2025 mocks - section A - the living world Flashcards
definition of a natural hazard
A naturally occurring event which has the potential to endanger human life, the economy and property
Types of natural hazards
Tsunamis, earthquakes, cyclones, typhoons, hurricanes, tornadoes, flooding
List 7 factors affecting hazard risk
- magnitude
- location
- population
- frequency
- poverty/level of development
- climate change
- the 3 p’s ( planning, protection and prediction)
how does magnitude affect the risk of hazard
the more powerful a Natural Hazard is ( or the higher the magnitude of the natural disaster), the larger the area of impact
how does frequency affect the risk of hazard
The more often a Natural Hazard occurs, the more risks people will constantly face and the longer time it will take to recover
how does population affect the risk of hazard
the higher the population density, the higher the number of people affected by the natural hazard
how does location affect the risk of hazard
- close to epicentre of an earthquake
- steep slopes prone to landslides
- near the coast or coast, affected by tsunamis
how does poverty affect the risk of hazard
poverty may force people to live in areas of risk
a shortage of housing causes people to live near steep slopes, or areas prone to flooding as it is more affordable or it’s their only resort.
how does climate change affect the risk of hazard
- Warmer sea temperatures provide more energy for hurricanes, typhoons, and cyclones, making them more powerful and destructive.
- Higher temperatures cause more evaporation, leading to heavier and more frequent rainfall, increasing the risk of flash floods and river floods
- Rising global temperatures lead to prolonged dry spells and heatwaves, which can cause wildfires and reduce water availability.
how does how does prediction affect the risk of hazard
the use of science and technology can give us information about the hazard, and could also give us a warning about the event, which limits the impact of a natural hazard
how does how does planning/preparation affect the risk of hazard
involves land use zoning and hazard zone maps.
evacuation routes , setting laws and building codes.
educating people about natural hazards and what to do in the event of one can help to reduce panic and people know what to do and get to safety.
how does how does protection affect the risk of hazard
offering people protection -> eg. building sea walls, houses on stilts, shelters
- keeps people safe and can reduce the numbers of fatalities.
- protects some buildings from being damaged, which reduces the economic impact
how does how does level of ECONOMIC DEVELOPMENT affect the risk of hazard
- wealthier countries can invest in more advanced technology and equipment used for planning, predicting, monitoring for natural hazards, aswell as protection against them
- education and training programmes could be set up for the public and emergency services
- poorer countries often construct buildings with cheap and weaker materials, that cannot withstand a natural hazard well or easily. compared to earthquake proof buildings in HICs such as Japan
what is the plate tectonics theory
The earth is made up of different layers: crust, mantle, outer core, inner core.
what is the crust
thin outer layer, consisting of continental and oceanic plates. it’s solid rock
what’s the mantel
thickest section of the earth (80% volume)
semi-molten rock
thermal convection happens here
what is the outer core
liquid iron and nickel
what is the inner core
solid iron and nickel. hottest part of the earth
what is thermal convection / convection currents
when super heated magma rises to the surface, cools and sinks back down, to where it is reheated. this process is repeated again and again, causing the movement of tectonic plates.
what happens at a constructive plate margin
-the plates move away from eachother.
-formation of new crust
-mid-ocean ridges: eg. the Mid-Atlantic Ridge ( between Eurasian and North American plate)
-volcanoes
- rift valleys
what happens at a destructive plate margin
- plates move towards eachother
- subduction zone -? earthquakes and volcanoes
- ocean trenches
what happens at a conservative plate margin
- plates move along/past eachother causing earthquakes
- fold mountains
NO VOLCANOES
global distribution of earthquakes
- located in long narrow belts along all types of plate boundaries
- mainly on the coast, around the pacific ring of fire, mid atlantic ridge and in the himalayan region
global distribution of volcanoes
- subduction zones and constructive plate boundaries
- found in small clusters ( iceland) and isolated locations (hawaii) in narrow zones of activity
how are earthquakes formed at a subduction zone
- The thinner, but denser oceanic crust is subducted underneath the thicker, but less dense continental crust.
- As the plates move, friction occurs, causing high amounts of heat and pressure to build up
- It is then released, causing huge amounts of energy to be sent out, releasing shockwaves which cause movement and earthquakes
how are volcanoes formed at subduction zones
-Oceanic crust is subducted underneath the continental crust where it sinks.
-It is then heated and melts into magma
- magma rises through cracks and fissures in the continental crust , creating a volcanic eruption
where and how is a ocean trench formed
destructive plate margins
the oceanic plate is forced underneath the continental plate. gravity bends the edge of the oceanic plate, forming a v-shaped trench on the ocean floor
example: iceland
how do volcanoes form at constructive plate margins
- when the plates move away from eachother, magma rises from the mantle to make new crust. When magma rises through the gap, it pushes the plates further apart and more magma rises (convection currents)
how are earthquakes formed at constructive margins
movements of the plates over the mantle can cause earthquakes
how are ocean ridges formed and where are they formed
constructive plate margin
- formed when the plates move away from eachother, causing magma to rise and then cool, forming a ridge when it BUILDS UP
example: mid atlantic ridge
where do fold mountains form and how?
destructive and conservative margins
- movement of rock forces layers of sedimentary rocks upwards into a series of folds
example: the Andes fold mountains
what is slab pull
a process where a sinking oceanic plate pulls the rest of the plate behind it as it subducts into the mantle - BECAUSE OF GRAVITY.
which causes the plates to move
order of the cells in the global atmospheric circulation model
(top)
Polar, ferrel, hadley
(middle)
hadley, ferrel, polar
(bottom)
how is high pressure created
when air sinks towards the ground
how is low pressure created
when air rises from the ground
where do trade winds meet
at the equator
what happens when trade winds meet
At the Equator, the northeast trade winds and the southeast trade winds meet, converge and are forced upwards, causing air to rise.
