This page contains the AQA GCSE Biology B18 Biodiversity and Ecosystem kerboodle answers for revision and understanding .This page also contains the link to the notes and video for the revision of this topic.
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B 18.1 The Human Population ExplosionAQA GCSE Biology B18 Biodiversity and Ecosystem Kerboodle Answers: Page No. 287
1a The human population has increased so rapidly over the past couple of hundred years because we have discovered how to grow more food than we could ever gather from the wild. We can cure or prevent many killer diseases. We have no natural predators. This helps to explain why the human population has grown so fast.
b People reduce the amount of land available for other animals and plants as more and more land is used for building houses, shops, industrial sites, and roads on. This destroys the habitats of other living organisms and reduces biodiversity.
• We use billions of acres of land around the world for farming. Wherever people farm, the natural animal and plant populations are destroyed.
• We dig up vast areas of land for quarries to obtain rocks and metal ores, reducing the land available for other organisms.
• The waste produced by humans pollutes the environment and processing it takes up land, affecting biodiversity.
2 Resources that humans are using up are
1 Land.
2 Metal ores.
3 Fossil fuels, wood.
b The standard of living has improved over the past 100 years as
• Use of electricity for lighting/heating/entertainment.
• Increased food production.
• Improved medicines.
• Use of fossil fuels for transport.
• Development of plastics • improved waste disposal • improved sanitation.
3 Different ways that the ever-increasing human population is causing pollution :
Points may include:
• Increased waste – including bodily waste, industrial waste, packaging, uneaten food, and disposable goods.
• Exhaust gases from transport.
• Use of pesticides and fertilisers in farming.
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B18.2 Land and water pollutionAQA GCSE Biology B18 Biodiversity and Ecosystem Kerboodle Answers: Page No. 289
1 Human bodily waste and waste water is called seways.
b It important to dispose of sewage carefully because toxic chemicals can spread from waste into soil, toxic chemicals can be washed into waterways, sewage can pollute soil with dangerous chemicals and gut parasites, toxins build up in organisms along food chain (bioaccumulation), largest predators die or are infertile due to toxic chemical build‑up.
c Bioindicators are used to monitor pollution level in waterways.
2 a Farming can cause pollution of the land. The polluting effects farming can have on are
i land
Polluting effects are:
• Pesticides and herbicides spread from crops into soil.
• Plant material contaminated with toxins.
• Small levels of toxins taken in by animals eating affected plant material.
• Toxins build up along food chains (bioaccumulation) until toxic levels are reached in top predators.
ii water
Polluting effects are:
• Fertilisers washed from the soil into streams, ponds, and rivers.
• Nitrates in fertilisers encourage the rapid growth of algae and water plants.
• Microorganisms feeding on the plants use up oxygen decreasing the levels of oxygen.
• Other oxygen-dependent organisms then die because of a lack of oxygen.
b In the UK, a chemical called DDT was used up until the 1980s to kill insects. Large birds of prey and herons began to die and their bodies were found to have very high levels of DDT in them. It took a long time for any link to be made because:
• DDT in pesticide contaminated soil and waterways.
• Organisms contaminated with toxins.
• DDT builds up in organisms along food chain.
• DDT levels become dangerously high in top predators (birds of prey, herons).
• Effects of DDT not noticeable until dangerous levels reached.
• Route through food chain not obvious.
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B18.3 Air pollutionAQA GCSE Biology B18 Biodiversity and Ecosystem Kerboodle Answers: Page No. 291
1 Acidic gases from cars and factories burning fossil fuels can pollute:
a air
Acidic gases released into atmosphere and spread around by wind in this way pollute air.
b water
Sulfur dioxide and nitrogen oxides dissolve into rain and snow, contaminating lakes/rivers/streams.
c land
Dilute sulfuric acid and nitric acid fall as acid rain and soak into soil.
