Biology 4

The population is increasing rapidly and so we are using up raw materials very quickly. When goods are produced there is alot of industrial waste, the more waste we produce the more pollution there is. Humans also reduce the amount of land avaliable for animals and plants by building, quarrying, farming and dumping waste. Humans also pollute many things such as:

- waterways with sewage which cause high levels of nitrates in the water, toxic chemicals from landfill which leak into waterways killing organisms in the water and fertilisers which get washed into rivers and streams polluting water.

- air with smoke and gases when fuels are burnt such as sulfur dioxide which causes acid rain. Acid rain kills organisms and plants and it can change the ph of the soil damaging roots. 

- land with toxic chemicals like pesticides and herbicides. Large quantities of household and industrial waste are placed in landfill which leak toxic chemicals. 

Deforestation means that many trees are cut down, it has:

- increased the release of carbon dioxide into the atmosphere

- reduced the rate at which carbon dioxide is removed by photosynthesis

- reduced biodiversity due to loss of food and habitats

Deforestation has occured so that crops can be grown to produce ethanol based biofuels and so there can be an increase in cattle and rice fields for food. 

The destruction of peat also releases carbon dioxide into the atmosphere because the peat is removed from the bogs and used in the compost for gardens which is then decayed by microorganisms. 

Naturally carbon dioxide is released into the air by respiration and removed by plants in photosynthesis. It also dissolves in water. Levels of carbon dioxide and methane are increasing in the atmosphere, they are called greenhouse gases and cause the greenhouse effect which contributes to global warming.

An increase in the earths temperature may:

- cause big changes of the earths overall climate

- cause a rise in sea levels due to melting ice caps and glaciers

- reduce biodiversity

- cause changes in migration patterns e.g. bird migration

- result in changes in the distribution of species 

Biofules are made from natural products such as ethanol based fuels or biogas. 

Ethanol based fuels are produced by anaerobic yeast fermentation of glucose and sugar cane juices. The ethanol is then extracted by distillation and can be used as fuel in motor vehicles. Using ethanol based fuels could replace fossil fuels in the future because it is much more carbon friendly and is carbon neutral. 

Biogas can be produced during anaerobic fermentation by bacteria. Plants and any waste containing carbohydrates can be broken down in a biogas generator. The generators produce ideal conditions for bacteria to reproduce and ferment the carbohydrates. They must be maintained at a suitable temperature and in oxygen free conditions. The gas produced is a fuel and provides energy, the more methane it contains the better the quality of the biogas. 

The shorter the food chain the less energy that is wasted through movement, respiration and body temperature control. By reducing all of these things you make more efficient meat production. 

Sustainable food production involves managing resources and finding new types of food like mycoprotein to ensure there is enough food for the population now and future generations. 

The fungus fusarium is grown to produce mycoprotein which is a food suitable for vegetarians and rich in proteins. Fusarium is grown aerobically on sugar syrup made from waste starch and then the mycoprotein is harvested.

Microorganism can be grown in a fermenter where conditions must be controlled to ensure maximum growth of fusarium. They have a good air supply providing oxygen for respiration, a stirrer to maintain an even temperature, a water cooled jacket around the outside using the energy from microorganism respiration to heat it and sensors to monitor both temperature and ph.