the conditions for life on earth Flashcards

1
Q

When was the Earth formed?

A

Around 4.6 billions years ago

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2
Q

Name the 4 essential elements in the early atmosphere

A

carbon, hydrogen,oxygen and nitrogen

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3
Q

Name 3 compounds in the atmosphere

A

methane, ammonia and carbon dioxide

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4
Q

What is the axis of rotation?

A

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

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5
Q

Why is the speed of rotation important?

A

The 24 hour period of rotation reduces temperature extremes

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6
Q

What produces the Earth’s magnetic field?

A

molten iron in the Earth’s core

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7
Q

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

A
  1. solar winds

2. radiation

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8
Q

Why is the distance from the sun important?

A

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

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9
Q

When was the first life developed?

A

Around 3.5 billion years ago

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10
Q

What were the first single-celled organism?

A

Archaea

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11
Q

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

A
Solvent water (general physiological solvent) 
Transport within organisms 
temperature control
anomalous expansion on freezing 
High specific heat capacity 
Aquatic habitats 
Absorption of UV radiation
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12
Q

Why is carbon dioxide important?

A

for photosynthesis and synthesis of carbohydrates,proteins and lipids

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13
Q

Why is nitrogen important?

A

Protein synthesis, synthesis of DNA and chlorophyll and ATP

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14
Q

What does albedo mean?

A

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

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15
Q

What does ozone absorb (atmosphere)?

A

ultra -violet light

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16
Q

What is carbon sequestration?

A

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

17
Q

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

A

Reduced atmospheric carbon dioxide. Prevented long term temp rise.

18
Q

What are biogeochemical cycles?

A

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

19
Q

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

A
  1. vapour
  2. Atmosphere
  3. Increased
20
Q

Name 2 early methods to monitor historical conditions on earth

A

dendrochronology and pollen analysis

21
Q

Name 2 modern methods to monitor historical conditions on earth

A

Ice core and ratio of oxygen isotopes

22
Q

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

A

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

23
Q

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

A

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

24
Q

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

A
  1. low accuracy as many trees weren’t present billions of years ago.
  2. size of rings could be affected by other abiotic factors
25
Describe how electronic technology may be used to monitor long term changes in the mean surface temperature of the Earth
data loggers i.e. argo floats, meteorological balloons measure reflectance, infrared
26
Why is the temp range found on Earth suitable for living organisms? (2)
1. allows efficient enzyme activity | 2. High temps denature enzymes
27
With more oxygen being produced, why is respiration more efficient?
enables aerobic respiration, complete breakdown of glucose = more energy released
28
Why is UV harmful to organisms?
causes mutations, skin cancer