History of biology in 19th and 20th century

History of biology in 19 and 20 century

Biology is a science which studies living organisms. The history of biology is very long and there are many scientists who study that. First man who used the word “biology” was Jean Babtiste Lamarck (1744 - 1849). The history of biology is the study of the living world from ancient to modern times. The first biologists were in an ancient Greece, for example Plato or Aristotle, they started to study nature and living organisms around them. During the Renaissance and early modern period, biological thought was revolutionized by a renewed interest in discovery of many new organisms. The most important scientists in this movement were Vesalius and Harvey, who used experimentation and careful observation in physiology, and naturalists such as Linnaeus and Buffon who began to classify the differences of life, as well as the development and behavior of organisms. The discovery of microscopes explore previously unknown world of microorganisms, laying the groundwork for cell theory.

The cell theory:

This theory was developed in 1838 by botanist Mattias Schleiden and zoologist Theodor Schwan. This theory says:

1. All known living organisms are made from cells.
2. The cell is a basic structural and functional unit of all living organisms.
3. All cells come from pre-existing cells by division.
4. Cells contain hereditary information which is passed from cell to cell during cell division.
5. All cells are basically the same in chemical composition.
6. All energy flow (metabolism and biochemistry) of life occur within cells.

In the 19 century biological sciences such as botany and zoology became more professional scientific disciplines. Lavoisier and other physical scientists began to connect the living and nonliving worlds through physics and chemistry. Explorer-naturalists such as Alexander von Humboldt investigated the interaction between organisms and their environment, and the ways this relationship depends on geography, and started to make new sciences like biogeography, ecology and ethology. Cell theory provided a new perspective on the basic forms of life. These developments, as well as the results from embryology and paleontology, were published in Charles Darwin's theory of evolution by natural selection. In the early 20th century, the rediscovery of Mendel's work led to the rapid development of genetics by Thomas Hunt Morgan and his students. New disciplines developed rapidly, especially after Watson and Crick who propose the double helical structure of DNA .


The most important and famous scientists in 19 and 20 century:

Jean Baptiste Lamarck- In either 1802 or 1809, published his theory of evolution. A number of another attempts were made to support or disprove this theory without the benefit of our modern knowledge of genetics. One experiment involved amputation of mouse tails for successive generations, showing that even after twenty generations, there was no effect: baby mice were still born with tails.

Charles Darwin- He was one of the most important scientists in the history. He published his own theory of evolution. In this theory he publish his opinion what was: the every organism, animal or human, evolve from a few common ancestors through the process of natural selection and every organism has to change or adapt to the nature around them. He first thought about this theory in 1838. Historians think that he didn’t publish his theory because he was afraid that people wouldn’t accept his theory because it was in the difference with the religion. So he didn’t publish it until 1859, when he heard that another scientist, Alfred Wallace had the same ideas. Wallace was close to publishing his ideas. So Darwin published his theory in the book. The name of the book was: On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life. This is also just called The Origin of Species.

Theodor Schwan- He was zoologist. Among his many contributions to biology there was the development of cell theory, the discovery of Schwann cells in the peripheral nervous system, the discovery and study of pepsin, the discovery of the organic nature of yeast and the invention of the term metabolism.

Mattias Schleiden- He was a German botanist and co-founder of the cell theory. Schleiden preferred to study plant structure under the microscope. While a professor of botany at the University of Jena, he wrote Contributions to Phytogenesis (1838), in which he stated that the different parts of the plant organism are composed of cells.

Alfred Russel Wallace- He was another naturalist. He was independently working on the theory what was same like Darwin’s. The result of his work was: Darwin was the first person to come up with these ideas, while until recently, Wallace’s work was almost totally ignored. Darwin’s friends want from him to publish his theory, and the Origin of Species was the result. Darwin eventually published several other books describing his ideas and theories. And the Wallace’s work has been forgotten and ignored.
Louis Pasteur- He was a French chemist and biologist best known for his discoveries in microbiology. His experiments confirmed the germ theory of disease and he discover that microbes, viruses and bacteria makes the diseases, also reducing mortality from puerperal fever, and he created the first vaccine against rabies. He is best known to the general public for showing how to stop milk and wine from going sour - this process came to be called pasteurization. He is regarded as one of the three main founders of microbiology, together with Ferdinand Cohn and Robert Koch.

Johan Gregor Mendel- He was an Austrian monk, published a paper on genetics that earned him the nickname “the Father of Modern Genetics.” One of Mendel’s jobs at the monastery was to care for the garden. He noticed the differences between the plants of the same kind. From this he developed a theory of genetics that refuted the pangene idea and enabled people to predict the outcome of a genetic cross if the genes of the parents were known. When Mendel first published his paper, the idea of the pangenes it was ignored his work or dismissed it as false. It wasn’t until 1900 that a couple of botanists working on other research rediscovered his work.

