Classification of economic activities –

Industries can be classified in four groups or sectors – Primary, Secondary, Tertiary and Quaternary.

Primary Industries - Primary industries employ people to collect or produce natural resources from the land and sea.

Fishing, forestry, Farming, and mining are examples of primary industries.

Secondary Industries - Secondary industries are those which take the raw materials[1]produced by the primary sector and process them intomanufacturedgoods[2] and products. It also includes the construction industry.

Examples of secondary industries includeheavy manufacturing[3],light manufacturing[4], food processing, oil refining and energy production.

Tertiary Industries - Thetertiarysector is also called the service sector and involves the selling of services and skills. They can also involve selling goods and products from primary and secondary industries. Examples of tertiary employment include the health service, transportation, education, entertainment, tourism, finance, sales and retail.

The biggest area of expansion in the tertiary sector in the UK has been in financial

and business services. According to government statistics, 25 years ago one in ten people worked in this industry, now it is one in five.

Quaternary Industries - Thequaternarysector consists of those industries providing information services, such as computing, ICT (information and communication technologies), consultancy (offering advice to businesses) and R&D (research, particularly in scientific fields).

The quaternary sector is sometimes included with the tertiary sector, as they are both service sectors. The tertiary and quaternary sectors make up the largest part of the UK economy, employing 76% of the workforce.

Comparing employment structures

The employment structure of a country shows how the labour force is divided between the primary, secondary and tertiary sectors. Different countries have different employment structures. The employment structure of a given country can tell you quite a lot about that country's economy.

In the richest countries, for example, there will usually be more people working in the tertiary/quaternary sector than in the primary and secondary sectors. In the poorest countries, there tend to be more people working in the primary sector than in either the secondary or tertiary sectors.

Look at figure 1 below. Based on the employment structure, which countries do you think are the richest and poorest?

Figure 1

In the richest country (USA), most people work in the tertiary sector. In the poorest country (Nepal), most people work in the primary sector. In Brazil, the labour force is more evenly distributed between the three sectors.

Note that the quaternary sector has been included in the tertiary sector.

Industrial location factors

Different industries require different inputs. Industries are more likely to locate where these inputs are readily and cheaply available. Factors that influence where an industry locates include:

  • Power supply
  • Communications- including transport, telecommunications.
  • Labour supply- including workers with the right skills.
  • Access to market- where the goods are sold.
  • Grants and financial incentives- usually from governments.
  • Raw materials

Agglomeration and footloose industries

These are two 'special cases' of industrial location.

Agglomerationis when a number of producers in the same or related industries group themselves together. They do this to benefit from local skill pools, economies of scale or the prowess of a locality in a particular field. An example is the large number of financial services companies (e.g. banks and insurance companies) which are headquartered in the City of London.

Footloose industriesare those that are less dependent on factors that tie them to a specific geographical location. Unlike manufacturing industries, tertiary or services companies do not have to be near a source of raw materials. As long as they have suitable transport, energy and communications links, they can locate themselves virtually anywhere in the world. Examples of footloose industries are computer software development, telephone sales and call-centres.

Characteristics of Industries –

Industry as a System

Inputsare the things that go into the system. The main three inputs are:

Physical inputs. These include sun, soil and water in primary industriesand raw materials such as cotton, metal or oil in Secondary Industries.

  • Labour- either skilled or unskilled.
  • Capital. This is the money invested in the business to pay for raw materials, staff, machinery and the buildings used for production and storage.

Processesare all the things that happen to those inputs to help turn them into outputs. These include:

  • Production- for example the manufacturing of cars, or the sewing of textiles.
  • Factory maintenance, which is necessary to keep machines in working order.
  • Packagingwhich protects products during transit and presents them in a way that makes customers want to buy them.
  • Transport, which is needed to move products from the factory to the warehouse and then on to the shops.

Outputsare the finished products, together with profits and wages.

Feedbackincludes anything that refines or improves the system, such as:

  • Customer feedback. Companies find out what consumers think of their products throughMarket Research. They may alter or adapt their range according to feedback to sell more products and maximise profits.
  • A profitis the money left over after inputs (staff wages, raw materials, machinery and buildings) have been paid for. Profits need to be high enough to make it worthwhile for the company to continue investing in making the product. If profits fall too low, the company will need to change the inputs, process or outputs to improve profit or diversify into other products. If they do not they will go bust!

Ecosystems

Ecosystemscan be small-scale, covering a small area (such as a pond) or large-scale covering a large area (such as a tropical rainforest).

The world is divided up into ten major ecosystems. These large-scale ecosystems are calledbiomes. These are listed below.

