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Phylogeny and Systematics

What is meant by phylogeny? Evolutionary history of a species… Based on common ancestry Supported by shared characteristics and genetics Documented by fossils and genetics. Phylogeny and Systematics. Systematics? = study of the organismal diversity of life

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Phylogeny and Systematics

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  1. What is meant by phylogeny? Evolutionary history of a species… Based on common ancestry Supported by shared characteristics and genetics Documented by fossils and genetics Phylogeny and Systematics

  2. Systematics? = study of the organismal diversity of life How do we make sense of all this diversity? Organize it…. Taxonomy & classification

  3. Hierarchy = organizational levels Domain Kingdom Phylum Class Order Family Genus Species Each level is nested within the one above Broad or less specific More specific Diversity of Life

  4. Closely related species belong to the same genus, similar genera are included in a family, etc…Species that share the same structures, behaviors, etc, can interbreed and produce fertile offspring.

  5. Grouped by shared characters (Evolutionary relationships) Embryology Reproduction strategies Symmetry (body plan) Morphology Feeding mode Etc…

  6. 5 Kingdoms

  7. 3 domains, many kingdoms

  8. Prokaryotic cell

  9. Eukaryotic cell

  10. Single cell Very small Cell wall Lacks nucleus Lacks membrane bound organelles Binary fission Domains: Bacteria and Archaea More structural & functional characteristics in (Ch.27) Prokaryotes

  11. How can we organize/compare Prokaryotes? • Morphology • Biochemistry • Modes of nutrition • Heterotrophic (hetero = other, trophic = food or feeding) • Must consume organic molecules • Autotrophic (self feeding) • Photoautrophic can photosynthesize; get energy from sun • Chemoautotrophic obtain energy from inorganic molecules • Toxicity of Oxygen • obligate aerobes, obligate anaerobes, facultative anaerobes • Genetic Analysis

  12. Rod shaped Example: E. coli Usually solitary Sometimes chains streptobacilli Bacilli

  13. Spherical Clumps or clusters (like grapes) E.g. Staphylococcus aureus Streptococci – chains of spheres Diplococci – pairs of spheres E.g. Neisseria gonnorheae Cocci

  14. Streptococcus 1

  15. Streptococcus 2

  16. Diplococcus 1

  17. Diplococcus 2

  18. Spirilla – spiral shaped With external flagella Variable lengths Spirochaetes Internal flagella Corkscrew-like Boring action E.g. Treponema pallidum (Syphilis) Spiral prokaryotes

  19. Gram stain Counter stains to differentiate between cell wall characteristics Gram-positive Gram-negative Adaptations to environmental variations salinity, temperature, pH, O2 levels Biochemistry & cell surface structures

  20. Thick layer of peptidoglycans Retains crystal violet Doesn’t wash out Masks red safranin Stains dark purple or blue-black Gram positive bact

  21. Thin sandwiched layer of peptidoglycans Rinses away crystal violet Stains pink or red Gram negative bact

  22. Clades of bacteria • Fig 27.18 (27.13 in 7th ed.) • Proteobacteria • Cyanobacteria • Spirochaetes • Gram positive bacteria

  23. Proteobacteria • Includes Gram negative bacteria • E. coli • common intestinal flora • Enterobacter aerogenes • Pathogenic; causes UTI • Serratia • Facultative anaerobe • Characteristically red cultures

  24. Subgroup of Proteobacteria Slime-secreting decomposers Elaborate colonies Thrive collectively, yet have the capacity to live individually at some point in their life cycle Proteobacteria: Myxobacteria

  25. Cyanobacteria • “blue-green algae” • Photoautotrophic • Typically colonial

  26. Oscillatoria (Cyanobacteria) 1

  27. Oscillatoria 2

  28. Anabaena (Cyanobacteria) 1 • Vegetative cell • Primary metabolic function (photosynthesis) • Heterocyst • Nitrogen fixation • Akinete • Dormant spore forming cell

  29. Anabaena 2

  30. Anaebena 3

  31. Nostoc (Cyanobacteria) 1

  32. Nostoc 2

  33. Gleocapsa (Cyanobacteria) 1

  34. Gleocapsa 2

  35. Spirochaetes • Long spiral • Flagellated cell wall • Decomposers & pathogens

  36. Gram positive bacteria • Gram stains – purple • Thick cell wall • Includes: • Micrococcus • Common soil bacterium • M. luteus cultures have a yellow • Bacillus • B. subtilis are relatively large rods; common “lab organism” • Obligate aerobes or facultative anaerobes

  37. Archaea family tree

  38. Archaea -- “Extremophiles” Tolerant to extreme environments Extreme thermophiles High and low temperature Commonly acidophilic E.g. hot sulfer springs, deep sea vents Extreme halophiles High salt concentration Often contains carotenoids E.g. Salton Sea Methanogens Anaerobic environments Release methane E.g. animal guts

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