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Diversity in living organisms


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Diversity in living organisms

  2. 2. DEFINITION CLASSIFICATION A system of arrangement oforganisms into different groups onthe basis of their similarities,differences and relationship.
  3. 3. Classification is also known asTAXONOMY. It is the branch of sciencewhich deals with and is definedas Identification, nomenclatureand classification of organismswith certain principles.
  4. 4. NEED / IMPORTANCE OF CLASSIFICATION1. It makes the study of wide variety of organism easy.2. The study of organisms is made easy as learning about an organism belonging to a specific ‘GROUP’ is easy.3. It also helps to understand the interrelationship among different organisms.4. Many other biological sciences depend on the correct knowledge of characteristics of organisms which classification provide. Eg in ecology, forestry, biogeography , applied
  5. 5. Hierarchy of Classification Groups As classification deals with grouping theorganisms ,which are called TAXA {Taxon} ,each taxa is given a name and they arearranged in a specific pattern in the flowchartof order/sequence. The organisms that closely resemble areplaced in a taxon and further the taxa relatedare put together in a larger taxon. There are 7such taxa.
  7. 7. HISTORY• Aristotle gave the first but crude classification.• Carolus Linnaeus in the 18th century gave the first basis of modern classification. He divided organisms into 2 kingdoms : PLANTAE [ Plant Kingdom] and ANIMALIA [ animal kingdom] because he could see only these .• Ernst Haeckel , a german zoologist , further added one more kingdom PROTISTA which included all unicellular organisms.
  8. 8. • Robert Whittaker , as more developments in biological sciences happened, found that there were significant differences among organisms of the protista and hence he defined two more kingdoms MONERA , FUNGI.• Thus the 5 kingdom classification by R.H. Whittaker came into existence, which is still the basis of modern classification.
  9. 9. Whittaker based his classification on 4 factors namely :1.Cellular structure- whether the organism is Prokaryotic or Eukaryotic.2.Cellular organization- whether the organism is Unicellular or Multicellular. In multicellular organisms what is the level of organization.3.Mode of source of nutrition- whether the organism is Autotrophic or Heterotrophic.4.Phylogenetic relationships- phylogeny means evolutionary history of a species.
  11. 11. Evolution and Classification• Darwins theory of evolution states that all present – day organisms have originated from the same source and during the course of time have evolved into complex organisms by bringing about variations within it’s body to adapt to the changing environment.• This can be easily seen and studied in the classification because it is an arrangement where phylogeny is considered as one of the main criteria.
  12. 12. Classification and Nomenclature• Nomenclature means to name an organism.• Naming an organism is essential to identify it as well as distinguish it from the others.• In biology all organisms are given specific scientific names. This is done to avoid any confusion when an interaction is held among people of different vernacular regions.• Binomial Nomenclature : It was proposed by Carolus Linnaeus, according to this a scientific name consists of 2 components, first the generic name and second is the specific name.
  13. 13. • This system is accepted internationally and is guided by rules stated in the INTERNATIONAL CODE OF NOMENCLATURE. They are further branched as international code of botanical nomenclature , international code of Zoological nomenclature, international code of bacterial nomenclature as plants, animals and bacteria are named with slightly different codes.• General rules to name an organism scientifically are: