Checkpoint Human Influences

8/8/2019 Checkpoint Human Influences

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Human Influences

On

The Environment

Name: _______________ Teacher: __________


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Task: Make a list of the major needs of a population of humans (a) living in a desertregion and (b) living in a big city. Try to make your 2 lists as complete as possible, but

group similar needs under major headings (e.g. write Mineral Resources instead of listingall the different minerals that may be required)

Ask your teacher how you should present your list should it be on A4 paper as a simplelist, a web topic, or maybe you will be asked to just make a rough list for discussion inclass.

Clean Air

In Marbella we are quite lucky to have reasonably clean air. In some cities, students doexperiments where they leave a damp white tissue out overnight next day they can seesolid particles of pollutants from smoke etc on the tissue.

Your teacher will demonstrate what happens to a clean tissue or cotton wool when it isheld near a burning fuel. This will give you an idea of the problem. Many airbornepollutants are invisible for example those from car exhausts so we are not exempt fromthis problem in this region!

What two courses of action have been taken in Europe and most developed countries tohelp limit the problems caused by pollutants from car exhausts?

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You will remember the graphs of Human Population Growth we looked at recently. Formany hundreds of thousands of years the human population was so small that we madelittle impact on our environment.

The earliest people lived a simple life style and often used natural materials such aswood and animal bones. Even when they became more advanced in their usage ofmaterials and the discovery and utilisation of metals and the development of agricultureand farming, they made little impact on the global environment as there were so few ofthem.

With our exponential population growth this all changed there have been morepeople born in the past hundred years than there were for the entire previoushistory of mankind!Up until about a thousand years ago the entire human populationof the world was less than a million people. Form the year 1500 to the year 1900 thepopulation increased by about 3 million per year. Since 1900 it has been increasing byan average of about 33 million per year and this figure is increasing still!

All this increasing population places enormous demands on the Earth and its resources.In turn the amount of environmental damage has increased dramatically.

In this sub topic we will be looking at some of the influences that we humans have onthe environment and how these affect us as well as other organisms sharing our planet.


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Cars are not the only causes of air pollution what is a possible solution for the problem ofpollution caused by burning of fossil fuels (Coal, Oil & Natural Gas)?

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Use your textbook to find out more about the following pollutants and theproblems they create:

Carbon dioxide (Global Warming); Oxides of Nitrogen & Sulphur (Acid Rain);Smoke

(Smog).

Write two or three paragraphs about each and make a labelled diagram to

show how CO2 influences Global warming & The Greenhouse Effect.

A Space to Live

An increasing population requires increasing amounts of space to live, also for industryand agriculture. As well as needing ever more natural resources. The Sahara desert wasonce a source of timber for the building of ships for the armies and navies of ancient times.Human activity has reduced the Great North African Forest into the biggest man madedesert on this planet! And the Sahara creeps further south every year as pressurecontinues on its borders with humans needing wood for cooking and also by the grazing of

their livestock.

Deforestation causes numerous problems. Most of which are very obvious such as thelack of the resources the forest formerly provided such as fuel, shelter and food as well as

a habitat for many species. There is also the problem of loss of soil when forests areremoved the soil is no longer bound together well and can be easily washed away. This isa problem in itself but can also lead to flooding and pollution of waterways when the soilgets carried away by such floods.


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Look what happens when tree roots are removed from soil:

http://www.fincaleola.com/photo_gallery.htm(underscore between the words photo &gallery).

Try to check out this website. If you visit, you will be able to tell your teacher threeproblems happening in Costa Rica and what is being done to help fight against theseproblems.

Clean Water

We take it for granted but for many people, clean water is a scarce resource. Even here onthe Costa del Sol, there is a problem with sewage reaching the sea - not nice in fact verydangerous as raw sewage can contain Cholera, Typhoid and Poliomyelitis. Uncommondiseases here in Spain but casuing huge loss of life in parts of the world where people usethe same water as a source for drinking, cleaning, washing and as a waste dump and toiletfacility!

Indicator Species

Some organisms are so fussy about the cleanliness of the air or water in their environmentthat they are only found when conditions are perfect or pollution free. Some species ofTrout (fish of the Salmon family) are even kept in tanks at water treatment works to checkthat the water is finally clean enough to return to rivers etc. Salmon are only found in waterthat is very clean and free from pollution. They are an Indicator Species they indicate by

their presence that the water is free of pollutants.

