Conditions For Life On Earth Flashcards
How does the mass of the earth a suitable condition for life on earth?
Mass of the earth is great enough to prevent gases essential to life form escaping into space. E.g. carbon, hydrogen, oxygen, nitrogen.
How does the atmospheric pressure of the earth a suitable condition for life on earth?
High enough to prevent liquid water from boiling, and helps to regulate the temperature.
How does the distance from the sun of the earth a suitable condition for life on earth?
The earth is in the ‘Goldilocks zone’ about 150 million Km from the sun.
This maintains a suitable temperature for liquid water and metabolic processes.
How does the axis of rotation of the earth a suitable condition for life on earth?
Provides seasonal changes and an even distribution of sunlight over the earth.
How does the planetary configuration and asteroid belt of the earth a suitable condition for life on earth?
Reduces the chances of a catastrophic collision.
Jupiters strong gravitational field diverts many space objects.
How did the early condition: presence of liquid water allow life to develop on earth?
- A solvent = chemical reactions
- Transport within organism = the solvent in blood which carries gases, sugars, amino acids, etc.
- Temperature control = greenhouse gas, evaporation of water absorbs heat.
- Anomalous expansion of water = water is most dense at 4’C so water cooler than this floats, stopping the convection currents that may have cools the whole body of water down.
- High specific heat capacity = warms up and cools down slowly, which helps to moderate the rate and size of temperature changes.
- Aquatic habitats = oceans, seas, lakes, marshes, rivers.
How does the moon of the earth a suitable condition for life on earth?
Stabilises the tilt, gravitational pull of the moon creates tidal forces on earth.
How does the speed of rotation of the earth a suitable condition for life on earth?
- The 24 hour period of rotation of earth around its axis reduces temperature extremes
How did the temperature range allow life to developed on earth?
- Most of earth has a temperature range of 0-35’C, so most areas are warm enough to have liquid water but not so hot it denatures proteins.
How did atmospheric gases allow life to developed on earth?
- Carbon dioxide for photosynthesis and the synthesis of carbohydrates, proteins and lipids
- Nitrogen for protein synthesis
- Oxygen for respiration
How did solar insulation allow life to developed on earth?
- Sunlight provides energy for photosynthesis
- Drives the water cycle
- Amount of sunlight absorbed by the earths surface depends on the albedo of the surface
How did atmospheric oxygen cause environmental change on earth?
- Archea in the ocean developed ability to photosynthesis and release oxygen
- Oxygen in the atmosphere absorbed UV making ozone
- Making animal and plant life to develop
How did carbon sequestration cause environmental change on earth?
- CO2 is a greenhouse gas and helps to retain heat energy in the atmosphere
- Photosynthetic organisms, photoautotroph, absorbed CO2 which was stored inn geological sediments
- Reduction in CO2 helped to prevent a long-term temperature rise even though the brightness of the sun increase by 10% every billion years
How did bio geochemical cycles cause environmental change on earth?
As a greater variety of organisms evolved inter-connected biological processes developed which produced biogeochemical cycles, allowing small amounts of elects to support life over long periods of time.
How did transpiration cause environmental change on earth?
Transpiration returned water vapour to the atmosphere and increased the amount of rainfall in other areas, making more plant life able to grow.
What new analytical techniques have been developed that can estimate past conditions?
- Radioisotope composition such as carbon-12 and carbon-14 as well as oxygen-18 and oxygen-16 to estimate past temperatures
- Composition of past atmosphere analysed from air bubbles in ice cores
- Ratio of magnesium to calcium in calcite deposits can be used to estimate the temperature. More magnesium is incorporated at higher temperatures.
How does the magnetic field of the earth a suitable condition for life on earth?
- Molten layers beneath the crust produce the earths magnetic field that deflects the ‘solar wind’ and prevents biologically damaging radiation reaching the earths surface
How did presence of liquid water allow life to developed on earth?
- Solvent water: general phisological solvent, for chemical reactions
- Transport within organisms: in blood and sap, transports dissolved gases, sugars, amino acids, etc
- Temperature control: evaporation of water absorbs heat, causing temperatures to decline
- Anomalous expansion on freezing: water most dense at 4’C so water cooler than this floats, stopping the whole body of water being cooled down
- High specific heat capacity: warms up and cools down slowly
- Aquatic habitats: oceans, lakes, rivers, marshes
- Absorption of UV radiation: protected living organisms in the oceans before the ozone layer developed
