Life on Earth
No description yet. This curated deck is ready for daily study.
Card preview (8)
State one role of living organisms other than humans in soil formation (1)
soil formed from the remains of organisms; decomposers/detritivores; break down dead organisms/forms humus; organic sorting/mixing/aeration/improve structure; release nutrients/ nutrient recycling; weather/erode/break up bedrock/parent material
State one role of living organisms other than humans in soil conservation (1)
vegetation/soil biota reduces the rate of runoff; vegetation reduces wind erosion; vegetation reduces impact/damage due to rain; root binding/slope stabilisation; humus binds soil together;
Describe the main conditions that allow life to survive on earth. (8)
Water: role of water;; solvent for chemical reactions transport within organisms mineral uptake required for photosynthesis structure of cells/organisms habitat/medium for organisms/cells anomalous expansion specific heat capacity/temperature regulation albedo transparency allows light penetration (allow only once see similar mp in light) acts as a carbon sink Temperature: importance of temperature range;; suitable for stable biological molecules/enzymes warm enough for chemical/metabolic reactions liquid water Ambient gases: role of gases;; O2 for (aerobic) respiration O2 forms O3 (ozone) N2 for nitrogen fixation/proteins CO2 for photosynthesis greenhouse gases gaseous water for hydrological cycle atmospheric pressure allows liquid water (allow 1 mark if all of O2,CO2,photosynthesis and respiration mentioned but not clearly linked) Light/solar radiation: importance of radiation;; source of energy for photosynthesis/conversion to chemical energy ozone layer protection from UV radiation vision/directional stimulus photolysis of water transparency of water allows light penetration (allow only once, see above) Geology: importance of geology;; mass controls gravity/gravitational pull retention of atmosphere source of minerals magnetic field protects from solar wind Position in solar system: importance of position;; distance from sun controls temperature larger planets protect from asteroids/comets moon controls tides/axis of rotation
Give two ways in which atmospheric carbon dioxide is important for life on earth. (2)
needed for photosynthesis; climate/temperature control/heat absorption/acts as greenhouse gas; raw material for carbonaceous structure; eg coral reefs, exoskeletons, shells
Describe how sunlight is important for the survival of life on earth. (2)
energy for photosynthesis; photolysis; (converted) to heat; vision; enables sense of time/periodicity; energy for hydrological cycle/winds/ocean currents; energy for nitrogen/carbon/biogeochemical cycle; synthesis of vitamin D;
Describe how early photosynthetic organisms changed the composition of the atmosphere. (2)
reduced concentration of/absorbed carbon dioxide/CO2; increased concentration/released oxygen/O2; (oxygen enables) formation of ozone/03 layer;
State one way in which plants increase atmospheric humidity. (1)
(evapo)transpiration/ evaporation;
Explain how research into unexploited species may aid future food production. (3)
new food species; different range of tolerance/ adapted to different conditions; source of new genes/new characteristics/GM/hybridisation (to improve existing food species); biological pest control; source of natural pesticides; improve nutrient supply; eg green manures, legumes, pollination/ seed dispersal; named examples;