Paper 3: People And The Biosphere Flashcards
Ecosystem
Grouping of plants and animals that interact with each other and their local environment
Biome
Large ecosystem; grouping plants and animals over a large area of the earth
Taiga (boreal)
Only at high latitudes, where sun rays are weak.
Trees are adapted with needle like leaves
Temperate forests
High rainfall and seasonal variation in sun rays. Trees loss their leaves in cool winters.
Tundra biome
Within the Arctic circle. Very weak sun and low rainfall.
Only tough short grasses survive.
Tropical rainforests
Either side of the equator. Very hot and very high rainfall.
Desert biome
Close to the tropics (cancer and Capricorn). Where are sinks with high pressure due to circulation cells making it very hot in the day.
Biotic
Living component of an ecosystem : plants and animals
Abiotic
Non-living components of an ecosystem. Eg. Soil, rock, water and the atmosphere
Example of how an abiotic and biotic ecosystems interact
Taiga biome has low biodiversity ->
Abiotic: long cold winters, low precipitation, frozen soil. ->
Biotic: Only specialist plants can tolerate the conditions meaning a lower population.
Nutrient cycle
Shows how biotic and abiotic components interact.
Litter store, Biomass store, Soil store.
Size of arrows: size of nutrient transfer between each store.
Biosphere providing resources for people (including indigenous)
Food, Medicine, fuel, building materials.
Food from the biosphere
Fishing and meat from farming
Natural vegetation like wheat and rice
Sustainable harvesting of fruits, berries and nuts
Fuel from the biosphere
Animal dung can be dried and burnt as fuel.
Wood from trees can be combusted.
Biofuels: converting plant to fuels: eg.bioethanol from fermenting sugarcane.
Biosphere
The collection of the worlds ecosystems
Biosphere and demand
Becoming increasingly exploited
Eg. Overfishing causing decline in fish numbers
Biosphere and a life support system
It regulates gases in the atmosphere (carbon sink) absorbs CO2 and replaces with O2.
Regulates water cycle - plants slow the flow of water into rivers to make it clean.
Keeps soil healthy and fertile by rotting plant material
World population growth
Exponential growth demands food, energy and water.
Urbanisation and world population
2018 - 54% urban
2050 - 66% urban
Food Production
Must double by 2050 to feed the worlds population.
Water shortages
Demand for water will rise by 55% by 2050
Affluence
The middle class will grow fro, 1.8 billion to 4.9 billion by 2030
Thomas Malthus
It is impossible to create enough food as rapidly as population growth so if it grows too much there will be famine reducing the population acting as a control.
Ester Boserup
Human innovation will be sparked on the demands for resources. So if there is a high demand, new techniques will be invented to maintain the supply.
Adaptations to the canopy blocking out light.
Emergents grow 40m high.
10m above the canopy.