EVOLUTION…OF THE CLASSIFICATION

SYSTEMFOR ORGANISMS

The History of Classification

Out of this concept was developed the "scale of nature" idea that suggested living things were arranged on a scale of perfection, with man at the top.

originated the concept of genera (used in a much broader sense than present-day biologists use the term) and then distinguished the species.

350 BC - Aristotle - living things were animated by a vital force different from anything found in nonliving matter.

300 BC - Theophrastus, a student of Aristotle, classifies 500 plants under herbs, shrubs, pre-shrubs & trees.

1758 - Carolus Linnaeus (Karl von Linné) Swedish Naturalist- (Linnean System) - Introduced Class, Order, Genus & Species and Binomial Nomenclature (A system in which two names are employed.

The History of Classification

His system, the Linnaen System, which included the 7 level taxonomy was based on the most evident characteristics of organisms - their morphology.

1859 - Charles Darwin "The Origin of Species by means of natural selection"This started a new effort to classify groups which had descended from a

common ancestor. 1866 - Ernst Haeckel Organized a "tree of life" and proposed

new kingdom Protista for protozoa and most algae. Early 20th century - The systematics movement was

characterized by the detailed study of organisms as members of populations

The History of Classification

1942 - Ernst Mayr publishes "Systematics and the Origin of Species from the Viewpoint of a Zoologist" The major problem with the evolution of taxonomy

is that it was created before Darwin and was too slow in adopting the evolutionary relationship between species.

Modern Phylogenetic Taxonomy uses DNA analysis and embryological development in addition to traditional characteristics to show evolutionary relationships.

The History of Classification

1977 - Carl Woese, professor of Microbiology at the University of Illinois at Urbana-Champaign, defined the Archaea (a new domain or kingdom of life) by phylogenetic taxonomy of 16S ribosomal RNA.

1978 - WHITTAKER FIVE KINGDOM SYSTEM

1994 - Carl Woese (U. Ill.) publishes "Universal Phylogenic tree in rooted form"Archaea (Archaebacteria) was split out

of what was called the SuperKingdom of Prokaryota or Monera (Bacteria).

The History of Classification

Summary The classifications of living

organisms has evolved from two kingdoms (animal and vegetable) to six kingdoms to the current (2004) system of three Domains.

Historically, classification has been by comparison of anatomy since 1960, use of molecular tools has allowed classification based on differences in DNA (and proteins) to identify common ancestries (a shared genetic heritage).

Unfortunately Zoologists and Botanists have different views on how things should be classified.