Published on

  • Be the first to comment

  • Be the first to like this

No Downloads
Total views
On SlideShare
From Embeds
Number of Embeds
Embeds 0
No embeds

No notes for slide


  1. 1. Guess how manybacteria are in a singlehandful of soil?A single gram of soil (thesize of a pencil eraser)has 2.5 billion bacteria,so a handful wouldcontain trillions!There are more types ofbacteria on Earth than allother living thingscombined
  2. 2. Most bacteria are toosmall to see without amicroscopeThe largest knownbacteria are 1,000times larger than theaverage bacteriumOne of these giantbacteria lives inside asurgeonfish—it is 0.6mm long and can beseen with the nakedeye
  3. 3. Characteristics of BacteriaBacteria make up thekingdoms Eubacteria andArchaebacteriaThese two kingdoms containthe oldest forms of life onEarthAll bacteria are single-celledorganismsBacteria are usually one ofthree main shapes: bacilli,cocci, or spirilla
  4. 4. The Shape of BacteriaMost bacteria have a rigidcell wall that gives them theirshapeEach shape of bacteriahelps it in a different waySome bacteria have hairlikeparts, called flagella, whichspin and help push abacterium through water orother liquids
  5. 5. Cocci (spherical)Bacilli (rod shaped) Spirilla (long and spiral shaped)
  6. 6. Bacilli– Rod shaped– Large surface area (take in nutrients quickly, but dry out easilyCocci– Spherical– Do not dry out as quickly as bacilliSpirilla– Use flagella at both ends to move like a corkscrew
  7. 7. No Nucleus!All bacteria aresingle-celled and donot have a nucleusThis makes bacteria aprokaryoteProkaryotes functionas independentorganismsProkaryotesreproduce differentlythan eukaryotes do
  8. 8. Bacterial ReproductionBacteria reproduce by processof binary fissionBinary fission: a form of asexualreproduction in a single-celledorganism by which one celldivides into two cells of thesame sizeNo nucleus, so DNA is just acircular loop with no membrane
  9. 9. DNA is copied, loops separate New cell wall forms and cells separate
  10. 10. EndosporesMost species of bacteria do well in warm,moist placesIn cold or dry surroundings, the bacteriawill either die or become inactive and formendosporesEndospores: contains genetic materialand proteins and is covered by a thick,protective coat
  11. 11. Many endosporessurvive in cold, hot,and very dryplacesWhen conditionsimprove, theendospores breakopen, and thebacteria becomeactive again
  12. 12. Scientists foundendospores inside aninsect that waspreserved in amberfor 30 million yearsWhen the endosporeswere moistened in alab, bacteria began togrow!
  13. 13. Kingdom EubacteriaEubacteria are classified by the way theyget their foodMost are consumers, which get food byeating other organismsMany bacteria are decomposers, whichfeed on dead organismsEubacteria that make their food areproducers (use energy from sunlight tomake own food, often green)
  14. 14. Cyanobacteria– Are producers– Usually live in water– Contain green pigment chlorophyll– Some have a blue tint that helps in photosynthesis
  15. 15. Othercyanobacteriahave a redpigmentFlamingos gettheir pink colorfrom eating redcyanobacteria
  16. 16. Kingdom ArchaebacteriaThree main types of Archaebacteria: heatlovers, salt lovers, and methane makersHeat lovers– Live in ocean vents and hot springs– Live in very hot water, can survive temps of more than 250 degrees CelsiusSalt lovers– Live in environments of high salt, like the Dead Sea and Great Salt LakeMethane makers– Give off methane gas and live in swamps and animal intestines
  17. 17. Heat lovers in ocean vent Salt lovers in Dead Sea Methane makers in swamp
  18. 18. Harsh environments– Archaebacteria often live where nothing else can– Most prefer environment with little to no oxygen– Very different from eubacteria– Not all archaebacteria have cell walls– When they do, the cell walls are chemically different from eubacteria