DID YOU KNOW? If you had fallen into the River Thames in London 50 years ago youwould be more likely to be poisoned than to drown! It was one of the most polluted rivers in
http://www.fincaleola.com/photo_gallery.htmhttp://www.fincaleola.com/photo_gallery.htmhttp://www.fincaleola.com/photo_gallery.htm


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the world. Yet now after a successful Clean-Up Campaign and serious action being takenagainst pollution, Salmon can be seen travelling through London on their way to the upperThames valley where they are breeding successfully for the first time in centuries! Thesalmon really are an indicatorthat this river is recovering!

Read more about Indicator Species on page 212 in your Biology textbook andanswer questions 1 & 2.

Water Treatment

Take a look at the diagram above; one of the most important stages in water treatment isduring the sedimentation process where bacteria digest the sewage sludge or any wastematerials and render them harmless. This is what happens in nature but here on asmaller scale and under our control. It is a similar idea to when people keep tropical fish in


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tanks if you have a small number of fish in a large well planted tank you can managewithout any kind of filtration. However, with large numbers of fish and / or limited spaceyou will need to have a powerful mechanical and biological filter to keep the water clean.

Q. What would be an important ingredient in the biological filter?

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Intensive Farming

Fertilisers are necessary if we are to feed the world and its ever expanding population.Plants grow much better and faster when given Nitrogen, Phosphorus and Potassium(NPK) based fertilisers. However, there are many drawbacks of using these artificialfertilisers.

For example when they are overused they can run off or leach through the soil to pollutewaterways. The main problem here is that they act as food for bacteria and other microorganisms these undergo population explosions and then use up all the oxygen in the

water. The name given to this process where water bodies (lakes & rivers) get too manynutrients is Eutrophication.

Eutrophication usually leads to the water becoming anoxic or lacking oxygen. This leadsto the death of fish and other organisms. It can also lead to waterways becoming cloggedwith blanket weed a kind of algae and other pest plant species which grow out ofcontrol due to all the extra nutrients around. These can block the light from other waterplants which are more beneficial.

Fertilisers can also damage soil structure. Read more in the textbook on pages 213 & 214.

Pesticidesare poisonous and if they get into waterways can cause serious problems forwildlife and possibly even to ourselves.


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One answer to many of these problems is to use so called organicmethods of farming relying on natural animal waste fertilisers and avoiding using chemical based fertilisers.Also, remember your previous topics, we could encourage people to eat less meat. Canyou think how that would help?

Limited Resources

Carry out research on the mining of a named mineral or fossil fuel. Then write a report(minimum of one page of A4 including diagrams) on your findings. You should include howthe mineral / fuel is mined; what its main uses are; the environmental problems associatedwith its extraction and whether there are alternatives available.

Plastics have been one of the most useful developments in recent history you can try tomake a list of some of the items in your home and here in school which are made from orbased on plastics (even CD and DVD discs!). However, they also cause may problems.Many are not biodegradable and / or not recyclable. This means they can cause problems

with our limited raw materials as well as being another cause of pollution.

Oil Rig

Examining rock strata for minerals


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Selective Breeding

Previously we looked at Adaptation & Selection. When Nature results in some organisms

surviving in their environment better than others we call it Natural Selection. Whenhumans choose which animals or plants to breed from to give the best desiredcharacteristics in the next generation we call it Artificial Selection.

Selective Breeding is the basis of Artificial Selection. Human beings have been carryingout selective breeding for maybe thousands of years without understanding exactly how itworks. Everyone knows that if we want to breed big fierce dogs we choose the biggest andmost fierce male and female available and mate them together hoping theircharacteristics will be enhanced in the puppies they produce.

DID YOU KNOW?

All varieties of domestic dogs are descendants of the wolf Canis lupus. We haveproduced everything from Chihuahuas to German Shepherd Dogs, Poodles and IrishWolfhounds by selectively breeding from parents that have the required characteristics.

Read about Selective Breeding in your textbook (pages 219 to 223) then write an accountof a flower grower trying to achieve a flower of a new colour variety or if you prefer, avegetable grower trying to improve a particular character in his or her plants. Use theknowledge you have gained from here and the textbook along with your imagination tomake your account both realistic and interesting. You may be asked to read it out to therest of the class!

Check the Summary for this section on page 223

Extension Work:

Read page 224 and answer the questions posed and consider the discussion points withyour neighbour or in a small group.

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