pa3 Flashcards
what is a biome
a biome is a large scale ecosystem
what is an ecosystem
An ecosystem is a localised biome made of abiotic and biotic environment?
what 3 factors of how CLIMATE determines the locations and characteristics of biomes
the locations and characteristics of biomes due to temperature are defined by temperature, precipitation and sunshine
how is temperature a factor of climate that defines the location and characteristics of a biome
Plants needa temperature of over 5 degrees celcius to grow so the length of growing season varies in places. Latitude influences biomes due to the temperature and sinshine being controled by latitude. The nearer the equator, the warmer temperature.
how does precipitation as a factor of climate aid the location and characteristics of biomes
plants need water spread across all seasons so they will not grow if there is a dry season or frozen water during winter. Precipitation - similarly to sunshine- is also influenced by latitude (pressure precipitation zones?)
how - due to climate- ‘sunshine (hours) effect ‘the location and characteristics of. biomes
Effects of photosynthesis so affects plant. growth
How altitude (height) effects ecosystems
Temperature drops by 6.5 degrees celsius for every 1000m increase in height
Rainfall increases with height
At high altitudes, there are below freezing conditions so limited plant growth
How rock and soil types effect biomes
When rocks undergo chemical weathering they release nutrients and chemicals into the soil…the soil can be neutral, acid or alkaline depending on the rock type. The acidity/alkalinity of the soil influences plants that will grow there.
how water availability and drainage (sinking into soil/removal of excess water from the ground surface or rootzone) affect ecosystems
How wet the soil is depends on
- the amount of precipitation
- the amount of evaporation (influences by temperature)
- how permeable the soil is; sandy soils are dry and clay soils are wet
Some plants grow with their roots waterlogged in soil or boggy areas whereas others prefer dry soils
Goods vs services
Goods are physical materials we get, services are functions we get
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provisioning (supplying) services (goods) - products obtained from the ecosystem -locally important as local people depend on these stuff for building and making furniture…examples of what goods/services ecosystems provide
- Foods - nuts, berries, fish, crops
- Fuelwood
- Timber for buildings
- Chemical materials
Supporting services examples - aka. these keep healthy. ecosystems so it can provide others services
examples of these services
Nutrient cycle
photosynthesis and food webs
soil formation
Regulating services - these keep plannet healthy
examples ecosystems provide
Storing carbon , emitting oxygen to keep oxygen in balance
Purifying water, regulating the flow of water in the hydrological cycle
Cultural services - these are benefits people get from visiting or living in a healthy ecosystem
examples
Recreation and tourism
Education and science
Happiness
how some indigenous people directly depend on ecosystems?
- small circular houses from wood and leaves
- wood for cooking fires
- hunt monkeys and antelope for bushmeat and fish from rivers
- will gather wild nuts, mushrooms, berries from ofrest
- use plants and wild honey to make traditional medicine
how ecosystem services are exploited
Farmers clear small areas of forest by cutting and burning
ash from burning adds nutrients to the soil
land is farmed for 5-6 years but after the soil and becomes infertile and farmer moves to a new area
aka slash and burn farming
Destroying ecosystem services?
Most exploitation is like slash and burning and is NOT temporary
large areas of biomes are cleared for: Commercial crops like palm oil, cocoa beans or cereal
timber, used to make paper, furniture or construction wood
mining metal ores eg copper and iron
commercial farming, particularly for beef cattle
why/how humans depend on biomes
- for keeping the atmosphere in balance by regulating co2 LEVELS
- Healthy soils needed in which to grow food crops
- Healthy hydrological cycle and ecosystems provide us with all these kep services
Healthy air? From biomes as they are a carbon sink (carbon sink is natural store for carbon containing chemical compounds like CO2)
Store CO2 by removing it from the atmosphere and locking it up in biotic material; this is called CARBON SEQUESTRATION and the process making this work is photosynthesis
6CO2 + 6H2O ——-> C6H12O6 +6O2
Biomes store carbon as biomass (leaves, branches, trunks, roots and animal tissue)
> when plants and animals die, the dead biomass goes to soil . making the soil also an important carbon sink!:)
How are we destroying biomes
Via deforestation (so biomes can absorb less) biomass eg trees are burned, soil destroyed, releasing their stored carbon(C02 in atmosphere = global warming)
How is soil health mainaied
by the nutrient cycle, a cycle which keeps both plants and soil healthy
Even though soil health is maintained via the nutrient cycle, the nutrient cycle can be easily disrupted, putting soils at risk
Removing biomass eg logging timber takes away a large nutrient store
heavy rain and surface runoff can wash away litter
deforested areas are at risk from soil erosion, removing another store
biomes are important in the hydrological cycle
In turn, the hydrological cycle provides humans with clean, reliable water supply, destroying a forest biome’
this can have big impacts on the water cycle…how?
Well, with no trees, interception is reduced so rain directly hits the soil causing erosion
Without trees there is less infiltration of water in soil so important groundwater supplies are lower
surface runoff increases which in turn increases soil erosion and means water gets into river channels faster
Flooding increases and river water is made dirty by all the soil washed into the river
with no forest, soil dries out quickly so overall evaporation is reduced which means less clouds, less rain and drier climate.
Demands for natural resources is rising and humans use of natural resources has implications for the biosphere….explain
Biomes can be directly destroyed to create land for farming, housing, factories
Obtaining timber, fish, or hunted animals from biomes can degrade them by removing kep species
Humans use of natural resources can pollute the wider environment which damages biomes eg burning fossil fuels, polluting the atmosphere and dumping waste in rievers, poluting water
Pressure on natural resources has grown since 1975….explain
Larger populations means more of a demand
Increasing average wealth means that people use more energy resources
Most population lives in towns and cities - sprawled (meaning urban sprawl, also called sprawl or suburban sprawl, the rapid expansion of the geographic extent of cities and towns, often characterized by low-density residential housing, single-use zoning, and increased reliance on the private automobile for transportation.)
Over biomes and increased demand for water and food
Talk about industrialisation
Many countries have been through industrialisation since the 1970s, less in countryside, more in cities working in factories and offices - this means a dramatic rise in construction and resource consumption
In developing regions, the combined impact of population growth , industrialisation, urbanisation and rising wealth has led to a dramatic increase in demand for resources
eg Asia growth
Dramatic population rise and an average people are richer so more energy resources than before
As people get richer their diets change - they eat more but also eat more meat, fat and dairy products
Challenge for the 21st century is whether Earth can provide enough resources for more people and for increasing wealthy people too
malthusians/neo-malthusians view
pessimistic
population will eventually grow so large that Earth will run out of food, water, energy and other resources, leading to a crisis
Population would increase geometrically (1, 2, 4, 8, 16etc) by doubling each time. but food would only increase arithmetically (1, 2, 3, 4, 5 etc). In this way, population would outstrip food leading to :
Population versus resource crisis
To solve, population would have to fall by
-Positive checks - war , starvation and famine would reduce the population
-Preventative checls - people marrying later, having fewer kids
The balance between people and resources would hence be restored
Boserupians view
As population grows, humans will invent new technologies to allow more food to be grown and resources to be supplies
As population increases, innovative poeple invent new ways of producing new food eg
- farming machinary
- fertilisers
- genetically modified (GM) crops and irrigation
What is irrigation
The artificial method of watering the plants for assisting in their growth is called irrigation. Main sources of irrigation are wells, tube-wells, ponds, lakes, rivers.
