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BIOLOGY FORM 4 CHAPTER 8 - DYNAMIC ECOSYSTEM PART 5

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BIOLOGY FORM 4 CHAPTER 8 - DYNAMIC ECOSYSTEM PART 5

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BIOLOGY FORM 4 CHAPTER 8 - DYNAMIC ECOSYSTEM PART 5

  1. 1. DYNAMIC ECOSYSTEM PART 5
  2. 2. Microorganism Microorganisms are tiny organisms that can only seen clearly under the microscope
  3. 3. TYPES OFTYPES OF MICROORGANISMSMICROORGANISMS VirusesViruses BacteriaBacteriaProtozoaProtozoa AlgaeAlgae FungiFungi MICROORGANISMA
  4. 4. Bacteria N : Bacteria C : - unicellular organisms which have basic cell structure that includes a cell wall, plasma membrane and DNA that is not enclosed in a membrane - have cell walls made of a polymer called peptidoglycan - certain bacteria form spores under unfavourable conditions - their shape may be spherical (coccus), rod shape, (bacillus) or spiral (spirilium)
  5. 5. Algae N : Algae C : - photosynthetic eukaryotic plant-like organisms in the kingdom protista - have a chlorophyll and chloroplast - cell walls are made of cellulose - do not have leaves, stems or roots E : phytoplankton and Spirogyra sp.
  6. 6. Fungi N : Fungi C : - heterotrophic multicellular or unicellular - do not have chlorophyll - have a cell wall made up of chitin - fungi feed by secreting enzymes that break the surrounding organic material down into simple molecules before they are absorbed E : Mucor sp. and yeast
  7. 7. Protozoa N : Protozoa C : - unicellular organism - have nucleus, cytoplasm and plasma membrane - capable carry out living processes such as respiration, reproduction and excretion - have flagella, cilia or pseudopodia to move E : Euglena sp., Paramecium sp., Amoeba sp.
  8. 8. Viruses N : Viruses C : - is not a living cell because it cannot survive or reproduce on its own outside the host - is composed of DNA and RNA, surrounded by a protein coat - can be crystallised E : T4 bacteriophage and tobacco mosaic virus
  9. 9. e Effect of Abiotic Components on the Activity of Microorganis 1.Nutrient: - all microorganisms except viruses need nutrient and water for reproduction and growth. - without nutrient and water, microorganisms will die or form spores
  10. 10. e Effect of Abiotic Components on the Activity of Microorganis 2. pH - most bacteria prefer slightly alkaline condition (pH around 7.4) - moulds, yeast and protozoa (pH between 4.5 and 5.0)
  11. 11. 3. Temperature - most microorganisms are inactive at low temperatures - optimum temperature for most microorganisms is between 35 ⁰C and 40 ⁰C - beyond 60 ⁰C, the growth of microorganisms is inhibited - microorganisms and their spores can only be destroyed when they are sterilized at a temperature of about 121 ⁰C e Effect of Abiotic Components on the Activity of Microorganis
  12. 12. 12/18/14 1.1_Classificationofmicros
  13. 13. 4. Light intensity - microorganisms prefer places which are dark or have a low light intensity - a high intensity of sunlight and ultraviolet rays can kill microorganisms - however, algae and photosynthetic bacteria need light to photosynthesis he Effect of Abiotic Components on the Activity of Microorgani
  14. 14. Impact Of Microorganism on Life  Decomposition – Bacteria & fungi break down complex organic matter into simple inorganic matter  Alimentary canal of termites- microbes produce celulase enzyme to break down cellulose in wood  Digestive system of humans – bacteria in intestines produce Vit B12 & K  Nitrogen cycle
  15. 15. 1. Decomposition: - bacteria and saprophytic fungi break down complex organic matter into simple inorganic matter
  16. 16. The Role of Useful Microorganisms in the Ecosystem 2. Digestion: Alimentary canal of termites - microbes Trichonympha sp. (flagellated protozoan) produce celulase enzyme to break down cellulose in wood
  17. 17.  Digestive system of humans – bacteria in intestines produce Vit B12 & K The Role of Useful Microorganisms in the Ecosystem
  18. 18. The Nitrogen Cycle The Role of Useful Microorganisms in the Ecosystem
  19. 19. Where is the reservoir of nitrogen? AirAir SoilSoil
  20. 20. The Nitrogen Cycle Nitrogen 78%  Atmospheric Gases
  21. 21.  plants & animals need nitrogen to make: proteins Nitrogen 78%  plants cannot use atmospheric nitrogen Gases in air. From where do plants get the nitrogen they need?
