Topic 1 conditions for life on earth Flashcards
How have temperature and the atmosphere helped life on earth? (water) ?
Maintained water to be at a liquid state which is best for most organisms on earth, if it was too hot it would be gas, too cold would be ice
Limitations of early methods
Lack of ancient historical data, limited reliability of proxy data for ancient conditions, limited coordination between researchers, lack of sophisticated equipment for accurate measurements, inability to measure many factors, lack of data collection in many areas, reliance on proxy data eg pollen analysis
Earths atmosphere compared to the mass
Earths atmosphere is only 1/1,200,000 of the mass
How much is the force of gravity on earth?
9.807 m/s squared
Gases in the atmosphere
The atmosphere provided gaseous resources, these were probably just helium and hydrogen, these evolved into nitrogen, oxygen, carbon dioxide and argon then small amounts of other gases. The main gas is nitrogen and these amounts have changed a lot over the years
How was oxygen produced?
Oxygen was first produced by photosynthetic bacteria, then by algae and plants. Oxygen was much more prominent when plants could photosynthesise.
When did oxygen first arrive?
It was thought that oxygen made its first appearance 2.34 billion years ago but it only took 10 million years for atmospheric oxygen to build up
Suns distance from earth
The light emitted from the sun and the distance from the sun were suitable to produce temperatures on earth that would be suitable for life. Being too close or far away from the sun would prevent liquid water being present, the time taken for the earth to rotate on its axis produced a day/ night cycle that was fast enough to minimise excessive cooling or heating.
Improved methods of data collection
Collection of long-term data sets
The use of electronic monitoring equipment
Gas analysis of ice cores
Isotope analysis of ice cores
Improved monitoring for monitoring equipment eg helium balloons, aircraft or satellites
Ozone facts
Produced by chemical reactions involving oxygen and UV light in the stratosphere
A chemical compound, it’s a pale blue gas with a distinctively pungent smell
Over 2 billion years ago, early aquatic organisms called blue-green algae began using energy from the sun to convert molecules of water and CO2 and recombine them into organic compounds and molecular oxygen
What is the earths magnetic field?
The molten layers beneath the crust produce the earths magnetic field that deflects ‘solar wind’ and prevents biologically damaging radiation reaching the earths surface.
When life first developed
The first life on earth developed around 3.5 billion years ago, the conditions on earth then were very different from those that exist now, more like mars.
The solar energy reaching the ground included high levels of UV radiation l, the chemical compound of the sea included increasingly complex organic molecules
The rotation of the earth
The axis of rotation is at an angle to its orbit around the sun which produces seasonal variations in conditions as the earth orbits the sun.
The temperature of the earths surface rises when it is exposed to sunlight and falls when it is not.
The 24 hour period rotation of earth around its axis reduces temperature extremes. April days and nights have equal times, December it has shorter days, September has equal days and nights and June has long days
What is a biogeochemical cycle?
The ways in which an element of compound, such as water, moves between its various living and non living forms and locations in the biosphere, eg water.
These are important to living organisms
The process of biogeochemical cycles are linked by living organisms, preventing the build-up of waste products or shortages of tea sources
What is the biosphere?
The regions of the surface and atmosphere of the earth or another planet occupied by living organisms
The area of the planet where organisms live