The rising air cools and condenses, forming a belt of low pressure, cumulonimbus clouds and wet climates.
where do winds move from and why
areas of high pressure, to areas of low pressure, creating winds.
this happens because winds on the ground are distorted by the earth’s rotation
where do winds move in the northern and southern hemisphere
northern: winds moves to the right
southern: winds move to the left
what are tropical storms
intense low pressure weather systems that usually develop in the tropics
where do tropical storms usually occur
30 degrees North and South of the equator, within the hadley cell where air masses converge,
global distribution of tropical storms
between 5-30 degrees north and south of the equator.
country examples: Japan, Australia, USA, South East Asia, The Philippines
Impact of General Atmospheric Circulation on Tropical Storms
Global Winds: The trade winds push storms westward, while westerlies can alter their paths as they move towards higher latitudes.
Coriolis Effect: Causes the rotation of storms and determines their direction.
Tropical storms depend on the circulation patterns of the atmosphere to form, move, and dissipate. The Hadley Cell helps initiate their development by creating the conditions for rising air and low-pressure systems.
primary ( immediate) effects of tropical storms
- bridges, buildings and other infrastructure destroyed
-roads, railways, ports and airports destroyed - electricity lines and gas lines damaged
- rivers and coastal areas flooded
- sewage overflows
- businesses destroyed
- fatalities
secondary ( long term) effects of tropical storms
- homelessness, causing distress, poverty, ill-health and death due to a lack of shelter
- blocked/damaged roads, which prevent rescue and emergency vehicles and aid reaching those who need help
- homes and hospitals left without electricity and power
- risk of fires and explosions if gas lines are broken
- storm surge: can cause people to drawn, and areas to flood, damaging crops and could cause them to be contaminated
-potential unemployment, causing an economic loss - schools closed, people can’t access education
what are the four ways of managing tropical storms
Monitoring, predicting, planning, protecting
how can monitoring and prediction help reduce the effects of a tropical storm
- monitoring: gathering data and using science to measure size of storm and potential for storm surges, and other factors
- prediction: also uses scientific equipment - can predict storm structure and intensity.
- Both allow time for preparation, evacuation and planning.
example of prediction and monitoring
- SLOSH Model: storm surge prediction
- hurricane centre in Miami: can locate storms within a 200 mile radius. uses satellite imagery to measure size of hurricane.
how can planning reduce the effect of a tropical storm
-Raising individual community awareness and educating people, can help reduce the amount of stress and panic when a tropical storm occurs, and people can think properly. People are informed of what to do and they know of evacuation routes.
- Teaching people about first aid: can help with reducing number of fatalities or injuries.
- Example: National Hurricane Preparedness week in the USA
how can protection reduce the effect of a tropical storm
- Designing something with standards or features which offer protection for people against tropical storms.
- Cyclone shelters, houses on stilts etc.
- Buildings won’t be fully damage, and will cost less to fix
example: Bangladesh Cyclone centre -> made of concrete and can withstand forces. 2000 of them
What is climate change
a long-term change in the average weather patterns, caused by natural and human factors.
( temperature and precipitation of regions in the world, or the whole world changes)
list natural factors of climate change
- changes in orbital tilt
- volcanic activity
- solar output / power of the sun
how does changes in orbital tilt affect climate change
This causes the distance between regions of the earth and sun to change, causing a change in solar radiation intensity. This causes natural cooling and warming periods.
Shorter the distance, the higher the intensity of solar radiation
how does the power of the sun / solar output affect climate change
sunspots can increase the earth’s temperature, as they release more solar radiation.
more sunspots = more solar radiation
how does volcanic activity affect climate change
- Ash can block solar radiation, causing the earth’s temperature to decrease.
- Sulfuric acid can also block solar radiation
List some human factors of climate change
- burning/use of fossil fuels
- deforestation
- agriculture
- vehicles
how does the use of fossil fuels affect climate change
greenhouse gases are released ( gases such as CO2, Methane, water vapour, nitrous oxides), which enhances the greenhouse effect
- these greenhouse gases trap long wave radiation and re-emits it back to earth, causing the earth’s surface to increase
how does deforestation affect climate change
Trees absorb Carbon dioxide during photosynthesis and release oxygen.
Forests can act as a carbon sink. If these trees are cut down, the CO2 levels in the atmosphere would be higher, and O2 levels lower.