  22. 22. Animal Dead animal & plants Ammonia / Ammonium Nitrites Nitrates Nitrosomonas sp. Nitrobacter sp. Plants Denitrifying bacteria Atmosphere fixation Nitrogen fixing bacteria Fertiliser Nostoc sp., Rhizobium sp. Thiobacillus sp. NITROGEN CYCLE
  23. 23. The Nitrogen Cycle Converts:  N2 into a chemical form that living organisms can use NameName two formstwo forms in whichin which plants can use nitrogen fromplants can use nitrogen from the soil.the soil.
  24. 24. NOT Nitrites!!
  25. 25. Biological processes involved in the nitrogen cycle: 1. Nitrogen fixation 2. Ammonification 3. Nitrification 4. Denitrification
  26. 26. Nitrogen fixation What does ‘fixation’ refer to? Converting atmospheric nitrogen into compounds such as nitrates which can be used by plants
  27. 27. N2 must be fixed to be of any use to plants:  This is done in two ways:  mostly by nitrogen fixing bacteria  lightning
  28. 28. Animal Dead animal & plants Ammonia / Ammonium Nitrites Nitrates Nitrosomonas sp. Nitrobacter sp. Plants Denitrifying bacteria Atmosphere fixation Nitrogen fixing bacteria Fertiliser Nostoc sp., Rhizobium sp. Thiobacillus sp. NITROGEN CYCLE
  29. 29. Lightning:  is an electrical discharge through the air can cause: N2 & O2 molecules to change into the atomic form Combine with water to form weak nitric acid (HNO3)
  30. 30. Atmospheric nitrogen precipitates to the earth, adding nitrogen to the soil in a usable form (nitrate, NO3)
  31. 31. Question: Atmospheric nitrogen may give rise to nitrate through a natural, non-biological process. What is this process called? (1) Lightning
  32. 32. NITROGEN-FIXING BACTERIA absorb nitrogen gas from the air and ‘fix’ it into a form which the plant can use to build protein change nitrogen gas into ammonium compounds Root nodule full of bacteria.
  33. 33. NITROGEN-FIXING BACTERIA live: Root nodules 1) freely in the soil e.g. Clostridium 2) in the root nodules of leguminous plants (e.g. peas, beans, clover) e.g. Rhizobium
  34. 34. Nitrogen fixation  Carried out by:  nitrogen fixing bacteria e.g. Azotobacter and Clostridium  the cyanobacterium Nostoc  90% of the total nitrogen- fixation:  is carried out by free-living micro-organisms Nostoc Cyanobacteria
  35. 35. Rhizobium  aerobic nitrogen-fixing bacilli Rhizobium in ruptured nodule  live in:  root nodules of leguminous plants
  36. 36. Leguminous plants: LegumesLegumes: probably the largest source of fixed nitrogen Clover Beans Peas
  37. 37. Mutualism: is the relationship between nitrogen fixing bacteria and leguminous plants Plant gains: Ammonium compounds Bacteria gain: 1.Food 2.Shelter carbohydrate N
  38. 38. When leguminous plants decay: the nitrogen which the bacteria have fixed goes into the soil where it can be used by plants  Nitrogen-fixing bacteria are very useful because they increase the amount of useful nitrogen compounds in the soil.  Nitrogen-fixing bacteria are very useful because they increase the amount of useful nitrogen compounds in the soil.
