the conditions for life on earth Flashcards
When was the Earth formed?
Around 4.6 billions years ago
Name the 4 essential elements in the early atmosphere
carbon, hydrogen,oxygen and nitrogen
Name 3 compounds in the atmosphere
methane, ammonia and carbon dioxide
What is the axis of rotation?
the axis of rotation is at an angle to its orbit around the sun which produces seasonal variations in conditions
Why is the speed of rotation important?
The 24 hour period of rotation reduces temperature extremes
What produces the Earth’s magnetic field?
molten iron in the Earth’s core
The Earth’s magnetic field deflects the _____ ____ and prevents biologically damaging ________ reaching the surface
- solar winds
2. radiation
Why is the distance from the sun important?
Distance from the sun controls the amount of insolation. and so the temp and presence of liquid water
When was the first life developed?
Around 3.5 billion years ago
What were the first single-celled organism?
Archaea
List 7 reasons why liquid water is important (for early life to develop)
Solvent water (general physiological solvent) Transport within organisms temperature control anomalous expansion on freezing High specific heat capacity Aquatic habitats Absorption of UV radiation
Why is carbon dioxide important?
for photosynthesis and synthesis of carbohydrates,proteins and lipids
Why is nitrogen important?
Protein synthesis, synthesis of DNA and chlorophyll and ATP
What does albedo mean?
the proportion of the incident light that is reflected by a surface
What does ozone absorb (atmosphere)?
ultra -violet light
What is carbon sequestration?
When carbon dioxide is removed from the atmosphere and held in solid (carbonate rocks or fossils fuels) or liquid form
Why was carbon sequestration important in the development of early life?
Reduced atmospheric carbon dioxide. Prevented long term temp rise.
What are biogeochemical cycles?
process of biogeochemical cycles are linked by living organisms preventing the build up of waste products or shortages of resources
Transpiration returned water ______ to the ________ which _______ the amount of rainfall.
- vapour
- Atmosphere
- Increased
Name 2 early methods to monitor historical conditions on earth
dendrochronology and pollen analysis
Name 2 modern methods to monitor historical conditions on earth
Ice core and ratio of oxygen isotopes
How has the evolution of photosynthetic plants regulated the Earth’s temp?
CO2 concentration in atmosphere reduced by photosynthesis. Greenhouse gases absorb infrared
how has the evolution of green plants may have led to a reduction of solar radiation from reaching the earth’s surface?
Photosynthesis increases oxygen levels, formation of ozone which absorbs UV radiation
Assess the accuracy of estimating the historical temp of the earth using dendrochronology (2)
- low accuracy as many trees weren’t present billions of years ago.
- size of rings could be affected by other abiotic factors
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
Why is the temp range found on Earth suitable for living organisms? (2)
- allows efficient enzyme activity
2. High temps denature enzymes
With more oxygen being produced, why is respiration more efficient?
enables aerobic respiration, complete breakdown of glucose = more energy released
Why is UV harmful to organisms?
causes mutations, skin cancer
