Posts Tagged ‘energy’

  • Outline the concept and characteristics of systems.
System: Assemblage of parts and relationships between them, which together make up a whole.
The components are connected together through the transfer of energy and matter, with all parts linking and effecting eachother.
Examples of these are:
  • atoms
  • molecules
  • cells
  • organs
  • organ systems
  • communities
  • ecosystems
  • biomes
  • earth
  • solar systems
  • galaxies
  • universes
Systems consist of:
  • storages ( of matter and energy )
  • flows ( inputs into the system, output from the system )
  • processes (which transfer or transform energy or matter )
  • feedback mechanisms that maintain stability and equilibrium
System diagrams consist of: 
  • boxes show storages
  • arrows show flows (inputs/outputs)
Diagram can be labelled with the processes on each arrow:
  • Photosynthesis – transformation of CO2, H2o and light into biomass and oxygen O2
  • Respiration – transformation of biomass into CO2 and water
  • Diffusion – movement of nutrients and water
  • Consumption – tissue transfer from trophic level to another
  • Apply the systems concept on a range of scales.
There are different scales of systems; there can be small-scale local ecosystem, large ecosystem as a biome, and global ecosystems.
For example: Forests contain many small-scale ecosystems.
  • Define the terms open system, closed system and isolated system.
Open: exchanges matter and energy between the system. They are organic and must interact with environment to obtain new matter and energy. Ex: People are open systems.
Closed: exchanges energy but not matter. Ex: the earth can be seen as a closed system.
Isolated: Neither energy or matter is exchanged. But these systems do not seem to exist. However the universe could be looked at as an isolated system,
  • Describe how the first and second laws of thermodynamics are relevant to environmental systems.
First law:
  • Energy is not created nor destroyed
  • Energy can only change from one to another
  • Ex: solar radiation -> sugars -> chemical energy -> chemical energy again
  • Energy has only moved and changed form
Second law:
  • not efficient energy (the more processes/transfers the less energy)
  • transformations lead to energy loss
  • living systems are only maintained through constant input of new energy from the sun
  • energy= work+heat
  • Explain the nature of equilibria.
Steady-state equilibrium:
Is the common property of most open systems in nature. There is a tendency in natural systems for the equilibrium to return after the disturbances, but some systems (succession) may go through long-term changes to keep their equilibrium while keeping their integrity.
Open systems have steady-state equilibrium, where any change to a stable system returns to the original equilibrium after the disturbance.
Stable changes then goes back to the normal state.
Unstable changes and does not go back to the normal state.
  • Define and explain the principles of positive and negative feedback.
Negative feedback: tends to damp down, neutralize or counteract any deviation from an equilibrium, and promotes stability.
Positive feedback: increases change in a system and deviation away from a equilibrium.
A system may include both feedbacks.
  • Describe transfer and transformation processes.
Both material and energy move or flow throw ecosystems.
Transfers: normally flow through a system and involve a change in location. When the flow does not involve a change in form just location.
Ex: Material through biomass, and energy movement.
Transformations: lead to an interaction within a system in the formation of a new and product, or involve a change of state. A flow involving a change in form.
Ex: Matter and energy transformations, energy to matter transformations.
  • Distinguish between flows (inputs and outputs) and storages (stock in relations to systems)
Inputs and outputs from systems are called flows and represented by arrows in system diagrams. The stock held within a system is called the storage and is represented through boxes.
  • Construct and analyse  quantitative models involving flows and storages in a system.

