cheat sheet biology and more essays title s and all, Cheat Sheet of Biology

Download cheat sheet biology and more essays title s and all and more Cheat Sheet Biology in PDF only on Docsity! 0 level IGCSE 20222023 Nihal Cabr Biology Team 16/2/2023 Part [ Nutrients cycle Dr. Nihal Gabr , Role of the nitrogen fixing bacteria 1. Growing in the root nodules of the leguminous plants turning nitrogen gas 2. By combing with hydrogen from air into ammonia / ammonium ions 3. Then it forms nitrates / nitrogen containing compound in the soil 4. which is then absorbed by plants from soil by active transport or diffusion 5. To make amino acid needed to make proteins for growth , making enzymes , hormones , nucleic acid ( DNA) Role of the saprophytic bacteria 1. Carry decomposition of dead plants and animals and their organic waste products 2. Where they release extracellular enzymes ( digestive enzymes ) that break down proteins in dead bodies into amino acids 3. Which in turn will be deaminated into ammonium ions /ammonia Proteins ………………amino acids Amino acids ………….ammonium ions and sugars Role of the nitrifying bacteria : 1. Carry nitrification under aerobic conditions ( in well aerated soil ) 2. Where in will turn ammonium ions into nitrites then nitrates in the soil 3. To be absorbed by the plant needed to make proteins and nucleic acids . Denitrification 1. Under anaerobic conditions where the water logs the soil ..no soil aeration 2. Denitrification where nitrates are turned back into nitrogen gas by denitrifying bacteria Carbon cycle Photosynthesis , respiration , combustion , decomposition CO2 Plants Animals Respiration Respiration Photosynthesis Feeding Nutrition Dead bodies Decomposition Optimum temperature By decomposers returning minerals back to soil Decomposition / respiration Under high temperature and pressure Fossilisation Fossil fuels Combustion Factors affecting carbon cycle : 1. Deforestation : increase Co2 concentration in the atmosphere • less plants …less photosynthesis ….less CO2 absorbed from the atmosphere • decomposers break down dead roots left behind ….so adding to large amount of CO2 to the atmosphere 2. Burning of fossil fuels : due to increase in energy demand and increase in number of vehicles . 3. Increase in population …..increase in respiration . ele Describe consequences of increasing CO2 in atmosphere Short wave radiation Long wave radiation Light rays from the sun hit the EARTH”S atmosphere As short wave radiation Reflected as long wave radiation So CO2 trap long wave radiation In Earth’s atmosphere This is called ENHANCED GREEN HOUSE EFFECT Cause global warming +ve effect Increase temperature Increase CO2 concentration . Increase rate of photosynthesis Increase growth Increase crop yield Melting of ice caps Cause rise in sea level ….floods Destruction of habitat No food , no shelter , no breeding site So increase in animal extinction -whats the effect of increase in CO2 on habitat / on plants X X 202 (o E - Part 1 energy flow Food chain: represents the energy flow from one organism to another Grass .....................................deer.............................................lion ................................ 🦖 Producer Organisms making their own food from photosynthesis First trophic level Primary consumer Heterotrophic( herbivore s feeding only on plants ) Second trophic level Secondary consumer Carnivores feed only on other animals . Found in the third trophic level Tertiary consumer ( carnivores/ omnivores) Found in the fourth trophic level Dead ( decomposition by decomposers such as bacteria and fungi ) Which get their energy from dead materials. Returning minerals back to the soil. NOT A CYCLE AS ENERGY DOESN”T GET BACK TO SUN Food web: several food chains linked together. Advantages : that each living organism can have more than one food source Trophic levels Position of an organism in a food web / a food chain Plant ............................giraffe ................................lion First trophic level Producer Second trophic level Primary consumer Herbivores Third trophic level Secondary Consumer Carnivores 10, 000K.J 1000 k.J 100 k.J 10% energy trasnferred 10% energy trasnferred 90% lost 90% lost 90% lost to the surrounding 1. Active transport of minerals 2. Evaporation of water using heat energy followed by transpiration 3. In dead leaves / roots 4. Part of light is not absorbed / reflected 5. Parts of the plant are non edible 6. Parts lost in undigested cellulose fibres 7. Part lost in respiration . 