Topic 7: People & The Biosphere

Question 1

What are biomes?

Answer 1

Large-scale, global ecosystems with distinctive vegetation

Question 2

Why do different parts of the world have different biomes?

Answer 2

The climate in an area determines what type of biome forms. So different parts of the world have different biomes as they have different climates

Question 3

Name 3 biomes

Answer 3

• Tropical forest
• Temperate forest
• Boreal forest

Question 4

Climate of Topical forests

Answer 4

• Same all year round, no definite seasons
• Hot (temperatures 20-28 degrees) due to being near the equator
• Day lengths are the same all year round (12hrs) due to being near the equator, so recieves plenty sunshine all year
• High rainfall (2000mm per year), rains everyday

Question 5

Characteristics of Tropical forests

Answer 5

Plants - most trees are evergeen to take advantage of the continual growing season. Plants grow quickly & are adapted to take in maximum light

Animals - the dense vegetation provides lots of food & different habitats, so there are lots of different species of animal (gorillas, jaguars, etc). Lots of species of insects and birds

Soil - plants grow quickly & shed leaves all year round. These decompose quickly, so theres constant supply of nutrients in soil that are cycled quickly

Question 6

Climate of Temperate forests

Answer 6

• 4 distinct seasons. The summers are warm & winters are cold
• High rainfall (1500mm per year), all year round
• Shorter days in winter, longer in summer. Hours of sunshine vary through the year

Question 7

Characteristics of Temperate forests

Answer 7

Plants - the mild, wet climate supports fewer plant species than tropical forests, but more than boreal forests. Forests made up of broad-leaved trees that drop leaves in autumn, shrubs & undergrowth

Animals - mild climate & range of plants provides food & habitats for mammals (eg. foxes, quirrels), birds and insects

Soil - plants lose their leaves in autumn, leaf litter decomposes quickly in moist, mild climate. Meaning soils are relatively thick & nutrient-rich

Question 8

Climate of Boreal forest

Answer 8

• Short summers & long winters. Average temperature in winter is below -20 degrees, and 10 degrees in summer
• Low Precipitation (less than 500mm per year), mostly falls as snow
• Lots of daylight during summer, but little to none during winter. Clear skies so plenty of sunshine in daytime

Question 9

Characteristics of Boreal forest

Answer 9

Plants - most trees evergreen, so can grow whenever theres enough light. Coniferous trees (pine & fir) are common, as are low-growing mosses & lichen

Animals - relatively few animal species (eg. black bears, wolves, eagles) compared to tropical forests because less food available & animals need to be adapted to the cold climate to survive.

Soil - cool, dry climate means needles from trees decompose slowly, so soils are quite thin, nutrient-poor and acidic. In some areas, ground is frozen most of year

Question 10

What are the 2 types of Grassland

Answer 10

• Tropical grassland
• Temperate grassland

Question 11

Climate in Tropical grasslands

Answer 11

• Quite low rainfall (800-900mm per year)
• Distinct wet and dry seasons
• Temperatures are highest (35 degrees) before wet season & lowest (15 degrees) just after it
• Found near equator, so recieve lots of sunshine all year round

Question 12

Characteristics of Tropical grasslands

Answer 12

Plants - consists mostly of grass, scrub & small plants, with few scattered trees

Animals - home to lots of insects (grasshoppers, beetles), larger animals include (lions, elephants)

Soil - grass dies back during dry season forming a thin, nutrient-rich soil, but nutrients are washed out of soil during wet season

Question 13

Climate of Temperate grasslands

Answer 13

• Hot summers (up to 40 degrees) & cold winters (-40 degrees)
• Lower rainfall than tropical grasslands (250-500mm per year)
• As further from equator, the amount of light recieved varies throughout year

Question 14

Characteristics of Temperate grasslands

Answer 14

Plants - Much like tropical grassland, dominated by grasses & small plants, very few trees

Animals - home to fewer animal species than tropical grasslands, mammals (bison, wild horses), rodents (mole rats)

Soil - high temperatures in summer means that decomposition is fast, so soils are relatively thick & nutrient-rich

Question 15

Climate of Deserts

Answer 15

• Very low rainfall (less than 250mm per year). Might only rain once every 2-3 years
• High temperatures range from 45 degrees at day and 0 degrees at night
• Recieve more dayligt during the summer than winter. Little cloud cover, so lots of sunshine everyday

Question 16

Characteristics of Deserts

Answer 16

Plants - plant growth is sparse due to lack of rainfall. A few plants such as cacti, thornbushes grow

Animals - relatively few animal species. Those that do are adapted to cope with the harsh climate (eg. lizards, snakes, etc)

Soil - the sparse vegetation/plant growth means there is little leaf litter, & the dry climate means that organic matter is slow to decompose. As a result, soils are mostly thing & nutrient-poor

Question 17

Climate of Tundra

Answer 17

• Low temperatures (5-10 degrees in summer and -30 degrees in winter)
• Very low precipitation (less than 250mm per year). Most of this falls as snow
• Found at high altitudes so gets near-continuous daylight in the summer & little to no daylight in winter.

