topic 1 - bacterial classification schemes

Topic 1 - BACTERIAL CLASSIFICATION SCHEMES

22 Apr 2023 MIC250 by Miss Rashidah Iberahim 1

Topic contentCharacterisation of speciesBinomial systemProblems of classificationPhylogenetic classificationNumerical taxonomy


Characterisation of species

Taxonomist discover 200 yrs agoTaxonomy-field of biological species

classificationMany m/o look alike to be classified

according to the structureLiterally hundreds of bacterial species are

small rods or small cocci


Shapes


Arrangements


Bacterial morphology

List down types of bacterial shapes that can be found in above picture.


Taxonomic HierarchyA number of species make up a genus,

related genera make up a family. Scientific name for m/o (Genus species)

How to write these names??Vibrio choleraeStaphylococcus spE.coli


Binomial system

Question?///Define taxaGenusSpeciesStrainTaxonomy


Problems in classification1. General problems

Establishing a standard names for organisms so that we can communicate about them

Usually classified according to their phylogenetic or evolutionary, but not always easy

Leads to introduction of a dichotomous key


Dichotomous keyHas paired statements describing

characteristic of organismsPaired statement can only have one

statement trueEach paired statement relate to each other


Reasons causing problems1. Deciding what constitutes a species –

because of some bacteria have the similar characteristics so taxonomist try to tolerate the organism within species

2. Deciding what constitutes a kingdom – because most of organism having sexually reproduction so have vary factors affecting the variable of the characteristics


Focusing on bacterial classificationOther organism categorized from domain to

species, but for prokaryotic cell, start from strain to genus

However facing problems reaching the classes and orders level

Wide range of studies needed on identification and building up taxonomy of bacteria


Phylogenetic classificationHierarchy domain – Bacteriakingdom – none assign for bacteriaphylum – Proteobacteriaclass – Gamma-proteobacteriaorder – Enterobacterialesfamily – Enterobacteriaceagenus – EschericiaSpecies – E.coli


start

Three domain system classification


Based on the idea that increasing the number of characteristics of organisms that we observe, increases the accuracy with which we can detect similarities among them

The more characteristics of two organisms share, the closer their evolutionary relationship

By laboratory investigation, the similarities and differences will be detected and categorized in particular group


Numerical taxonomy

Terminologies (answer)Taxa – subdivisions used to classify organism:

domain, kingdom, phylumPhylogeny / sytematic – the evolutionary

history of a group of organism; phylogenetic relationships are evolutionary relationship

Taxonomy – the science of the classification of organism


topic 1 - bacterial classification schemes

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