Ecosystems

Question 1

What is an ecosystem?

Answer 1

A natural system that comprises plants (flora), animals (fauna), and the natural environment in which they live. There are often complex relationships between the living and non-living components in an ecosystem. Non-living components include the climate, soil, water, and light.

Question 2

What are the different sizes of ecosystems?

Answer 2

Local ecosystems e.g. a pond or hedge
Large ecosystems e.g. a lake or woodland
Biomes - global scale e.g. tropical rainforests or deciduous woodland

Question 3

What is a food chain?

Answer 3

A series of links showing the relationships between producers and consumers, and predators and prey

Question 4

What is a food web?

Answer 4

A collection of food chains found within a single ecosystem. It is much more complicated than a food chain as it shows connections and energy transfers between more than one plant or animal

Question 5

What are adaptions?

Answer 5

The ways that organisms evolve to cope with environmental conditions

Question 6

What are producers?

Answer 6

Organisms that get their energy from a primary source such as the sun

Question 7

What are consumers?

Answer 7

Organisms that get their energy by eating other organisms

Question 8

What are scavengers?

Answer 8

Organisms that consume dead animals or plants

Question 9

What are decomposers?

Answer 9

Organisms such as bacteria that break down plant and animal material

Question 10

What is the climate of a tropical rainforest like?

Answer 10

It is very wet, with significant variation in precipitation between the months. There are two seasons - a short dry season from June to October and a long wet season from December to May. It is hot all year round with a very small temperature range

Question 11

What is the climate of a hot desert like?

Answer 11

It is extremely dry. There is very little variation in rainfall, with some rain in winter. It is very hot, but temperatures do vary, and winters are generally mild. It is very cold at night

Question 12

What is the climate of a deciduous forest like?

Answer 12

It is quite wet, with very little variation in rainfall between the months. Temperatures are mild but with some variation. Winters are cool, while summers are warm. There is a fairly large temperature range

Question 13

What is air pressure?

Answer 13

The weight of the atmosphere pressing down on the Earth’s surface

Question 14

Why are deserts dry?

Answer 14

They are found 30 degrees above or below the equator, in an area of high atmospheric pressure. Air is sinking, so it gets warmer. This means any water vapour held in it will not be able to condense, so no clouds will form and rainfall levels are very low.

Question 15

Why are tropical rainforests wet?

Answer 15

They are found at the equator, in an area of low atmospheric pressure. Lots of water is evaporated from the surface making the air very humid. As the air rises it cools and the water vapour condenses back into liquid then clouds. This causes heavy downpours. This process is called convectional rainfall.

Question 16

Why is the equator hotter than the north and south poles?

Answer 16

The curvature of the Earth means that heat energy from the Sun is very focussed and intense at the equator, as rays are hitting the equator almost dead on, so they cover a small area. At the poles heat energy is spread over a larger distance, as it is not hitting it as directly, meaning heat is more spread out and therefore less intense, making it cooler

Question 17

What are the characteristics of tropical rainforests?

Answer 17

30-40m: emergent layer. Only the tallest, fastest growing trees reach here, like the kapok and mahogany trees, as well as insects and birds.
20-30m: main canopy. Lots of light so contains 80% of forest flora and fauna. Mature trees and epiphytes, as well as lots of animals live here.
10-20m: lower canopy/ shrub layer. Younger trees trying to reach the canopy. Quite dark. Insects and other animals.
0-10m: forest floor. Very dark. Shade loving shrubs grow here. Decomposers and detritivores rapidly decompose trees and leaves. Soil is very infertile apart from fertile topsoil.

Question 18

What are some adaptions of rainforest flora?

Answer 18

Leaves have flexible bases so they can turn to face the sun
Leaves have a ‘drip tip’ allowing heavy rainfall to drip off the leaf
Trees have thin, smooth bark to allow water to flow to the soil
Young trees grow directly upward and do not grow branches
Tallest trees have butress roots which branch outward for greater stability

Question 19

How does a rainforest transfer nutrients?

Answer 19

Rapidly and constantly between trees, shrubs and animals (biomass), the layer of fallen leaves and decaying vegetation on the surface (litter), the soil layer below it (soil), and then back to the biomass.

Question 20

Why is the tropical rainforest important?

Answer 20

Helps maintain global biodiversity
Research into higher yielding varieties of seeds for farming
Research into plants that provide medicines
Helping to reduce the greenhouse effect

Question 21

What is agroforestry?

Answer 21

When trees and shrubs are harvested to make space to grow crops and keep livestock. Trees in the other layers are left, so the rainforest can be mostly preserved and land can be used for agriculture. The soil is also not left open to rainfall and moisture is kept in the soil. Crops are rotated so soil is not exhausted.

Question 22

What is selective logging?