  • Evaluate the strengths and limitations of models.
Pros: 
  • allow scientist to predict/simplify complex systems
  • inputs can be changed and outcomes examined without having to wait for real events.
  • results can be shown to scientists and the public
Cons:
  • might not be totally accurate
  • rely on the expertise of people making them
  • different people may interpret them in different ways
  • vested interests might hijack them politically
  • any model is only as good as the data goes in and these may be suspect
  • different models may show different effects using the same data

  • Explain the concepts of limiting factors and carrying capacity in the context of population growth.
Carrying  capacity is the maximum number of organisms that an area or ecosystem can sustainably support over a long period of time.
There are however limiting factors including temperatures, water and nutrient availability. The main factors are temperature and water availability.
Limiting factors are factors that limit the distribution or numbers of a particular population. Limiting factors are environmental factors which slow down population growth.
Temperature:
There are many ways the temperature can affect species. For example some seeds only grow in extremely high temperatures as it enriches the soil with nutrients and kills competition. However some are damaged if they are too warm or too cold. Some are able to survive low temperature. Animals adapt to the hot/ cold temperature either by burrowing under the ground to avoid heat or having cold blood in the heat.
Water:
All plants/animals need water to survive, for plants have no water could cause the plant to not germinate or seeds to die. No water = Death.
  • Describe and explain S and J populations curves.
S-curve (Sigmoidal) : population growth curve that shows a rapid growth at the beginning then a slow down as the carrying capacity is reached.
J-curve:
A population curve which shows only exponential growth. It starts slow the becomes increasingly fast.
  • Describe the role of density-dependent and density-independent factors, and internal and external factors, in the regulation of populations.
Density-dependent factors:
Factors that lower the birth rate or raise the death rate as a population grows in size. They are negative feedback mechanisms leading to the stability or regulation of the population.
When prey increases so does the predator, but when this occurs the prey decreases and then again the predators decrease too causing the prey to increase again.
Density-independent factors:
Factors that affect a population irrespective of population density notably environmental change. Abiotic factors are density-independent factors, the most important ones are the extremes of weather (droughts, fires and hurricane) and long-term climate change.
These factors have an impact that can increase the death rate and reduce the birth rate, it all depends on how severe the event was.
Factors which regulate population size can be divided into either INTERNAL or EXTERNAL.
Internal:  fertility rates, territory sizes
External: predation, pressure, parasitism
The major cause of population regulation are in the environments, these can be physical or biological.
The physical class of environmental factors are water availability, nutrient availability anf so on.
Biological factors include predators, and competition.
Ways humans can cause population growth:
  • increase available resources
  • reduce competition
  • reduce pressure from predators
  • introduce animals to new areas
Ways to decline population:
  • change environment, cause habitat disruption
  • change the biological environment by introducing new species
  • cause secondary extinctions
  • overkill
  • Describe the principles associated with survivorship curves including, K and r strategists.
Survivorship curves and r and k strategists:
K-strategists are slow growing and produce few, large offspring that mature slowly.
R-strategists, slow and mature quickly and produce many, small offspring.
K= carrying capacity
R= growth rate
K-strategist:
  • low reproductivity
  • large investment in parental care
  • late maturity/longer living
  • slow growth
  • larger size
  • require stable environment
R-straegists:
  • high reproductivity
  • short life
  • low investment in parental care
  • early maturity
  • rapid growth
  • small organisms
  • highly adaptable
  • large number of few species
Survivorship rates:
What influences survivorship rates:
  • competition for resources
  • adverse environmental conditions
  • predator-prey relationships
Example of survivorship curve:
  • curve for species where individuals survive for their potential life span, and die at the same time. Salmons/humans (K-strategists)
  • curve for species where individuals die young but who survives lives very long life turtles/ oysters. (r-strategists)
  • Describe the concept and processes of succession in a named habitat.
Succession: Change in the community structure of a particular area over time.
Primary succession: colonization of newly created land by organisms (rock).
Secondary succession: occurs in places where a previous community has been destroyed. (forest/fire) It is faster than primary succession because of the presence of soil and a seed bank.
Pioneer= earliest community of the succession.
Climax community= the last and final community.
The change from pioneer to climax is called a sere.
Succession is the process of change over time in a community changes in the community of organisms frequently cause changes in the physical environment that allow another community to become established and replace the former through competition. They get more complex at the end.
Zonation:
The arrangement or patterning of plant communities or ecosystems into bands in response to change, over a distance, in some environmental factor.
The main biomes display zonation with altitude on a mountain, or around the edge of a pond in relation to soil moisture.
  • Explain the changes in energy flow, gross and net productivity, diversity and mineral cycling in different stage of succession. 
GP, NP and diversity will change over time as a ecosystem goes through succession. GP is low in early stages then increases as soils become more structured. As food webs become more structured NPP and diversity stabilize as the ecosystem reach climax population.
  • Describe factors affecting the nature of climax communities. 
Climax community:
  • greater biomass
  • higher levels of species diversity
  • more favourable soil condition
  • better soil structure
  • lower pH
  • taller and longer living plant species
  • more k-strategies or fewer r-strategist
  • greater habitat diversity
  • steady state equilibrium
Climate and edaphic factors determine the nature of a climax community. Human factors frequently affect this process through, for example; fire, agricultures, grazing and/or habitat destruction.
  • Distinguish between biotic and abiotic (physical) components of an ecosystem.