Less carbon sinks can cause ocean warming
how does agriculture affect climate change
Livestock, decaying organic waste farming releases a lot of methane, which is a greenhouse gas.
overall effects of climate change ( social, economic and environmental)
social - heatwaves, air pollution, leading to health issues
economic - changes in rainfall, droughts and floods can affect crops, reducing yield and threatening food security. could affect lower income countries that rely on agriculture for income
economic - rising sea levels, extreme weather events
what is an ecosystem
a community of living organisms interacting with each other and their physical environment
what are the 8 large scale global ecosystems
- Tundra
- Deciduous and Coniferous forests
- Temperate grassland
- Mediterranean
- Desert
- Tropical rainforest
- Tropical grassland
-Polar
Distribution and characteristics of:
Tropical rainforest
Located near equator
Found in areas such as the Amazon Basin, the Congo Basin, and parts of Southeast Asia.
Characteristics
- Hot climate: average temperature of around 27°C and humid, High rainfall.
- High temperatures and heavy rainfall create ideal conditions for vegetation.
- Huge variety of wildlife and plant species.
Distribution and characteristics of:
Deserts
- covers 5% of the earth’s land surface
- between 15-30 degrees latitude
- Sahara Desert (Africa)
Characteristics: - High temperatures in the daytime, low temperatures in the night time
- very low rainfall, which restricts plants from growing and animals to highly specialised species
- Sparse vegetation
Distribution and characteristics of:
Temperate Grassland
- between 30-40 degrees NORTH of equator, always inland
Characteristics - Warm, dry summers, cold winters with moderate rainfall
- vegetation is dominated by grasses suited for grazing animals
Distribution and characteristics of:
Deciduous and coniferous forests
- located roughly 50-60 degrees NORTH of the equator
Characteristics: - deciduous trees shed their leaves in winter
- coniferous trees don’t shed, and are better suited to colder climates and they dominate further north (evergreens)
Distribution and characteristics of:
Tundras
- located between the Arctic Circle (60-70 degrees north) Eg. northern Russia, Canada
- found in high latitudes
Characteristics: - Cold, windy and dry conditions
- limited to mosses, low shrubs and grasses
Distribution and characteristics of:
Mediterranean
between 30 and 40 degrees latitude - Mediterranean basin, southern Australia etc.
characteristics:
- Hot, dry summers and mild winters
- vegetation: olive trees/groves and citrus fruits
Distribution and characteristics of:
Polars
- located around the North and South poles
Characteristics: - very low temperatures below 50 degrees Celsius
- dry conditions
- animal and plant life prohibited
Distribution and characteristics of:
Tropical Grasslands
- located between 15-30 degrees North and South of the equator
- example is the Savanna
Characteristics: - distinct wet and dry seasons
- large herds of grazing animals, as well as their predators
what is a biome
Biomes are large-scale ecosystems defined by one dominant type of vegetation
examples of small scale ecosystems
woodlands, hedgerow, ponds etc.
what we learn: freshwater pond ecosystem
Consumer definition + example
creatures that eat herbivores and/or plant matter. they obtain their energy from what they eat
- pond snail
producer definition
convert energy from environment into sugars.
All producers are plants
decomposer definition + example
break down plant and animal material, and then return nutrients to the soil.
- bacteria and fungi
food chain definition
shows connections/links between producers and consumers that rely on one another as their source of food
food web definition
a complex hierarchy of plants and animals relying on eachother for food
nutrient cycling definition
A set of processes where organisms extract nutrients necessary for growth from the soil or water, passing them on though the food chain, eventually returning them back to the soil and water when they die.
what does a freshwater pond ecosystem consist of
- ,Pond Bottom
- Mid water
- Pond surface
- Pond margin
- Above the pond surface
features of pond bottom
- very little oxygen and light
- decomposers and scavengers live here and feed on dead material such as water worms and rat-tailed maggots
features of mid water
- fish are the main predators
- animals here breathe through their skin or gills. examples include stickleback fish and dragonfly nymphs
features of pond surface
- animals here breathe through their gills, skin or lungs.
- plenty of oxygen and light here
- animals found here include ducks, water boatmen, midge larvae and tadpoles
features of pond margin
- lots of plants
- plants provide a sheltered habitat for insects and small animals such as frogs.
- lots of light and oxygen so plants such as marsh marigold thrive
wildlife found above the pond surface
birds such as kingfishers and insects like dragonflies
what is the freshwater pond ecosystem balanced by
the food chain and the food web
what is a food chain
a sequence that shows how energy and nutrients are passed through an ecosystem
what is a food web
a more complex diagram that shows how multiple food chains within an ecosystem are interconnected. It illustrates how energy and nutrients flow through various organisms in an ecosystem, with each species potentially having multiple feeding relationships.
examples of producers
grass, duckweed, water lillies, detritus
examples of consumers:
primary
secondary
tertiary
primary: water snails, tadpoles, insect larvae
secondary: Frogs, Newts, Diving beetles
Tertiary: Larger fish, herons, Kingfishers
natural factors that cause the change of ecosystems
- droughts
- floods
- fire
- disease
human factors that cause the change of ecosystems
- introducing more fish (fish stocking)
- altering the drainage of the land which may influence the amount of water
- changing the pH level of the water
- altering the nutrient levels of the water if fertilisers are leached into the water, resulting in eutrophication
what is eutrophication
hyper nutrition, resulting from fertiliser pollution of aquatic systems
two main factors that cause change to eco-systems
- global scale changes, such as climate change
- local scale changes such as changes to a habitat for example, when a hedge is removed.
what do agricultural fertilisers do or lead to
they can lead to eutrophication.
