Living World - Rainforests

Question 1

what is nutrient cycling

Answer 1

important minerals that plants need to grow and survive are cycled around an ecosystem to keep it balanced

Question 2

what are the stores in nutrient cycling

Answer 2

nutrients in leaves (humus) , trees (biomass) and soil

Question 3

what are the inputs in nutrient cycling

Answer 3

tree roots taking nutrients from soil
rain washing nutrients from humus to soil
sun and train helping trees produce nutrients

Question 4

what are the outputs in nutrient cycling

Answer 4

rocks breaking down to soil (weathering)
leaves decaying into humus
rain washing nutrients out of soil (leaching)

Question 5

what is an ecosystem

Answer 5

a natural system made up of living (biotic) and non living (abiotic) components

Question 6

what is a food chain

Answer 6

a line of links between different trophic levels that shows how energy passes from organism to organism, relying on a producer which creates its own energy

Question 7

what is a biome

Answer 7

a large scale ecosystem defined by abiotic factors such as climate, temperature and soil as well as biotic factors such as vegetation

Question 8

why do biomes form ‘belts’ across the world

Answer 8

because the climate and ecosystem characteristics are controlled by the latitude of ecosystems and the altitude can cause variations as well as ocean currents

Question 9

where are tropical rainforests found

Answer 9

Brazil, Southern Asia, Africa and upper regions of South America

Question 10

why are tropical rainforests hot

Answer 10

the sun’s rays travel through less atmosphere to rainforests so it’s less concentrated and looses less heat

Question 11

why are tropical rainforests wet

Answer 11

the sun’s energy heats up the soil and the moisture in it evaporates and condenses then it repeats

Question 12

describe the top layer of soil

Answer 12

nutrient rich as the warm, moist soil speeds up decomposition but its thin so gets washed away easily

Question 13

describe lower levels of soil

Answer 13

most lower levels are called latosol and is infertile

Question 14

what is biodiversity

Answer 14

the variety of organisms living in a particular area - plants and animals

Question 15

describe the biodiversity in TRFs

Answer 15

the most biodiverse ecosystem as they contain 50% of the world’s animal species
higher latitude so are more adaptable and stable
perfect growing conditions
lots of niches
always hot and wet

Question 16

what is deforestation

Answer 16

the act of chopping down and removing trees to clear an area of forest

Question 17

why does deforestation matter

Answer 17

trees absorb CO₂ and give out oxygen
they reduce flood risk as they take up water and reduce speed of flow
climate regulators as they reflect some of the sun’s heat
protect biodiversity as 80% of species live in TRFs
great medicine sources as lots of ingredients are extracted from them

Question 18

what are 4 causes of deforestation

Answer 18

logging
mineral extraction
energy development
illegal trade in wildlife
commercial cattle farming
commercial crop farming
road building
settlement and population growth

Question 19

explain logging

Answer 19

one of the main causes and first step in conversion of forest land
most timber companies use mahogany and teak for furniture and smaller trees are used for fuel or pulps
vast areas of forests are cleared in one go

Question 20

explain mineral extraction

Answer 20

in places like the Amazon, mining is mainly about gold
in 1999, there were 10,000 hectares of land used
nowadays, there are over 50,000 hectares of land used

Question 21

explain energy development

Answer 21

an unlimited amount of water has made people build dams for hydroelectric power
this involved flooding areas of forest
this causes the rainforest to slowly rot - making the soil acidic
the dams also become blocked with soil washed from deforested areas

Question 22

explain illegal trade in wildlife

Answer 22

hunting, poaching and trafficking are still big businesses in Brazil
this isn’t a direct cause but is endangering species that live in rainforests such as jaguars
this is upsetting the natural balance and therefore degrading it

Question 23

explain commercial cattle farming

Answer 23

large areas of land have been cleared for livestock rearing
this is believed to account for 80% of rainforest destruction
the pasture quality quickly declines this means that the farmers have to move on and destroy more land

Question 24

explain commercial crop farming

Answer 24

forest has to be cleared for large plantations of things such as bananas, pineapple, sugar cane and coffee
the amount of rainforest cleared between 1990 and 2010
soil won’t sustain crops for long so the farmers have to cut down more trees for more land

Question 25

explain road building

Answer 25

roads are needed for transporting materials
this means clearing large areas of land for them to be built
this also makes the rainforest easily accessible for others exploiters
the trans-amazonian highway is 4000km long and has made the rainforest easily accessible to remote areas

Question 26

explain settlement and population growth

Answer 26

all the causes of deforestation have a knock-on effect
they need workers and the workers need somewhere to live so settlements are built
challenges with these are their scale, speed and wasteful use of the land and resources

Question 27

what are the impacts of deforestation

Answer 27

loss of biodiversity as habitats are cut down

soil erosion as it leaves the soil exposed to wind and rain so it is washed away and removed

climate change as trees take up carbon dioxide and burning trees causes an increased concentration of carbon dioxide

economic development as Brazil financially benefits from the profits of ore and timber as well as rubber and palm oil

Question 28

environmental TRF values

Answer 28

they absorb and store about 20% of man made carbon dioxide emissions

they contain 50% of all known plant and animal species

they prevent the climate from becoming too hot and dry

they are valuable as they are the only known ones in the universe

Question 29

social / economic TRF values

Answer 29

important source of clean water

estimated 80% of world’s diet originated from TRF plants

25% of medicine comes from TRFs

the trees provide wood, nuts, fruit and rubber

they provide employment opportunities

reduce flooding and soil erosion by rainfall

attracts tourism which provides jobs for people and income for the country

home to many indigenous tribes

Question 30

how are TRFs managed

Answer 30

selective logging and replanting - doesn’t destroy mass areas of land and still has financial benefit and picks certain trees as well as trees being planted

conservation and education - educates people of all ages on TRFs and their importance and it allows people to come ans study the area

international agreements - limits how much logging can occur and still has financial benefit

ecotourism - provides income so benefits the government as well as educating tourists on TRFs

Question 31

starting at the top, what are the layers in a TRF

Answer 31

emergent
canopy
under canopy
shrub layer

Question 32

what are the features of the emergent layer

Answer 32

trees are straight and branchless, energy goes into being taller
emergent leaves are big to catch sunlight
slim, flexible trunks with wide, triangular bases and buttress roots

Question 33

what are the features of the canopy layer

Answer 33

trees grow in gaps
maximises absorption of sunlight
lianas use trees to reach canopy as there’s more sun

Question 34

what are the features of the under canopy / shrub layer

Answer 34

dead trees rot quickly
little undergrowth
dense undergrowth on river banks
quick decomposition due to heat and water
leaves have drip tips to get rid of excess water
less than 5% of sun reaches shrub layer
thick, waxy leaves to help with strong sun and prevent water loss