Conditions for life on earth Flashcards
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
aquatic habitats
anomalous expansion
specific heat capacity/temperature regulation
albedo
acts as a carbon sink
Temperature:
importance of temperature range;;
suitable for stable biological molecules/enzymes
warm enough for chemical/metabolic reactions
liquid water
Geology:
importance of geology;;
mass controls gravity/gravitational pull
retention of atmosphere
source of minerals
magnetic field protects from solar wind
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; energy for hydrological cycle/winds/ocean currents;
State one way in which plants increase atmospheric humidity. (1)
(evapo)transpiration/ evaporation;
Features of earth that created suitable conditions for life
Mass
Distance from sun
Axis of rotation
Speed of rotation
Magnetic field
Early conditions on earth that allowed life to develop
Presence of liquid
Temperature range
Atmospheric gases
Solar insulation
Presence of atmosphere
1.Large mass and gravitational pull which keeps the atmosphere close
2. Contains important gases: CO2, N2 AND CH4
3. Temperature and pressure means water is in liquid form
Solar Insulation
Suitable temperature range for enzyme action and water in liquid state
Provides energy for photosynthesis
Amount absorbed depends upon the albedo of the surface
Earth orbital behaviour
1.Rotation and tilt of the earth on its axis and its orbit around the sun
2.Controls daily and seasonal variations in isolation and temperatures
3. Enough day length to stop temperature extremes and light for photosynthesis
Presence of liquid water
Solvent water
Transport within organisms
Temperature controls
Anomalous expansion on freezing (most dense at 4°C)
High specific heat capacity
Aquatic habitats
Absorption of UV radiation
Atmospheric gases
Carbon dioxide for photosynthesis and the synthesis of carbohydrates, proteins and lipids
Nitrogen for protein synthesis
How life on earth caused environmental change
Atmospheric oxygen
Carbon sequestration by photosynthetic organisms
Biogeochemical
Transpiration
Limitations of early methods
Lack of ancient historical data.
* Limited coordination between researchers.
* Lack of sophisticated equipment for accurate measurements.
* Lack of data collection in many areas.
* Reliance on proxy data, eg dendrochronology, pollen analysis.
Improved methods of proxy data
- 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, eg helium balloons, aircraft, satellites.
How did distance from the Sun allow life to develop on Earth?
Provides a suitable temperature range on Earth which maintains liquid water and allows for photosynthesis
How did insolation allow life to develop on Earth?
Provides a suitable temperature range on Earth due to its atmospheric behaviour
How did orbital behaviour allow life to develop on Earth?
Earth’s orbit and its rotation and tilt on its axis controls daily and seasonal variations in insolation and therefore temperature
How did the magnetosphere allow life to develop on Earth?
Deflects harmful solar radiation which could be biologically damaging
How did the atmosphere allow life to develop on Earth?
Earth’s mass and gravitational force retains an atmosphere which provides gaseous resources and maintains liquid water (due to pressure and temperature)
In which 4 ways did early life on Earth cause environmental change?
Biogeochemical cycles
Oxygen production
Ozone layer
Carbon sequestration
How did the ozone layer cause environmental change?
Reactions between oxygen and UV in the stratosphere created the ozone layer which protects Earth from harmful UVC and UVB radiation
How did carbon sequestration cause environmental change?
Photosynthetic organisms reduced atmospheric CO2 levels which reduced the greenhouse effect
What are the 5 examples of proxy data to determine past conditions on Earth?
Historical data
Coral reef analysis
Pollen analysis
Dendrochronology
Ocean and lake sediment analysis
How does historical data help determine past conditions on Earth?
Sources such as ships logs, diaries and news articles provide information about the weather and climate at the time
How does coral analysis help determine past conditions on Earth?
The density of a coral reef changes due to temperature and the presence of carbon for the CaCO3 structure
How does pollen analysis help determine past conditions on Earth?
Pollen grains can be used to determine which types of plants were present in the past
What are the limitations of proxy methods?
Historical data may be subjective
Trees do not grow in all climates
Coral is only present in specific climates
Many areas lack data collection
What are the 3 examples of improved methods to determine conditions on Earth?
Ice-core analysis
Satellite imagery
Weather balloons
Describe how early life caused environmental changes that reduced the amount of ultraviolet radiation reaching the Earth’s surfaces (3 marks)
Photosynthetic organisms released oxygen. The oxygen then reacted with Ultraviolet to create Ozone (03). Ozone then either absorbs UV radiation, reducing the amount reaching the Earth’s surface
Explain two ways that atmospheric carbon dioxide has been important for the survival of living organisms on Earth (4 marks)
1) Use in photosynthesis, produces oxygen for aerobic respiration
2) Greenhouse gas, maintains warmer temperatures
