CH7 - Climate And Terrestrial Biodiversity Flashcards
Weather
Short term properties of the troposphere at a given place and time
Climate
Average long term weather of an area
Most important factors in climate
Temperature & precipitation
Five main factors influencing climate (temperature + precipitation)
1) uneven heating of the Earth’s surface (heated at the equator, cooled at the poles)
2) seasonal changes (Earth’s axis is tilted —> opposite seasons in the N and S hemispheres)
3) Coriolis effect (rotation of the Earth) —> deflection of winds to the right in N hemisphere and to the left in S hemisphere
4) long-term variations in the amount of solar energy hitting Earth (due to orbital changes)
5) properties of air & water (evaporation of heated water —> low pressure systems on Earth’s surface)
Greenhouse effect
- trapping of heat in the troposphere
- greenhouse gases allow light, infrared radiation, and some UV radiation from the sun to pass through the troposphere —> Earth’s surface absorbs this energy & radiates it back out as heat —> heat is absorbed by greenhouse gases/radiated back toward Earth —> heats up the atmosphere
Greenhouse gases
Water vapour, carbon dioxide, ozone, methane, nitrous oxide, chlorofuorocarbons
El Niño - Southern Oscillation
- periodic climate change that can trigger extreme weather changes throughout the Earth
- during an El Niño, the westerly winds weaken in the Pacific Ocean —> surface water warms along the N and S American coasts
Biome
Terrestrial region with characteristic natural, undisturbed ecological communities
- these communities are adapted to the climate of the region
Desert Biomes
- evaporation > precipitation; typically <25cm precipitation a year
- cover about 30% of earth’s surface (between 30ºN and 30ºS latitude)
- plants: small or no leaves, wax-coated leaves, tap roots, spines
- slow growth, low species diversity, slow nutrient cycling
- animals: nocturnal, thick outer coverings, dry/concentrated waste
- human impact:
- habitat destruction- particularly harmful due to plant characteristics (above)
- salinisation/irrigation- buildup of salt in soil due to the evaporation of water
- aquifer depletion- causes deserts to subside/sink
- extraction of natural resources- oil, iron, copper, gold, silver, diamond, sand
Grassland Biomes
- enough precipitation to allow grasses to grow; not enough precipitation that drought/fires prevent large trees from growing
- human impact:
- grazing of domesticated animals- mostly in Asia, Africa
- conversion to cropland- due to fertile soils in grasslands
- mining & drilling- oil, natural gas, natural resources
Tropical Grasslands
- high average temperature, low to moderate precipitation, prolonged dry season
- i.e. savannas
Temperate Grasslands
- large temperature differences from season to season, uneven/erratic rainfall
- i.e. prairies, pampas, veldt, steppes
Polar Grasslands
- a.k.a Arctic tundra, alpine tundra
- very cold, little precipitation (snow)
- permafrost: perennially frozen layer of soil
Chaparral Biomes
- a.k.a. shrubland
- along coastal areas, mild winters, long/hot/dry summers, moderate rain,
- plants: dense growth, spiny evergreen shrubs
Tropical Rainforest
- warm temperatures, high humidity, heavy rainfall (almost daily)
- plants: broadleaf evergreen trees, grow in LAYERS
- animals: specialists, avoiding competition, high biodiversity
Tropical Deciduous Forest
- a.k.a. tropical monsoon forests, tropical seasonal forests
- warm year-round, most rainfall occurs during monsoon season
Tropical Rain Forest Plant Growth Layers
1) emergent layer
2) canopy layer
3) understory layer
4) immature layer
5) herb layer, or shrub layer
E-CU-ISH
Temperate Rain Forests
- a.k.a. coastal coniferous forests
- moderate temperature, frequent rain
Temperate Deciduous Forests
- moderate temperatures that change significantly between seasons, abundant precipitation throughout the year
Boreal (Polar) Forests
- a.k.a. evergreen coniferous forests, taigas
- dry/cold climate, long winters, short summers
Forest Biomes Human Impact
- logging: particularly tropical rain forests; dramatically decreases biodiversity
- clear-cutting: particularly temperate deciduous forests; for use as cropland/grazing
- hunting: loss of large predators
- mining: particularly boreal forests; peat, iron, gold, diamonds, other minerals
- air pollution
- acid deposition
Mountain Biomes
- make up about 20% of Earth’s land surface
- dramatic changes in altitude, climate, soil, vegetation within short distances
- contain the majority of the world’s forests
- each 100m gain in elevation on a mountain = mountain km change in altitude
- human impact:
- extraction of timber & mineral resources
- hydroelectric dams & reservoirs: alters local ecosystems
- recreational disturbances: skiing, trekking, tourism
- air pollution: primarily from vehicle use
- global warming: ozone depletion, climate change, UV radiation
- war !!!
Rain Shadow Effect
- windward side of the mountain receives rain; the rain in the troposphere must move up the mountain in order to continue moving; the rain doesn’t make it over the mountain; the leeward side of the mountain is dry/no rain hits it
/ \ / mountain \ \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_/ \\_\_\_\_\_\_\_\_\_\_\_\_ water windward leeward - wet - dry rain —> rain must go over mountain —> little rain makes it over mountain
