BIO 315 Lecture 10

BIO 315 Lecture 10 - Classification of microorganisms (and....

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Unformatted text preview: Classification of microorganisms (and. es-ery—thing else for that matter) - TAXONOMY - the science of the classification of organisms - Purpose — to show evolutionary relationships between groups — to provide a means of identifying organisms Two methods of classification ' Most scientists favor a PHYL-(i)GENETIC classification scheme; this reflects the actual ancestry (evolutionary relationships) between different organisms ' Phenetics is an alternative method, in which classification of organisms is based solely on obsen'able characteristics and the goal is more practical - identification and connnon language The Fire-kingdom System Manon - Luiieellular prolearyotea (ibaeteriai) (barred upon eellular organization) Protiata - Luiieellular eul<:ar3-'otea (protozoa algae) (Lbaaed upon eellular organization} Fungi - niultieellular lieterotroplia with extenial digestion {fr-’BflStSfilTlDldSfi niualiroonia) (baaed upon nutritional pattenii) Plantae - niultieellular autotroplia Lplanta) (ibaaed upon nutritional pattern) Animalia - niultieellular lieterotroplia with intenial {ligeation (animals) {ibaaed upon nutritional pfllttflfllj] KINGDOM MDNERA Plants Fungi Animals DOMAIN BACTERIA DOMAIN ARCHAEA DOMAIN EU KARYA '2’ The three Domains A domain is considered to be a new level apart from Kingdom, based en the fact that cells are really of three fundamental types: Eukarya (eukaljretea) Bacteria (meat bacteria) Are-llaea (arehaebaeteria) - no peptide gljgean in cell walla, extreme environmenta and Strange bieellenliatr}: lxleleeular atudiea of their DNA reveal the}? are not very related to eubaeteria. KINGDOM MONERA _. Plants Fungi HI‘Iil‘IE‘IEIB DOMAIN BACTERIA DDMAIN ARCHAEA DOMAIN EU KARYA / The Linnaean Taxonomic Hierarchy ' Traditionally has 7 tiors (8 if you count tho domains) * Domain, Kingdom, Phylum (Division), Class, Order, Family, Genus, Species * Tho tie-rs go from most inolusiyo to least, until you roaoh tho spooios or spooifio namo, usually donotod as gonus and species. This is oallod a binomial designation, and IV'IUST BE undorlinod or ffolfofssd. Also, tho gonus name must be capitalized, * Examples - Escherichia coir, Homo sag-Hons Examples: Classify this! Human being Demain - Euler-“try a Kingdem - Animalia Phylum - Cherdata Class - lx-lammalia Order - Primates Family - Heminidae Genus - Home speeies - sapiens Deg Demain - Euler-1r}? a Kingdem - Animalia Phylum - Cherdata Class - lvlammalia Order - Canrivera Family - Canidae Genus - {Yarns species -firmiiim*rs Examples: Classify this! Human being Dcmain - Eulcaryr Kingdcm - miimalia Phylum - Cherdata Class - lylr-unmalia Order - Primates Family - Heminidae Genus - Home species - snpr‘ems bacterium lilce E. cc??? Dcmain - Bacteria Kingdcm - Mcnera Phylum - Gracilicutes Class - Scctcbacteria Order - Entercbacteriales Family - Entercbacteriacieae Genus - Escherichia Species - cch' S Ernehetee '3 Green sulfur Eire-en r"|::m:;t.1|fur baflEfia Liar.” [L‘Fid Chiarnydias Pretee bacteria Simplified phylogeny of selected groups {kingdems} of the Domain Bacteria. TREE OF BACTERIAL PHYLOGENY Bacteria are classified according to... - Bergey‘s h-—lanual of Bacteriology - In 1923. the first edition of the lyfanual was published under the auspices of the organization that is today the American Society for lylicrobiology (Dr. David H. Bergey was the Clrairn‘raif}. - The official title of this publication is “Bergey’s lvfanual of DETE-Rly-IINATIRE Bacteriology. " The latest edition was published in 1994. - It should be clear that through much of its history. the classification was performed based on “obseryal‘ile characteristics". or phenetics. although care was talcen to try to reflect phylogeny as much as was possible. Characteristics used to classify bacteria - h-Icrphclcgical characteristics Lshapc. ctc.) - Diffcrcntial Staining (Grant stain) - Nutriticnal Pattcm - Rclaticnship with cxygcn - Bicchcmical charactcristics (cg, catalasc +.-"'-:} - Scrclcgical analysis - ability cf specific antibcdics tc rcact with spccific micrcbc - Phagc typing - can bactcria bc infcctcd by thc samc phagc - Prctcin and DNA scqucncing arc bcccming 1n crc pcpular - pcwcrful! (Thcsc arc nct ccnsidcrcd “cbscr rablc charactcristics”. and arc thc basis fcr racrc racdcni classificaticn schcmcs.) Bacterial classification is changing! * Since the advent of sophisticated DNA RNA and protein analysis tBClflllqllfifi more data on phylogeny has emerged and is continually emerging. ' Therefore. the first edition of “Bergeyis h-lanual of SYSTE-lx-lATIC Bacteriology” was published during the 1980s to reflect phylogeny - the categories in this book are quite different and it is clear that the DETERlN-lflflATl‘x—E h-lanual has limitations. It is also usefulfi howeyen if yotu‘ goal is identification and as the transition to a fully phylogenetic classification is realized. The second edition of the SYSTEl‘v-lATlC h—lanual was finished in 2003. Another philosophical problem - what is a species a11}--'u--':«.1}-"? A species is usually defined as a group of 1:)otentiall}-* interbreeding organisms that can produce viable offspring Does this “Fork for bacteria? No. Why"? Sex again! I Ithml; you have gathered Baoteria do not have sex! I I II So? a bacterial speoies is usually defined as a population of cells with similar oharaoteristios. How similar? It‘s sort of subjeotirei Ii The ourrent oonrention is that more than 39-h difference in merall genome sequence refleots 111embership in a different species But, remember - both the sexual and non-sexual definitions are just ways of getting at similarity: Viral classification ' Traditionall}; as we know, Viruses are not considered alive and thus are not classified in an}; of the preceding groups. - Hon-"even we still need to identify types of Yifllfléfl for clinical and evolutionary *easons (erg. HIV: I) - So? a Yll‘fll species is defined as a population of Ylfllfléfi that have similar characteristics - Some scientists have proposed that viruses get classified according to whom the}? can infect - makes sense esmlutionarily; but not in common usage. ...
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This note was uploaded on 05/03/2010 for the course BIO 315 taught by Professor Schmidt during the Spring '08 term at SUNY Stony Brook.

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BIO 315 Lecture 10 - Classification of microorganisms (and....

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