Water and temperature range.
Why waters essential:
- Physiological Solvent
- Transport of water
- Temperature control
- Anomolous expansion on freezing
- High specific heat capacity
- Provision of aqauatic habitats
- Most areas upon earth are over 0 degrees C which means it can support liquid water .
- Enzymes need water as a solvent as at higher tempratures they can denature.
- Some organisms can survive tempretures higher than this an example of these are thermophilic bacteria.
1 of 3
Gases and the Sun.
Suitable ambient gases:
- Carbon Dioxide (Photosynthesis and climate control)
- Nitrogen (Protein synthesis)
Light and radiation from the sun:
- Sunlight-Energy for photosynthesis
- Heat production when absorbed-The source of energy for the water cycle and climate.
- UV and Ionising radiation.
This can be caused by the earth itself or its posiion:
- Distance from Sun
- Daily Rotation
- Tiltled Axis
- Molten layers beneath the crust
2 of 3
Environmental Change through the presence of life:
- Oxygen is very reactive and due to this its abundance has declined in the atmosphere.
- Photolysis of water releases oxygen and photosynthesis.
- Oxygen absorbed UV light from the sun.
Atmospheric Carbon Dioxide:
- Essential green house gas-without this the earth would be to cold to support life.
- Excess levels of carbon dioxide can also cause the decline in life due to the high temperature levels.
- Carbon dioxide gets reduced by photosynthesis, absorbed by fossil fuels,carbonate rocks, organisms and the sea.
3 of 3