Classifying NatureLinnaeus, Buffon, Cuvier, Whittaker

Linnaeus (Carl von Linnae, 1707-1778)• Swedish naturalist

who studied medicine in the Netherlands.

• Main concern was naming and classifying natural objects.

• Studied plants in Dutch gardens that had been collected from around the world.

Linnaeus • Journeyed to Lapland to

study the animals and plants, later published Flora Lapponica in 1737.

• Soon after his return, Linnaeus was offered a position as house physician and garden curator to George Clifford, a wealthy merchant.

Linnaeus• 1735: Linnaeus published Systema Naturae, his

first system for ordering natural history. He admitted that it was an “artificial” rather than a “natural” system, but felt that its utility justified using a less natural system.

• Linnaeus’ choice of terms reflect his cultural background. Referred to plant stamens as andria (“husband”) and pistils as gynia (“wife”). His writings refer to “marriages” between plants, including multiple spouses and concubines. Shocking to other Dutch naturalists, but his terms were adopted nevertheless.

Linnaeus• 1736: Linnaeus formally publishes his system of

binomial nomenclature. Proposes that all natural objects, including plants, animals, minerals, etc. receive a single name consisting of a genus and a specific epithet.

• 1753: Linnaeus publishes the Species Plantarum, a description and classification of known organisms. Included are human beings, given the species name Homo sapiens. Interestingly, Linnaeus also placed the known great apes in genus Homo.

Georges-Louis LeClerk, Compte de

Buffon 1707-1788

• Buffon was a competitor of Linnaeus, advocating for the development of a natural system of classification.

Buffon

• Buffon’s taxonomy was based on “natural families.” He noted, for example, that wolves, foxes, and dogs all have similar features, and constitute a natural family. Horses, zebras, and donkeys would belong to a different natural family.

• Later Buffon would propose an early theory of evolution, describing how organisms could change by their environment into similar species within the same natural family.

Georges Cuvier 1769-1832

Studied Buffon, and agreed that there should be a natural taxonomy.

However, Cuvier parted with other taxonomists at the time, as he believed the taxonomic system should not be hierarchical.

Cuvier

• Cuvier used internal anatomy of animals to sort them into categories, based mainly on neural anatomy: Vertebrata, Mollusca, Articulata, and Radiata.

• Comparative anatomist: looking for patterns in structure, especially among vertebrate animals.

The Two Kingdom System• Linnaeus’ two-kingdom system for living

organisms was practical for naturalists working in the field, and eventually took precedence.

• In this system, all living organisms are classified as Animals or Plants (the Mineral kingdom encompassed the non-living part of the world). As time went on and microorganisms were studied more, problems arose with the two-kingdom system. Some organisms just didn’t fit neatly.

Robert Whittaker (1920-1980)

• Dissatisfied with the two-kingdom system, as many single-celled organisms didn’t fit well in it.

• For example, Euglena has chloroplasts and photosynthesizes like a plant, but is motile and can ingest food like an animal.

• Developed first a three-kingdom, then four-kingdom and five-kingdom systems.

Today’s System• Recently, Domains were added above the

level of kingdom to express how different the two large groups of bacteria are from one another.

• Domains:

• Archaea

• Bacteria

• Eukarya: Protists, Fungi, Plants, Animals