1 / 17

Classification of microbes (and other living things)

Classification of microbes (and other living things). Major events in the history of life: life was originally microscopic and unicellular. Taxonomy: the science of naming and classifying organisms (Carolus Linnaeus) Phylogeny: evolutionary history

vilmos
Download Presentation

Classification of microbes (and other living things)

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Classification of microbes (and other living things)

  2. Major events in the history of life:life was originally microscopic and unicellular

  3. Taxonomy: the science of naming and classifying organisms (Carolus Linnaeus) Phylogeny: evolutionary history Systematics: the science of classification based on evolutionary history of organisms

  4. Linnaean classification system is used today (with modifications) • Binomial (“scientific name”) • Genus and species names (specific epithet) • Hierarchical classification

  5. How is classification achieved? • Observation • Similarities and differences • Fossil record • Molecular analysis • DNA • Ribosomal RNA • Mitochondrial DNA • Proteins

  6. Ideas about classification have changed • Linnaeus- plants and animals (1735) • Where do bacteria and fungi belong? • Von Nägeli- with plants (1857) • Haeckel- Kingdom Protista (1866) • Whitaker – five kingdoms (1969) • Woese- domains (1978)

  7. Classification may change again

  8. Classification by RNA sequence data

  9. Phenotypes (physical differences) between the domains

  10. Classification of prokaryotes • Morphology (Gram-staining) • Nutrition • Metabolism • Environmental niche • rRNA sequences (all living cells have them) • Reference: Bergey’s Manual of Systematic Bacteriology; Bergey’s Manual of Determinative Bacteriology) • Most prokaryotes have not been discovered!

  11. Microbial identification • Differential media • Biochemical testing • Serology • Phage typing • Genetic testing • rRNA sequencing

  12. A dichotomous key • Classic tool for identification • Most of these tests can be administered simultaneously • Different keys can be developed for groups of bacteria

  13. How do you make bacteria look different? Genomic analysis Phage typing

  14. Archaea: “extreme bacteria” • Discovered in late 1970’s • Species live at extreme temperature, pH, have unusual metabolic properties • Hard to study

  15. Classification of eukaryotes • Plantae- mosses, ferns, conifers, flworing plants (some algae) • multicellular, photosynthetic • Animalia- sponges, worms, various vertebrates and invertebrates • multicellular, ingest nutrients • Fungi (1959)- yeasts, molds, mushrooms • Absorb nutrients, form hyphae if multicellular • Protists- unicellular organisms • Don’t fit anywhere else!

  16. Classification of viruses • Not cellular, so are not classified in hierarchical system • Viral species- population of viruses with similar characteristics and that occupy a particular ecological niche

  17. Summary • Eukaryotes are much more diverse than prokaryotes • Some have evolved much more recently than others • All are “successful” in their niche • Classification is an ongoing process • Genetic and phenotypic differences are considered in classification

More Related