Topic-7 Flashcards
What us a biome?
Biomes are large scale,global ecosystem with distinctive vegetation
Shat is an ecosystem?
An ecosystem includes all the living and non-living things in an area
What is a climate
The climate an area determines what type of biome forms.
Tropical rainforests-climate and characteristics
Climate:
-same all year round-no definite seasons
-its hot(temp varies between 20-28 degrees and only varies by a few degrees over year). Because near equator the sun is overhead all year
-because near equator, day length is the same all year round. This means the forests get plenty of sunshine all year round.
Characteristics:
Plants- most trees are evergreen to take advantage of the continual growing season.
leaves in a
Plants grow quickly and are adapted to take in maximum light.
particular season.
Animals - the dense vegetation provides lots of food and different habitats, so there are lots of different species of animal, for example gorillas, jaguars, anacondas, tree frogs and sloths.
There are loads of species of insects and birds.
Soil — plants grow quickly and shed leaves all year round. These decompose quickly, so there’s a constant supply of nutrients in the soil, and these nutrients are cycled quickly.
Temperature forests-climate and charcteristics
Climate:
-Temperate forests have four distinct seasons. The summers are warm and the winters are cool.
-Rainfall is very high (up to 1500 mm per year) and there’s rain all year round.
-Days are shorter in winter and longer in summer — the hours of sunshine vary through the year.
Characteristics:
1)
Plants - the mild, wet climate supports fewer plant species than tropical forests, but more than boreal forests . Forests are often made up of broad-leaved trees that drop their leaves in autumn (e.g. oak), shrubs (e.g. brambles) and undergrowth (e.g. ferns).
2)
Animals - the mild climate and range of plants provides food and habitats for mammals (e.g. foxes, squirrels), birds (e.g. woodpeckers, cuckoos) and insects (e.g. beetles, moths).
3)
Soil - plants lose their leaves in autumn, and the leaf litter decomposes quite quickly in the moist, mild climate. This means that soils are relatively thick and nutrient-rich.
Boreal forests- climate and charcteristics
Climate:
-Boreal forests have short summers and long winters. In winter, average temperatures are below -20 °C and can drop much lower. In summer, average temperatures are about 10 °C.
-Precipitation is low - generally less than 500 mm per year. A lot of this falls as snow.
-Boreal forests get lots of daylight during the summer months, but little or none during the winter.
-Skies tend to be clear, so during daylight hours there’s plenty of sunshine.
Characteristics:
1).
Plants — most trees are evergreen, so they can grow whenever there’s enough light. ‘ the talga.
Coniferous trees such as pine and fir are common, as are low-growing mosses and lichen.
2)
Animals — there are relatively few animal species in boreal forests compared to e.g. tropical forests, because there is less food available and animals need to be adapted to the cold climate to survive. Animals that do live there include black bears, wolves, elk and eagles.
3) Soil - the cool, dry climate means that needles from the trees decompose slowly, so soils are quite thin, nutrient-poor and acidic. In some areas the ground is frozen for most of the year.
Grasslands-climate and characteristics
Climate:
1)
Tropical grasslands have quite low rainfall (800-900 mm per year) and distinct wet and dry seasons.
Temperatures are highest (around 35 °C) just before the wet season and lowest (about 15 °C) just after it. They are found around the equator, so they get lots of sunshine all year round.
2)
Temperate grasslands have hot summers (up to 40 °C) and cold winters (down to -40 °C).
They receive 250-500 mm precipitation each year, mostly in the late spring and early summer.
Because they’re further from the equator, the amount of light they receive varies through the year.
Characteristics:
1) Tropical grasslands consist mostly of grass, scrub and small plants, with a few scattered trees, e.g. acacia. They are home to lots of insects, including grasshoppers, beetles and termites. Larger animals include lions, elephants, giraffes, zebras and antelope. Grass dies back during the dry season, forming a thin, nutrient-rich soil, but nutrients are washed out of the soil during the wet season.
2)
Temperate grasslands are also dominated by grasses and small plants, and have very few trees.
They are home to fewer animal species than tropical grasslands - mammals include bison and wild horses, and rodents such as mole rats. High temperatures in summer mean that decomposition is fast, so soils are relatively thick and nutrient-rich.
Desert-climate and characteristics
-Rainfall is very low - less than 250 mm per year. It might only rain once every two or three years.
-Hot desert temperatures range from very hot in the day (e.g. 45 °C) to cold at night (below 0 °C).