2 a Flow chart to show how acid rain is produced:
Flow chart should include: Cars/power stations burn fossil fuels → acidic gases (e.g., sulfur dioxide, nitrogen oxides) formed → gases carried in the winds in atmosphere → sulfur acidic gases dissolve in rainwater and react with oxygen to form dilute sulfuric acid and nitric acid → acid rain falls.
b Some countries that have strict controls on sulfur emissions still suffer acid rain damage to their buildings and ecosystems as sulfur dioxide and nitrogen oxides can be carried high in air by winds. Acidic gases can be blown from a country that does not control its sulfur emissions to a country that has strict emission controls and fall as acid rain.
3 a The percentage reduction in sulfur dioxide emissions in the EU between 1990 and 2010:
25000 − 5000 = 20000,
× 100 = 80, reduction of 80%.
b Reasons for the observed reductions are
• More efficient catalytic converters in cars.
• Cleaner fuels.
• Legislation to control emissions from factories.
c Observations to affect the levels of acid rain in Europe:
Levels of acid rain should fall as sulfur dioxide emissions fall, unless prevailing winds carry acidic gases from non-European countries.
4 a The change in sulfur dioxide emissions for:
i China, between 1850and 1975
1850: 0 million tones.
1975: 4 million tones.
4 million tone increase.
ii the USA, between 1975 and 2000
1975: 14 million tones.
2000: 8 million tones.
6 million tone decrease.
b The implications for global biodiversity of the trends seen in Figure 2b as figure 2b shows increasing global sulfur dioxide emissions, causing increasing acid rain. Acid rain directly damages plant life by falling on plants and by soaking into soil and being taken up by roots. Acid rain contaminates soil and watercourses, making them more acidic and eventually unable to sustain life. Increasing sulfur dioxide levels threaten to reduce global biodiversity as whole ecosystems can be destroyed.
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B 18.4 Deforestation and peat destructionAQA GCSE Biology B18 Biodiversity and Ecosystem Kerboodle Answers: Page No. 293
1 deforestation is defined as removal of large areas of forest by felling/burning without trees being replaced.
b Deforestation affects biodiversity as tropical rainforests contain more biodiversity than any other land environment. Loss of forests means biodiversity of plant and animal life is also lost as habitats are destroyed and species become extinct. Many species are being destroyed before being identified and studied, so potential new sources of medicine or food could be lost.
2 Deforestation increases the amount of carbon dioxide in the atmosphere as :
Carbon dioxide produced by burning of trees.
Carbon dioxide produced by decomposition of dead vegetation.
Less carbon dioxide removed from atmosphere by growing plants.
3 a The numbers of peat bogs and peat lands in the world are decreasing because use of peat as fuel and by gardeners as compost.
B This is cause for concern because CO2 is released into atmosphere as peat is burnt or used as compost, increasing atmospheric levels of carbon dioxide and depleting the carbon store.
Destruction of peat bogs destroys habitats and reduces biodiversity.
4 The conflict between the need for cheap available compost and the need to conserve peat bogs and peatlands are
• Cheap compost needed by gardeners and horticulturists to improve soil properties, promote seed germination, and increase food production, alternative, ‘peat‑free’ composts are available but are less popular.
• Peat bogs and peat lands vital to biodiversity as they form habitat for many organisms adapted to live in acidic conditions.
• Peat forms very slowly and under very specific conditions – cannot be replaced as quickly as it is being used.
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B 18.5 Global warming AQA GCSE Biology B18 Biodiversity and Ecosystem Kerboodle Answers: Page No. 295
1 The data in Figure 1 to produce a bar chart showing the maximum recorded level of carbon dioxide In the atmosphere every tenth year from 1960 to 2010 as Correct y-axis label and scale, Correct x-axis label and scale, data plotted correctly.
b Trend you can see on your chart :
Carbon dioxide levels rising steadily over time, partly as a result of human activities.
c The greenhouse effect is energy transferred from Sun to Earth.
Much of this heat is reflected back into space but some is absorbed by greenhouse gases in the atmosphere and reradiated back to Earth. Earth’s surface and atmosphere are warmed (greenhouse effect), maintaining conditions ideal for life
2 a Global warming is occurring because atmospheric levels of greenhouse gases increasing as a result of human activity, increasing greenhouse effect and causing global temperatures to rise.
b The biological consequences of global warming are
• Loss of habitat – reducing biodiversity.
