Environmental science - conditions for life on Earth
- Created by: zbeale
- Created on: 21-02-19 20:13
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- Conditions for life on Earth
- The conditions that allowed life to develop and survive
- position in solar system
- suitable temperature - the sun is stable/not too big
- orbital behaviour
- tilt, rotation and orbit controls daily/seasonal variations
- atmosphere
- protects Earth from UV and meteors
- reduces variability of temperatures
- prevents water and gases being lost to space
- gaseous resource
- Magnetosphere
- deflects harmful short wave radiation
- water
- protected early life from UV
- high specific heat capacity
- causes water to warm and cool slowly which moderates temperature changes
- good solvent
- physiological solvent - most chemical reactions in cells take place in water
- solvent in blood/sap, transports essentials - O2, nutrients, sugars
- water cycle
- Ice
- ice floats stops water below from cooling as much and freezing so life can survive under ice
- provision of aquatic habitats
- position in solar system
- water
- protected early life from UV
- high specific heat capacity
- causes water to warm and cool slowly which moderates temperature changes
- good solvent
- physiological solvent - most chemical reactions in cells take place in water
- solvent in blood/sap, transports essentials - O2, nutrients, sugars
- water cycle
- Ice
- ice floats stops water below from cooling as much and freezing so life can survive under ice
- provision of aquatic habitats
- old methods of measuring past climate
- ancient landforms
- relict cliffs mean sea levels were higher
- u shaped valleys were eroded by glaciers = cooler
- erosion will eventually remove all landforms created in past so can only be used in recent past
- tectonic plates move - affect climate due to location in world
- some landforms may be difficult to interpret
- palynology/ pollen analysis
- pollen preserved in lake/peat bog deposits can be analysed to show past vegetation
- can be contaminated as pollen can travel large distances
- different species produce different amounts of pollen
- may overestimate pollen transferred by wind rather than insects
- pollen may not be found if the area wasn't colonised fast after the ice age. It doesn't mean area had unsuitable climate
- dendro chronology tree rings
- if planet is warmer more growth, wider rings
- can be used to work out what temps and water may have been
- tree growth can be affected by many factors - drought, disease, forest fires
- local variation and species variation
- qualitative and not very precise
- only for the past few thousand years
- Coral heads
- some coral produce large heads with annual growth rings which can be used to estimate past sea temperatures
- Cave art and historical records
- paintings of woolly mammoths could indicate cooler
- many paintings of frost fairs on River Thames in 17th century
- people may have painted things for many reasons
- accounts of weather throughout almost entire human history - extreme weather
- met office since 1880
- problems
- proxy data -don't tell specific temperature
- general lack of historical data with many large gaps/time periods with little evidence
- early equipment lacked accuracy
- lack of data collection on a global scale
- temperature records in towns may show warming that is caused by an increase in the heat-island effect
- ancient landforms
- new methods of measuring climate
- Ice cores
- as snow and ice is laid down over thousands of years air is trapped
- bubbles of air can be analysed and used to estimate past co2 concentration
- oxygen isotopes in ice cores (16+18) are temp dependent and can tell us past temperatures
- volcanic dust layers also help comparison between areas
- Satellite data
- sensors carried by satellites are used to collect data for wind velocity, ocean currents, temp, wave height, ice and vegetation cover
- LEO (low earth orbit) satellites collect detailed info on whole of Earth's surface
- geostationary satellites get less detailed info from a constant position above equator
- ocean currents
- surface currents are monitored with satellites, buoys/floats
- deeper currents can be monitored with drifting floats like the Argo floats which are programmed to sink for specific durations
- data is collected on temp and salinity. sequence of position plots shows direction and speed of current
- computer models
- allows the impact of interconnections and their consequences to be estimated
- model can be tested by using old data and seeing if it predicts the outcome for a later year
- model can be continually modified using more data and by analyzing differences between predicted and real outcomes
- the IPCC collects the data for models
- Ice cores
- The conditions that allowed life to develop and survive
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