-Hot deserts get more daylight during the summer than the winter. Because there is little cloud cover, they get lots of hours of sunshine every day.
Characteristics:
-Plants — plant growth is sparse due to lack of rainfall. A few plants do grow, e.g. cacti, thornbushes.
-Animals - relatively few animal species live in hot deserts - those that do are adapted to cope with the harsh climate. Animals that live there include lizards, snakes, insects and scorpions.
-Soil - the sparse vegetation means that there is little leaf litter, and the dry climate means that organic matter is slow to decompose. As a result, soils are mostly thin and nutrient-poor.
Tundra-climate and characteristics
Climate:
-Temperatures are low — around 5-10 °C during the summer and lower than = 30 °C in the winter.
-Precipitation is also very low — less than 250 mm per year. Most of this falls as snow.
-Tundra is found at high latitudes, so it gets near-continuous daylight in the summer and little or no daylight in the winter. There is more cloud cover in the summer.
Characteristics:
-1) Plants — the cold climate and lack of light in winter make it hard for plants to grow, and there are hardly any trees. Vegetation includes mosses, grasses and low shrubs.
2)
Animals - the cold climate and lack of vegetation means that relatively few animal species live in the tundra. Those that do include Arctic hares, Arctic foxes, mosquitoes and lots of birds. Some animals migrate south for the winter.
3)
Soil - the sparse vegetation produces little leaf litter, and the cold, dry climate means that organic matter decomposes slowly, so soil is thin and nutrient-poor. There is a layer of permafrost (permanently frozen ground) below the soil surface, which can stop water from draining away.
How are biome distributions affected by local factors
1) Altitude - higher altitudes are colder, so fewer plants grow there, which also limits the number of animal species. This means there’s not much organic matter, so soils are thin or non-existent.
2) Rock type - some rock types are easily weathered (see p.46) to form soils, and different rock types contain different minerals. This affects how nutrient-rich the soil is. Some rocks are also permeable (water can flow through them) and others are impermeable (they don’t let water through).
3)
Soil type - more nutrient-rich soils can support more plants. The acidity and drainage of soils also varies, affecting the plants that can grow. E.g. peat soils are very acidic, so only acid-tolerant plants such as conifers can grow, and clay soils are sticky, so water can’t flow through very easily.
4)
Drainage - if drainage is poor, soil gets waterlogged and only plants adapted to wet conditions can grow there. Very wet areas may be home to aquatic species of plants and animals.
Difference in abiotic and biotic facors and how they link
The biotic components are the living parts of a biome
e.g. plants (flora) and animals (fauna).
The abiotic components are the non-living parts -
- e.g. soil, water, rock, atmosphere.
The different components interact with each other, for example:
1) Water availability affects the plants that can grow
e.g. if the soil is very dry, only desert plants
such as cacti will be able to survive. Plants take in water from the soil and release it into the atmosphere, providing moisture for further rainfall.
2)The type and density of vegetation that grows affects the type of soil that forms, and the type of soil that forms affects the type of vegetation that can grow - e.g. dense vegetation cover and lots of leaf fall means that lots of nutrients will be added to the soil, which can then support more plant growth.
How does the biosphere provides lots of resources-indigenous people
Food-Many indigenous people get all of their food directly from plants and animals. Some forage for food, picking wild fruit,vegetables and nuts,hunting and trapping animals and catching fish. Other grow food for their own use e.g raising livestock
Medicine-Lots of plants have medicinal properties and are used ti cure illnesses and keep people healthy. Plant species in tropical forests have been used to create over 7k drugs
Building materials-trees and other plants are often used as building materials e.g pine from taiga forests is used to make furniture and to build houses. Sap from trees can be used as glue or make buildings waterproof,reed and straw can be used for roofs and plant fibres can be used to make rope.
Fuel-indigenous people rely on plants and animals for fuel for cooking and keeping warm. Wood,moss,dried grass and dried animal dung is burnt as fuel. Some indigenous people in areas with little vegetation use animal fat.
Different ways ecosystem services are used
Hydroelectric power-energy
Efe tribe in Congo basin- indigenous people
Slash and burn farming-for water
Commercial farming-timber
Timber for logging-timber
Iron ore mine-for minerals
Humans exploiting bisophere
Energy-Demad for energy is increasing as the world population increases and people ahve more electronic devices. Large area of forest are cut down to clear land for growth of crops that can be used for biofuels,coal mines and power station. Some been floded by building of hydroelectric dams. Drilling for oil and gas in tundra damaging biosphere due to melting of pipelines
Water-Demand for water is also increasing because of increases in global population — people use water for washing, irrigating farmland.can be over-exploited — this is happening in arid areas like the Sahara desert. This can cause damage ot the biosphere, as plants and animale no longer have enough water ot survive.
