study of the relationships among organisms and their environment
relationships include interactions of organisms with physical features
of the environment and interactions of organisms with one another
comprises all the organisms in a given area together with the surrounding abiotic and biotic factors
region of the Earth inhabited by living organisms:
1.hydrosphere-water supply,freshwater and marine
2.lithosphere-soil and rock tha includes the Earth's crust
3. atmosphere-gaseous envelope surrounding Earth
consists of all the kinds of organisms tha are present in a given environment, cataegorized by indigenous (will always thrive,except for cataclysmic changes) and nonindigenous(only thrive when conditions are favorable)
physical location of the organism
the role organism plays in the ecosystem
habitat in which the oxygen,nutrients,and light are stable,including the environment immediately surrounding the microbe.
organisms(autotrophs) capture the energy from the sun, photsynthesize or create their own food from soil and other nutrients
heterotrophs,obtain nutrients by eating the producers or other consumers
obatin energy by digesting dead bodies or wastes of producers and consumers,then release subtances that producers can use as nutrients
mechanism of recycling for water and chemicals that serve as nutrients
also known as the hydrologic cycle(recycles water),reaches Eath's surface as precipitation form the atmosphere
CO2,enters producres during photosynthesis or chemosynthesis...consumers obtain CO2 by eating and returned to the atmosphereby respiration,actions of decomposers, and wastes of other organisms,oceans and carbonate rocks are largest reservoirs
atmospheric carbon dioxide and water vapor form a blanket ovet the Earth's surface,trap much of the infrared(heat) radiation produced by the warm surface.
nitorgen moves from the atmosphere through various organisms and back into the atmosphere,cyclic flow depends not only on decomposers but also on various nitrogen bacteria.Clostridia,actinomycetes,and many fungi produce extracellular proteinase
nitrogen fixation is the reduction of atmospheric nitrogen gas(N2) to ammonia (NH3).Bacteria and cyanobacteria fix it.eenergy for nitrogen fixation can come from fermentation,aerobic repsiration,or photosynthesis
nitrogen-fixing bacteria must have functional nitrogen fixing enzyme, a reducing agent thatsupplies hydrogen and ATP.in aerobic environments, nitrogen fixers must also have a mechanism to protect theoxygen-sensitive nitrogenase from inactivation.Azotobacter and some methylotrophic bacteria
Rhizobia change from their free-living rodshape and become spherical,flagellated cells , thought to produce indoleacetic acid, a plant growth hormone that causes curling of root hairs.
swarmer cells become large,irregularly shaped cells, which are tightly packed into root cells,form nodules at plant roots during accumulations
nitrification, process by which ammonia or ammonium ions are oxidized to nitrites or nitrates,carried out by autotrophic bacteria,supplies plants with nitrate for metabolism,but producing too much nitrite can be toxic to plants
denitrification,process by which nitrates are reduced to nitrous oxide or nitorgen gas,most performed by Pseudomonas species,wasteful process because it removes nitrates from soil and interferes with plant growth
movement of sulfur through an ecosystme,resemble the nitrogen cycle in several respects,special importance in aquatic environments, where sulfate is common,especially in ocean water
reduction of sulfate to hydrogen sulfide,oldest form of life form,Desulfovibrio,Desulfomonas,and Desulfotomaculum,strict anaerobes
reduction of sulfur to hydrogen sulfide,provides energy for organisms when sunlight is not available for photosynthesis.
oxidation of vatious forms of sulfur to sulfate,Thiobacillus,lowers pH
involves the movement of phosphorus among inorganic and organic forms,phosphorus is often the limiting nutrient in many environments
microororganisms do not grow in air,because it lacks the nutrients neede dfor metabolism and growth.But is a vector for spores and vegetative cells,like the mold spore Cladosporium, bacteria Bacillus subtilis,nonspore formers such as Micrococcus and Sarcina
Sick building syndrome
a collection of symptoms, including :headache,dizziness,nausea,burning eyes,nosebleeds, and respiratory and skin problems...due to dirt,dust,Legionellas,etc.
bacteria,fungi,algae,protists,and viruses are present...bacteria most numerous.Soil fungi aremostly molds,serve 2 funtions:decompose plant tissues such as cellulose and ligning, and mycelia form network around soil particles,giving soil a crumbly texture.
mucus-like strings of bacterial colonies,these bacteria eat sulfur and drip sulfuric acid.
1.littoral zone-an area of shallow water near the sore where light penetrates to the bottom
2.limnetic zone- comprises sunlit water away from the shore;resident microorganisms include algae and cyanobacteria.
3.profundal zone-between limnetic zone and lake sediment,when organisms in limnetic zone die,they sink to the profundal zones.
4. benthic zone- sediment, composed of organic debris and mud
seasonal fluctuations of phytoplankton populations affet the Earths' temperature
less variable in both temperature and pH(6.5-8.3),display a far grater range of hydrostatic pressure than do freshwater water.
biological oxygen demand(BOD)
organic wastes suspended in water decompsed by microorganisms,provided that the water contains sufficient oxygen for oxidation of the substances.
abundant nutrient enrichment of water
E.coli,presence in water indicated that the water is contaminated with fecal matter
water purification procedures
1. flocculation-alum,like clay added to suspend colloids
2. filtration-passage of water though beds of sand
3. chlorination-addition of chlorine to water,readily kills bacteria but is less effective in destorying viruses and cysts of pathogenic protozoa.
includes E.coli,gram-negative,nonspore forming aerobic or facultative anaerobic bacteria that ferment lactose and produce acid and gas
multiple-tube fermentation method
1. presumptie test-water sample is used to inoculate lactose broth tubes
2.confirmed test-samples from the highest dilution showing gas production are streaked onto eosinmethylen blue
3. completed test-organisms from dark colonies are used to inoculate lactose broth and agar slants.
membrane filter method
presence of more thatn one colony per 100ml of water indicates that the water may be unsafe for human consumption
ONPG and MUG test
ability of coliform bacteria to secrete enzymes that can be detected by a color change