Presentation on theme: "PowerPoint to accompany CONCEPTS IN BIOLOGY"— Presentation transcript:
1 PowerPoint to accompany CONCEPTS IN BIOLOGY Enger • Ross • BaileyCHAPTER 21
2 What are microorganisms? A tiny organism that cannot be seen without a microscope.Live in a variety of different habitats
3 Domains eubacteria and archaea Used to be lumped into one group, bacteriaEubacteria have cell walls with peptidoglycan.Archaea and eubacteria have chemically unique cell membranes. So different from each other necessary to classify into different Domains of life.
4 Domain eubacteria Identified by Their shape Metabolic reactions Can be rods, spheres or spiral-shapedMetabolic reactionsChemistry of their cell wallsGram (+) and Gram (-)
7 Domain eubacteria Occupy many different ecological niches Decomposers Heterotrophs that break down organic matterCalled saprophytesCan live on dead organic matterSome are anaerobic. – tetanus, botulismOthers are aerobic and break down organic matter into carbon dioxide and water.Important in recycling carbon, nitrogen, phosphorus, etc.Could be used to break down sewage, clean up oil spillsUsed in food production (blue cheese, yogurt, beer, wine, etc.)Are responsible for food spoilage
9 Domain eubacteria Commensal bacteria +/ø Mutualistic +/+ Bacteria that live on or in organisms without benefiting or harming the hostMutualistic +/+Normal microflora-Bacteria on our skinE. coli in our large intestine
10 Domain eubacteria Mutualistic bacteria E. coli in our large intestine Produce antibiotics and compete for resourcesReducing the growth of pathogenic bacteriaThey produce and release vitamin K.Cyanobacteria and fungi in lichensPlants and nitrogen-fixing bacteria in their roots
11 Cyanobacteria Photosynthetic eubacteria Cyanobacteria performs photosynthesis like plants.ChlorellaSpirulina
13 Domain eubacteria Bacteria and mineral cycles Nitrogen cycle Nitrogen-fixing bacteria transform atmospheric nitrogen into ammonia.Ammonia can be used by plants to make amino acids.Other bacteria convert ammonia waste to nitrate or nitrite.Other bacteria convert nitrite to atmospheric nitrogen.
14 Domain eubacteria Disease-causing bacteria Also called pathogens or parasites +/-Some commensalistic bacteria can become pathogenic.If they are given the opportunity to increase in numberIf they have the opportunity to invade new tissueExample: S. pneumoniae
16 Domain eubacteria Control of bacterial populations Bacterial populations grow rapidly becauseTheir generation time is so short.About every 20 minutes1 bacteria can lead to millions in a matter of daysThey can generate resistant forms or stages.SporesThey mutate rapidly.Can produce antibiotic resistant strainsMRSA, VRE
17 Kingdom protista A catch-all kingdom Divided into three groups Includes a diverse array of organismsMany are not evolutionarily related to one another.All are eukaryoticMost are single celled; some are multicellular.Divided into three groupsAlgaeAutotrophic, unicellularProtozoaHeterotrophic, unicellularFungus-like protists
19 Algae Contain chlorophyll and can carry out photosynthesis Most are aquatic.Plankton float in the water.Phytoplankton are photosynthetic.Zooplankton are heterotrophic.
20 Algae The terrestrial forms live in very moist areas. Most are unicellular; a few are multicellular.
21 Single-celled algae Euglenids Move by flagella Have a flexible outer covering called a pellicleGives them a shapeSome are heterotrophs, others are autotrophs.Many live in freshwater.
22 Single-celled algae Diatoms Found in freshwater, marine and soil environmentsMajor component of phytoplanktonA few are heterotrophs.Brownish in colorDo not have cilia or flagellaHave cell walls made of silicaDiatomeous earth
23 Single-cell algae Dinoflagellates Important primary producers in marine ecosystemsAlso occur in freshwaterHave two flagellaHave outer covering made of celluloseMost are autotrophs.Some are heterotrophs.Some are parasitic.Red tides
24 Single-cell algae Some produce toxins that can kill fish. Red tideCan poison humans if they eat poisoned fishSome are bioluminescent.
28 Multicellular algae Brown algae Green algae Live in cooler marine environmentsCan grow very longProduce alginates (food stabilizer)Green algaeFound in freshwater ecosystemsAre photosynthetic and have cellulose cell walls
30 Protozoa Eukaryotic Heterotrophic Unicellular Lack cell walls Classified by their means of locomotionFlagellatesAmeboidCiliatesApicomplexa
31 Flagellates Have flagella Live in moist environments Many are mutualistic.Found in termite gut; digest celluloseMany are parasitic .Trichomonas vaginalis-common sexually transmitted diseaseTrypanosomes cause sleeping sickness in humans and cows.Giardia causes intestinal distress, diarrhea, gas.
37 The apicomplexans Nonmotile parasites Have a spore-like stage in their life cycleMalaria is caused by an apicomplexan.Transmitted by mosquitoes to humansReproduces in the mosquitoEliminating mosquitoes helps reduce the incidence of malaria.
39 Funguslike protists Have a motile reproductive stage Slime molds Move like amoebaDigest dead organic matter
40 Multicellularity in the protista VolvoxVolvox is colonial.The flagella of each cell moves together to move the colony.Some of the cells are specialized to produce sperm and egg.Thought to be the ancestor of multicellular organisms
42 Kingdom Fungi Nonphotosynthetic; heterotrophic Eukaryotic Secrete enzymes that digest large molecules externallyEukaryoticHave chitin-containing cell wallsMade up of filaments known as hyphaHyphae form networks called myceliumDisperse through sporesCells with tough protective coatingCan be produced by sexual or asexual reproduction
45 The significance of fungi Fungi play many roles in ecosystemsDecomposersFungi and bacteria are the major composers in ecosystems.Recycles nitrogen, carbon and phosphorusCan destroy clothes, wood, leather, foodFoodFungi and their products can be used as food.MushroomsSoy sauce is made by fermenting an ascomycete.Citric acid in cola is released from a mold.Yeasts are used to make alcoholic beverages and bread.
46 The significance of fungi MycorrhizaeAssociations between fungi and the roots of plantsOne type penetrates the roots of the plant.The other type surrounds the roots but doesn’t penetrate.Found in 80-90% of all plantsIncreases the root’s surface area for absorption of nutrients up to 10-fold
48 Significance of fungi Lichens Symbiotic relationship between a fungus and either an alga or cyanobacterium.The alga or cyanobacterium is photosynthetic and provides food.The fungus provides a moist environment.Do not require soil for growthGrow on trees or rocksImportant in soil formation during ecological succession
50 Significance of fungi Pathogenic fungi Can infect plants Caused the extinction of Chesnut trees and Dutch elm treesCauses wheat rust and corn smutCauses costly damage to cropsFarmers have to use fungicides.Can infect humansPneumocystis is present in most people’s lungs.Can cause infection in people with compromised immune systems
52 Significance of fungi Toxic fungi Some fungi can produce mycotoxins The mushroom, Amanita spp, makes a toxin that is deadly. “Death Angel”Food contaminated with these spores can cause illness and death.The mushroom, Psilocybe contains a hallucinogenic chemical called psilobycin.Claviceps purpurea is a parasite on rye that generates a toxin that causes hallucinations, insanity, muscle spasms and death. Witches
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