LIVING WORLD Flashcards
What is a producer?
Organism that uses sunlight energy to produce food
What is a consumer?
An organism that gets its energy by eating other organisms
What is a decomposer?
An organism that gets its energy by breaking down dead material (e.g. bacteria and fungi)
What is the nutrient cycle?
Dead material decomposers and releases nutrients into soil
Plants take up these nutrients
Plants are eaten by consumer
Plant/consumer dies so nutrients returned to soil
What does a food chain show?
What eats what in an ecosystem
What does a food web show?
Lots of food chains and how they overlap
What determines what ecosystem forms?
The climate in an area
What are the seven major types of ecosystems?
Tundra
Grassland
Boreal forest
Tropical rainforest
Hot desert
Polar
Temperate deciduous forest
What are the characteristics of a Tundra ecosystem?
Found at high latitudes
Winters are very cold
Summer is brief
Little rainfall
Hardly any trees
Layer of permanently frozen ground
What are the characteristics of a Boreal forest ecosystem?
Winters are cold and dry
Summers are mild and moist
Trees are evergreen and have needles
What are the characteristics of a Tropical rainforest ecosystem?
Found around the equator
Hot and wet all year round
Lush forest and dense canopies
What are the characteristics of a Hot desert ecosystem?
Little rainfall
Very hot in day
Very cold in night
What are the characteristics of a Polar ecosystem?
Found around the north and south poles
Not much grows at all
They remain dark for several months each year
What are the characteristics of a Temperate deciduous forest ecosystem?
Four distinct seasons
Summers are warm
Winters are mild
Rainfall all year round
Trees lose their leaves in winter to cope with colder weather
What are the characteristics of a Savannah grassland ecosystem?
Found between the tropics
Distinct dry and wet seasons
Rainfall is low
Most vegetation is grass with a few scattered trees
What are the characteristics of a Temperate grassland ecosystem?
Higher latitudes
Variation in temperature
No trees just grasses
What is the climate of tropical rainforests?
Same all year round
Hot between 20-28 degrees
Rainfall is very high at around 2000mm per year
What are the plants like in tropical rainforests?
Most trees are evergreen
Many trees are really tall and vegetation cover is dense
Lots of epiphytes
What is the soil like in tropical rainforests?
Isn’t very fertile as heavy rain washes nutrients away
What is biodiversity?
The variety of organisms living in a particular area
Why do tropical rainforests have a high biodiversity?
Stable and productive environments because they’re climate stays the same so organisms don’t have to adapt to changing conditions
What can lead to loss of biodiversity in tropical rainforests?
Deforestation
How do the warm and wet conditions in tropical rainforests help the soil?
Helps fungi and bacteria to decompose dead material rapidly which makes the surface soil high in nutrients so plants can grow easily
Why is the animal population very high in tropical rainforests?
Because there is lots of dense vegetation which provides food for animals
When animals die their nutrients are passed back to the soil which makes it richer and encourages more vegetation to grow
What are symbiotic relationships?
When plant and animal species depend on each other for survival
What are the effects of deforestation?
Climate change
Increase drought due to less trees intercepting water and releasing it back into the atmosphere
Soil has less protection due to less roots so more nutrients can be washed away
How have trees adapted in tropical rainforests?
Grown taller to compete for sunlight
How have plants adapted in tropical rainforests?
Thick waxy leaves with drip-tips
Encourages run off so weight of the water doesn’t damage plant
No water for bacteria and fungi to grow in
How have climbing plants adapted in tropical rainforests?
Use tree trunks to reach sunlight
How have trees bark adapted in tropical rainforests?
Smooth thin bark because no cold temperatures
Helps water to run off easily
How have trees roots adapted in tropical rainforests?
Large stable buttress roots support tall trees trunks
How can animals adapt to finding food and escaping predators?
Camouflage to hide from predators
Adapt to low light levels
Nocturnal (colder)
Swim to cross river channels
Short pointed wings manoeuvre between trees
Suction cups help animals climb
Strong limbs so can move around quickly
What are the reasons for deforestation in the Amazon rainforest?
Commercial farming
Mineral extraction
Energy development
Road building
Subsistence farming
Commercial logging
What is commercial farming?
Forest is cleared to make space for cattle grazing or for huge plantations e.g. soy
What is subsistence farming?
Forest is cleared by small-scale farmers who need land to grow food for themselves and families
What is commercial logging?
Valuable hardwood can be cut down hear for materials
How does deforestation cause climate change?
Trees remove co2 from the atmosphere and this is released whe deforestation occurs
How does deforestation cause soil erosion?
Less tree canopy to intercept rainfall and fewer tree roots to absorb it so more water reaches the soil which washes away the nutrients
How does deforestation impact the economy?
Mining industry creates many jobs
Logging contributes a huge amount to Brazil’s economy however destroys its resources
Farming has brought lots of wealth
How can deforestation be reduced?