  1. Rainforests
  2. Deciduous Forests
  3. Coniferous forests
  4. Hot Deserts
  5. Semi-arid regions
  6. Grasslands
  7. Savannah
  8. Tundra
  9. Mountains
  10. Mediterranean

Biomes are large-scale ecosystems defined byabioticfactors. These are:

  • climate
  • relief
  • geology
  • soils
  • vegetation

Biome characteristics

  • Tropical forestsare found near the equator in Central and South America, parts of Africa and Asia. They are hot and humid and contain a huge variety of plants and animals - around half of all the world's species. The trees are mostly hardwood. The climate is called equatorial.
  • Savannahor tropical grasslands are hot and dry, dominated by grass,scruband occasional trees. They have two distinct seasons - a dry season when much of the vegetation dies back, and a rainy season when it grows rapidly. They are found in central Africa (Kenya, Zambia, Tanzania), northern Australia and central South America (Venezuela and Brazil).
  • Desertis the driest and hottest of areas. The world's largest desert is the Sahara in North Africa. Areas of scrub land that border the desert are calleddesert scrub.
  • Mediterraneanclimates are not too hot or cold. They are found around the Mediterranean Sea, near Cape Town in South Africa and Melbourne in Australia.
  • Temperategrasslands are dominated by grass and trees and large bushes are scarce. They have a temperate continental climate - the weather is mild with moderate rainfall. Grasslands include the Puszta in Hungary, the Veldt in South Africa, the Pampas in Argentina and the Prairies in the USA.
  • Temperate deciduous forestscontain trees that lose their leaves and are found across Europe and USA. The weather is mild and wet. The climate is called temperate maritime.
  • Coniferous forests, containing evergreen trees, are found in Scandinavia, Russia and Canada. They have a cool climate with moderate rainfall called cool temperate.
  • Mountainareas can be very cold at night and during winter. The growing season is short and at higher levels trees will not grow.
  • Tundrasurrounds the North and South poles. They have an extremely cold climate, with limited numbers of plants and animals able to survive there.

Biomes map – Map showing the general location of the major biomes worldwide.

Tropical Rain Forests Biome

The tropical rainforest is abiomewith a constant temperature and a high rainfall. The level ofhumidityand density of the vegetation give the ecosystem a unique water and nutrient cycle. Rainforests around the world are threatened by human expansion.

Characteristics and climate

See where tropical rainforests are found on thisbiomes map.

Atropicalrainforest biome is found in hot, humid environments in equatorial climates. They contain the most diverse range and highest volume of plant and animal life found anywhere on earth.

In general, tropical rainforests have hot and humid climates where it rains virtually everyday. The level of rainfall depends on the time of year. Temperatures vary through the year - but much less than the rainfall.

The graph shows average rainfall and temperature in Manaus, Brazil, in the Amazon rainforest. The rainy season is from December to May. Notice how much the rainfall varies over the year - the highest monthly rainfall is in March with over 300mm, while the lowest is in August with less than 50mm. Over the year, the temperature only varies by 2°C.

Monthly average of rainfall/temp in rainforest area of Manaus, Brazil

Rainforest water and nutrient cycles

Rainforest ecosystems are characterised by heavyconvectional rainfall, high humidity, lushness of vegetation and nutrient-rich but shallow soil. These factors give rise to a unique water andnutrient cycle.

Rainforest water cycle

The roots of plants take up water from the ground and the rain is intercepted as it falls - much of it at the canopy level. As the rainforest heats up, the water evaporates into the atmosphere and forms clouds to make the next day's rain. This is convectional rainfall.

Rainforest nutrient cycle

The rainforest nutrient cycling is rapid. The hot, damp conditions on the forest floor allow for the rapid decomposition of dead plant material. This provides plentiful nutrients that are easily absorbed by plant roots. However, as these nutrientsare in high demand from the rainforest's many fast-growing plants, they do not remain in the soil for long and stay close to the surface of the soil. If vegetation is removed, the soils quickly become infertile and vulnerable to erosion.

If the rainforest is cleared for agriculture it will not make very good farmland, as the soil will not be rich in nutrients.

Rainforest soils

Soils are red due to the high iron and aluminium content. There is a thick layer of leaf litter and decomposing organic matter on the surface.

Rainforest vegetation levels

Tropical rainforests have dense vegetation. From ground level up these levels of vegetation are:

  • Theshrub layer. It is dark and gloomy with very little vegetation between the trees. During heavy rainfalls this area can flood.
  • Theunder canopyis the second level up. There is limited sunlight. Saplings wait here for larger plants and trees to die, leaving a gap in the canopy which they can grow into. Woody climbers called lianas avoid having to wait for gaps by rooting in the ground and climbing up trees to get to the sunlight.
  • Thecanopyis where the upper parts of most of the trees are found. The canopy is typically about 65 to 130 feet (20 to 40 metres) tall. This leafy environment is home to insects, arachnids, birds and some mammals.
  • The emergentsare the tops of the tallest trees in the rainforest. These are much higher, and so are able to get more light than the average trees in the forest canopy.

