Chapter 1- Conditions For Life On Earth

Question 1

What are the features that make life suitable on earth?

Answer 1

Mass-prevents gases from escaping, atmospheric pressure is high enough to prevent liquid from boiling

Distance from the sun- not too close or too far to prevent the presence of liquid

Speed of rotation- 24 h period reduces temp. extremes

Magnetic field- deflects the solar wind and prevents biologically damaging radiation

Question 2

Most chemical reactions in living organisms….

Answer 2

Involve reactants that are dissolved in water

Question 3

Water is most dense at what temperature?

Answer 3

4°c

Question 4

What zone is earth in?

Answer 4

The Goldilocks zone

Question 5

What ways did the presence of liquid water allow life to develop?

Answer 5

• solvent water: ‘general physiological solvent’ most chem reactions in living organisms take place here
• transport within organisms: water is the solvent in blood and sap- transports dissolved gasses, amino acids, mineral nutrients, waste products
• Temp control: evaporation of water absorbs heat
• Anomalous expansion on freezing: water cooler than 4°c floats- stopping the convection current that would cool the whole body
• Aquatic habits
• Absorption Of UV radiation:protected living organisms before the ozone layer developed

Question 6

What are the 2 atmospheric gases and what are they for?

Answer 6

Carbon dioxide: photosynthesis & the synthesis of carbohydrates, proteins, & lipids

Nitrogen: protein synthesis

Question 7

What is albedo

Answer 7

Measures the reflectivity of a surface

Question 8

How has the presence of life brought about environmental change?

Answer 8

Oxygen production: first produced by bacteria then algae and then plants

Carbon sequestration: photoautotrophs absorb carbon dioxide- prevents temp rises

Ozone layer: produced by chem reactions involving oxygen and ultraviolet light in stratosphere

Biogeochemical cycles: linked by living organisms- prevents build up of waste

Transpiration: plants return water to atmosphere which increased rainfall in other areas

Question 9

What are the limitations of early methods into the research of past conditions on Earth?

Answer 9

• Lack Of sophisticated equipment
• Lack Of data collection in many areas
• Lack Of ancient historical data

Question 10

How have methods of collecting research on the past conditions on Earth improved?

Answer 10

• Collection Of long term data
• Electronic monitoring equipment
• Improved carriers for monitoring equipment: helium balloons, satellites

Question 11

What are abiotic factors?

Answer 11

Non-living organisms that can influence where a living organism can live