Pollution and Conservation

ShreyaDas
Note by , created over 5 years ago

IGCSE Biology (B3 Energy Flow in Ecosystems and Human Influences) Note on Pollution and Conservation, created by ShreyaDas on 03/27/2014.

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ShreyaDas
Created by ShreyaDas over 5 years ago
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POLLUTIONAir pollution by greenhouse gasesGreenhouse effect is a good thing: without carbon dioxide and water vapor, heat energy from the sun = reflect off the surface of the Earth and pass back into spaceEarth's surface = -40CToo much CO2 and methane = too much absorption of heat energy by atmosphere GLOBAL WARMING = - result in rising sea levels (melting ice and thermal expansion of seawater) - increased extremes of weather ie. droughts, hurricanes, flooding, very hot summers, very cold winters

Carbon MonoxideSource: incomplete combustion of fossil fuels (car engines)Effect: poisonous gas, deadly in high concentrations

Sulphur DioxideSource: heavy industry and power station combusting fossil fuels that contain sulphur (coal, oil, gas etc)- volcanoesEffect: dissolves in atmospheric water to produce acid rain --> corrosion of buildings (limestone/metal) and damage of forests and aquatic life

SootSource: Source: incomplete combustion of fossil fuels Effect: respiratory problems (asthma and emphysema)

NOx (oxides of nitrogen)Source: air coming into contact with a very hot environment --> nitrogen and air have enough energy to react and form oxides.Effect: can cause acid rain, smog = irritation in nose and throat- asthma

Nitrogen and oxygen react and make nitric oxidesCarbon monoxide in the air because of combustionCan cause acid rain by reacting with sulphur dioxide (in the air because of combustion of fossil fuels)

Catalytic converters:- fitted in a car- honeycomb structure covered with thin layer of catalyst (platinum, rhodium, palladium or mixture of these)- Nitrogen oxides converted to nitrogen and oxygen- carbon monoxide reacts with oxygen to produce carbon dioxide = :)

Ac

Acid RainWhen fossil fuels (coil and oil containing sulphur) are burned, they release sulphur dioxide into the air. - sulphur dioxide is harmful to living organisms when it comes into contact with them as dry fallout- SO2 dissolves in rainwater to form sulphuric acid = acid rain- Nitrogen oxide combines with water to form nitric acid= acidic rainpH between 5 and 2 and are very damaging

Effects:- soils become acidic = leaching of minerals and inhibition of decomposition- water in lakes and rivers collect excess minerals = death of fish and invertebrates = disrupted food chain- forest trees suffer starvation because of leaching of ions and destruction of photosynthetic tissue

Re

Reduce acid rain by:- scrubbers at power stations- catalytic converters in car exhausts

Conservationists work to slow down or stop the decline in biodiversity (number of species)Natral resouces may be renewable but limited (water) or non-renewable (fossil fuels)

Bioaccumulation is defined as  the increase in concentration of a substance(s) in an organism or a part of that organism.Toxic substances are lipophilic or fat-loving, the reason why these substances are deposited and concentrated in the fat tissues of the organisms. The affected organism has a higher concentration of the substance than the concentration in the organism's surrounding environment. The toxic substances are very slowly metabolized or excreted so if the organism keeps on consuming prey or food contaminated with toxic substances, the concentration of the substance will further increase in its body, hence, bioaccumulation results. When a certain threshold level is reached, measured in parts per million (ppm), symptoms due to the type of toxin are manifested.

Biomagnification is also called Bioamplification. It is simply the increase in concentration of a substance in a food chain, not an organism. Persistent organic pollutants (POPs) are compounds that biomagnify. Persistent organic pollutants (POPs) are chemical substances that persist in the environment. These substances bioaccumulate through the food web and pose risk not only to humans but also other living organisms because of their adverse effects. These pollutants consists of pesticides (such as DDT), industrial chemicals (such as polychlorinated biphenyls, PCBs) and unintentional by-products of industrial processes (such as dioxins and furans). In essence, biomagnification is similar to bioaccumulation but is descriptive of higher level biological processes, not individual.

Forest managementReasons for planting trees:- cash crop -- providing timber for building (coniferous plantations in the UK) or for fuel- to reverse soil erosion (valuable for desert areas)- to provide valuable wildlife habitats - recreational areasEndangered speciesreasons:- pest control - pest = any species that cause inconvenience to humans (red deer damage trees)- commercial exploitation - species of value to humans that have been exploited (fur etc)- loss of habitat - more land being used for agriculture

Bioaccumulation: increase in concentration of a pollutant from the environment to the first organism in a food chain Biomagnification: increase in concentration of a pollutant from one link in a food chain to another

Pollution and the Greenhouse Effect

Acid Rain and Catalytic Converters

Conservation

Bioaccumulation and Biomagnification