Nitrates increase the growth of algae, which will deplete oxygen and fish may die
what happened if a pond owner added some perch (a predator) to the ecosystem
- The perch will eat more of the smaller fish and small animals, like frogs
- this will reduce the amount of food for creatures further up the food chain, like herons
- with fewer frogs, there will be an increase of creatures below frogs, like slugs
Describe the global distribution of the tropical rainforest ecosystem
found in a narrow belt nearing the equator. vast majority located around 10 degrees north and south of the equator.
The Amazon rainforest is found in South America. They have high temperatures and high levels of rainfall all year round, creating ideal growing conditions
- ALL FOUND WITHIN THE TROPICS:
tropic of cancer: 23.5 N
tropic of cap: 23.5 S
give one reason why energy is lost at each level in a food chain
through respiration. Organisms use energy for essential processes like movement, growth, and maintaining body functions, and much of this energy is released as heat. This energy is not passed on to the next level
how do decomposers help return nutrients to the soil
Decomposers, such as bacteria, fungi, and worms, help return nutrients to the soil by breaking down dead plants and animals.
explain the role of decomposers in an ecosystem
They recycle nutrients by decomposing organic matter, releasing essential elements like nitrogen and carbon back into the soil. This process enriches the soil, making nutrients available for plants to absorb, and helps maintain the balance of the ecosystem by preventing the build up of dead material.
explain the links between different levels in a food chain
Producers convert sunlight into energy through photosynthesis. Primary consumers eat producers, gaining energy. Secondary consumers eat primary consumers.
tertiary consumers eat secondary consumers. At each level, energy is lost as heat through respiration, while decomposers break down dead organisms, returning nutrients to the soil.
physical characteristics of a tropical rainforest
- Temperatures are high and constant throughout the year
- very high rainfall
- rainfall varies through out the year with a distinct wet season lasting around 6 months
- layered vegetation
- high humidity
- dense vegetation
where are tropical forests found
5 degrees north and south of the equator
- Central and South America
- Central Africa
- South East Asia
- Northern Australia
- Tropical Islands such as Madagascar
tropical rainforest climate
- climate is the same all year round, no definite seasons
- It’s hot - temperature between 20-28 degrees C, because the sun is overhead the equator all year round
- rainfall is very high, around 2000m a year.
- usually rains everyday
tropical rainforest soil
- soil isn’t very fertile as heavy rain washes nutrients away
- there are nutrients at the surface because of decayed leaf fall, but this layer is very thin as decay is fast in the warm, moist conditions
tropical rainforest plants
- most trees are evergreen (they do not drop their leaves), to take advantage of the continual growing season
- many trees are really tall and the vegetation cover is dense -> very little light reaches the forest floor
- lots of epiphytes ( plants that grow on other living plants and take nutrients and moisture from the air, examples are orchids and ferns)
tropical rainforest animals
- believed to contain more animal species than any other ecosystem
- examples are gorillas, jaguars, anacondas, tree frogs, sloths etc.
- lots of different species of birds and insects
- many animals are brightly coloured and make a lot of noise
tropical rainforests, people
home to many people, who have adapted life there over generations. they make a living by hunting, fishing, gathering nuts and growing vegetables
what does it mean for rainforests to be interdependent ecosystems
all parts of the rainforest - climate, water, soil, plants, animals and people are dependent on one another. if any one of them changes, everything else is affected
examples of changes to the rainforest ecosystem
- if some animals ( such as those that allow new seedlings of fruit, vegetables etc to grow) become extinct, the number of plants the seedlings would have turned into would reduce, and all the animals feeding on that plant would starve. People who sell these plants would be affected and not make enough money.
affect of deforestation on the rainforest
- Trees intercept water and takes up a lot of it and release it back providing moisture for rainfall. Deforestation means climate may change, causing a higher risk of drought, affecting animals and plants
rainforest interdependence cycle
- warm wet climate supports growth of lush vegetation
- dense, lush vegetation provides food and shelter for many species
- insects and animals pollinate plants and spread seeds so plants can reproduce and grow elsewhere
- trees release moisture into the atmosphere, to help form clouds and rain, keeping the rainforest wet and reduces risk of drought
cycle restarts
describe how nutrients are cycled in a land based eco system
- when there is dead matter on the ground, it gets decomposed by decomposers and nutrients are put back into the soil.
- the nutrients now in the soil get taken up by producers in the soil.
- the consumers eat the producers and now the consumer has the nutrients
- when the consumer dies, they decompose and the nutrients are returned to the soil again
What happens when trees are removed in a TRF
- will reduce number of animals higher up the food chain
- Fewer trees mean fewer leaves and less leaf litter, so the soil will have fewer nutrients and become less useful
A pond has been dug out to make it wider and deeper, and as a result, the bottom detritus layer is removed. what are the possible impacts?
If you remove the detritus layer (decayed leaves), it means the food source for initial stages of the food web and chain are removed.
Primary consumers such as worms won’t be able to have food and eventually starve/die out. This will affect secondary consumers and tertiary consumers, since they have no food source.
The life in the pond would eventually die out
What are the possible impacts if chemicals such as fertilisers leak into the pond?