  39. 39. Biological processes involved in the nitrogen cycle: 1. Nitrogen fixation 2. Ammonification (decay) 3. Nitrification 4. Denitrification
  40. 40. ammonia Organic nitrogen in dead bodies or animal waste Ammonification Ammonification (Decay)  Bacteria:  Pseudomonas  Bacillus  Clostridium  Fungi:  Mucor
  41. 41. Ammonification (Decay)  anaerobic decomposition of proteins (putrefaction) releases foul-smelling compounds like hydrogen sulfide  once ammonification has been accomplished, nitrification, can occur
  42. 42. Biological processes involved in the nitrogen cycle: 1. Nitrogen fixation 2. Ammonification 3. Nitrification 4. Denitrification
  43. 43. NITRIFYING BACTERIA change ammonia into nitrites and then into  nitrates this is called nitrification ammonia is present in: dead remains animal waste
  44. 44. Nitrification involves two stages: 1. Nitrosomonas bacteria change: 2. Nitrobacter bacteria change: NO2 - nitrite NH4 + ammonium O2 + energy NO2 - nitrite O2 NO3 - nitrate + energy Nitrobacte r
  45. 45. Production of nitrates from organic nitrogen involves ammonification and nitrification nitrate nitrite ammonia Organic nitrogen in dead bodies or animal waste Ammonification Nitrification Nitrification Nitrobacter Nitrosomonas Bacillus
  46. 46. Biological processes involved in the nitrogen cycle: 1. Nitrogen fixation 2. Ammonification 3. Nitrification 4. Denitrification
  47. 47. 3. Denitrification  is the conversion of nitrate (NO3 - ) into nitrogen gas (N2) under anaerobic conditions Nitrogen gas Nitrate
  48. 48. Animal Dead animal & plants Ammonia / Ammonium Nitrites Nitrates Nitrosomonas sp. Nitrobacter sp. Plants Denitrifying bacteria Atmosphere fixation Nitrogen fixing bacteria Fertiliser Nostoc sp., Rhizobium sp. Thiobacillus sp. NITROGEN CYCLE
  49. 49. Denitrification   Denitrification is carried out by:  denitrifying bacteria  These bacteria utilise the nitrate as an oxygen source Nitrogen gas Nitrate
  50. 50. Denitrifying bacteria are:  facultative aerobes [can live in the presence or absence of oxygen] Pseudomonas denitrificansThiobacillus denitrificans
  51. 51. Denitrification  is more likely in waterlogged soil Why do farmers dig up the land? To improve drainage and aeration
  52. 52. Why can carnivorous plants live in nitrogen-poor soils?
  53. 53. Animal Dead animal & plants Ammonia / Ammonium Nitrites Nitrates Nitrosomonas sp. Nitrobacter sp. Plants Denitrifying bacteria Atmosphere fixation Nitrogen fixing bacteria Fertiliser Nostoc sp., Rhizobium sp. Thiobacillus sp. NITROGEN CYCLE
  54. 54. Question: This question is concerned with the role of nitrogen in the biosphere: 1. Why is nitrogen essential for living organisms? (1) To be a component of nitrogenous compounds like nucleotides, coenzymes and proteins. 2. Why is nitrogen generally a significant limiting factor in agriculture? (1) Plants take up nitrogen in the form of nitrates and ammonium in soil but is not recycled. Plants grow close together and place a heavy demand on the soil.
  55. 55. 3. Briefly describe each of the following processes in the context of the nitrogen cycle: a) Nitrogen fixation Nitrogen in air is converted into ammonium by nitrogen fixing bacteria e.g. Rhizobium and cyanobacteria e.g. Nostoc. b) Nitrification Ammonium is oxidised to nitrites by nitrifying bacteria e.g. Nitrosomonas and then to nitrates by for example Nitrobacter. c) Denitrification (6) Nitrogen is released into the air by denitrifying bacteria from nitrates e.g. by Pseudomonas.
  56. 56. 2. The diagram below shows some of the processes involved in the cycling of nitrogen in an ecosystem. a) Name the processes represented by the arrows X and Y. X: ammonification/decay; Y: denitrification
  57. 57. b) State the genus of one organism represented by the letter S and one organism represented by the letter T in the diagram. (2) Rhizobium; AzotobacterPseudomonas; Thiobacillus
  58. 58. Distinguish between nitrification and denitrification. (5) Nitrification is carried out under aerobic conditions but denitrification under anaerobic conditions. In the process of nitrification, ammonia is converted into nitrites and then into nitrates. In denitrification, nitrates are converted into nitrogen gas.
  59. 59. END OF SECTION Dung beetles play a remarkable role in agriculture. By burying and consuming dung, they improve nutrient cycling and soil structure.
