Thursday, October 27, 2016

Taxonomy


List-makers, rule followers and professional organizers can appreciate taxonomy, the branch of science concerned with the classification and organization of organisms. The taxonomic code is more than grouping spiders with spiders and mushrooms with mushrooms, however. Taxonomy explains how living things on Earth relate to one another, whether a bacterium, an ape or an oak tree.

Working in the 18th century, Swedish naturalist Carl Linnaeus organized living things based on physical similarities. And in further proof that organization matters, this binomial nomenclature led to Charles Darwin making important discoveries about evolution. Taxonomy even contributed to the understanding of DNA.

Attempts to understand how distinct organisms are related to each other go back • farther than the 1700s. Probably the best known example is the Greek philosopher Aristotle, who was also most likely the first to classify each known organism, or "being." It is Aristotle's writings on how to divide and classify organisms that brought us the terms substance, genus and species. Aristotle used several features to classify organisms, such as whether they had "red blood: how they reproduced and what kind of habitat they lived in. Aristotle's work also paved the way for naturalists like Linnaeus, who—as a student of the Enlightenment—would have read his classical works.

Carl Linnaeus (1707-1778) is often known as the "father of modern taxonomy"—and for good reason. An eclectic polymath, he drew heavily on the research of his peers to create a robust system of codified classification for all living things. His Systema Naturae, first published in 1735 and continually updated, utilized a new system of classifying organisms based on a hierarchy that we still use today. The categorization by kingdom, phylum, class, order, family, genus and species was pioneered by Linnaeus, and gave rise to the system of binomial nomenclature to differentiate every organism, such as humans (Homo sapiens) from chimpanzees (Pan troglodytes). 

The organization of how he grouped various organisms has since been heavily modified due to advances in developmental biology. In simple terms, scientists divide and classify organisms based on the similarities or differences between them. However, the actual process is much more complicated. This is because two animals can look alike, but have vastly different evolutionary histories. For example, both birds and bats have wings, but are not closely related at all, whereas dinosaurs are now thought to be the ancient ancestors of birds. So these scientists—called systematists—must distinguish between similarities that are meaningful, and similarities that simply arose by chance. In order to do this, systematists examine very closely such features as anatomy, development and methods of sexual reproduction, as well as the fossil record. Recently, advances in genetics have allowed taxonomic classification at the genetic level.

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