The Conditions For Life on Earth

Question 1

Features of Earth that created suitable conditions for life:
Mass

Answer 1

Prevents most gases from escaping into space. Atmospheric pressure high enough to prevent liquid water boiling.

Question 2

Features of earth that created suitable conditions for life:
Distance from sun

Answer 2

Produces suitable temperatures

Question 3

Features of earth that created suitable conditions for life:
Axis + speed of rotation

Answer 3

At an angle to its orbit around sun to produce seasonal variation.

Question 4

Features of earth that created suitable conditions for life:
Magnetic field

Answer 4

Deflects solar winds that strip the atmosphere.

Question 5

Features of earth that created suitable conditions for life:
Temperature

Answer 5

Enzymes don’t denature, biological processes can occur.

Question 6

How life on earth caused environmental change:
Atmoshperic oxygen

Answer 6

2.7 billion years ago, Archaea developed ability to photosynthesise. Oxygen reacted with iron in oceans.
2.45 billion years ago, surplus of oxygen released in atmosphere. Oxygen absorbed UV, created ozone.
540 million years ago, most Archaea and anaerobic respiration died out, aerobic organisms evolved.

Question 7

How life on earth caused environmental change:
Biogeochemical cycles

Answer 7

Inter-connected biological processes developed = relatively small amounts of nutrients could support life for long periods.

Question 8

How life on earth caused environmental change:
Transpiration

Answer 8

Once plants evolved + colonised, returned water vapour to atmosphere, increased precipitation in areas = more plant growth.

Question 9

Early conditions on earth that allowed life to develop:
Presence of liquid water

Answer 9

Solvent
Transport within organisms
Temperature control
High specific heat capacity
aquatic habitats
Uv absorption

Question 10

Early conditions on earth that allowed life to develop:
Atmospheric gases

Answer 10

CO2 for photosynthesis, nitrogen for protein synthesis, greenhouse effect.

Question 11

Early conditions on earth that allowed life to develop:
Temperature range

Answer 11

Warm enough for liquid water, not hot enough to denature proteins.

Question 12

Early conditions on earth that allowed life to develop:
Solar insolation

Answer 12

Sun for photosynthesis, provides energy.
Infrared absorbed, converted to heat.

Question 13

What are the limitations of early methods to monitor conditions on earth?

Answer 13

• Lack of ancient historical data.
• Limited reliability of proxy data.
• Limited coordination between researchers.
• Lack of sophisticated equipment for accurate measurements.
• Inability to measure many factors.
• Lack of data collected in many areas.

Question 14

How have more recent methods of monitoring climatic factors improved the reliability of conclusions drawn?

Answer 14

• More accurate, quantitative data.
• Can extend further back in time.
• Allows collection in remote areas.
• Data collected continuously.
• Data collected is more reliable than proxy data.

Question 15

What are 2 examples of proxy data to monitor early conditions on Earth?

Answer 15

Dendrochronology - Tree’s growth rate changes in response to seasonal climate changes. Can be altered by other things.

Pollen analysis - Determine what plants were living in an area at a particular time.