Presentation on theme: "Kingdom Monera The Bacteria. What are bacteria? Very old form of life ~ 3.5 billion years Extremely abundant ~ 2.5 billion/gram of soil, found Live almost."— Presentation transcript:
What are bacteria? Very old form of life ~ 3.5 billion years Extremely abundant ~ 2.5 billion/gram of soil, found Live almost everywhere, even where nothing else can live Unicellular organisms No nucleus Simple cell structure – lacks complex organelles of higher life forms
How Bacteria Get Food Most are heterotrophic, but some are autotrophic Cyanobacteria – also called blue-green algae are autotrophic Photo by: Matthewjparker http://en.wikipedia.org/wiki/File:Tolypothri x_(Cyanobacteria).JPG http://en.wikipedia.org/wiki/File:Tolypothri x_(Cyanobacteria).JPG "Cyanobacteria" by Argonne National Laboratory Attribution-NonCommercial-ShareAlike License http://www.flickr.com/photos/argonne/5909383026/ Public Domain – NASA http://commons.wikimedia.org/wiki/Fil e:Cyanobacteria_guerrero_negro.jpg
How Bacteria Get Food Chemosynthetic bacteria are also autotrophic - they use sulfur- or iron- containing compounds to make their food Heterotrophic bacteria may be parasites, or they may eat other organisms, or they may be decomposers living on dead organic material.
Bacteria and Oxygen Like higher life forms many bacteria need oxygen to live Some bacteria do not need oxygen Some bacteria are actually inhibited or killed by the presence of oxygen, for example the tetanus bacterium.
Forms of Bacteria 1.Bacilli – rod-shaped bacteria (singular – bacillus) The first bacteria discovered to cause disease was a bacillus – Anthrax was discovered by Koch in 1877 May form chains (Streptobacillus)
Bacilli Escherichia coli Light Micrograph Photo by: Y_tambe http://commons.wikimedia.org/wiki/File:Escherichia_coli_Gram.jpg Escherichia coli Electron Micrograph Public Domain: National Institutes of Health http://commons.wikimedia.org/wiki/File:EscherichiaColi_NIAID.jpg
Forms of Bacteria 2.Coccus – spherical- shaped bacteria a.Streptococcus – chains of coccus bacteria Example- Streptococcus pyogenes that causes strep throat and scarlet fever and is the “flesh-eating bacteria” b.Staphlococcus – grape-like clusters of coccus bacteria Streptococcus pyogenes Public Domain – CDC http://en.wikipedia.org/wiki/File:Streptococcus_pyogenes.jpg
Staphylococcus Staphylococcus aureus – light micrograph Photo by Y Tambe http://en.wikipedia.org/wiki/File:Staphylococcus_aureus_Gram.jpg http://en.wikipedia.org/wiki/File:Staphylococcus_aureus_Gram.jpg Staphylococcus aureus – electron micrograph Photo by: Janice Carr, Public Domain – CDC http://en.wikipedia.org/wiki/File:Staphylococcus_aureus_01.jpg
Forms of Bacteria 3.Spiral – shaped Example – Spirillum sp. Spirillum Public Domain: http://en.wikipedia.org/wiki/File:Spirillen.jpghttp://en.wikipedia.org/wiki/File:Spirillen.jpg
Forms of Bacteria 4.Filamentous – mold-like, long, branching, threadlike Actinomycetes – primary decomposers of plant material Frankia sp. – important plant partners Streptomyces species: Branching filaments, abundant aerial mycelia, and long chains of small spores are visible Public Domain – CDC http://commons.wikimedia.org/wiki/File:Streptomyces_sp._PHIL _2983_lores.jpg http://commons.wikimedia.org/wiki/File:Streptomyces_sp._PHIL _2983_lores.jpg
Forms of Bacteria Some bacteria do not fit into any of the four basic forms such as Bifidiobacterium that are Y-shaped
Reproduction in Bacteria Bacteria reproduce by a process known as binary fission where one cell divides into two equal cells 1→2 →4 →8 →16 →32 →64 →128 →256 →512 →etc. Under ideal conditions reproduction can happen every 20 minutes. Why doesn’t this usually happen? Image by: Mcstrother http://commons.wikimedia.org/wiki/File:Binary_fission2.svgMcstrother http://commons.wikimedia.org/wiki/File:Binary_fission2.svg
Structure of Bacteria Cell Wall - a tough, rigid structure that surrounds, supports, shapes and protects the cell almost all bacteria have cell walls Capsule - An additional coating/layer surrounding the cell wall that some bacteria have Public Domain: http://commons.wikimedia.org/wiki/File:Average_prokaryote_cell-_en.svghttp://commons.wikimedia.org/wiki/File:Average_prokaryote_cell-_en.svg
Structure of Bacteria Cell membrane Hereditary Material (DNA) – not within a nucleus Public Domain: http://commons.wikimedia.org/wiki/File:Average_prokaryote_cell-_en.svghttp://commons.wikimedia.org/wiki/File:Average_prokaryote_cell-_en.svg
Movement of Bacteria Many bacteria are motile, meaning they can move themselves. They move by means of one or more flagella. Flagella are long, thin, whip-like structures on the outside of a bacterium. Public Domain – CDC http://en.wikipedia.org/ wiki/File:Alcaligenes_f aecalis_PHIL- stained.jpg http://en.wikipedia.org/ wiki/File:Alcaligenes_f aecalis_PHIL- stained.jpg Author: Mike Jones http://commons.wikimedia.org/wiki/File:Flagella.png http://commons.wikimedia.org/wiki/File:Flagella.png
Movement of Bacteria Non-motile bacteria depend upon environmental factors to move them – air currents, water, physical objects, etc.
