The Conditions For Life On Earth Flashcards
(15 cards)
How long ago was the earth formed ?
4.6 billion years ago
What are the 5 features that make earth suitable for life?
Mass
Distance from sun
Axis of rotation
Speed of rotation
Magnetic field
How does the mass of the earth make it suitable for life?
The mass is great enough to prevent most gases escaping into space . These are essential for life - carbon , hydrogen, oxygen and nitrogen.
Water is present as a liquid.
What are the 5 gases essential for life on earth?
Carbon
Hydrogen
Oxygen
Nitrogen
Why is water being in liquid form important for life on earth?
It is the general physiological solvent in most biological reactions
Important in transport and temperature regulations .
Anomalous expansion of water
High specific heat capacity
Aquatic habitats
Absorption of uv radiation .
How is the distance from the sun important to life on earth?
Right distance so the Temperature means water is in liquid form.
The time taken for earth to rotate on its axis produces a day/night cycle.
How is the axis of rotation important for life on earth?
The axis of rotation is at an angle to its orbit around the sun which produces seasonal variations .
Why is speed of rotation important to life on earth?
The 24 hour period of rotation reduces extreme temperatures .
Why are magnetic fields important to life on earth?
They deflect the solar winds
Prevent biologically damaging radiation reaching the earths surface
Why is a temprature range of around 0°-35° important to life on earth?
Warm enough to have liquid water but cold enough to not denature enzymes.
Why are atmospheric gases important for life on earth?
Carbon dioxide for photosynthesis and the synthesis of carbohydrates, proteins and lipids
Nitrogen for protein synthesis
How did atmospheric oxygen caused environmental change?
As time moves on more organisms produce more oxygen meaning the organisms can take in more and grow larger .
How is carbon sequestration important in environmental change ?
Carbon dioxide is a greenhouse gas and helps retain heat energy , if photosynthetic organisms absorb more co2 then there is a reduction in the atmospheric levels and so which prevents long term temperature rise.
How has transpiration caused environmental change ?
As plants grew on land transpiration returned water vapour into the atmosphere and so therefore increased the amount of rainfall in other areas , leading to more plants growing.
Name the 4 techniques that have been developed to determine past climates,and how they work.
Radioisotope composition-date samples of carbon , such as the ratio of carbon-12 to carbon-14
Ice cores- air bubbles in the ice cores to see the past climates
Calcite deposits- the ratio of magnesium to calcium can be used to estimate the temperatures , more magnesium=warmer climate
Dendrochronology- seeing the size of rings inside a tree , a thicker ring indicates a warmer,moisture year.