*Biotic: refers to the living components of an ecosystem. (the community)

*Abiotic: refers to the non-living factors of an ecosystem. (the environment)

Ecosystems are made up of living and non-living components. The living part of the environment consists of the organic part of the ecosystem; animals, plants, algae, fungi and bacteria. These are called biotic components. The non-living part of the environment is made up of physical components such as; air, light, water, temperature, soil, minerals and climatic atmosphere. These are called abiotic components. These two components work together to sustain the environment.

  • Define the term trophic level.

Trophic level refers to the feeding level within a food chain. It is the position that an organism occupies in a food chain, or a group of organisms in a community that occupy the same position in food chains.

  • Trophic level 1 – producer
  • Trophic level 2 – herbivore (primary consumers)
  • Trophic level 3 – carnivore (secondary consumers)
  • Trophic level 4 – carnivore (tertiary consumer)
    • Identify and explain trophic levels in food chains and food webs selected from the local environment.

    *Producer: The organism in the ecosystem that converts abiotic components into living matter, they help the ecosystem by producing new biological matter.

    *Consumer: These organisms cannot produce their own food, so they eat other organisms to get the energy and matter they need.

    * Decomposer: Feed on dead biomass which is created by the ecosystem.

    *Herbivore: Only feed on producers.

    *Carnivore: Feed on all organisms including producers and consumers.

    *Top carnivore: This organism can not be eaten by any other organism.

    Sun: Provides the abiotic matter to the grass

    Grass: Producer and autotroph, provide food for the deer.

    Deer: The primary consumer and herbivore of the grass.

    Wolf: The secondary consumer/Top consumer and carnivore, feeds on the deer and cannot be eaten by any other organism.

    Ecosystems contain many interconnected food chains that form food webs. Food chains always begin with the producers (usually photosynthetic organisms), followed by primary consumers (herbivores), secondary consumers (omnivores or carnivores) and then higher consumers (tertiary, top). Decomposers feed at every level of the food chain.

    Diagrams of food webs can be used to estimate the knock-on effects of changes to the ecosystem.

    Biomass and energy decrease at each trophic level so there is a limit in how much trophic levels can be supported in a ecosystem. Energy is lost as heat at each stage of the food chain, on only energy stored in biomass is passed on to the next trophic level. After 4 or 5 trophic levels there is not enough energy to support another stage.

    Local example: (Lake in Sweden)

    Producer: Freshwater shrimp

    Primary consumer: Bleak

    Secondary consumer: Perch

    Secondary consumer: Northen Pike

    Top consumer: Osprey

    • Explain the principles of pyramids of numbers, pyramids of biomass, and pyramids of productivity, and construct such pyramids from given data.

    Pyramids are graphical models showing the quantitative differences between the trophic levels of an ecosystem. There are three types:

    • Pyramids of numbers: This records the number of individuals in each trophic level.