Minerals-Minerals such as gold and iron are used in building, scientific instruments,
electrical appliancee and lots of other things — and demand for them is increasing. Minerals are often extracted by mining. Mines in tropical forests are responsible for lots of deforestation and toxic chemicals are washed into streams and rivers,
killing wildlife.
How does biosphere help regulate the gases in atmosphere
Biosphere helps control proportion of different gases in atmosphere:
-plants take in carbon dioxide and give out oxygen during photosynthesis
-animals take in oxygen from the air and give out carbon dioxide when they breathe
Maintaining Balance of gases in atmosphere is important because:
-most living organisms need oxygen to survive
-increased levels of CO2,lead to global warming
-Increased levels of CO2, can also make the ocean acidic,affecting the organisms that live there
-Some CO2, is needed to keep the earth warm enough to support life.
Bisophere helps reuglate the gases in atmosphere to keep soil healthy and regulate water cycle
Healthy soil:
-plant roots and animals spread nutrients through the soil-this help maintain soil structure and fertility, which allows the plant to grow
-the roots of vegetation also hold the soil together-without this, the soil can be eroded by wind and rain
-vegetation intercepts rainfall before it reaches the ground. This helps to prevent leaching-where nutrients in soil are washed downwards out of reach of plants
Water cycle:
- clouds form, it rains, water runs to river and sea, water evaporates and then process repeats
• Water is taken up by plants, so less reaches rivers.
This helps to prevent flooding and soil erosion.
• Plants also help to regulate the global water cycle by storing water and releasing it into the atmosphere slowly.
Large areas of forest, e.g. the Amazon rainforest, can reduce the risk of drought and flooding in areas a long way away.
Nutrient cycle
1)plants absorb nutrients from the soul and use them to grow
2)plants drop their leaves or animals eat plants,taking in the nutrients they contains
3) animals and plants die and decompose,returning nutrients back to soil
4)process repeats
Population increasing demand for resources
-population increasing so people require more resources so greater demand fkr resources
3) Increased demand for one resource can also increase demand for another, for example:
• More people means that more food needs to be grown, which increases demand for water.
• As demand for water increases, it may need to be transported from areas where there’s plenty to areas where there’s not enough - this takes lots of energy.
Factors increasing demand for resources
Increasing wealth:
-Economic development means that more people are getting wealthier.
-wealthier people have more disposable income, which affects resource consumption:
-more money to spend on food and often buy more than they need
-can afford cars,fridges,televisions
-more people can afford flushing toilets,showers,dishwashers. This increases water use.
Urbanisation:
Urbanisation tends to increase resource consumption because:
• Cities tend to be more resource-intensive than rural areas — street lights and neon signs use energy, and fountains and urban parks require water.
• Food and water have to be transported long distances to meet the increased demand in cities, and waste needs to be removed — this increases energy use.
Industrialisation:
-manufacturing goods such as cars,chemicals and electrical appliances uses a lot of energy-e.g to run machines or heat components so they can be shaped. Manufacturing also uses a lot of water e.g cooling and washing components. As countries become more industrialised, their demand for energy and water increases
- industrialisation is increasing the production of processed goods,p e.g foods such as margarine. This increases the demand for ingredients such as palm oil, which are often grown on huge plantations
Malthus’s theory
• Thomas Malthus was an 18th-century economist. He thought that population was increasing faster than supply of resources, so eventually there would be too many people for the resources available.
• He believed that, when this happened, people would be killed by catastrophes such as famine, illness and war, and the
Key
Resource supply
- Population
population would return to a level that could be supported
Amount
by the resources available.
-The point where the lines cross on the graph is the point of catastrophe
population starts to decrease after this, until it
is low enough that there are enough resources to support it again.
Boserup’s theory
• Ester Boserup was a 20th-century economist. Her theory was that however big the world’s population grew, people would always produce sufficient resources to meet their needs.
• She thought that, if resource supplies became limited, people would come up with new ways to increase production (e.g. by making technological
Key
Resource supply
- Population
advances) in order to avoid hardship.
• The graph shows that, as population increases to
Amount
be equal with resource supply, resource supply increases so there are always enough resources available for the population.
