Lecture 5: Taxonomy and Nomenclature PDF

LECTURE 5 Taxonomy and Nomenclature Ms. Peters  Taxonomy Taxonomy - the science of discovering, describing, and naming related species and group of organisms Carolus Linnaeus , known as Father of Taxonomy is credited with establishing taxonomy as a separate science...

LECTURE 5 Taxonomy and Nomenclature Ms. Peters  Taxonomy Taxonomy - the science of discovering, describing, and naming related species and group of organisms Carolus Linnaeus , known as Father of Taxonomy is credited with establishing taxonomy as a separate science and binomial nomenclature Main aims of Taxonomy – Classification of organisms – Show relationships among organisms – Way to provide universal identification of an organism making them easily understood  Taxonomy Cont. Phylogenetic Classification System: – Groups reflect genetic similarity and evolutionary relatedness – Grouping organisms descending from a common ancestor – Produces a nested hierarchy where an organism is assigned a series of names that specifically locate it within said hierarchy. Phenetic Classification System (Numerical Taxonomy) : – Groups are based on convenient, observable characteristics and morphology  Taxonomic Hierarchy. Taxonomic ranks are the categories used in the classification of living organisms. A group of organisms occupying a specific rank is called a taxon Nested; each successively lower level being contained within the one above.  Taxonomic Hierarchy. Broad divisions are divided into smaller divisions: – Domain – Kingdom – Phylum (Division) – Class – Order – Family – Genus – Species Dumb Kids Playing Chase On Freeways Go Splat!  Taxonomy Cont. Currently five Kingdoms exist: – Plantae – Animaliae – Monera – Protista – Fungi Which kingdom does bacteria and protozoa belong to?  Taxonomic Hierarchy Each organism is assigned a species name Species of similar organisms are grouped into a genus. The genera having very similar characteristics are grouped into a family Several families grouped into an order Several orders are group into a class All similar classes are grouped into a Phylum.  Taxonomic Hierarchy Organisms in a similar phylum can be grouped under the same Kingdom All fall under the domain Eukaryotes or Prokaryotes  Taxonomic Hierarchy Domain Prokaryote Prokaryote Kingdom Monera Monera Phylum Gracillicutes Gracillicutes Class Scotobacteria Scotobacteria Order Eubacteriales Spirochaetales Family Enterobacteriaceae Spirochaetaceae Genus Escherichia Treponema Species Escherichia coli Treponema pallidum Strain: E. coli O157:H7  Binomial Nomenclature Name of every organism is composed of two parts: – The generic name represents the taxon i.e., the genus to which the organism belongs – The second name is called specific epithet – i.e., the species to which the organism belongs – The generic name always begins with a capital letter and the specific name with a lowercase letter.  Binomial Nomenclature Cont. The scientific name of an organism is always written in italics or underlined font style. E.g., Staphylococcus aureus or Staphylococcus aureus Homo sapiens or Homo sapiens If the identical species is written repeatedly, it can be abbreviated after the initial mention e.g., Escherichia coli is often written as E. coli Binomial Nomenclature Cont.  Binomial Nomenclature Cont. Abbreviation “sp.” is used when the precise specie is not known or does not need to be stated or cannot be specified. The abbreviation “spp.” indicates several species. E.g., Canis sp. - an unspecified species of the genus “Canis”, “Canis spp.” - two or more species of the genus Canis” These scientific names are used globally regardless of language or region Different organisms cannot posses the same scientific name.  Binomial Nomenclature Cont. The nomenclature of organisms is governed by a set of rules framed by International Codes of Nomenclature. Different codes of nomenclature exist for different groups of organisms Naming of bacteria - International Code for Nomenclature for Bacteria (ICNB) Naming of animals - International Code of Zoological Nomenclature (ICZN) Naming of plants - International Code of Botanical Nomenclature (ICBN) Naming of algae and fungi - International Code of Nomenclature for algae, fungi  Binomial Nomenclature Cont. Advantages of Binomial Nomenclature: – Biological names are simple, meaningful, and universally accepted. – Easy to remember and understand. – Shows the evolutionary history of the species. – Distinguish each organism from others. – Provides stability  Binomial Nomenclature Cont. Disadvantages of Binomial Nomenclature – If two or more names are currently in use, the correct name will be the one used first – Names used prior to those included in the “Systema Naturae”, by Linnaeus are not recognized.  Viral Nomenclature The International Committee on Taxonomy of Viruses (ICTV) is responsible for developing this system. Important because it places the clinical, biological and evolutionary features of a virus into a framework that accommodates and connects all viruses Classified into groups (taxa) according to their similarities and dissimilarities The endings used to denote the different ranks and the format in which names are written  Viral Nomenclature The order always ends in the suffix – ‘virales’ The family ends in – ‘viridae’ The subfamily ends in – ‘virinae’ The genus ends in – ‘virus’ The species is stated as the individual virus E.g., Polio Disease – Order - Picornavirales – Family - Picornaviridae – Genus – Enterovirus – Species – Polio virus Viral Nomenclature Homework State the Family, genus and species for the causative agent of the following: – Yellow Fever – Chicken Pox – AIDS – COVID Define bacterial species and bacterial strain.