    • Pyramid of biomass: This represents the biological mass of the standing stock at each trophic level at a particular point in time. Biomass should also be measured in units of energy, such as J m-2. They can show greater quantities at higher trophic levels because they represent the biomass present at a given time. Both pyramids of numbers and biomass represent storages.

    • Pyramid of productivity: This shows the flow of energy through each trophic level. Measured in units of flow gm-2 yr-1 or Jm-2 yr.

    In accordance with the second law of thermodynamics, there is a tendency for numbers and quantities of biomass and energy to decrease along food chains; therefore pyramids become narrower as one ascends.

    • Discuss how the pyramid structure affects the functioning of an ecosystem.

    This Youtube clip explains the interactions in food chains and the vulnerability of the top carnivores.

    • Define the term species, population, habitat, niche, community and ecosystem with reference to local examples.

    *Species: A group of of organisms that interbreed and produce fertile offspring. If two species breed together they create a hybrid, this cannot produce viable gametes and is sterile.

    *Population: A group of the same species living in the same area at the same time, and can interbreed.

    *Habitat: The environment in which a species normally lives.

    *Niche: Where and how a species lives. A species share of a habitat and the resources in it.

    *Community: A group of populations living and interacting with each other in a common habitat.

    *Ecosystem: A community of inter-independent organisms and the physical environment they inhabit.

    • Describe and explain population interactions using examples of named species.

    Ecosystems contain many interactions between the populations, the interactions are varied and can be divided into; competition, predation, mutualism and parasitism.

    *Competition: A common demand by two or more organisms upon a limited supply of a resource; for example, food, water, light, space, mates, nesting sites. It may be intraspecific or interspecific.

    *Parasitism: A relationship between two species in which one species (the parasite) lives in or on another (the host), gaining all or much (in the case of the partial parasite) of its food from it.

    *Mutualism: A relationship between individuals of two or more species in which all benefit and non suffer.

    *Predation: This is when on animal or plant hunts and eats another animal.


    Here are 3 Youtube links about Interspecific interactions.

    • Outline the issues involved in the imbalance in global food supply.

    There is enough food on the world to feed us all, however there is an imbalance in the food supply globally. Many people from the LEDCs are suffering from not getting enough energy, proteins and minerals. Around 3/4 of the world’s population is not eating enough and an average of 1 million are going hungry, the majority of these people lives in the LEDCs. It is estimated that every 6 seconds a child dies of hunger.

    The price of food plays a major role here, if prices were to just increase by 10% it could lead to an increase of 40 million people in food poverty. However even though there is such a huge group of people in need of food there is a surplus of food in the MEDCs with markets producing to much food for the population.

    This has lead to people in the MEDCs to consumer more food then they need as the MEDCs increased wealth has allowed them to buy more. There are import tariffs imposed by the MEDCs to make the import of food more expensive, which can ruin the exporting countries.

    In the LEDCs they make money for the country through food production, from crops such as sugar cane and tobacco. So they need this production for making money but when the MEDCs increase import tariffs the LEDCs are in trouble.

    MEDCs want to make money from products in the country and not let the imported goods become the cheaper choice. Despite all this prices of food in the MEDCs is fairly expensive as seasonal foods have disappeared as imports fill gaps. The struggle in the LEDCs to make money has caused prices to rise, this makes it difficult for the population to afford local productions.

    Climate changes have also affected the LEDCs as droughts for example reduce the amount of growing land. Global warming could lead to countries suffering from high temperatures which could destroy crops.

    As more land is used for settlement and industry, there is an increase in intensifying production on existing farm land. MEDCs food production is complex as it involves high levels of technology, low labour and high fuel costs. MEDCs have become more technocentric.

    Agriculture in the LEDCs are in contrast and have low levels of technology, lack of capital and high levels of labour.

    • Compare and contrast the efficiency of terrestrial and aquatic food production systems.