The graphic shows the levels of rainforest vegetation and the relative amount of sunlight that each one receives.

Vegetation levels in tropical rainforest

Adaptations by trees to live in the rain forests

  • Buttress roots to stabilise the trees.
  • Drip tips on leaves.
  • Tree trunks are straight.
  • No branches on the lower trunks.
  • Fan shaped in order to gather as much light as possible.
  • Trees are evergreen to use the light all year round.
  • Vegetation grows in layers, with different specialisations.
  • There is little undergrowth on the forest floor, except near clearings and near rivers due to the lack of sunlight.

Savannah Biome

The savannahbiomeis located further away from the equator than the tropical rainforest biome in the central part of Africa and in South America. It is dry, but not as dry as desert areas.

Characteristics

See where savannah grasslands are found on thisbiomes map.

Savannahs - also known as tropical grasslands - are found to the north and south of tropical rainforest biomes. The largest expanses of savannah are in Africa, where much of the central part of the continent, for exampleKenyaandTanzania, consists of tropical grassland. Savannah grasslands can also be found inBrazilin South America.

Savannah regions have two distinct seasons - a wet season and a dry season. There is very little rain in the dry season. In the wet season vegetation grows, including lush green grasses and wooded areas. As you move further away from the equator and its heavy rainfall, the grassland becomes drier and drier - particularly in the dry season. Savannah vegetation includesscrub, grasses and occasional trees, which grow nearwater holes, seasonal rivers oraquifers.

Plants and animals have to adapt to the long dry periods. Many plants arexerophytic- for example, the acacia tree with its small, waxy leaves and thorns. Plants may also store water, for example the baobab tree) or have long roots that reach down to the water table. Animals maymigrategreat distances in search of food and water.

The graph below shows average monthly temperatures and rainfall levels in the savannah region of Mali. Notice how the temperature and rainfall patterns relate to each other - the hottest temperatures come just before heavy rainfall, and the coolest time of the year comes just after the rains. This pattern is typical of savannah climates.

Soils

Savannah grassland soils are not very fertile. The nutrients in the soil are found near the surface as they come from decayed organic matter (vegetation) from the previous growing season. This organic matter decays rapidly due to the high temperatures.

Soils tend to be red in colour due to their high iron content. The diagram below shows the different horizons, or layers, of soil in savannah grassland. Plant roots cannot penetrate the hard 'pan' layer in the B-horizon, or subsoil. This restricts vegetation growth.

Alterations to vegetation

The vegetation has been altered over a period of time by fire, either started deliberately or through natural causes. More recently, places near to desert margins have experienced desertification mainly from people destroying the natural vegetation to feed themselves, and to have fuel for cooking. Many cultures here survive on nomadic herding, but if the cattle are too much in number or confined to a small area, the vegetation will be destroyed. This will also lead to more soil erosion and the expansion of the desert in areas where the savannah is changing over to the desert environment.

Desertification

Desertificationcan result from poorly managed human intervention in the savannah. Areas of desert are created by the destruction of natural vegetation. Causes of desertification include:

  • Removal of vegetation cover.
  • Overgrazing.
  • Uncontrolled fuel wood collection.
  • Unsustainable farming practice and loss in fertility of soil.
  • Excessive tree felling.

Desert Climate

Deserts are hot during the day and cold at night. Animals and plants that live in deserts have adapted to survive in these harsh conditions.

Characteristics and climate of deserts

See where deserts are found on thisbiomes map.

Deserts have extreme temperatures. During the day the temperature may reach 50°C, when at night it may fall to below 0°C. Deserts have less than 250 mm of rainfall per year. The rain can be unreliable. Most deserts are found between 20° and 35° north and south of the equator.

The Sahara is the largest desert, covering 9 million km2.

There are three factors which form desert areas:

  1. the presence ofhigh pressure, creating cloud-free conditions
  2. cold ocean currents
  3. mountain rangesto create rain shadow

Desert Biome

Plant and animal adaptations

Camels live in deserts that are hot and dry during the day, but cold at night. They are well adapted for survival in the desert. Camels have:

  • Large, flat feetto spread their weight on the sand.
  • Thick furon the top of the body for shade, and thin fur elsewhere to allow easy heat loss.
  • A large surface area to volume ratioto maximise heat loss.
  • Theability to go for a long time without water(they don't store water in their humps, but they lose very little through urination and sweating).
  • The ability totolerate body temperaturesup to 42°C.
  • Slit-like nostrils and two rows of eyelashesto help keep the sand out.