- an excessive volume of algae in the pond because of phosphates and nitrates, so number of other producers will decrease because the algae is taking in all the O2. This leads to a lower volume of detritus and there’ll be a knock on effect of producers and consumers dying out
- algae bloom can cause eutrophication resulting in the death of aquatic life
- chemicals can contaminate crops and kill consumers when they eat producers
Give some plant adaptations for rainforests
- buttress roots
- thin, smooth tree trunk
- climbing plants
- drip tips
- epiphytes
- large leaves
how are animals adapted to the rainforests
- strong limbs, so they can climb trees and leap from tree to tree, since they spend their lives high up in the canopy ( howler monkeys)
- flaps of skin enabling them to glide between trees ( flying squirrels)
- camouflage to hide from predators
- nocturnal: sleep at day, feed at night where it’s cooler, saving energy
- sharp sense of smell and hearing to detect predators without seeing them, since light levels are low on rainforest floor
what is biodiversity
the variety of organisms living in a particular area - both plants and animals
do rainforests have high biodiversity
yes - they contain 50% of the world’s plant, animal and insect species
deforestation and uncontrolled development of the rainforest is likely to lead to what
extinction of many species, since they lose their habitats and the loss of biodiversity
list the following layers a tropical rainforest is made up of
- rainforest floor ( ground level)
- shrub layer
- under canopy
- main canopy
- emergent
function of buttress roots
supports the tree trunk, as the tree grows up to a high level to reach sunlight
function of climbing plants such as lianas
By climbing up tall trees, lianas reach the canopy where sunlight is abundant, avoiding the competition for light on the forest floor. Lianas produce fruits, and can be consumed by animals and primates
function of drip tips and leaves having a thick, waxy layer
allows water to run off the leaf, to avoid the weight of the water damaging the leaf and to prevent any standing water on the leaf, which fungi and bacteria could grow in
function of think bark and it being smooth
- thin because the temperature is quite warm and not cold
- smooth to allow water run off
function of large leaves
light levels are low on the rainforest floor, so if the leaves are bigger, the plant has a higher chance of receiving sunlight, so they can use it for photosynthesis
function of epiphytes
- Epiphytes are plants that grow on other plants or surfaces for physical support but do not derive nutrients from their host.
- they help recycle nutrients by absorbing water and minerals from the air and debris, reducing competition with soil-based plants.
toucan adaptation
long, curved beaks to reach into tree holes and get unreachable food
bats adaptation ( nocturnal)
nocturnal - to avoid hot temperatures and lose energy when awake, and avoid competition for food
rainforest floor
- very dark
- steamy and humid because of heat moisture
- only 2% of light reaches here
- dead, decaying plant matter and rotting leaves
- thin layer of soil nutrients
- sparse vegetation due to the lack of sunlight
- home to decomposers and large animals such as jaguars
-layer of rotting leaves and dead animals called litter. This decomposes rapidly to form a thin humus, rich in nutrients.
shrub layer
low light levels
0-10m high
- dense vegetation: shrubs, small plants
- high humidity and dampness
- Habitat for Insects and Small Animals
- Slow Plant Growth: Limited light slows down the growth of many plants.
-densest plant growth. It contains shrubs and ferns and other plants needing less light. Saplings of emergents and canopy trees can also be found here.
under canopy
- 10-20m high
-Limited Sunlight: Receives around 5% of the sunlight, making it dim and shaded.
-Small Trees and Shrubs:
-Large Leaves: Plants often have large, broad leaves
-High Humidity
-Rich in Biodiversity: Provides a habitat for animals such as leopards, snakes, frogs, and insects
-Climbing Plants and Epiphytes: Many lianas (vines) and epiphytes are present, using larger trees for support to reach sunlight.
main canopy
20-30m high
acts as an umbrella for shading
Dense Layer of Trees: Composed of closely spaced, mature trees with interlocking crowns.
Blocks Sunlight: Absorbs around 70–90% of sunlight, creating a shaded environment below.
Height: Trees in the canopy are typically 25–45 meters tall.
High Biodiversity: Supports a wide range of species, including birds (e.g., toucans), monkeys, sloths, and insects.
Epiphytes and Lianas: Hosts many epiphytes (plants that grow on trees) and lianas (vines), which use the canopy for support and sunlight access.
-Protects the rainforest layers below by regulating temperature and humidity.
emergent layer
Emergents are the tallest trees and are usually over 50 metres tall
-Tallest Trees: Emergent trees reach heights of 40–60 meters, standing above the canopy.
Full Sunlight Exposure: These trees receive the most sunlight, facing intense heat and wind.
Adapted Leaves: Leaves are small and waxy to reduce water loss from wind and heat.
Thick Trunks: Trees have strong, thick trunks to support their height and withstand wind.
Home to Unique Wildlife: Provides habitats for birds like eagles and parrots, as well as bats, monkeys, and insects adapted to open spaces.