• Changes in distribution – some organisms may disappear from some areas as habitat changes.
3 An organism that has been, or might be, affected by global warming. The effect of global warming on the survival of this organism is that the effects of global warming are the environmental and social changes caused (directly or indirectly) by human emissions of greenhouse gases. There is a scientific consensus that climate change is occurring, and that human activities are the primary driver. Many impacts of climate change have already been observed, including glacier retreat, changes in the timing of seasonal events (e.g., earlier flowering of plants), and changes in agricultural productivity. Anthropogenic forcing has likely contributed to some of the observed changes, including sea level rise, changes in climate extremes, declines in Arctic sea ice extent and glacier retreat.
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B18.6 The impact of changeAQA GCSE Biology B18 Biodiversity and Ecosystem Kerboodle Answers: Page No. 297
1 a i seasonal environmental change: Natural changes in environmental factors such as temperature, rainfall level, water availability, dissolved gases in water, and daylight hours between different seasons in temperate parts of the world.
ij geographical environmental change
Natural changes in environmental factors such as soil structure or pH, altitude, water salinity, and water availability between different geographical areas of the world.
b Organisms adapt to environmental changes are natural mutations cause features that enable some individuals within a population to cope better with a change to their environment. These individuals are more likely to survive and breed (natural selection), passing on the beneficial feature to offspring.
2 a Number of breeding pairs of Dartford warblers in UK increasing.
b Reasons for the changes in the numbers of breeding pairs of Dartford warblers in 1963 and in 2010 : Dartford warblers cannot survive very cold winters. Number of breeding pairs dropped sharply in 1963, suggesting cold winter that reduced population. Number increased sharply in 2010, perhaps as a result of temperature increase.
C Aspect of climate change seems to be most closely linked to a change in the distribution of British birds : As temperature changes:
Changes in number of Dartford warblers indicate that numbers have increased as UK temperatures have increased but drop sharply after cold winters. Drop in number of Dartford warblers in Spain indicates that too high a temperature also affects distribution. Evidence suggests that change in mean UK temperature and seasonal extremes of temperature affect distribution of UK birds both within the country and between countries.
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B18.7 Maintaining biodiversityAQA GCSE Biology B18 Biodiversity and Ecosystem Kerboodle Answers: Page No. 299
1 a It is important to maintain biodiversity because it is important for environmental health, offers potential source of new food crops, offers potential source of new medicines.
b Breeding programs for endangered species – restoring endangered species to sustainable populations, protection and regeneration of rare habitats – protecting different animals and plants, reintroduction of field margins and hedgerows – allowing biodiversity to be maintained in agricultural land, reduction of deforestation – maintaining habitats, recycling resources – reducing habitat loss and pollution.
c There is a conflict between maintaining biodiversity and human needs as
• Increased field margins limiting land available for food production,
• Reduction of deforestation limiting land available for food production,
• Taxes on landfill waste increasing costs to businesses.
2 Using the data in Figure 3a
a Levels have fallen steadily.
b This data demonstrates the effect of governments on carbon emissions as this data suggests that Kyoto agreement drove UK government to take action to limit carbon dioxide emissions and that government intervention via legislation has been successfully.
c A fall in carbon dioxide emissions globally might help maintain biodiversity as
• Reduce or prevent increase in greenhouse effect and global warming – maintaining biodiversity by preserving Arctic and Antarctic ice habitat.
• Preventing rises in sea levels that will destroy biodiverse mangrove forests.
3 Taxes can be used to help reduce human damage to ecosystems and biodiversity as data shows that as landfill tax increased, amount of material going into landfill fell. Taxes on waste and emissions can be used as an effective incentive to change human habits and promote research into less damaging alternatives (e.g., recycling rather than landfill).
