Earth before life Flashcards
how was the earth formed
gravity pulled rock fragments together, created heat and produced a ball of molten rock
the surface gradually cooled to produce a surface crust of solid rock
list the features of Earth which made it sustainable for life
1) mass
2) distance from the sun
3) axis of rotation
4) speed of rotation
5) magnetic field
explain how the mass of earth made it suitable for life
1) mass was great enough to prevent gases escaping into space
2) this allowed the formation of an atmosphere containing essential gases such as CO2 and O2
3) the atmospheric pressure was high enough to prevent liquid water boiling which is vital for biological reactions and nutrient uptake
how did the distance from the sun make earth sustainable for life
1) created suitable temperatures
2) being too close or too far= prevent liquid water being present
3) too close/ too far= enzyme activity prevented
explain how the axis of rotation of the earth was suitable
it is at an angle to its orbit which produces seasonal variations- no temperature extremes
outline how the speed of rotation created suitable conditions for life
Temp rises when exposed to sunlight and falls when it is not
the 24 hours rotation period reduces temperature extremes
explain the the magnetic field of the earth made it suitable for life
the molten layers beneath the crust produced a magnetic field which deflects solar winds and prevents biologically damaging radiation reaching the earths surface
explain the the magnetic field of the earth made it suitable for life
the molten layers beneath the crust produced a magnetic field which deflects solar winds and prevents biologically damaging radiation reaching the earths surface
explain the the magnetic field of the earth made it suitable for life
the molten layers beneath the crust produced a magnetic field which deflects solar winds and prevents biologically damaging radiation reaching the earths surface