Sparse Distribution: Emergent trees are widely spaced and not densely packed.
what is the difference between a food chain and a food web
a food chain is a sequence that shows how energy and nutrients are passed through an ecosystem. A food web is a more complex sequence, showing how multiple food chains are connected within an ecosystem
how can rainforest vegetation support high animal populations
- provides a wide variety of food sources, such as fruits and nuts which animals can consume
- creates many diverse habitats and shelters for animals to live in
- high density of vegetation
explain how the climate affects the characteristics of the soil that form in tropical rainforests
- high rainfall can cause the rapid decomposition of plant material, releasing nutrients into the soil. But this can also cause leaching where nutrients are washed out of the soil
explain how human development of tropical rainforests may reduce biodiversity
Development may require deforestation. Deforestation causes habitats for animals to be destroyed, so there’s a loss of animal habitats and therefore plant and animal species, that may eventually go extinct. Decreasing biodiversity
where is Malaysia and what are the features of it
Malaysia is a country in South East Asia, It is made up of Peninsular Malaysia and East Malaysia that is part of the island Borneo
- natural vegetation in Malaysia is tropical rainforest
- 67% of Malaysia’s land is covered by rainforest
What is deforestation
The cutting down of trees, often on a very large scale. The land is used for other profit enter prises like cattle ranching, commercial farming etc.
main causes of deforestation in Malaysia
-logging
- road building
- energy development
- mineral extraction
- population pressure
- commercial farming
- subsistence farming
Causes of deforestation:
Logging
1980, Malaysia became world’s largest exporter of tropical wood, causing the total destruction of forest habitats
Selective logging was introduced, where only fully grown trees are cut down. trees that have important ecological value are left unharmed
Causes of deforestation:
Road building
- roads are constructed to provide access to mining areas, new settlements and energy projects
- logging requires road construction to bring in machinery and take away the timber.
example: Sarawak, east malaysia
Causes of deforestation:
Energy Development
The Bakun Dam:
- Is Asia’s highest dam (205m) outside China
-The dam supplies energy and electricity for industrialised peninsular Malaysia
-The Dam’s reservoir flooded over 700km squared of forests and farmland
-Several more dams are planned to boost Malaysia’s electricity supplies
Causes of deforestation:
Mineral extraction
- mining (mainly tin and smelting) is common in Peninsular Malaysia
- Rainforest has been cleared for mining and road construction
-Drilling for oil and gas has recently started on Borneo
Causes of deforestation:
Population Pressure
- In the past, poor urban people were encouraged by the government to move into the country side from the rapidly growing cities. This is called TRANSMIGRATION
- between 1956 and the 1980s, 15,000 hectares of rainforest was felled for the settlers. Many then set up plantations
Causes of deforestation: commercial farming
Malaysia is the world’s largest exporter of palm oil.
During the 1970s, large areas of land were converted into palm oil plantations
Plantation owners receive 10-year tax incentives, so increasing amounts of land have been converted into plantations
Causes of deforestation:
subsistence farming
-Tribal people living in the rainforest practise subsistence farming
Local communities would hunt and gather food from the forest and grow some crops in cleared pockets of forest. This type of farming is small scale and sustainable
- One method of clearing land is ‘slash and burn’. Involving the use of fire to clear the land. The burning creates valuable nutrients that help plants to grow, but these fires can grow out of control and destroy large areas of rainforest.
Impacts of deforestation in Malaysia
- soil erosion
- loss of biodiversity
- contribution to climate change
- economic development ( gains and losses)
Impacts of deforestation:
Soil erosion
Soil takes thousands of years to form, but it can be stripped away in a matter of hours.
Removal of soil by wind and rain is called soil erosion. deforestation means soil can easily become loose and erode away
Impacts of deforestation:
Loss of biodiversity
Biodiversity is a measure of the variety of plants and animals in a particular ecosystem.
Deforestation destroys the ecosystem and the many habitats that exist on the ground and in the trees, reducing biodiversity
Impacts of deforestation:
contribution to climate change
-Trees in rainforests absorb carbon dioxide and release oxygen.
Carbon dioxide is a greenhouse gas, that is partly responsible for global warming.
-Rainforests act as a carbon sink, so if they are removed, more carbon dioxide is in our atmosphere, causing global warming.
- trees give off moisture by the process of transpiration. deforestation reduces the moisture in the air resulting in a drier climate
Impacts of deforestation:
economic gains
- development of land for mining, farming and energy will increase the number of job opportunities
- companies will pay taxes to the government, which can be used to improve public services like education and water supply
- improved transport infrastructure, that can open up new areas for industrial development and tourism, generating more wealth
- palm oil and rubber provide raw materials for processing industries
- hydro-electric power will provide cheap and plentiful energy
- minerals such as gold are very valuable
Impacts of deforestation:
economic losses
- pollution of water sources and an increasingly dry climate may result in water shortages
- fires can cause harmful pollution, and can burn out of control, destroying areas of valuable forest
- rising temps could devastate some forms of farming like tea, fruit and flowers
- plants that could bring huge medical benefits and high profits may become extinct
- climate change could have economic costs as people would have to adapt to living in a warmer world
- number of tourists attracted rainforests could decrease
name the different fluvial processes
erosion: hydraulic action, abrasion, attrition, solution, vertical and lateral erosion
transportation: traction, saltation, suspension, solution
Deposition - why rivers deposit sediment
what is hydraulic action
The sheer force of the water erodes the stones, bed and banks of the river, since air is trapped inside cracks.
what is abrasion
when pebbles grind along the river bank and bed in a sand-papering effect, eroding the bed
what is attrition
when rocks that the river is carrying knock and smash against eachother, they break apart and become smaller and more rounded
what is solution ( erosion)
when the water contains weak acids that dissolve minerals in rocks or certain types of rocks such as limestone
what is traction
large, heavy rocks or pebbles are rolled along the river bed.
