Conditions for Life on Earth Flashcards
Finish the sentence: Most chemical reactions in living organisms….
Involve reactants that are dissolved in water
Water is most dense at what temperature?
4°c
What zone is earth in?
The Goldilocks zone
What ways did the presence of liquid water allow life to develop?
-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
What are the 2 atmospheric gases and what are they for?
Carbon dioxide: photosynthesis & the synthesis of carbohydrates, proteins, & lipids
Nitrogen: protein synthesis
What is albedo
Measures the reflectivity of a surface
How has the presence of life brought about environmental change?
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
What are the limitations of early methods into the research of past conditions on Earth?
Lack Of sophisticated equipment
Lack Of data collection in many areas
Lack Of ancient historical data
How have methods of collecting research on the past conditions on Earth improved?
Collection Of long term data
Electronic monitoring equipment
Improved carriers for monitoring equipment: helium balloons, satellites
What are abiotic factors?
Non-living organisms that can influence where a living organism can live
how did earth’s mass it suitable for life
great enough to prevent most gases from escaping
atmospheric pressure high enough to prevent all liquid water from boiling
how did earth’s distance from the sun make it suitable for life
suitable temp.
light
allows liquid water to be present
time taken for earth to rotate produced day/night cycle fast enough to minimise excessive heating or cooling
how did earth’s axis of rotation make it suitable for life
produces seasonal variations in conditions
how does earth’s speed of rotation make it suitable for life
temp. of earth’s surface rises when exposed to sunlight and falls when not
24-hour rotation prevents temp. extremes
how does earth’s magnetic field make it suitable for life
molten layers beneath crust produce magnetic field
deflects solar wind and prevents biologically damaging radiation from reaching earth’s surface