Endospores Under adverse conditions some bacteria form a resting cell called an endospore that can survive. An endospore consists of hereditary material, a small amount of cytoplasm and a thick protective outer coat. Examples: Tetanus and Anthrax Clostridium botulinum vegetative cells and endospores Public Domain - CDC http://en.wikipedia.org/wiki/File:Clostridium_botulinum_01.png http://en.wikipedia.org/wiki/File:Clostridium_botulinum_01.png
Bacteria in Nature An essential part of the food and energy relationships that link all life on Earth Decomposers free up nutrients needed by autotrophs Small heterotrophs (protists and tiny animals) feed on bacteria and in turn become food for larger heterotrophs
Bacteria in Nature Cyanobacteria were the first oxygen producers and raised oxygen levels from 1% to 20% allowing oxygen-using organisms to evolve Bacteria continue to change their environment – for example they are the first colonizers of land after a volcanic eruption
Symbiosis Symbiosis = a relationship in which one organism lives on, near or inside another organism and at least one of the organisms benefits Mutualism = a symbiotic relationship where both of the organisms benefit Parasitism = a symbiotic relationship where one organism benefits but the other one is hurt in some way
Bacteria in Nature Bacteria form extremely important mutualistic relationships 1. Actinorhizal plants and Frankia bacteria 2. Legumes and Rhizobia bacteria Both are extremely important relationships where the bacteria live within the roots of the plants and change nitrogen gas (N 2 ) into ammonia (NH 3 ) that the plant can use (called Nitrogen fixation). The plant gets nitrogen it can use and the bacteria get food (sugar) from the plant.
Bacteria in Nature Actinorhizal plants and Frankia bacteria Alder Root Nodule Photo by: Roger Griffith Public Domain: http://en.wikipedia.org/wiki/File:An_alder_root_nodule_gall.JPG http://en.wikipedia.org/wiki/File:An_alder_root_nodule_gall.JPG
Bacteria in Nature Legumes and Rhizobia bacteria Clover Root Nodules Photo by: Jeremy Kemp http://en.wikipedia.org/wiki/File:Nitro genFixingNodulesOnClover.jpg Root Nodules on Medicago italica http://en.wikipedia.org/wiki/File:Medicago_ita lica_root_nodules_2.JPG Medicago italica is related to alfalfa.
Bacteria in Nature Bacteria form extremely important mutualistic relationships 3. Bacteria living in the digestive systems of many animals including all ruminants, horses, termites, etc. digest plant materials that the animal can’t (cellulose).
Bacteria and Humans Food – used to make yogurt, cheese, soy sauce, etc. but also caused food spoilage Food spoilage can be prevented for long periods by the canning process Pasteurization (heating to kill bacteria) is used to prevent disease transmission (tuberculosis) and increase shelf life Fuel – methane production, also responsible for petroleum production Environmental Cleanup – treat sewage, cleanup oil spills
Bacteria and Humans Health – necessary in intestines where they make vitamins and protect against bad bacteria Medicine – provide many antibiotics but cause many diseases (diphtheria, tetanus, cholera, strep throat, bubonic plague, staph infections, Lyme disease, some pneumonias) Industry – many uses including tanning leather and extracting valuable metals from rocks but can also damage industrial materials