Classification PPT

The History of Classification
350 BC - Aristotle - living things were animated by a vital
force different from anything found in nonliving matter.
 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 presentday biologists use the term)
and then distinguished the
The History of Classification
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
His system, the Linnaen System, which included the 7 level
taxonomy was based on the most evident characteristics of
organisms - their morphology.
The History of Classification
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
 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
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.
 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 classifications of living
organisms has evolved
from two kingdoms (animal
and vegetable) to six
kingdoms to the current
(2004) system of three
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.