MODULE 3

• Etymology of Taxonomy: From a Greek word

  taxis - arrangement or order

  nomos – law

  nemein - means to distribute or govern)
• Taxonomy - the science of biological classification.
• Taxa or Taxon – a group or level of classification or hierarchy categorized at different levels
• Systematics or phylogeny - the study of diversity of organism and their evolutionary relationship
• Classification - taxa are classify based on the similarities in phenotypic (phenetic) characteristics which are expressed in an organism and can be examined visually or can be tested by other means.
• Nomenclature - branch of taxonomy concerned with the assignment of names to taxonomic groups in agreement with published rules.
• Artificial System – share the same characteristics but they are not closely related to one another genetically.
• Natural System – with many of the same characteristics and highly predictive.
• Phylogenetic (Phyletic) System – classifying organism on the basis of descent from a common ancestor
• Phenotypic (Phenetic) Classification System -Groups do not necessarily reflect genetic similarity or evolutionary relatedness. Instead, groups are based on convenient, observable characteristics.
• Genotypic Classification System - considers characteristics of the genome
• Family - encompasses a group of organisms that may contain multiple genera and consists of organisms with a common attribute.
• Genus - Grouping similar genera into common families and similar families into common orders is used for classification of plants and animals (i.e., division, class, and order)
• Species

  • population or groups of populations that can potentially interbreed freely within and among themselves.
• Subspecies are taxonomic subgroups within a species.
• Biotype - a group of organisms having the same or nearly the same genotype
• Serotype - a group of organisms within a species that have the same type and number of surface antigens.
• Genotype may be given to groups below the subspecies level that share specific but relatively minor characteristics.
• Clone is a population of cells derived from a single parent cell and identical
• Strain - came from pure cultures of the same species are not identical in all ways.
• Serovar - a strain differentiated by serological means. Strains vary in their antigenic properties
• Biovar (biotype) - strains that are differentiated by biochemical or other non-serological means.
• Morphovar (morphotype) - a strain which is differentiated on the basis of morphological distinctions.
• Isolate - a pure culture derived from a heterogeneous, wild population of microorganisms. The term isolate is also applicable to eucaryotic microorganisms as well as to viruses.
• Nomenclature - rules governing microbial nomenclature is limited to two taxa known as binomial nomenclature.
• Identification - the process by which a microorganism’s key features are delineated.
• Genotypic characteristics - relate to an organism’s genetic makeup, including the nature of the organism’s genes and constituent nucleic acids
• Phenotypic characteristics - are based on features beyond the genetic level, including both readily observable characteristics and features that may require extensive analytic procedures to be detected.