Conditions for life on earth Flashcards
What are the key conditions that allowed early life to develop and survive on earth
- presence of an atmosphere
- a magnetosphere
- distance from the sun
- presence of liquid water
How has the position in the solar system allowed for the development of life on earth
- controls temperature
- causes presence of liquid water
- temperature is perfect for photosynthesis
Where is the magnetosphere
region around a planet dominated by the planet’s magnetic field
Why is the magnetosphere important for the development for life on earth
- deflects solar winds
- protects us from cosmic radiation, which can be dangerous to our health (cause cancer)
What is the importance of water for the development of life
- it is a transporter of nutrients
- used in photosynthesis
- provides habitats
- universal solvent
What was the composition of the early atmosphere
- CO2 - 95%
- Nitrogen - 3%
- O2 - 0.05%
What is the current composition of the atmosphere
- Nitrogen - 78%
- O2 - 21%
- Other gases - 0.1%
How does the earths orbit around the sun allow for development of life on earth
- controls year length
- frequency of seasons
How does the earths rotation on the axis allow for development of life on earth
- controls day length
How does the earths tilt on the axis allow for development of life on earth
- controls seasons
What is the importance of cyanobacteria
- they break down CO2 into C and O2, to produce sugars and give off O2 as a waste product
How have CO2 levels changed and what has caused it
- low levels of CO2 in atmosphere
- due to photosynthesis
- due to C being locked up in living things as carbohydrates
How do living organisms affect the cycling of water
- transpiration
- interception
- photosynthesis
What other ways have living things changed conditions on earth
- combustion
- competition
- photosynthesis
- respiration
- food chains