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1 a biomass is defined as mass of biological material in living organisms.
b Advantages and disadvantages of using wet and dry biomass in building up a pyramid of biomass for a food chain are dry biomass shows amount of biological material at each level more accurately but necessitates killing and drying out organisms. Wet biomass values much easier to obtain as does not involve killing organisms, but is less useful as water content of living organisms varies constantly, making results less repeatable and reproducible.
2 a Award marks for accurate pyramid correctly labeled.
b The sheep ticks have so much less biomass than the grass cropped by the sheep as amount of material contained in biomass of organisms at each stage of a food chain less than it was at the previous stage. Not all of organism at one stage eaten by organism at next stage (only leaves of grass eaten by sheep, only blood of sheep eaten by ticks). Some materials taken in passed out and lost as waste products.Much of materials taken in used in cellular respiration to release energy for cell metabolism and some energy transferred to surroundings. Relatively small amount of material taken in converted to new biomass. Large percentage of biomass in grass cropped by sheep not converted to biomass in sheep and large percentage of biomass in sheep not converted into biomass in sheep ticks.
3 a Percentage biomass passed on from the producer to the primary consumers = 5000/100000×100 = 5%.
b Percentage biomass passed on from the primary consumers to The secondary consumers = 30/5000×100 = 0.6%.
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1 a Biomass lost in faeces as some of the biomass ingested by an animal cannot be used. Most herbivores cannot digest cellulose in plant material. Most carnivores cannot break down and digest hooves, claws, bones, and teeth. Indigestible materials are egested as faeces, meaning biomass is lost.
b Animals that are very active use up more of the biomass they eat than animals that don't move much because biomass used in cellular respiration to provide energy for movement and to supply energy and raw materials needed for building new biomass. Active animals carry out lots of respiration as active, contracting muscles respire more. More of the biomass eaten is broken down and used for movement in active animals and more energy is transferred to surroundings as muscles warm up.
2 a Flow chart of a food chain : producers → primary consumer → secondary consumer → tertiary consumer → decomposers.
b Biomass is lost at each trophic level in your flow chart as biomass lost by consumers in faeces – cellulose cannot be digested by herbivores, animal parts such as hooves/claws/bones/teeth cannot be digested by carnivores. Biomass lost by producers and consumers in waste – excess protein and water lost in urine, carbon dioxide and water lost in respiration. Biomass lost in consumers in maintaining a constant body temperature – energy transferred to surroundings.
3 Light from the Sun that lands on the surface of the Earth is not used in making biomass in animals because only about 1% of energy from Sun’s light falling on Earth (incident energy) used by plants for photosynthesis to create biomass. Plant biomass eaten by animals cannot all be digested. Some is broken down and used in respiration to provide energy for living processes such as movement and regulating body temperature. Only small amount of biomass eaten by animals used for growth to produce new biomass.
B18.10 Factors affecting food security AQA GCSE Biology B18 Biodiversity and Ecosystem Kerboodle Answers: Page No. 305
1 Food security means having enough food to feed a population.
2 Ways in which food security might be reduced
• increasing birth rate,
• new pests and pathogens,
• changing diets in developed countries,
Ways in which food security might be increased
• maintaining or improving soil quality,
• efficient ways to produce food (e.g., selective breeding or GM technology),
• managing fish stocks,
.
3 Changing diets in one country can affect food security in another as Quinoa staple food in Bolivia. Production of quinoa in Bolivia has increased since 1997. Quinoa has increased in popularity in other countries, leading to increased exports as farmers can charge more to foreign buyers than to local consumers and make more money. Local consumption of quinoa has fallen as exports have increased. Food security in Bolivia reduced as population increasingly dependent on imported pasta
4 'Food security is one of the biggest problems facing the human population today’. Yes we are agree with this statement.
Afghanistan
Afghanistan about 35% of household is food insecure. Prevalence of under-weight, stunting, and wasting in children under 5 years of age is also very high.