common near source of river as the load here is larger
what is saltation
when pebbles are bounced along the river bed, near the source
what is suspension
when lighter sediment is suspended/carried within the water, most commonly near the mouth of the river where there is a large river discharge
what is solution (transportation)
when dissolved chemicals are transported along the river. this varies dependeding on the presence of soluble rocks
what is deposition
when the river loses its energy, it drops any of the material it has been carrying
what causes deposition
- when volume of water/river discharge decreases
- at the end of the river - the mouth, where the river water meets the sea water / tide, and water velocity decreases
- when the velocity of the water decreases such as the inside of a bend/meander, estuaries
what is a drainage basin
the area of land around a river that is trained by the river and its tributaries
how does the shape of a river change as it flows downstream
In the upper course, the river is narrow with a shallow channel and V-shaped valleys and features like waterfalls.
In the middle course, the gradient becomes gentler the channel becomes wider and deeper, and lateral erosion leads to the formation of meanders.
In the lower course, the gradient is now flat and the river has a wide, deep channel. Deposition dominates, creating features like floodplains, levees, and oxbow lakes as the river loses energy.
upper course characteristics
V- shaped valley
steep gradient
water volume is low
low kinetic energy
friction is higher here (large rocks)
High GPE
middle course characteristics
Gradient/slope becomes gentler
The volume of the water increases.
Channel becomes wider and deeper
River starts to bend - meanders start to form
lower course characteristics
- smoother bed and bank
-gradient is flat/ land around is completely flat. - river discharge/volume of water is very high
- lateral erosion
- GPE is low
- friction is low
- channel is at its widest and deepest
- deposition
- oxbow lakes
- mouth meets sea, lots of deposition, estuaries form here, water velocity slows down
where do meanders occur
in the middle course of a river, as a result of erosion and deposition processes on a river
how are meanders formed
Water flows faster on the outside of the bend where the river channel is deeper and there is less friction. This causes lateral erosion through processes like hydraulic action and abrasion, which undercuts the bank and creates a river cliff. On the inside of the bend, the water flows more slowly because it is shallower, leading to more friction and less energy and less erosive power. This results in deposition of sediment, forming a slip-off slope. Over time, erosion and deposition cause the meander to grow, migrate, and change shape.
how are ox-bow lakes formed
-As the outer bend of a meander continues to be laterally eroded, through processes such as hydraulic action, the neck of the meander becomes narrower and narrower.
-As a result, the 2 outer bends eventually meet and the river cuts through the neck of the meander.
-The bend is eventually cut off, forming an ox bow lake. this is because the water takes the shortest route rather than flowing through the bend and bypasses the curve
-The ox bow lake has a crescent/horseshoe shape, since deposition seals off the old meander at the ends and isolates it
- Overtime, the lake may fill up with sediment and gradually dry up and be left as a meander scar
what is a flood plain
wide/flat area of land either side of a river, found in the middle/lower course. It is prone to flooding and becomes wider over time as the meander migrates due to lateral erosion
feature of erosion and deposition
how is a food plain formed?
-lateral erosion widens the valley and removes interlocking spurs
-when the river floods, sediment is deposited across the valley floor
-Over time, repeated flooding builds up layers of deposited sediment, forming a flat, fertile floodplain.
what is a levee
A levee is a natural embankment formed along the banks of a river.
occurs in the lower course of a river, where there is an increase in the volume of water flowing downstream and flooding occurs
how are levees formed
- When a river floods, transported sediment is deposited on the sides due to an increase in friction with the flood plain.
- as the velocity of the water decreases, its ability to transport material is rapidly reduced
- larger sediment is deposited first along the edge of the river channel, and finer sediment is deposited further away
- As the river repeatedly floods, the sediment builds up, increasing the height of the river banks.
what is an estuary
wide, sheltered body of water at a river’s mouths when it broadens into the sea
- as the river meets the sea at high tide, the flow of water slows down leading to deposition of sediment. mudflats can be seen at low tides.
what human and physical human factors affect the flood risk?
- Deforestation
- Relief of drainage basin
- precipitation
- agriculture
- rock type
- ice melt
- urbanisation
- drainage density
how does rock type affect flood risk?
Impermeable rocks (e.g., granite) do not allow water to infiltrate, leading to increased surface runoff and a higher flood risk ( since the water flows to the river, instead of being absorbed)
Permeable rocks (e.g., limestone) allow water to infiltrate, reducing surface runoff and lowering flood risk.
how does precipitation affect flood risk
Prolonged rainfall - if it rains for a long time, the land around a river can become saturated
(holds as much water as can be absorbed). If there is more rainfall it cannot be soaked up, so it runs along the surface - this is known as surface run-off
Heavy rainfall - if there is heavy rainfall there is less chance of it being soaked up by the soil so it runs off into the river. The faster the water reaches the river, the more likely it will flood.
how does ice melt affect flood risk
ice and snow are water stores, so if they melt, the water will go into the river and will increase the water level
how does drainage density affect flood risk
High drainage density (many rivers and streams in an area) means water reaches the main river quickly, increasing surface runoff and flood risk.