Answer 22

Where only the most valuable trees are removed without disturbing the surrounding area. Heavy machinery does not destroy vegetation, reducing the risk of soil erosion. Animal habitats are preserved. Trees are replanted so native plant species survive.

Question 23

What is ecotourism?

Answer 23

Small scale buildings and little staff are used so surrounding rainforest can survive, attracting tourists looking to see the natural rainforest around them while also not damaging much of the rainforest.

Question 24

What are some international agreements to help conserve rainforests?

Answer 24

Forest stewardship council - sustainably sourced products carry the FSC logo
Debt relief for sustainable logging - countries in debt often clear rainforests to make money to pay debts. Some countries are reducing debt in return for not destroying the rainforest
Funding to create national forest parks - reduces global wadming

Question 25

What are some social and environmental effects of deforestation?

Answer 25

Loss of tribal groups
Climate change
Loss of biodiversity
Soil erosion
Pollution of rivers from mining waste products

Question 26

What is desertification?

Answer 26

Where land is gradually turned into a desert, usually on the edge of an existing desert. This can happen when land is overgrazed by livestock or stripped of vegetation. The exposed land will then crack and break up and be eroded by wind and water

Question 27

What is appropriate technology?

Answer 27

Technology able to be carried out by people in the area it is needed. It is usually affordable, uses locally available material and can easily and cheaply maintained

Question 28

What are some appropriate technologies to reduce desertification?

Answer 28

Rainwater conservation - trapping water behind stones and planting trees on bare slopes, stopping water and soil from being washed or blown away
Soil conservation - sculpting land on steep hills into terraces so it can be used for farming and stopping soil erosion
Contour ploughing - farming around a slope parallel to its contour lines to reduce movement of soil and water down the slope
Large scale tree planting - creating a green belt along the desert fringe, binding together soil and providing shade (Great Green Wall, 15% done)

Question 29

What are examples of different organisms in a freshwater pond?

Answer 29

Producers: detritus, algae and microscopic plants
Primary consumers: midge larva, blackfly, worms
Secondary consumers: great diving beetle, stonefly, dragonfly
Tertiary consumers: fish
Quaternary consumers: heron, kingfisher

Question 30

What is Malaysia’s tropical rainforest like?

Answer 30

63% of Malaysia is forested and commercial tree crops take up 13% more. 18% of Malaysia is primary rainforest.
There are over 5500 species of flowering plants, 2600 species pf tree, and 1000 species of butterfly.
Over 80% of the tropical rainforest has been degraded by logging
The deforestation rate is accelerating faster than any other country - between 1990 and 2010 it lost 8.6% of rainforest

Question 31

What are the main causes of deforestation in Malaysia?

Answer 31

Commercial logging
Mining - tin, copper, oil, gas, and mining towns
Energy production - hydroelectric power floods rainforests e.g. Bakun Dam will flood 700km^2 of land, displace 9000 people, and generate 2,400MW of power
Palm oil and rubber plantations - forest cut down and replaced with palm and rubber trees
Transmigration - government encouraged people to move to the rainforest, urbanisation and new cities like Shah Alam
Slash and burn farming - to create space for crops and animals

Question 32

What are the social impacts of deforestation in Malaysia?

Answer 32

Impacts on the health of rainforest tribes - e.g. the Penan have been forced out of homes into basic government camps with little clean water and power, so many have fell ill
Loss of tribal lands and way of life - land has been destroyed by deforestation, also meaning they cannot hunt and gather foodstuffs

Question 33

What are the environmental impacts of deforestation in Malaysia?

Answer 33

Pollution of rivers and water - from mining for tin and other metals
Increasing soil erosion - without trees rain hits soil directly, washing it away, as roots also do not bind it together, leaving infertile soil
Destruction of wildlife, loss of biodiversity - plants and animals like the orangutang will lose their habitats and go extinct

Question 34

What are the economic impacts of deforestation in Malaysia?

Answer 34

When land is cleared for farming soil erosion occurs and topsoil is washed away, leaving infertile soil. This leaves the land like a desert, so no farming can take place and more rainforest has to be cleared.

Question 35

Why are tropical rainforests important?

Answer 35

Biodiversity - they contain 50% of the world’s plant, insect and animal species in 8% of the surface area
Medicines - many medicines, such as quinine, a malaria treatment, come from rainforests
Reducing the greenhouse effect - rainforests produce ~25% of the world’s oxygen

Question 36

What is Yachana Lodge and how does it protect the rainforest?

Answer 36

An ecotourism business in the Amazon Rainforest in Ecuador. Only 30 visitors are allowed at a time, trek routes are changed every week, visitors cannot collect plants or leave litter, and hot water and electricity come from solar panels

Question 37

What is the Forest Stewardship Council?

