conditions for early life on earth

-mass -distance from the sun (goldilocks) -speed of rotation -magnetic field - axial tilt

-earth formed 4.6 billion years ago -ball of molten rock -surface cooled to produce crust of solid rock -physical features controlled abiotic features -led to early life on earth

A smaller planetary body. Theia, collided with a proto-earth. This provided the material to fully form earth and our moon.

-earth is found in the ‘Goldilocks zone,’ -maintained suitable temperatures due to distance from the sun -too close= too hot - burn water would boil away - too far= too cold - freeze

earth rotates fully every 24 hours this allows us to have a day/night cycle it is fast enough to minimise excessive heating or cooling

earths axial tilt is 24.5 degrees this allows seasonal variation in conditions (seasons) it is also why different placed have different seasons at the same time.

a gradual change or “wobble,” in the orientation of earth’s axis this affects the relationship between earths tilt and eccentricity

it is orbit changes earth has an elliptical orbit around the sun, which is why we have seasons. more elliptical orbit produces more extreme seasons more spherical orbit produces hotter conditions

-movement of the iron-rich molten layers beneath the crust produce a magnetic field. -this deflects harmful solar radiation from mutating life

-allows for chemical reactions -transports nutrients within an organism -helps control temperature -some absorbing of UV radiation ice floats on water- has a given albedo- reflects some UV radiation

Earliest known life appeared about 3,700 Mya. Known as Archea

a suitable temperature range controlled by incoming insolation and its behaviour in the atmosphere. This was controlled by the surface albedo, absorption of infrared energy and the presence of the atmosphere. Solar insolation also drives the movement of water and chemical reactions. too much it kills to little we freeze

the mass of earth and the force of gravity retained an atmosphere. the atmosphere provided gaseous resources: carbon dioxide, methane, nitrogen. Atmospheric pressure and temperature maintained liquid water trapped oxygen became the ozone layer which prevents harmful UV radiation from mutating life

oxygen was first produced by photosynthetic bacteria, then by algae and plants. This is important as it allows organisms to respire

ozone was produced by chemical reactions involving oxygen and ultraviolet light in the stratosphere. Ozone layer absorbs some UV light preventing it mutating life.

Atmospheric carbon dioxide concentrations were reduced by photoautotrophs. This helped reduce the temperatures.

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

plants need co2 for photosynthesis o2 is important because it allows certain organisms to respire carbon also traps heat, to regulate our temperature but too much= too hot

-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 may factors - lack of data collection in many areas - reliance on proxy data, eg dendrochronology, pollen analysis

-collection of long-term data sets -the use of electronic monitoring equipment -gas analysis of ice cores isotope analysis of ice cores improved carriers for monitoring equipment, e.g. helium balloons, aircraft, satellites

it is the analysis of tree rings by looking at cross sections through a tree. a bigger ring= more co2 as it is healthier so growing more tree species grow at set times yet their speed of growth changes each ring in a tree= a year of growth strengths= quick, visual representation of past conditions problems= have to cut down trees, cant store for long as they rot trees are only fairly modern

this is very modern more pollen = more co2 as trees produce pollen trees need co2

sometimes miles deep these ice cores have trapped oxygen and other gases in them. the oxygen isotopes 16 and 18 can be used to reverse engineer climate- estimate past temperatures from the ratio of carbon 18 to carbon 16 the oldest ice we can get from ice cores is 42,000 years old 1998= 3.623 metres deep - supplied data about atmospheric composition strength= much older than tree rings limitation= expensive, specialist equipment, have to be stored in a freezer (rock cores= a lot older but harder to get)

2,400 million years ago a huge and sudden increase in the volume of oxygen in the atmosphere (due to iron being oxidised and stromatolites) due to so much o2 and not enough co2 most stromatolites died- their “dead body” acting as a carbon sink