Low drainage density (fewer rivers and streams) slows down water movement, reducing flood risk.
how does deforestation affect flood risk
Deforestation increases flood risk because trees intercept rainfall and absorb water through their roots. Without trees, there is less interception and absorption, leading to increased surface runoff and higher river levels, which can cause flooding.
how does urbanisation increase flooding risk
Impermeable surfaces: Concrete, tarmac, and buildings prevent water infiltration, leading to increased surface runoff.
Drainage systems: Drains and sewers quickly transfer rainwater to rivers, increasing river levels rapidly.
This reduces the time for water to infiltrate, making flooding more likely during heavy rainfall.
how does relief affect flood risk
a steep valley is more likely to flood than a flatter valley because the rainfall will run off into the river more quickly.
how does vegetation affect flood risk
trees and plants absorb water, this is known as interception.
the more trees and plants there are, the more water is intercepted, reducing the amount of water that flows or ends up in the river that might cause a flood
how can river management affect flood risk
straightening a river channel and lining it with concrete increases the water flow and areas further downstream will be at a greater risk of flooding.
what is hard engineering
hard engineering involves using man-made structures to prevent or control natural processes from taking place
examples of hard engineering
- dams and reservoirs in the upper course
-channel straightening or channelisation - embankments
- flood relief channels
what is channel straightening or channelisation
when the river is straightened and made deeper so river water will flow away faster.
This removes meanders
advantages of channel straightening
water leaves the area more quickly, rather than building up, which reduces the flood risk.
disadvantages of channel straightening
-flooding may happen downstream instead since the water is flowing fast towards the lower course
- faster moving water may cause more erosion downstream
what are dams and reservoirs
Dams are barriers built across rivers usually in the upper course
Reservoirs are artificial lakes built behind the dam
They trap/store water
advantages of dams and reservoirs
Reservoirs store water (eg. after heavy rain) and can control the water flow and make it slower, preventing floods downstream
reservoirs can also be used for recreational purposes and to generate hydro electric power
disadvantages of dams and reservoirs
Dams and reservoirs are very expensive to build
Building a reservoir can flood existing settlements
Can lead to a loss of land and displace a lot of people ( they have to move house)
what are embankments ( flood management terms)
raised walls that are built along river banks to keep the water contained in the river
advantage of artificial embankments
the river can hold more water so floods are less frequent and there is a lower flood risk
disadvantages of artificial embankments
they are quite expensive and there’s a risk of severe flooding if the water rises above the embankment or if it breaks
what are flood relief channels
channels that are built around built up areas or built to divert excess water if the river level gets too high
advantages of flood relief channels
gates on the channels mean that the release of water can be controlled, reducing flood risk
disadvantages of flood relief
there will be an increased discharge where the relief re-joins the river or joins another river, which could cause flooding in that area
What is soft engineering
involves the use of the natural environment surrounding a river and using schemes that work with the river’s natural processes
examples of soft engineering
-flood plain zoning
- river restoration
-planting trees
- flood warnings and preparation
general benefits of hard engineering
financial savings are made by preventing flooding which will prevent damage to buildings and the environment.
general disadvantage/cost of hard engineering
the financial cost of the scheme can be very very expensive.
there can be negative impacts on the environment and on people’s lives
general benefits of soft engineering
-sustainable
-cost-effective
-works with natural processes to reduce flood risks, minimizing environmental damage.
general disadvantages of soft engineering
-less effective in severe floods
-take longer to show results
-may require ongoing maintenance and land use changes.
what is flood plain zoning
- creating restrictions of land use on certain parts of the flood plain
- High-risk areas near rivers are kept for activities like farming or parks, while buildings and infrastructure are placed in lower-risk zones.
advantages of flood plain zoning
-Reduces flood risk by keeping high-risk areas clear of buildings.
-Minimizes damage to property and infrastructure.
-Maintains natural floodplains, supporting wildlife and ecosystems.
-Low-cost and sustainable long-term solution.
disadvantages of flood plain zoning
-Expansion of an urban area is limited if there are no other building sites
-can’t help in areas with existing buildings
-Can cause disputes over land use and economic impacts.
what is river restoration
making the river more natural, by removing man made levees so the flood plain can flood naturally
advantages of river restoration
-Discharge is reduced, so there’s less risk of flooding downstream
-little maintenance is needed
-better habitats for wildlife
disadvantages of river restoration
- local flood risk can increase, especially if nothing is done to prevent major flooding
- Natural processes might take time to establish, delaying benefits.
- Potential loss of agricultural or developed land.
- Risk of unintended environmental consequences, like erosion.
what would planting trees in a river valley do
increase interception of rainwater and lag time
advantages of tree planting (flood management)
-river discharge and flood risk decrease
- vegetation reduces soil erosion in the valley and provides habitats for wildlife
disadvantages of tree planting (river management)
Less land is available for farming
examples of flood warnings and preparation
- The environment agency issuing flood warnings through various media types, such as TV, the radio and internet
- Buildings are modified to prevent flood damage
- Residents can prepare sandbags and flood boards prior to floods
advantages of warnings and prep
warnings give people time to move possessions upstairs, put sandbags in place or evacuate
reduces impact of flooding
disadvantages of warnings and prep
- warnings don’t physically prevent floods
- people may not have access to warnings
- modifying buildings is expensive
- preparation doesn’t guarantee safety from a flood and could give a false sense of security