Answer 37

An international organisation that promotes sustainable forestry. Sustainably sourced products carry the FSC logo, making them more attractive to consumers

Question 38

What is debt relief for sustainable logging/farming?

Answer 38

Indebted countries with rainforests often destroy them in order to make money to pay back debts. Some countries have started to forgive some debt in return for countries protecting these rainforests. Sometimes called ‘debt for nature’ swaps

Question 39

What is providing funding to create forest parks?

Answer 39

HICs giving funding to poorer countries to create protected national parks. These then reduce global warming, as deforestation and illegal activity decreases, so more CO2 is absorbed.

Question 40

How is Malaysia trying to develop a more sustainable form of forestry?

Answer 40

Machinery size - restricting the use of bulldozers and heavy machinery
The Malaysian government is creating new national parks

Question 41

Why are deserts cold at night?

Answer 41

There is little to no cloud cover, so heat can easily escape into space

Question 42

What are desert soils like?

Answer 42

Most have no organic content, made up of pieces of rock and sand. Where water is found closer to the surface, soils are sometimes saline. Soils can be fertile, however, if enough water is provided.

Question 43

How are cacti, cholla and camels adapted to desert life?

Answer 43

Cacti store water in their stem to use in droughts, and are covered in thorns to protect themselves from animals. They have shallow spread out roots.
Cholla have thick waxy cuticles to reduce transpiration and reflect heat. They also have spines
Camels can close their eyes, nose and mouth for protection in a sandstorm. They have large pads on their feed and tough mouths to eat thorny plants.

Question 44

What are the characteristics of the population of the Western Desert?

Answer 44

~9 million people live there, but the area spreads across 5 states, so it is fairly sparsely populated
~50% of the population lives in big cities e.g. Phoenix and Tucson
Indigenous tribes live in communities spread throughout the desert e.g. the Navajo people

Question 45

What development opportunities does the Western Desert offer?

Answer 45

Farming vegetables and fruits
Tourism
Mining and quarrying
Solar energy, HEP and fossil fuel mining

Question 46

How and why does farming take place in the Western Desert?

Answer 46

High temperatures and intense sunlight offer favourable conditions for agriculture, and water can be provided by aquifers and water transfer schemes. 15% of the USA’s crops and 13% of its livestock are produced here; it is worth $1.5bn/ year

Question 47

What are aquifers and water transfer schemes?

Answer 47

Aquifers - large, underground water stores that can be accessed with wells
Water transfer schemes - transporting water from lakes (e.g. Lake Powell and Lake Mead) to rivers (e.g. the Colorado river) using canals

Question 48

How and why does tourism take place in the Western Desert?

Answer 48

Tourism is the main employer in the region because of national parks e.g. the Grand Canyon, cities like Las Vegas (37m annual visitors), festivals like the Coachella Valley Music and Arts Festival, and water activities in Lake Mead and Powell (2m annual visitors)

Question 49

How and why does mining and quarrying take place in the Western Desert? Why have opportunities not been fully exploited?

Answer 49

The region is rich in minerals like copper, uranium, zinc, and coal. Underground water means opencast mining can be carried out on a larger scale. There are conflicts with other land uses (e.g. farming), environmental concerns, and clashes with indigenous tribes.

Question 50

How and why does solar energy production, HEP, and fossil fuel burning take place in the Western Desert?

Answer 50

Intense sunlight and empty land means large solar fields can be created e.g. the Sonoran Solar Project, which will produce energy for 100,000 homes
The Hoover Dam in Lake Mead creates hydroelectric energy
There is lots of oil present, with 25 active production sites in Arizona, all owned by the Navajo people. The economic gain from this is $50m.

Question 51

What is the Central Arizona Project?

Answer 51

A $4bn scheme that involves piping water from the Colorado river to Lake Mead and Lake Powell through aqueducts, as well as extracting water from underground aquifers and rivers close to Phoenix and Tucson.

Question 52

What are the benefits of the Central Arizona Project?

Answer 52

It provides a guaranteed water supply for the farming industry
It provides water for homes in an area of population 8m, including the cities Phoenix and Tucson.
Water can be used for leisure activities on lakes like Lake Powell and Lake Mead

Question 53

What are the costs of the Central Arizona Project?

Answer 53

Water transfer schemes are very expensive - the scheme will cost $4bn
The water table lowers when water is pumped out, causing land to compact to subside, meaning lots of land is wasted
Water taken from rivers can cause the rivers to dry up completely, causing plants and animals around it to die

Question 54

What are the main causes of desertification in the Sahel?

Answer 54

Climate change - causing drier conditions and reduced rainfall, so less plants grow, so soil is more easily blown away
Population growth - higher demand for food, so land is overgrazed by animals and over-cultivated by crops, exhausting it, and trees are cut down for firewood
These lead to soil erosion, meaning it can be swept away, leaving infertile dust