    *Second law of thermodynamics: states that energy goes from a concentrated form (like the sun) to a dispersed form (like heat), the  availability of energy to do work therefore diminishes on the system becomes increasingly disorder. It explains how energy transformations in living systems can lead to loss of energy from the system. The order in living systems is only maintained by constant input of new energy from the sun.

    We get to see from the second law of thermodynamics that energy conversion through food chains is inefficient and that energy is lost by respiration and waste production at each level within the food web.

    Energy in sunlight -> producer (90% energy lost) -> primary consumer (9% energy lost) -> secondary consumer (0.9% energy lost)

    100% -> 10% -> 1% -> 0.1%

    Terrestrial systems:

    Most food is harvested from low trophic levels (producers and herbivores). Systems that produce crops are more energy efficient then those which produce livestock. This is because energy is greater in proportion in the low trophic levels. Even though it is efficient to use arable systems, many cultures still use livestock as part of their farming system. Taste and cultural demand play a major role in this and the animals also provide a source protein which is essential for the human diet. Animals are also used as working animals in some cultures.

    Terrestrial farming systems are divided into several types:

    • Commercial farming: is farming for profit, often of a single crop
    • Subsistence farmer: produces only enough yo geed their family with non to sell for profit

    Both commercial and subsistence can be intensive or extensive farms.

    • Intensive farms: take a small area of land but aim for a high input
    • Extensive farms: are large in comparison to the money and labour put into it

    The efficiency of the system can be calculated by comparing outputs to inputs per unit area of land.

    Aquatic systems:

    Due to human taste, most food harvested is from the higher trophic levels where the total storage is much smaller. There is less energy then crop production, although energy conversion is aquatic systems are more efficient then terrestrial chains, the system receives less sunlight then terrestrial chains.

    • Compare and contrast the inputs and outputs of materials and energy (energy efficient), the system characteristics, and evaluate the relative environmental impacts for two named food production systems.

    Terrestrial Systems:

    Intensive Charolais beef production in France:

    In Western Europe the Charolais beef is one of the beef brands chosen. Through selective breeding and genetic engineering bloodlines that puts weight on exist but has a low fat cover. Charolais lives under controlled conditions, they are fed with high proteins and treated with antibiotics to make sure they are healthy. Lots of energy is used in transporting and processing the finished meat.

    Cattle raised outdoors however grown on single monoculture ( cultivation of a single crop on a farm or in a region or country) grass land in large fields with a high stock rate. To keep the productivity of these fields going, large amounts of fertilizer are used.

    This intensified farming e the 1940’s with the aim of producing cheaper meat has led to habitat loss as they have been removed to make bigger fields and cases of Eutrophication have increased as excess use of fertilizers and large amounts of slurry produced in the system enter water courses. Fear of causing antibiotic resistance in human bacteria through bioaccumulation.

    Inputs:

    • energy for food distribution
    • food supplements
    • selective breeding and genetic engineering (system characteristics)
    • indoor rearing
    • fertilizers to maximize grass production
    • antibiotics and hormones

    Outputs:

    • cheap meat (socio-cultural)
    • habitat destruction to make bigger fields (environmental impact)
    • antibiotic resistance
    • Eutrophication

    Nomadic cattle grazing of the Himba:

    The Charolais beef production can be contrasted with the Nomadic cattle grazing of the Himba. The Himba people are from North West Namibia, they survive by being Nomadic hunters/grazers. They also have a tight bond with the cattle they graze. During the dry seasons the Himba move their cattle from area to area until the grass is used up until the raining season, they go to better pastures. Cattle to the Himba are very important as they provide; meat, milk, skins and even dung for fires. Prestige between the Himba is seen by how many cattle they have, not the size of the cattle. The cattle during the dry season may start competing with herbivores. This has increased especially with global warming drought periods. This can lead to soil erosion as extra grazing pressure removes the grasses that hold the top soil together.