90% lost to the surrounding: 1. Movement 2. Respiration 3. Excretion 4. Undigested food / faeces 5. Not all animal parts are eaten Advantages of having shorter food chain / fewer trophic levels Fewer organisms at a top of food chain ( population size) Its better to feed human on plants rather than animals Explain why Explain why Explain why Efficient energy transfer Grass .................rabbit .................tiger /human Grass is found at first trophic level Rabbit is found at second trophic level 1’ As we move up in trophic levels more energy is lost to the surrounding and less energy is being transferred Where only 10% of the energy is transferred while 90% of the energy is lost Where 90% is lost to the surrounding in ….excretion, respiration , movement , egestion( undigested food) So less energy is being reached /available for organisms at higher trophic levels So less energy to support the life of large population 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 May be due to disease, hunting , introducing new species that increased the competition on food resources , habitat destruction by human activities.6 Suggest a disadvanatge for feeding on plants only Plants don’t contain all essential amino acids Parts of the plant are not digested ( cellulose fibers) so egested in faeces Food production 1. Using modern machinery 🚜 Positive effect Negative effect Cultivation and harvesting will be quicker , and more land area can be used • More fossil fuels …more CO2 …green house gas ….pollution • Soil is compacted , so difficult for rainwater to penetrate the soil . 2. Use artificial fertiliser Eutrophication Increase in population of bacteria …decrease the O2 concentration in water ..damage to the aquatic life Increasing soil fertility by Availability of minerals. such as nitrates and magnesium to plant Importance if nitrate , magnesium 3. Pesticides Insecticides ….kill insect Herbicide …..kill herbs / weeds Kill pest ( weeds / insect ) Less competition on nutrients and light and water Avoid damage of crop Increasing crop yield 1. Non biodegradable Bioaccumulation Toxic concentration in animals at highest trophic level. So might disrupt food chain Decrease biodiversity and increase risk of extinction . 2. Herbicide kill useful plants Insecticide ..kill useful insects as pollinators 3. Weeds might become resistance to herbicide Insect might become resistant to insecticide 4. Monoculture 🫑 🫑 🫑 🫑 🫑 🫑 🫑 🫑 🫑 🫑 🫑 🫑 🫑 🫑 Advantages 1. Efficient food production , less land area required 2. Mechanical harvesting easier . Disadvantages 1. increase the risk of spread of disease …..crowded place with same type of plant 2. Use up specific minerals from the soil …decrease soil fertility …use of artificial fertilser ….lead to eutrophication …..damage aquatic life 3. Increase pest population ….more use of insecticides ..kill useful insects/ animals such as pollinators + non biodegradable causing bioaccumulation 4. Decrease the OTHER pest population … disrupt food chain ….decrease biodiversity …increase risk of extinction 5. Deforestation…destruction of habitat ….no food , no shelter and no breeding site…decrease biodiversity … increase of extinction . 🐛 🐞 Solution Crop rotation / mixed crop rotation 🍎 🍌 🍉 🍋 🍓 Different crops in same field …reduce pest population by breaking their life cycles ….allow mineral balance , so less use of fertiliser 🥝 Biodiversity A) species diversity B) habitat diversity C) genetic diversity 5. Modern irrigation system Advantages Disadvantages Provide water to growing plant therefore removing a limiting factor Can lead to leaching of minerals from soil 6. Selective breeding ( intensive farming ) 🐄 🐃🐐 Intensive farming Live stock +ve effect: 1. Improvement in the variety of animals and plants 2. Farmers use high energy food to feed their animals so increasing production of milk meat and wool from animals 3. Regular medications given to animals so they stop developing diseases 4. Animal are kept under controlled temperature to maximize their growth rate 1. Over crowded places lead to spread of