History

While some descriptions of taxonomic history attempt to date taxonomy to ancient civilizations, a truly scientific attempt to classify organisms did not occur until the 18th century. Earlier works were primarily descriptive and focused on plants that were useful in agriculture or medicine. There are a number of stages in this scientific thinking. Early taxonomy was based on arbitrary criteria, the so-called "artificial systems", including Linnaeus's system of sexual classification for plants (Of course, Linnaeus's classification of animals was entitled "Systema Naturae" ("the System of Nature"), implying that he, at least, believed that it was more than an "artificial system"). Later came systems based on a more complete consideration of the characteristics of taxa, referred to as "natural systems", such as those of de Jussieu (1789), de Candolle (1813) and Bentham and Hooker (1862–1863). These classifications described empirical patterns and were pre-evolutionary in thinking. The publication of Charles Darwin's On the Origin of Species (1859) led to new a explanation for classifications, based on evolutionary relationships. This was the concept of phyletic systems, from 1883 onwards. This approach was typified by those of Eichler (1883) and Engler (1886–1892). The advent of cladistic methodology in the 1970s led to classifications based on the sole criterion of monophyly, supported by the presence of synapomorphies. Since then, the evidentiary basis has been expanded with data from molecular genetics that for the most part complements traditional morphology.page neededpage neededpage needed

Pre-Linnaeanedit

Early taxonomistsedit

Naming and classifying our surroundings has probably been taking place as long as mankind has been able to communicate. It would always have been important to know the names of poisonous and edible plants and animals in order to communicate this information to other members of the family or group. Medicinal plant illustrations show up in Egyptian wall paintings from c. 1500 BC, indicating that the uses of different species were understood and that a basic taxonomy was in place.

Ancient timesedit

Organisms were first classified by Aristotle (Greece, 384–322 BC) during his stay on the Island of Lesbos. He classified beings by their parts, or in modern terms attributes, such as having live birth, having four legs, laying eggs, having blood, or being warm-bodied. He divided all living things into two groups: plants and animals. Some of his groups of animals, such as Anhaima (animals without blood, translated as invertebrates) and Enhaima (animals with blood, roughly the vertebrates), as well as groups like the sharks and cetaceans, are still commonly used today. His student Theophrastus (Greece, 370–285 BC) carried on this tradition, mentioning some 500 plants and their uses in his Historia Plantarum. Again, several plant groups currently still recognized can be traced back to Theophrastus, such as Cornus, Crocus, and Narcissus.

Medievaledit

Taxonomy in the Middle Ages was largely based on the Aristotelian system, with additions concerning the philosophical and existential order of creatures. This included concepts such as the Great chain of being in the Western scholastic tradition, again deriving ultimately from Aristotle. Aristotelian system did not classify plants or fungi, due to the lack of microscope at the time, as his ideas were based on arranging the complete world in a single continuum, as per the scala naturae (the Natural Ladder). This, as well, was taken into consideration in the Great chain of being. Advances were made by scholars such as Procopius, Timotheos of Gaza, Demetrios Pepagomenos, and Thomas Aquinas. Medieval thinkers used abstract philosophical and logical categorizations more suited to abstract philosophy than to pragmatic taxonomy.

Renaissance and Early Modernedit

During the Renaissance, the Age of Reason, and the Enlightenment, categorizing organisms became more prevalent, and taxonomic works became ambitious enough to replace the ancient texts. This is sometimes credited to the development of sophisticated optical lenses, which allowed the morphology of organisms to be studied in much greater detail. One of the earliest authors to take advantage of this leap in technology was the Italian physician Andrea Cesalpino (1519–1603), who has been called "the first taxonomist". His magnum opus De Plantis came out in 1583, and described more than 1500 plant species. Two large plant families that he first recognized are still in use today: the Asteraceae and Brassicaceae. Then in the 17th century John Ray (England, 1627–1705) wrote many important taxonomic works. Arguably his greatest accomplishment was Methodus Plantarum Nova (1682), in which he published details of over 18,000 plant species. At the time, his classifications were perhaps the most complex yet produced by any taxonomist, as he based his taxa on many combined characters. The next major taxonomic works were produced by Joseph Pitton de Tournefort (France, 1656–1708). His work from 1700, Institutiones Rei Herbariae, included more than 9000 species in 698 genera, which directly influenced Linnaeus, as it was the text he used as a young student.

The Linnaean eraedit

The Swedish botanist Carl Linnaeus (1707–1778) ushered in a new era of taxonomy. With his major works Systema Naturae 1st Edition in 1735, Species Plantarum in 1753, and Systema Naturae 10th Edition, he revolutionized modern taxonomy. His works implemented a standardized binomial naming system for animal and plant species, which proved to be an elegant solution to a chaotic and disorganized taxonomic literature. He not only introduced the standard of class, order, genus, and species, but also made it possible to identify plants and animals from his book, by using the smaller parts of the flower. Thus the Linnaean system was born, and is still used in essentially the same way today as it was in the 18th century. Currently, plant and animal taxonomists regard Linnaeus' work as the "starting point" for valid names (at 1753 and 1758 respectively). Names published before these dates are referred to as "pre-Linnaean", and not considered valid (with the exception of spiders published in Svenska Spindlar). Even taxonomic names published by Linnaeus himself before these dates are considered pre-Linnaean.