    Input:

    • nomadic grazing moving from place to place so land has a chance to recover
    • cattle survive on low grade natural forage with no supplements
    • during drought cattle die as grass disappears adding patches of nutrients to the soil (environmental impact)

    Outputs:

    • Himba cattle provide meat, milk and fuel (dung)
    • owning cattle gives status in community (socio-cultural)
    • during drought times Himba cattle compete with wild grazers for food this can lead to soil erosion as well as food shortage (environmental impact)
    • Discuss the links that exist between social systems and food production systems.

    There are many links between social systems and food production system. Examples given are shifting cultivation, wet rice agriculture (South-East Asia) and agrilbusiness

    Shifting cultivation

    Shifting cultivation supports small communities and sometimes individual families. It is also known as ”slash and burn” agriculture, as new land is cleared by cutting down small areas of forest and setting fire to them. Ash fertilizers the soil for a while and the clearing produced enables crops to grow. When the land can’t be used any more, the farmer goes to a new land area. Once the land has recovered, farmers go back to the land.

    This is performed in many tropical forest areas, such as the Amazon regions. This is possible as there is low population density. If population densities increase too much, old land is returned too before fertility has been restored, this encourages shifting cultivation. There are people who have close connection with nature, like shifting cultivators in the Brazilian Amazon. They show a closer connection between social systems and ecological systems than the societies living away from natural systems, such as city dwellers. Urban capitalists in Brazil are more likely to view the interior of a country as a new frontier, and the rainforest as a resource for development and cash (technocentric approach). The lack of understanding of the nature makes them underestimate the true value of natural resources. They may also make decisions which produce wasteful and damaging actions.


    Wet rice ecosystem of South-East Asia

    Padi field agriculture has become the dominant form of growing rice in South- East Asia. It is intensive subsistence farming, using high labour but low technology. As there is a high population, a lot of food is needed. Especially rice as it is part of the Asian diet as well as their culture. Padi fields are placed by rivers and areas that flood naturally, so that the fields get new deposits of silt and increased fertility. They should be placed in heavy clay soils, as sand and light textured soils are not suitable as water drains away. Warm weather and high rainfall help productivity all year round.

    Agribusiness

    Supply most of the products found in supermarkets. Many have travelled long distances from around the world. Its a non-seasonal climate food supply throughout the year, so once-seasonal crops are available year-round in MEDCs.

    The aim of agribusiness is to maximize productivity and profit to compete with the global market. This is large scale monoculture, intensive use of fertilizers and pesticides, mechanized ploughing and harvesting, and food production geared to mass markets including export.

    This type of agriculture has a huge impact on the environment, with loss of biodiversity, and increased run-off pollution. National political economies encourage agribusiness as it supports the national income, this had lead to many people living off farming to move into the towns and cities to get new work.

    • Outline the range of energy resources available to society.

    Energy can be generate by both non-renewable and renewable resources:

    • Renewable resources like solar, hydroelectric, geothermal, biomass, and tidal schemes are all sustainable as there is no depletion of natural capital. These energy resources can be large-scale for a whole country or small-scale for houses or communities for example.
    • Non-renewable resources however cannot be replenished at the same rate it is used which leads to depletion of the stock, examples of these are fossil fuels like coal, gas and oil. Nuclear power can be considered as a non-renewable source as the source of fission is uranium, which is non-renewable.

    Energy consumption is much greater in the MEDCs as the LEDCs do not have the technology to have such energy resources used. MEDCs use a lot of energy from fossil fuels as it was not that it caused pollution and global warming when first adapted as a primary source of energy generation. The main reason for non-renewable energy consumption being used is that it is the cheaper and easier choice. Renewable sources of energy are a bit slow when being adopted globally, compared to non-renewable sources it is expensive and still be newly used which makes them vulnerable to failures. Non-renewable resources are generally cheaper and can be burned directly. The technology at the moment is ready for this type of energy and no set-up costs are required. The cost of the non-renewable energy is likely to increase as the stocks will be depleted, especially the resources that are easily to mine, leaving the resources harder to mine. Which will cost a lot to reach. This will make fossil fuels more expensive and then renewable energy sources will be more popular and used more.