Mexico
Food insecurity has distressed Mexico throughout its history and continues to do so in the present. Food availability is not the issue; rather, severe deficiencies in the accessibility of food contributes to the insecurity. Between 2003 and 2005, the total Mexican food supply was well above the sufficient to meet the requirements of the Mexican population, averaging 3,270 kilocalories per daily capita, higher than the minimum requirements of 1,850 kilocalories per daily capita. However, at least 10 percent of the population in every Mexican state suffers from inadequate food access. In nine states, 25–35 percent live in food-insecure households. More than 10 percent of the populations of seven Mexica states fall into the category of Serious Food Insecurity.
The issue of food inaccessibility is magnified by chronic child malnutrition as well as obesity in children, adolescents, and family.
Mexico is vulnerable to drought which can further cripple agriculture
B18.11 Making food production efficientAQA GCSE Biology B18 Biodiversity and Ecosystem Kerboodle Answers: Page No. 307
1 a It is important to keep animals cool in hot temperatures so that animals do not have to use much biomass in cooling down, leaving more biomass for growth.
b Animals does not turn all of the food they eat into new biomass as biomass lost through faeces, urea, and respiration for movement and regulation of body temperature.
2 There would be more food for everyone if people only ate plants because earth has limited surface area for plant growth. Biomass lost at each stage of food chain. Shorter food chains more efficient. If people all ate plants instead of feeding plants to animals and then eating animals, food chains would be shorter. Efficiency of food production would be greatly increased as plant biomass would be used to produce human biomass directly.
3 Advantages of intensive methods for rearing farm animals and fish :
• indoor work,
• animals grow faster so ready for market sooner,
• control of movement and temperature maximizes conversion of food to biomass, • weather conditions don’t matter,
• fish farming conserves wild stocks.
Disadvantages of intensive methods for rearing farm animals and fish :
• initial cost of buildings,
• cost of light and heating,
• higher feed bills,
• animals may be stressed (gain biomass more slowly),
• ethical concerns.
B18.12 Sustainable food productionAQA GCSE Biology B18 Biodiversity and Ecosystem Kerboodle Answers: Page No. 309
1 a Fishing industry has reached crisis point because of development of large commercial fleets capable of catching huge quantities, uncontrolled overfishing.
b Fish stocks can be protected by control size of the holes in nets so only largest fish caught, ban fishing during breeding season, strict catch quotas.
c Possible reasons may include: people dependent on fishing for livelihood and wary of reduced income, difficult to obtain overall picture of global fish stocks, difficult to apply quotas across large oceans fished by multiple countries.
2 a 1969 (accept between 1967 and 1969) 1.8 million tonnes (accept 1.7 to 1.9 million tonnes).
b Cod caught in 2010:0.1 million tones.
c 1800000 − 100000 = 1700000,
Percentage fall in catches = 1700000/1800000 × 100 = 94%.
d The percentage increase in the Tuna catch from 1960-2000 in:
iAtlantic tuna.
0.4/0.1 × 100 = 400% increase.
ii Indian tuna.
1.2/0.25 × 100 = 480% increase.
iii Pacific tuna.
3.6/0.6 × 100 = 600% increase.
e The global fish crisis may have been left too late because some fish species almost extinct, fish caught over quota discarded dead so cannot increase populations, quotas difficult to enforce internationally.
3 Mycoprotein is an example of sustainable food production.
Similarities:
• fermenter equivalent to enclosed shed or barn.
• fermenter temperature regulated and food supply maintained to give the optimum conditions.
• designed to achieve maximum growth over minimum time.
• cost of maintaining conditions outweighed by increased production. Differences:
• fungus not an animal so controlled conditions cause no stress.
• no ethical issues.
• pH not monitored and maintained in farming.
• no free-range alternative in mycoprotein production.
Summary questions: Page No. 310
a i the percentage biomass passed on from producers to primary consumers 5 000/50 000 × 100 = 0.1,10% biomass passed on
ii the percentage biomass passed on from primary to secondary consumers 400/5000 × 100 = 0.08,8% biomass passed on
iii the percentage biomass passed on from secondary consumers to top carnivores 50/400 × 100 = 0.125,12.5% biomass passed on
b In any food chain or food web, the biomass of the producers is much larger than that of any other levels of the pyramid because the produces support the whole pyramid, most of the biomass is indigestible, so a little transferred to next level.
c In any food chain or food web, there are only small numbers of apex carnivores because there is a loss of biomass at each stage of food chain.
d Cold blooded animals do not maintain their own body temperatures they depend on environment, so they are more energy efficient than animals with maintain their inner body temperature so there is less biomass available for transfer.