In 1870 the process of mitosis, regular cell division by which one cell divides to make two cells, was observed, and researchers noticed that chromosomes, whose function was not understood, were moving around in the cell during mitosis so that each daughter cell got an exact set of them.

James Watson, an American, and Francis Crick, an Englishman, used the x-ray data collected by another scientists to propose a hypothetical structure for DNA molecule, which also showed how DNA could be the genetic code material and suggested a means what it could replicate itself. Another chemical analyses of DNA have confirm their prediction. For their work they received the Nobel Prize award in 1962.


Timeline

1655 - Robert Hooke (1635-1703) of Britain designed his own microscope and discovered matter made up of what he called cells.
1759 - C.F. Wolff (1733-1794) of Germany proposed a general cell theory.
1838 - Matthias J. Schleiden (1804-1881) of Germany published a cell theory as applied to plants.
1839 - Theodor Schwann (1810-1882) of Germany published cell theory as applied to animals.
1857 - Gregor Johann Mendel (1822-1884), an Austrian monk, began experiments with pea plants. He later became known as the "father of genetics."
1859 - English biologist Charles Darwin (1809-1882) published “On the Origin of Species,” explaining units of heredity and variations in species.
1865 - Mendel announced his theories of heredity, known as Mendel’s Laws.
1869 - Sir Francis Galton (1822-1911) of Britain published his book, Hereditary Genius, claiming that heredity alone is responsible for a person’s character traits.
1882 - German biologist Walther Fleming (1843-1905) used dyes to stain cells; he discovered rods he called “chromosomes.”
1886 - Dutch botanist Hugo de Vries (1848-1935) created term “mutation” while experimenting with primroses.
1887 - Belgian biologist Edouard van Beneden (1846-1910) discovered that all organisms of the same species have the same number
1892 - August Weismann (1834-1914) published an essay on heredity. He proposed heredity was transmitted by a substance with a “chemical and molecular constitution”--he greatly influenced subsequent biologists.of chromosomes
1900 - De Vries published a paper that included the laws of inheritance as do two others: German botanist Karl Erich Correns (1864-1933) and Austrian botanist Erich Tschermak von Seysenegg (1871-1962).
1901 - De Vries published a paper on mutations.
1902 - American biologist Walter Stanborough Sutton (1877-1916) demonstrated that chromosomes exist in pairs that are structurally similar.
1903 - Sutton proved that sperm and egg cells have one of each pair of chromosomes
1908 - American biologist Thomas Hunt Morgan (1866-1945) with Alfred H. Sturtevant of the U.S. showed that genes were located on chromosomes; he experimented with Drosophelia (fruit flies) to investigate sex chromosomes, and discovered X and Y chromosomes, sex-linked traits, and crossing-over.
1909 - Danish botanist Wilhelm Ludvig Johannsen (1857-1927) proposed that each portion of a chromosome that controls a phenotype be called a “gene” (Greek: “to give birth to”).
1913 - Alfred Henry Sturtevant (1891-1970) began constructing a chromosome map for Drosophelia (it was completed in 1951 for all four Drosophelia chromosomes).
1919 - Hermann Joseph Muller (1890-1976) of the U.S. experimented with Drosophelia to create more mutant flies
1941 - George W. Beadle (1903-1989) of the U.S. and Edward L. Tatum (1909-1975) of the U.S. discovered that genes control the production of enzymes.
1944 - Oswald T. Avery (1877-1955) of the U.S. announced that DNA alone is the substance responsible for heredity.
1952 - Francis H. C. Crick (1916- ) of Britain and James D. Watson (1928- ) of the U.S. made a model of the DNA molecule and proved that genes determine heredity.
1950’s - Maurice Wilkins (1916- ), Rosalind Franklin (1920-1957), Crick and Watson discover chemical structure of DNA, starting a new branch of science--molecular biology.
1957 - Arthur Kornberg (1918- ) of the U.S. produced DNA in a test tube.
1966 - The Genetic code was discovered; scientists are now able to predict characteristics by studying DNA. This leads to genetic engineering, genetic counseling
1972 - Paul Berg (1926- ) of the U.S. produced the first recombinant DNA molecule.

1982 - The first recombinant DNA drug approved by the FDA--genetically engineered insulin for diabetics.
1983 - Barbara McClintock (1902-1992) of the U.S. was awarded the Nobel Prize for her discovery that genes are able to change position on chromosomes.
1988 - An international team of scientists began the project to map the human genome.
The Late 1980’s - The first crime conviction based on DNA fingerprinting, in Portland Oregon.