disease 2.so they increase dosing of antibiotic so increasing chance that bacteria become resistant to antibiotics 3. Decrease in biodiversity ...increase risk of extinction 4. Waste and left overs from animals cause pollution ...bad smell Eutrophication Increase in population of bacteria ....decreasing the-concentration of oxygen in water .........damage the aquatic life A) excessive use of fertiliser 1. Drain into rivers 2. Promote the growth of algae 3. Block sunlight from reaching the rooted plants 4. So can’t undergo photosynthesis 5.Death of aquatic / rooted plants 6. Promote growth of bacteria 7. On dead plants and algae 8. Respire aerobically ..decreasing the oxygen concentration in water 9. Anaerobic conditions 10. Damage/ migration to aquatic life ( plants and animals ) B) throwing un treated sewage in water/ rivers 1. Throwing untreated sewage .....same steps from 2 to 10 Sewage contain nitrogen containing compounds promote growth of algae Solution 1. Control the use of fertiliser Apply only when crops are growing Never apply to empty field Don;t place when rain forecast Dont spray near rivers and streams 2. Use manure its heavier so not easily leached by water besides release minerals slowly allowing effecient absorption of minerals Sewage treatment ""% ' =I rl l ill ' V 1 Excessive use of fertiliser 💨 Drained / washed away into rivers 2 Promote the growth of algae on water surface 4 Plant deep in water cant carry photosynthesis …so they will die 5 Bacteria will grow and respire aerobically 6 Oxygen concentration in water will decrease 🐟 🐟 7 Fish die and damage to aquatic life - peo Increasing Food production 1. Modern machinery.. 2. Artificial fertilisers … 3. Use of pesticides ……… 4. Mono culture ………….. 5. Modern irrigation system ……. 6. Live stocks …………….. 7.genetic engineering 8. Deforestation… +ve faster cultivation -Ve fossil fuels , soil become compact +ve increase in soil fertility + importance of minerals -ve eutrophication +ve reduce competition , protect crop -ve kill nuseful insects / plants + non biodegradable +ve increase in food production -ve biodiversity , decrease of soil fertility , spread of disease +ve water becomes no longer limiting factor -ve leaching of minerals away from soil surface +v increase food production , increasing quality of food -ve spread of disease ..over use of antibiotics …resistance + decrease in biodiversity +ve more land for cultivation -ve destruct habitat Read Comment on the use of pesticides …..tips for answering questions Insecticides Herbicides Advantages To avoid damage of crop Increase in crop yield and quality Less competition Increase in crop yield and quality Kill useful insects such as pollinators Disadvantages Kill useful plants 1. Non biodegradable Bioaccumulation Toxic concentration in animals at higher trophic levels Disruption of food chain Loss of biodiversity and increase probability of extinction 2. Develop resistance What are factors / specifications while choosing 1. Weather forecast ….to avoid being transferred to another nearby places And kill useful insects /plants 2. Number of times need to be applied ….cost 3. Herbs / insects are not resistant 4. Biodegradable Human influence Air pollution Deforestation Water pollution 1.Green house gases ( CO2, methane , CFC) 2. Nuclear fall out Affects: 1. On soil ……soil erosion and desertification 2. On animals ….loss of habitat ….decrease in biodiversity and increase risk of extinction 3. Atmosphere….enhanced green house effect …global warming 4. On rivers ….floods 1. Untreated sewage and fertilser …eutrophication + spread of disease 2. Non biodegradable plastic. 3. Pesticides ….bioaccumulation , kill useful organisms 1. Green house gases 1. Co2 …..burning of fossil fuels ……ENHANCED GREEN HOUSE effect …….. 2. Methane gas : A) decay of rubbish in land fill B) from sludge ….. C) cattle chewing the cud D) anaerobic bacteria in mud paddy fields ( rice) 3. CFC; refrigerator and air conditions 3.nuclear fall out Nuclear explosion …..mutation ….damage DNA …cancer and deformities in babies …death Change in genetic material Water pollution ' 1. Fertilsers and untreated sewage …….eutrophication 2. Pesticides …..kill useful insects and plants ….non biodegradable …bioaccumulation …disrupt food chain . . 