2 a Flowchart of acid rain formation
b Figure 2 shows the sulfur emissions made by European countries from 1980 to 2002.
i The level of sulfur emissions in 1980 is 18 Tg
ii The approximate level of sulfur in the air in the year that you were born depends on person to person
iii the level of sulfur emissions in 2002 is 4 Tg
c This data tell you about trends in the levels of sulfur emissions since 1980 as emissions have fallen slowly.
3 a Food security refers to having enough food to feed population with balanced diet.
b Using pyramids of biomass, explain why there would be more efficient use of resources if people everywhere consumed less meat and more plant material . This will solve many problems of food security. If food chain is short the efficiency is more as biomass is lost at each stage. If people eat directly more plants and decrease the plant consumption of animal’s dependent of plants, as a result of it food chains will be shorter and efficiency increases.
c There are many problems with food security such as : Increasing population, we can control it by using contraceptive methods.
Climate change is the main concern, due to increasing pollution levels and global warming it can be threat to the global food security. By controlling emission of greenhouse gases we can overcome this.
Cost of agricultural inputs increasing day by day due to fertilizers and pesticides. We can overcome this by educating farmers to use compost and natural fertilisers.
4 a
b The temperature is carefully controlled in the broiler house to limit use of biomass from food in respiration to regulate body temperature.
c So many birds are reared together in a relatively small area in order to minimize the use of biomass from food in respiration for movement as working and contracting muscles needs high levels of energy. Energy is lost to the surroundings as muscles warm up.
d these birds reared like this to meet the augmenting demand for less expensive meat
Practice questions: Page No. 311
01 methane – global warming
sewage – Increased risk of diseases
smoke – blackening of buildings
02.1 Organisms that can survive in extreme conditions are called
extremophiles
02.2 Correct order of organisms from base to top of pyramid: bacteria, limpets, crabs
box sizes decrease from base to top of pyramid
02.3 The food chains show some organisms that live near a hydrothermal vent and some organisms that live near the surface of the sea. A food chain found near a hydrothermal vent: bacteria -> limpet -> crab. A food chain found near the surface of the sea: green seaweed -> iimpet -> crab
Difference
• food chain near hydrothermal vent begins with bacteria
• food chain near surface of the sea begins with seaweed
• use different energy sources
• producers (in the two chains) are different
Examples of scientific points made in the response
• seaweed is an alga
• seaweed absorbs light / energy from sun
• for photosynthesis
• to make glucose / sugar/ carbohydrate / food
• no light at bottom of sea
• plants can’t survive in the dark / conditions at the bottom of sea
• bacteria are extremophiles
• bacteria need different energy source / use chemical energy
• to make carbohydrate / food
03 The fungus Fusarium is used to produce a proteinrich food that is suitable for vegetarians.
03.1 The name of protein-rich food produced from a fungus is mycoprotein
03.2 Figure 2 shows a fermenter that is used to grow large quantities of Fusarium . The nutrient solution is sterilised before the Fusarium is added.The nutrient solution is sterilized by steam kills organisms in the solution
03.3 The main food source for the fungus in the fermenter is
glucose (syrup)
03.4 provides oxygen / aerobic conditions
for respiration
03.5 It is important to constantly stir the contents of the fermenter
• to prevent the fungus / Fusarium from settling at the bottom
• to keep the fungus / Fusarium in contact with oxygen / nutrients
03.6 The fermenter must have a cooling jacket around it respiration transfers thermal energy
if temperature rises (too much)
fungus / Fusarium would be killed\
Disclaimer: I have tried by level best to provide the answers and video explanations to the best of my knowledge. All the answers and notes are written by me and if there is any similarity in the content then it is purely coincidental. But this is not an alternative to the textbook. You should cover the specification or the textbook thoroughly. This is the quick revision to help you cover the gist of everything. In case you spot any errors then do let us know and we will rectify it.
