the body contain about three feet of DNA, if the molecules are laid end-to-end. There are three or four encyclopedias of information in these DNA molecules. They use another nucleic acid, RNA (ribonucleic acid), to translate this information into the proteins that make up new tissue.
Further research. For an excellent discussion of DNA, read The Cell, one of the books in the Life Science Library.
PSYCHIATRISTS, PSYCHOLOGISTS, AND PSYCHOMETRISTS
Problem. If you wanted to learn about your own mental abilities and interests, whom would you see? Would you go to a psychometrist, a psychiatrist or a psychologist ?
Background. Actually, you could go to any of these men. If he couldn’t help you, he would probably refer you to one of the others who specialized in solving your kind of problems.
Some of these names may seem strange to you. You probably realize that the psych in each of them refers to the mind and its workings. Psychologists, psychiatrists, and psychometrists all work with the human mind and study its behavior.
It has been only eighty years since mankind began thinking of the mind in a scientific way. Before 1870 people were somewhat superstitious in the way they viewed the workings of the mind. This way of thinking began to disappear when Sigmund Freud, an Austrian doctor, began studying the mind. He said that the unconscious part of the mind is extremely important in determining our actions. He developed a complicated theory to explain why we act in the ways we do. Because he was a doctor, he used these theories in the treatment of his mentally ill patients.
Freud’s theories formed the beginning of modern psychiatry. Psychiatrists no longer accept all of Freud’s theories, but they accept some of them.
Explanation. The study of the mind was not the concern of the medical men only. A few years after Freud’s work, two men, John Watson and E. L. Thorndike, became interested in making the study of the mind more scientific. They believed that the best way to understand the mind of man was to study his behavior. Understandably, the school of thought they founded is called behaviorism.
Once psychologists began studying behavior, they found that they could predict certain kinds of behavior and abilities. They devised tests to predict intelligence, personality traits, career aptitudes, and other areas of human performance.
Men called psychometrists specialized in giving and interpreting these tests. These tests are used to predict academic performance and many other aspects of behavior. Often clinical psychologists and psychiatrists use the tests to help diagnose the illnesses of their patients.
As you know, psychology is still a young science. In the short time since Freud, Watson, and Thorndike laid the foundations for this new science, men have found a new window into the human mind.
Further research. You may want to obtain more information about these subjects. You can consult the World Book. Look up the materials under the entries for psychiatry, psychology, and psychoanalysis.