Question 18

Characteristics of Tundra

Answer 18

Plants - cold climate & lack of light in winter makes it hard for plants to grow. Hardly any trees. Vegetation includes mosses, grasses, low shrubs

Animals - cold climate & lack of vegetation means relatively few animal species can survive. Those that do include arctic hares, arctic foxes, etc. Some animals migrate south for the winter

Soil - the spares vegetation produces little leaf litter, & the cold, dry climate means organic matter decomposes slowly, so soil is thin & nutrient-poor. There is a layer of permafrost (permanently frozen ground) below soil surface, which stops water draining away

Question 19

What factors affect biome distribution?

Answer 19

Alititude - higher altitudes are colder, so fewer plants grow there, which limits animal species. Meaning theres not much organic matter so soils are thin

Rock type - some rocks are easily weathered to form soils & different rock types contain different minerals, affecting how nutrient-rich the soil is. Some are permeable, others are impermeable

Soil type more nutrient-rich soils can support more plants. The acidity & drainage of soils also varies, affecting the plants that can grow

Drainage - if drainage is poor, soil gets waterlogged & only plants adapted to wet conditions can grow

Question 20

What are biotic components?

Answer 20

Living components of a biome (eg. plants, animals)

Question 21

What are abiotic components?

Answer 21

Non-living components of a biome (eg. soil, water, rock)

Question 22

What is the biosphere?

Answer 22

Includes all parts of the Earth that are occupied by living organisms

Question 23

What does the biosphere offer to people?

Answer 23

Food - many indigenous people get all their food directly from plants & animals. Some forage for food, picking wild fruit, veg & nuts, hunting & trapping animals

Medicine - lots of plants have medicinal properties & are used to cure illnesses & keep people healthy. Plant species in Tropical forests have been used to create over 7000 drugs

Building materials - trees & other plants often used as building materials. Sap from trees can be used as glue or to make buildings waterproof, reeds & straw used for roofs & plant fibres for rope

Fuel - indigenous people rely on plants & animals for fuel to cook & for warmth. Wood, moss, dried grass & dried animal dung is burnt for fuel

Question 24

How do humans exploit the biosphere?

Answer 24

Energy - demand for energy is increasing as global population increases. Forests are cut down to clear land for growing crops that can be used to make biofuels, or to make way for coal mines or power stations

Water - demand for water is also increasing due to increases in global population - people use water for washing, irrigating farmland, etc. Water sources are over-exploited, leaving plants/animals with lack of water to survive

Minerals - minerals such as gold & iron are increasing in demand for a variety of uses. They are extracted from mines found in tropical forests that are responsible deforestation, release of toxic chemicals, etc.

Question 25

How does the biosphere held regulate gases in the atmosphere?

Answer 25

• Plants take in CO2 & give out oxygen during photosynthesis
• Animals take in oxygen from the air & give out CO2 when they breathe

Question 26

Why is it important to maintain the balance of gases in the atmosphere?

Answer 26

• Most living organisms need oxygen to survive
• Increased levels of CO2 lead to global warming
• Increased levels of CO2 can also make the oceans acidic, affecting the organisms that live there
• Some CO2 is needed to keep the Earth warm enough to support life

Question 27

How is the biosphere important for maintaining soil health?

Answer 27

• Plant roots & animals spread nutrients through the soil, helping maintain soil structure & fertility allowing plants to grow. (Plants absorb nutrients from soil, animals eat the plants taking in the nutrients. Animals & plants die/decompose returning the nutrients to soil)
• Vegetation intercepts precipitation before it reaches the ground, prevening leaching (nutrients in soil being washed out of reach of plants)

Question 28

What is the water cycle?

Answer 28

—> water evaporates –> clouds form –> rain –> water runs to rivers, sea, etc

Question 29

How is the biosphere important for regulating the water cycle?

Answer 29

• Water is taken up by plants, so less reaches rivers, preventing flooding & soil erosion
• Plants also store water & release it into the atmosphere slowly - preventing drought & flooding

Question 30

What are population projections?

Answer 30

Predictions of how many people will be in the world in the future

Question 31

How can increased demand for ONE resource also increased demand for another?

Answer 31

For example:
- more people meands more food needs to be grown, which increases demand for water
- as demand for water increased, it may need to be transported from other areas, increasing demand for energy

Question 32

Factors that increase demand for resources

Answer 32

Increasing wealth - wealthier people have more disposable income so, more money to spend on food, able to afford manufactured goods (cars, fridges, etc.) all of which use energy, increased water use (showers, flushing toilets)

Urbanisation - increased population in urban cities. Cities tend to be more resource-intensive than rural areas, food & water have to be transported long distances to meet high demands in cities increasing energy use

Industrialisation - shift in economic activity from primary (farming) to secondary production (manufacturing). Manufacturing goods (eg cars) uses lots of energy and water. Also increases production of processed goods (ingredients such as palm oil which are grown on huge plantations)

Question 33

Who proposed theories about resource supply?

Answer 33

• Malthus
• Boserup

Question 34

What was Malthus’s theory?

Answer 34

Thomas Malthus (18th century economist) thought the 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 famines, illness & war, and the population would return to a level that could be supported by resources available.

Question 35

What was Boserup’s theory?

Answer 35

Ester Boserup (20th century economist) stated 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 in order to avoid hardship.

Question 36

Whats the difference between davut and Onur

Answer 36

Onur has a brain