References:
BBC Bitesize
AQA GCSE Science Kerboodle textbook
Wikipedia
Wikimedia Commons
This page contains the detailed and easy notes for AQA GCSE Biology Ecology for revision and understanding Ecology.
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ECOSYSTEM
It is a segment of nature consisting of a biological community and its physical environment both interacting and exchanging materials as well as energy. e.g – pond ecosystem.
Ecosystem is the group of communities interacting with the biotic and the abiotic factors.
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Most of the abiotic factors affects photosynthesis which affects the producers which inturn affect the complete food chain.
Light – Less light limits the photosynthesis and affect the entire food chain Plant in low light have broader leaves to increase surface area for absorption.
Water – Water is required for growth. Less water limits the photosynthesis and affect the entire food chain
pH – The low pH makes the soil acidic and limits the growth of plants and affect the entire food chain
Temperature – Temperature also limits the rate of photosynthesis which affects the food chain
Oxygen – The oxygen is required for the growth of the plant. In low levels of oxygen the organisms cannot survive
Carbon Dioxide – Carbon dioxide is required for growth. Less water limits the photosynthesis and affect the entire food chain.
Wind – Plants growing in high wind adapt different shapes. Wind also affects the rate of transpiration.
Constitute all the living members of an ecosystem. E.g Producers, Consumers, Decomposers.
FOOD – Food availability helps the species to grow and reproduce.
PATHOGEN – A pathogen can cause infectious disease d affect the growth of the population and can also wipe the whole population
PARASITES – Parasites can limit the growth of the host and affect the • population of the community.
COMPETITION – Increasing competition can affect the growth of the population and can outcome the individual of a population
PREDATORS – Increase in predation can decrease the population of the prey.
| INTERSPECIFIC COMPETION | INTRASPECIFIFC COMPETION |
| It is the competition between the members of different species. | It is the competition between the members of the same species. |
Food Territory Resources | Food Territory Mating |
| It leads to the movement of species to a new place, adaptation or extinction |
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Special Features that give the organisms the survival advantage and helps the organism to survive in the extreme conditions.
PLANT REQUIRMENTS
ANIMAL REQUIREMENTS
PLANT ADAPTIONS
| PLANT CHALLENGES | PLANT ADAPTATIONS | EXAMPLE |
| Water loss and dry conditions in desert | Small leaves; Leaves reduced to spines to decreases the surface area for water less. Extensive root system to absorb maximum water and succulent stems to store water. Plants are also covered with waxy cuticle to limit water loss | Cactus where leaves are reduced to spines Marram grass which has curled leaves and sunken stomata to trap moist air to limit water loss. |
| Lots of rain and water with less light in rainforest | Leaves are broad to trap maximum sunlight. They have thin cuticle | Epiphytes like Lianas |
| Plant growing in low nitrogen soils. | The plants trap insect and digest them to fulfil their nitrogen and mineral requirements | Carnivores plant like Venus Flytrap |
| Plants prone to insect attack | These plants secrete chemicals like alkaloids or tannins to repel insect | Tobacco produced Nicotine. |
| Aquatic Plants growing in excess water and less light | Flexible stem to withstand water current. Broad leaves to absorb maximum light. They have hair spaces in leaves | Water Lillies |
ANIMAL ADAPTATIONS
| DESERT ANIMALS Hot, dry conditions | ARCTIC ANIMALS Extreme cold | |
| Structural | They have large ears to give off maximum heat. They are small with large surface area to volume ratio. | They have small surface area to volume ratio to prevent heat loss. They have fur or thick fat deposit to provide insulation. White fur also comouflage with the ice. |
| Behavioural | They are more active during early morning and evening. When it is too hot or too cold they rest in burrows. | Polar bears form big dens and are strong swimmers and can swim through ice. |
| Functional | Produce very concentrated or no urine. | The fur or the coat change colours in summer and winters. |
EXTREMOPHILES
| EXTREME TEMPERATURE | EXTREME SALT |
| They have enzymes that work at high temperature and do not get denatured. | They have salt glands to expel excess salt. |
| For extreme cold they have antifreeze. | They also have adaptations in the cytoplasm so that they cannot gain or loose water. |
STUDYING COMMUNITIES
Quadrat Method – Random squares are placed at different point and the species within that squares are counted.
