The history of taxonomy is described in four periods by Mayr. The first period focused on local fauna studies by ancient Greek scholars like Aristotle. The second period was marked by the acceptance of evolution, influenced by Darwin's ideas. The third period saw the rise of population systematics in the 1930s, where Mayr defined species as interbreeding natural populations. Current taxonomy in the fourth period utilizes a wide range of data beyond just morphology, including genetics, biochemistry, and behavior.

1. HISTORY OF TAXONOMY

2. • Mayr described the history of taxonomy in
four periods.
• 1st Period
• 2nd Period
• 3rd Period
• 4th Period

3. 1st Period(Study of local fauna)
• Native of primitive tribes were excellent
naturalist.
• Study of fauna came from the contribution of
greek scholars.
• Aristotle(384-322 b.c) ,known as the father of
biological classification,referred to major
groups of animals as birds,fishes,whales and
insects.

4. • Aristotle thinking dominated for next two
thousand years.
• There are two major form of classification in
first period.
• i.Downward classification
• Ii.Upward classification

5. i.Downward classification
• Taxonomy based on local fauna reached its
peak by the work of Linnaeus(1707-1778).
• The method of downward classification are
principles of logical division which consists of
dividing larger groups by dichotomy into
smaller groups.e.g,
• Animals

6. Animals
blooded
Two-footed
Four-
footed
bloodless

7. • Linnaeus adopted the principle of downward
classification in 15th edition of his
book(Systema naturae)
• He for the first time applied Binomial
nomenclature to animal kingdom.
• Linnaeus believed in fixity of species.

8. ii.Upward classification
• By the mid of 18th century the shortcommings
of downward classification were recognized.
• Gradually it was replaced by upward
classification.
• It consists of assembling species by inspection
into a group of similar or related species and
forming hierarchy by again grouping of similar
taxa of next lower rank.

9. • This thought was applied by a botanist in 1873
and later by nearly all zoologists.
• This shift from downward classification to
upward classification was a major philosophic
change.

10. Family
Genus 1
spp1 spp2
Genus 2
spp1

11. 2nd Period(Acceptence of evoluton)
• Evolutionary thought was widespread in 18th
century but owes its foundation to second
period.
• Darwin believed in fixity of species.but after
observing natural fauna in Galapagos island,he
begin to believe in the plasticity of species.
• Empirical taxonomists were greatly influenced
by his idea.

12. • The phylogenetic tree of Ernest Haeckal also
stimulated the empirical workers.
• Large number of new species were discovered
and described.

13. 3rd Period(Population systematics)
• The greatest development of modern
taxonomy srarted around 1930,when the
workers realized that the Linnaeus species
based on one or two specimens are not as
perfect as those which are based on
population.
• Due to this Mayr in 1942 considered species
as a group of interbreeding natural
population.

14. • This idea of population taxonomy was useful in
developing the polytypic concept.
• New terms like new systematics and
biosystematics were added to extend the
taxonomic theory.
• The publication of the book ‘new systematics
become a landmark in the history of taxonomy.
• Thus taxonomy got a new label of biological
taxonomy.
• By 1955 taxonomy reach such a status that it was
called taxonomic explosion.

15. 4th Period (current trends)
• New systematics deal exclusively with species.
• The present day taxonomic work include all
available differences and similarities.
• Instead of morphology as an original
base,phylogenetic adaptations,embryological
patterns,biochemical variations,genetic
variabilities and similarities,behavioural
characteristics are all applicable to taxonomic
study.