International agreements
Increased global awareness
How are rainforests very valuable to people?
Contain many products
Economic benefits (ecotourism)
Reduce greenhouse effect
Help regulate climate change and water cycle
What are ways tropical rainforests can be sustainably managed?
Replanting
Selective logging
Ecotourism
What is replanting?
When new trees are planted to replace the ones that are cut down
What is selective logging?
Only some trees are felled down so less damaging to forest than clearing a whole area as it keeps the overall forest structure (canopy remains)
What is ecotourism?
Minimises damage to the environment and benefits local people
What are social ways to sustainably manage tropical rainforests?
Education
Conservation
Reducing debt
International hardwood agreements
How does reducing debt sustainably manage rainforests?
Reducing debt means LICs don’t have to log, farm or mine rainforests in order to make money and pay off their debts
How does conservation sustainably manage rainforests?
National parks and nature reserves where damaging activities are limited
What are international hardwood agreements?
Agreements in place to try to prevent illegal logging and to promote the use of hardwood from sustainably managed forests
What is the climate of hot deserts?
Very little rainfall less than 250 mm per year
Temperatures are extreme because of lack of cloud cover
Can reach 45 degrees in day then 0 degrees at night
What is the soil like in hot deserts?
Lack of leaf fall which limits soil fertility
Little rainfall means soil is dried out
Soil is often shallow and gravelly
What are animals like in hot deserts?
Tend to be small and nocturnal adapted to harsh environment
Some birds leave during the harshest conditions
What are plants like in hot deserts?
Plant growth is sparse though plants that do grow need little water
Usually short
How do plants and animals co-depend on each other in hot deserts?
Plants take up nutrients from soil and provides nutrients and water to the animals that eat them
Animals then spread seeds through their dung helping plants reproduce
How does the climate in hot deserts affect plants?
Soils are salty due to high evaporation rates and low in nutrients because there is little decomposition of dead material by decomposers
So plants struggle to grow
How have plant roots adapted to hot deserts?
Long roots to reach deep water supplies
Roots spread out wide near the surface to absorb as much water as possible when it rains
How have succulents adapted to hot deserts?
Large fleshy stems for storing water
Thick waxy skin to reduce transpiration
How have plant leaves adapted to hot deserts?
Small leaves or spines to lower their surface area to reduce transpiration
Spines contain toxins to protect from predators
How have plants germination patterns adapted to hot deserts?
Some plants only germinate after it rains and if it is too dry the seeds stay dormant (grow quickly to make most of wet condtions)
How have nocturnal animals adapted to hot deserts?
Become nocturnal to stay cool by sleeping when temps are the hottest
How have animals adapted their bodies to hot deserts?
Long limbs or ears to give them a larger surface area to lose heat from
How have animals adapted their living habits to hot deserts?
Some live in underground burrows where temps are less extreme
How have animals adapted their bodily processes to hot deserts?
Some bigger animals store fat that they break down into water when needed
How have animals adapted their water loss to hot deserts?
Some minimise water loss through sweat and urine
How have animals adapted to cope with the sand in hot deserts?
Camels - triple eyelids, long eyelashes, can close nostrils and have large flat feet so they don’t sink into the sand
Where in deserts is there the highest biodiversity?
Small areas around ponds/rivers/desert margins
How can biodiversity be threatened in hot deserts?
Desertification
Over-using/contaminating water supplies
Development around desert margin
Global warming
How is global warming threatening biodiversity in hot deserts?
Deserts are becoming hotter and drier
Forces species to move to colder areas
However some cannot so become extinct
How is development around desert margins threaten biodiversity in hot deserts?
Habitats are being divided by roads
Threatens animals that migrate over large distances
What is desertification?
The degradation of land making it drier and less productive
How does desertification occur?
When vegetation dies and is removed
Exposed soil can easily be removed by wind/water as there are no roots holding it together causing nutrients to be lost
How does climate change cause desertification?
Less rainfall in areas that are already dry means less water available to plant growth so more plants die
Increasing temps means more water evaporating so drier soils so plants struggle to grow
How do human activities cause desertification?
Removal of fuel wood (leaves soil exposes)
Overgrazing (plants are eaten faster than they regrow)
Over-cultivation (nutrients in soil are used up)
Population growth (more people putting pressure on land)
How can water management reduce desertification?
Growing crops that need little water so water use is reduced
Drip irrigation systems on crops means that soil isn’t eroded by lots of water
How can tree planting reduce desertification?
Trees act as windbreaks which reduced wind erosion
They stabilise sand
Protect crops and soil by providing shade/reducing temps
How can soil management reduce desertification?
Leaving areas of land to rest between grazing/planting so they can recover their nutrients e.g. rotating crops
Compost can add nutrients
How can the appropriate technology reduce desertification?
Cheap sustainable and easily available materials to build things that are easy for local people to maintain