3. Non biodegradable plastics : A) plastic contains toxins / harmful chemicals B) BLOCK digestive system of animals if mistakenly swallowed ..cause their death . C) BLOCK AIR WAYS of animals ….suffocation so they die D) BLOCK sunlight for photosynthesis E) BLOCK flow of water in streams …stationary water …spread of disease ….less aeration of water ….oxygen concentration decrease …migration / damage of aquatic animals . F) Non biodegradable….bioaccumulation . Conservation …….its the process of looking after natural environment to A maintain the biodiversity of plants and animals . B) maintain natural resources ( water, fossil fuels ) for coming generations Biotic Abiotic Why conserve ( living and non living ) …… A) why conserve plants and animals ( biotic ) : 1. Maintain biodiversity 2. Prevent extinction 3. Maintain resources like food availability 4. Increasing research such as finding resources for medicine 5. Encourage genetic diversity Within species ( gene pool) 6. Avoid disruption of food chain / food webs 7. Tourism. 8. Providing habitats for many species 9. Keeping beauty of nature for those who enjoy nature like poet , artist . B) abiotic ( non living ) Maintain natural resources Fossil fuels are non renewable source of energy that will end up soon And they need million of years to be formed again….so we need to conserve them for the coming generations D) keeping natural resources like conserving forest 1. Governmental rules : Refuse to grant license for cutting trees 2, selective felling Instead of clear felling ( cutting all trees) Just cut small part so remaining trees will provide habitat for some animals 3. Coppicing Cutting down tree leaving 1 meter to regrow 4. Planting new trees Yet better to conserve primary forest : Planting new tress to replace the old ones still cant replace primary forest . 5. Educating people about importance of conserving forest . D) seed banks Where seeds can remain dormant for many years and then germinate when conditions are right Also easier to store seeds as they take up less space So collect and store seeds of plant species that are endangered then grow them in capitatvity or reintroduce into their natural habitat B) abiotic ( a non living )factors Water + non sustainable resources ( use sustainable resources and allow recycling ) . 1. How to conserve abiotic factors……By using sustainable resources Resources that can be replaced as fast as they are removed Why? Non sustainable resources need million of years to be reformed and to conserve them for coming generations How? By recycling A) recycling paper Less forest cleared Less water used in paper production from recycled paper Use less energy for collection and transportation Less rubbish burnt so less carbon dioxide given off Less waste added to land fill Steps : Shredding Pulp Soaking in water De inking Bleaching Flattening B) recycling metals Save energy used in mining metal ores C) recycling plastic Less fossil fuels being used Decrease amount of wast added to land fill ................. D) recycling to water 1. Remove pathogen which cause disease ( water borne disease like cholera ) 2. Avoid bad smell and pollution 3.remove nutrients which promotes the growth of bacteria and cause eutrophication. 4. Reuse water E) recycling glass: Where glass is made by heating sand at high temp releasing large amount of CO2 So recycling .....less CO2 released, reduce use of raw materials as sand Definition of sustainable development ? Providing the needs of an increasing human population without harming the environment How ? 1. Local people as farmers 2. National goverments who set regulations to make sure that new developments are planned and constructed with environment need 3. In addition to role of conservation bodies ( international organisation) . 1. adaptive features: An inherited feature that helps an organism to survive and reproduce in its environment. Or The inherited functional features of an organism that increase its fitness. 2. Fitness: The ability of an organism surviving and reproducing in the environment in which it is found.( a word used to describe how well adapted an organism is to its environment. 3. Process of adaptation: The process resulting from natural selection, by which populations become more suited to their environment over many generations.