Transect Method – A line is placed and the species that are within this line or few cm above or below this line are counted and recorded.
Sample Size – The sample to be take for observation.
Mean – It is the statistical value calculate by adding all the values divided by total number of values.
Median – It is the middle value of the data.
Mode – The value that has the greatest frequency.
Range: It is the highest value take away the lowest value.
Producers: They produce their own food as they can photosynthesize and converts Sun’s energy to chemical energy.
Primary Consumers – They are herbivores which feeds on plants.
Secondary Consumers – They are carnivores or omnivores which feeds on herbivores.
Tertiary Consumers – They are at the top of food chain
Decomposers – Feed on dead and decay matter.
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PREDATOR- PREY RELATIONSHIP
Biomass is the mass of the materials contained in the living organisms.
Proteins in the dead and decay matter is converted into nitrates and returned to soil.
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Evaporation – water is evaporated from the water bodies like sea, lakes etc and form water vapours.
Transpiration – The water vapours are also lost from the surface of the plants.
Respiration – Respiration produced water vapour and it is lost in the form of water vapours
Condensation – The water vapour from all the above source cools and condense to form clouds.
Precipitation – When clouds get full the fall of as rain and the cycle continues.
Photosynthesis – It is the process by which green plants take in carbon dioxide from the
Respiration – The carbon dioxide is returned back to the atmosphere
Combustion – The fuel burns releasing carbon dioxide into the atmosphere
Decomposition – It is the process by which decomposer decay dead material and release carbon dioxide into the atmosphere
Fosslization – Dead Plants and Animals form fossil fuels which burns to release carbon dioxide into the atmosphere
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They are the microorganisms that breaks the dead and decay materials into simpler components. They are very important as they return the nutrients and minerals back into the atmosphere
Condition required for decay
Decay process forms methane which can be used as fuel.
Decay process also produce compost which can be used as a manure.
Plants
Animals
Breaks the dead and decaying plants and animals into simple components which are recycled in the atmosphere.
It is the measure of number of difference species in an area. Greater the biodiversity more stable is the ecosystem and less dependency on other organisms.
Uses of Biodiversity
Threats to Biodiversity: All factors are interconnected
Sulphur and nitrogen present in fossil fuels forms carbon dioxide and sulphur dioxide by combustion.
Carbon dioxide and sulphur dioxide combine with rainwater forming nitric acid and sulphuric acid and falls as acid rain.
Effects
Prevention
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Smog is opaque or dark fog having condensed water vapours, dust, smoke and gases.
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It is increase in the concentration of a persistent chemical with the rise in trophic level. As the toxic products go along the food chain the concentration of the toxic chemicals increases.
What is Peat ?
Uses of Peat
Effect of Peat Bog Reduction
It is warming effect found in green house by allowing solar radiations to pass in but preventing long wave heat radiations to pass out due to glass panes, water vapours and carbon dioxide.
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What is Food Security ?
Growing sufficient healthy food to feed the population and accessibility of the population to grow or buy the healthy food.
Factors Affecting Food Security
In intensive farming the animals are grown to limit energy loss and produce maximum biomass by
Mycoprotein are the proteins source from fungi. It is excellent food source and is sustainable grown in fermenter.
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w) Mycoprotein – Mycoprotein is a type of unicellular protein derived from fungi. It is excellent food source and is sustainable grown in fermenter
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References:
BBC Bitesize
Wikipedia
Wikimedia Commons
Image Source:
Wikipedia
Wikimedia
Commons
Flickr
Pixabay
Make sure you have watched the above videos and are familiar with the key definations before trying these questions. It is also good to time yourself while doing these questions so that you can work on the speed as well.