    • Evaluate the advantages and disadvantages of two contrasting energy sources.

    NON-RENEWABLE ENERGY:

    Fossil fuels:

    Pros:

    • cheap
    • plentiful
    • technology exists
    • oil can be transported over long distances by pipeline

    Cons:

    • contributes to climate change (builds up carbon dioxide in atmosphere)
    • unsustainable (liquidation of stock over time)
    • will become difficult to extract ( becomes dangerous as they go further into the sea or deeper into the ground)
    • oil spillages and pipelines burst damage ecosystems ( expensive to clear up)
    • mines clear up habitat from surface
    • coal not easily transported over long distance

    Nuclear Energy:

    Pros:

    • does not emit carbon dioxide
    • technology is available
    • vast amounts of electrical energy produced by a single power plant
    • very efficient ( 1kg uranium contains 20000 times more energy than 1kg of coal

    Cons:

    • nuclear waste is VERY dangerous, remains for thousands of years with no solution found yet
    • the more power plants, the higher risks of having a disastrous failure somewhere in the world
    • uranium is the energy source which is scarce and a non-renewable source with a estimated time of 30-60years left before depletion (depending on demand)
    • time to plan/build a nuclear plant is 20-30 years

    RENEWABLE ENERGY:

    Pros:

    • no pollutants released
    • will not  run out (renewable hello)
    • small ecological footprint

    Cons:

    • expensive to set-up
    • need to set them up
    • might spoil environment for people living nearby

    Hydroelectric power:

    Pros:

    • blocked lake can be used for leisure, irrigation and electricity generation
    • once built they are cheap to run

    Cons:

    • vast areas may be flooded, which causes loss of homes, farmlands and displacement of people
    • expensive
    • erosion rates increase
    • might silt up area and become unusable

    Tidal Power:

    Cons:

    • expensive
    • might be harmful to wildlife
    • needs good tidal range

    Solar energy:

    Pros:

    • solar energy with insulation is cheaper than fossil fuel energy when heating homes

    Cons:

    • expensive
    • useless in winter in northern countries

    Wind Power:

    Cons:

    • no wind = no energy
    • placement is critical, needs constant wind

    Biofuel:

    Cons:

    • produces emissions
    • requires large areas of land to plant biofuel crop
    • pushes up food prices
    • locals do not get enough food
    • may destroy surrounding ecosystems to grow on

    Wastes:

    Pros:

    • available
    • does not deplete natural gas
    • useful way of getting rid of waste

    Cons:

    • global warming gases released into atmosphere

    Geothermal energy:

    Pros:

    • no pollution

    Cons:

    • needs to be buried deep into the ground for greater heat capture
    • Discuss the factors that affect the choice of energy sources  adopted by different societies.

    MEDCs have higher energy demands than LEDCs, as they depend on energy for many things such as transport, heating, air-conditioning, cooking and all other aspects of their lives.

    The choice of what energy source should be used is different to countries. Some have large oil, coal and gas reserves and that makes fossil fuels an obvious choice for an energy source. However generation of energy also depends on its availability, economy, cultural, environmental and technological factors. When an energy resource is available and close, it is more easier and efficient to use.

    Culture fears based on the fear of nuclear accidents and waste, have made it quite unpopular to choose. Cultural and tradition means that non-renewable resources are favoured, and the places with renewable energy resources are limited. Renewable energy sources are not being used so much globally which means that it is still not ready to meet current demands. Renewable sources can be used more if the production prices of the non-renewable sources are increased. This may better the environment as higher costs of the fossil furls means that peoples view will change. Peoples interest in renewable resources has led to an increased demand for renewable and non-pollution sources. This leads to a greater investment and research into more alternatives or improvements.