  60. 60. BAD MICROORGANISM
  61. 61. Pathogens, Vectors and Symptoms of Some Diseases DiseaseDisease PathogensPathogens VectorVector SymptomsSymptoms Method of infectionMethod of infection TBTB BacteriaBacteria -- -Feeling tiredFeeling tired -Constant coughingConstant coughing -Coughing out bloodCoughing out blood Droplet infection, dust,Droplet infection, dust, food and drinks that arefood and drinks that are contaminatedcontaminated CholeraCholera Bacteria (Bacteria (VibrioVibrio sp.)sp.) House flyHouse fly -VomitingVomiting -Serious diarrheaSerious diarrhea Water or food that isWater or food that is contaminatedcontaminated FoodFood poisoninpoisonin gg Bacteria, fungiBacteria, fungi House flyHouse fly -VomitingVomiting -DiarrhoeaDiarrhoea -Abdominal painsAbdominal pains -FeverFever Water or food that isWater or food that is contaminatedcontaminated ColdCold VirusVirus -- - Fever, HeadacheFever, Headache - Muscle painMuscle pain Through the airThrough the air RingworRingwor mm FungiFungi -- - Red spot on theRed spot on the skinskin - ItchinessItchiness TouchTouch
  62. 62. Pathogens, Vectors and Symptoms of Some Diseases DiseaseDisease PathogenPathogen ss VectorVector SymptomsSymptoms Method ofMethod of infectioninfection DengueDengue VirusVirus Mosquito,Mosquito, Aedes aegyptiAedes aegypti - High feverHigh fever - HeadacheHeadache -RashesRashes - Pain at the jointPain at the joint -Bleeding from the nose,Bleeding from the nose, gums and tooth socketsgums and tooth sockets Mosquito biteMosquito bite MumpsMumps VirusVirus -- - FeverFever - Painful feeling whenPainful feeling when eatingeating -Difficulty opening theDifficulty opening the mouthmouth -Soft swelling in front andSoft swelling in front and below the earsbelow the ears Through the airThrough the air
  63. 63. DiseaseDisease PathogensPathogens VectorVector SymptomsSymptoms Method of infectionMethod of infection AIDSAIDS VirusVirus (HIV 1 and(HIV 1 and HIV 2)HIV 2) -- - FeverFever -Loss of body weightLoss of body weight -TirednessTiredness -Candidiasis around theCandidiasis around the mouth and throatmouth and throat -PneumoniaPneumonia -Kaposis’s sarcomaKaposis’s sarcoma -Through sexual contactThrough sexual contact with a person infectedwith a person infected with HIVwith HIV - Transfusion of bloodTransfusion of blood from a HIV victimfrom a HIV victim -Sharing of injectionSharing of injection needlesneedles MalariaMalaria ProtozoaProtozoa ((PlasmodiumPlasmodium)) MosquitoMosquito - FeverFever -HeadacheHeadache - Muscle painMuscle pain -ShiveringShivering Mosquito biteMosquito bite SARSSARS VirusVirus -- - High feverHigh fever -Cry coughCry cough -Shortness of breath orShortness of breath or breathing difficultybreathing difficulty -PneumoniaPneumonia -Headache, muscularHeadache, muscular stiffnessstiffness -Loss of appetiteLoss of appetite -Rash, diarrhoeaRash, diarrhoea -Droplet infection touchDroplet infection touch - Close contact withClose contact with someone who has SARSsomeone who has SARS -Body secretionBody secretion
  64. 64. Transmission of Microorganisms 1.Through five ways : i) the air ii) touch iii) food iv) vectors v) water
  65. 65. Controlling Pathogens Methods of controlling pathogens Antibiotics Penicillin and streptomycin are chemicals produced by microorganisms which inhibit the growth or kill other microorganisms, especially bacteria Vaccines Are modified or weakened forms of bacteria or viruses. Is a suspension of dead bacteria or viruses which is inoculated into our body to induce the production of antibodies. Examples of vaccine are Sabine vaccine and BCG Antiseptics Are used on cuts and wounds to kill and inhibit the growth of microorganisms. Examples of antiseptics are acriflavin and iodine solution Disinfectants Use to kill microorganisms on the floor, buildings or furniture and sterilise surgical equipment. Example : phenol, formaldehyde and carbolic acid
  66. 66. The Role of Useful Microorganisms in the Ecosystem 1. Medicine - fungi – produce antibiotic (prevent the growth of bacteria) Examples: Penicillium notatum – gonorrhoea, syphilis, lung infection, Streptomycine – tuberculosis (TB) - dead bacteria or viruses – produce vaccine Examples: BCG for TB
  67. 67. 2. Food Processing - production of alcohol – using yeast through the fermentation process of sugar, starch or grains - production of vinegar – the bacterium, Acetobacter, acts on alcohol to produce vinegar
  68. 68. 2. Food Processing - Making bread – using yeast and sodium bicarbonate to produce carbon dioxide to rises the bread dough - Production of butter – cream is made sour by the action of bacteria. Bacteria split protein from the fat of the cream. This will enable the fat molecules to stick together when the mixture is stirred strongly
  69. 69. 2. Food Processing - production of fermented milk – tairu and yogurt - bacteria, Lactobacillus sp. and Streptococcus sp. and yeast - the milk will become sour and has the smell of alcohol - production of vitamins – Vitamin B2 – yeast - Vitamin D – yeast and bacterium - textile industry – bacteria are use to decompose the soft plant tissues leaving the plant fibres

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