The germ theory is a theory that some diseases are caused by microorganisms Give the Authors name and contribution for the following dates 1150 1676 1857 1895 and 1900?

Answer 1

Biology in the 20th century, just as the 19th century, can be considered the age of cellular biology; the 20th century has been characterized by developments in molecular biology.

Important conceptual developments

By utilizing modern methods of investigation, such as X-ray diffraction and electron microscopy, to explore levels of cellular organization beyond that visible with a light microscope-i.e., the ultra structure of the cell-new concepts of cellular function have been produced. Not only has the study of the molecular organization of the cell probably had the greatest impact upon biology during the 20th century but it also has led directly to the convergence of many different scientific disciplines in order to acquire a better understanding of life processes.

Another 20th-century development has been the realization that man is as dependent upon the Earth's Natural Resources as are other animals. The progressive destruction of the environment can be attributed, in part, to an increase in population pressure as well as to certain technological advances. Thus, though lifesaving advances in medicine have resulted in a dramatic drop in the Death Rate, they have also been a factor contributing to the explosive increase in the human population. Moreover, chemical contaminants being introduced into the environment by manufacturing processes, pesticides, automobile emissions, and other means are seriously endangering all forms of life. It is for these reasons that biologists are beginning to pay much greater attention to the relationships of living things to each other as well as to their biotic and abiotic environments.

Changing social and scientific values

The biologist's role in society as well as his moral and ethical responsibility in the discovery and development of new ideas has led to a reassessment of his social and scientific value systems. A scientist can no longer ignore the consequences of his discoveries; he is as concerned with the possible misuses of his findings as he is with the basic research in which he is involved. This emerging social and political role of the biologist and all other scientists requires a weighing of values that cannot be done with the accuracy or the objectivity of a laboratory balance. As a member of society, it is necessary for a biologist now to redefine his social obligations and his functions, particularly in the realm of making judgments about such ethical problems as man's control of his environment or his manipulation of genes to direct further evolutionary development.

Coping with problems of the future

As a result of recent discoveries concerning hereditary mechanisms, genetic engineering, by which human traits are made to order, may soon be a reality. As desirable as it may seem to be, such an accomplishment would entail many value judgments. Who would decide, for example, which traits should be selected for change? In cases of genetic deficiencies and disease, the desirability of the change is obvious, but the possibilities for social misuse are so numerous that they may far outweigh the benefits.

Probably the greatest biological problem of the future, as it is of the present, will be to find ways to curb environmental pollution without interfering with man's constant effort to improve the quality of his life. Many scientists believe that underlying the spectre of pollution is the problem of surplus human population. A rise in population necessitates an increase in the operations of modern industry, the waste products of which increase the pollution of air, water, and soil. With predictions that, at the present rate of reproduction, the Earth's population will be approximately 7,000,000,000 by the year 2000, the question of how many people the resources of the Earth can support is one of critical importance.

Although the solutions to these and many other problems are yet to be found, they do indicate the need for biologists to work with social scientists and other members of society in order to determine the requirements necessary for maintaining a healthy and productive planet. For although many of man's present and future problems may seem to be essentially social, political, or economic in nature, they have biological ramifications that could affect the very existence of life itself.

Answer 2

1150: Ibn Sina (Avicenna) - Described the transmission of diseases through water and soil. 1676: Antonie van Leeuwenhoek - First observed microorganisms under a microscope. 1857: Louis Pasteur - Demonstrated that microorganisms can cause fermentation and disease. 1895: Wilhelm Roentgen - Discovered X-rays, which later became important in medical imaging. 1900: Paul Ehrlich - Developed the "magic bullet" concept for targeting specific disease-causing agents.