Systematic and Evolution

Schematic of Biology

Modern nomenclature based on a practical binomial system originated with Carolus Linnaeus. In addition to arranging plants and animals into genus and species based on structure, he introduced the categories of class and order. In 1817, Georges, Baron Cuvier, become the first to divide the entire animal’s kingdom into subgroups, for example, vertebrate, mollusca, articulate, and radiate.

During the 18th and 19th centuries numerous biological expedition were organized. On perhaps the most famous voyage, Charles Darwin circumnavigated (1831-36) the globe on the Beagle. His observation of birds, reptiles, and flowering plants in the Galapagos Island in 1835 laid the foundation for his theories on evolution.

The Discovery of Microorganisms

Argument about the spontaneous generation of organisms had been going on since the time of Aristotle. Louis Pasteur clearly demonstrated in 1864 that no organisms emerged from his heat sterilized growth medium as long as the medium remain in sealed flasks, thereby disproving spontaneous generation. Based on Edward Jenner’s studies of smallpox, Pasteur later developed a vaccine for anthrax and in 1885 became in the first to successfully treat a human bitten by a rabid dog. Beginning in 1876, Robert Koch developed pure culture techniques for microorganisms. His work verified the germ theory of disease. One of his students, Paul Ehrlich, developed chemotherapy and in 1909 devised a chemical cure for syphilis.

The value of antibiotics became evident when Sir Alexander Fleming discovered penicillin in 1928. Many additional antibiotics have since been developed, and their use has resulted in a decreased incidence of most infectious diseases.