the conditions for life on earth

Question 1

When was the Earth formed?

Answer 1

Around 4.6 billions years ago

Question 2

Name the 4 essential elements in the early atmosphere

Answer 2

carbon, hydrogen,oxygen and nitrogen

Question 3

Name 3 compounds in the atmosphere

Answer 3

methane, ammonia and carbon dioxide

Question 4

What is the axis of rotation?

Answer 4

the axis of rotation is at an angle to its orbit around the sun which produces seasonal variations in conditions

Question 5

Why is the speed of rotation important?

Answer 5

The 24 hour period of rotation reduces temperature extremes

Question 6

What produces the Earth’s magnetic field?

Answer 6

molten iron in the Earth’s core

Question 7

The Earth’s magnetic field deflects the _____ ____ and prevents biologically damaging ________ reaching the surface

Answer 7

1. solar winds

2. radiation

Question 8

Why is the distance from the sun important?

Answer 8

Distance from the sun controls the amount of insolation. and so the temp and presence of liquid water

Question 9

When was the first life developed?

Answer 9

Around 3.5 billion years ago

Question 10

What were the first single-celled organism?

Answer 10

Archaea

Question 11

List 7 reasons why liquid water is important (for early life to develop)

Answer 11

Solvent water (general physiological solvent) 
Transport within organisms 
temperature control
anomalous expansion on freezing 
High specific heat capacity 
Aquatic habitats 
Absorption of UV radiation

Question 12

Why is carbon dioxide important?

Answer 12

for photosynthesis and synthesis of carbohydrates,proteins and lipids

Question 13

Why is nitrogen important?

Answer 13

Protein synthesis, synthesis of DNA and chlorophyll and ATP

Question 14

What does albedo mean?

Answer 14

the proportion of the incident light that is reflected by a surface

Question 15

What does ozone absorb (atmosphere)?

Answer 15

ultra -violet light

Question 16

What is carbon sequestration?

Answer 16

When carbon dioxide is removed from the atmosphere and held in solid (carbonate rocks or fossils fuels) or liquid form

Question 17

Why was carbon sequestration important in the development of early life?

Answer 17

Reduced atmospheric carbon dioxide. Prevented long term temp rise.

Question 18

What are biogeochemical cycles?

Answer 18

process of biogeochemical cycles are linked by living organisms preventing the build up of waste products or shortages of resources

Question 19

Transpiration returned water ______ to the ________ which _______ the amount of rainfall.

Answer 19

1. vapour
2. Atmosphere
3. Increased

Question 20

Name 2 early methods to monitor historical conditions on earth

Answer 20

dendrochronology and pollen analysis

Question 21

Name 2 modern methods to monitor historical conditions on earth

Answer 21

Ice core and ratio of oxygen isotopes

Question 22

How has the evolution of photosynthetic plants regulated the Earth’s temp?

Answer 22

CO2 concentration in atmosphere reduced by photosynthesis. Greenhouse gases absorb infrared

Question 23

how has the evolution of green plants may have led to a reduction of solar radiation from reaching the earth’s surface?

Answer 23

Photosynthesis increases oxygen levels, formation of ozone which absorbs UV radiation

Question 24

Assess the accuracy of estimating the historical temp of the earth using dendrochronology (2)

Answer 24

1. low accuracy as many trees weren’t present billions of years ago.
2. size of rings could be affected by other abiotic factors

Question 25

Describe how electronic technology may be used to monitor long term changes in the mean surface temperature of the Earth

Answer 25

data loggers i.e. argo floats, meteorological balloons measure reflectance, infrared

Question 26

Why is the temp range found on Earth suitable for living organisms? (2)

Answer 26

1. allows efficient enzyme activity

2. High temps denature enzymes

Question 27

With more oxygen being produced, why is respiration more efficient?

Answer 27

enables aerobic respiration, complete breakdown of glucose = more energy released

Question 28

Why is UV harmful to organisms?

Answer 28

causes mutations, skin cancer