Living World - Rainforests Flashcards
what is nutrient cycling
important minerals that plants need to grow and survive are cycled around an ecosystem to keep it balanced
what are the stores in nutrient cycling
nutrients in leaves (humus) , trees (biomass) and soil
what are the inputs in nutrient cycling
tree roots taking nutrients from soil
rain washing nutrients from humus to soil
sun and train helping trees produce nutrients
what are the outputs in nutrient cycling
rocks breaking down to soil (weathering)
leaves decaying into humus
rain washing nutrients out of soil (leaching)
what is an ecosystem
a natural system made up of living (biotic) and non living (abiotic) components
what is a food chain
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
what is a biome
a large scale ecosystem defined by abiotic factors such as climate, temperature and soil as well as biotic factors such as vegetation
why do biomes form ‘belts’ across the world
because the climate and ecosystem characteristics are controlled by the latitude of ecosystems and the altitude can cause variations as well as ocean currents
where are tropical rainforests found
Brazil, Southern Asia, Africa and upper regions of South America
why are tropical rainforests hot
the sun’s rays travel through less atmosphere to rainforests so it’s less concentrated and looses less heat
why are tropical rainforests wet
the sun’s energy heats up the soil and the moisture in it evaporates and condenses then it repeats
describe the top layer of soil
nutrient rich as the warm, moist soil speeds up decomposition but its thin so gets washed away easily
describe lower levels of soil
most lower levels are called latosol and is infertile
what is biodiversity
the variety of organisms living in a particular area - plants and animals
describe the biodiversity in TRFs
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
what is deforestation
the act of chopping down and removing trees to clear an area of forest
why does deforestation matter
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
what are 4 causes of deforestation
logging
mineral extraction
energy development
illegal trade in wildlife
commercial cattle farming
commercial crop farming
road building
settlement and population growth
explain logging
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
explain mineral extraction
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
explain energy development
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
explain illegal trade in wildlife
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
explain commercial cattle farming
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
explain commercial crop farming
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
explain road building
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
explain settlement and population growth
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
what are the impacts of deforestation
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
environmental TRF values
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
social / economic TRF values
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
how are TRFs managed
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
starting at the top, what are the layers in a TRF
emergent
canopy
under canopy
shrub layer
what are the features of the emergent layer
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
what are the features of the canopy layer
trees grow in gaps
maximises absorption of sunlight
lianas use trees to reach canopy as there’s more sun
what are the features of the under canopy / shrub layer
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
