7 - people and the biosphere Flashcards
biome
a large scale ecosystem eg tropical rainforest
ecosystem
a community of plants and animals interacting with the non-living environment
biosphere
the living layer of Earth between the lithosphere and atmosphere
tundra
- close to poles 60 N - not in southern hemisphere
- limited growth due to low temp
- little precipitation due to sinking air
- mosses, tough leaves, close to ground
boreal/taiga forest
- 50-70N - northern hemisphere
- colder + little precipitation (air sinks)
- conifer trees with waxy needles and a small surface area to protect from cold
temperate forest
-40 - 55N
- rainfall year round (rising air)
- 4 seasons so animals hibernate in winter
- fewer sunshine hours slowing photosynthesis so drop leaves
temperate grasslands
- similar to temperate forest but inland
- seasons noticeable as away from moist ocean
- grasses thrive in summer and reduce growth in winter
deserts
- 25-35 N/S
-little rainfall (high pressure) - hot all year >30
- plants have water storing feature eg spines/roots
tropical grasslands (savannah)
- high seasonal rainfall but has a dry season
- hot all year
- tall grasses with drought adapted shrubs
tropical rainforest
- between tropics
- hot all year
- rain all year
- dense forests with several layers of trees and other plants competing for light
what affects distribution of biomes
- temperature
- precipitation
- sunshine hours
(all affected by latirude)
how does latitude affect temp/ precipitation
- sun intensity higher on equator as its less diluted and less solar radiation lost due to shorter distance
- direct sunlight on equator so air heats and rises bringing with it moisture, cools/condenses, falls as rain
local factors that affect biome distribution
- altitude
- rock / soil type
- drainage
how altitude affects biome distribution
temperatures fall at a rate of 1 degree per 100m
wind exposure increases higher up
how rock type affects biome distribution
diff types of soil = diff plants
- sandy soil - lots of air gaps - water drains and so it is dry
humus - is formed by decayed organic matter
- humus rich soils have high biodiversity
how drainage affects biome distribution
- impermeable rocks = waterlogged - prevents growth - marshes form
biotic vs abiotic
living vs non-living
biodiversity
variety of biotic components in an ecosystem
processes in ecosystems
photosynthesis
food webs
nutrient cycling
gas exchange
how abiotic and biotic interact
- plants take in CO2 and release O2 - animals do opposite
- energy flow along food webs through animals
- water moves through soil - then back to atmosphere via respiration/evaporation
- when plants die their nutrients return to soil
how local people use resources from biomes
- food - eat animals an natural vegetation
- medicine - use natural plants to make medicine
- building - dung and straw mixed with clay to build + wood / leaves
- fuel - wood / biofuels
exploitation of rainforest
- slash/ burn - natural vegetation cleared to cultivate land - regrows over time
- mining for ores - creates scars pollutes rivers
- commercial farming
- commercial crops
- logging
- dam building for HEP
carbon sequestration
locks carbon in biotic material - carbon sink
litter
dead leaves on ground - decompose to produce humus (by bacteria)
