Conds For Life On Earth Flashcards
(38 cards)
What are the main conditions that allowed early life to develop on Earth?
Atmosphere, insolation, position in the solar system, orbital behaviour, magnetosphere
These conditions include the retention of an atmosphere, suitable temperature ranges, and protection from solar radiation.
What role does Earth’s atmosphere play in supporting life?
Provides gaseous resources (CO2, methane, nitrogen), maintains liquid water through pressure and temperature
The atmosphere is essential for various biochemical processes and maintaining suitable living conditions.
How does the position of Earth in the solar system affect temperatures?
Distance from the Sun maintains suitable temperatures for life
This distance ensures that conditions are neither too hot nor too cold for liquid water.
What is the function of the magnetosphere?
Protects Earth from radiation by deflecting solar radiation
The magnetosphere is generated by the movement of the molten core and is crucial for protecting biological life.
What was the first source of oxygen on Earth?
Photosynthetic bacteria
Oxygen production later continued with algae and plants.
What environmental change is caused by the presence of life on Earth?
Oxygen production, ozone layer formation, carbon sequestration, and biogeochemical cycles
These processes are essential for maintaining life and preventing resource shortages.
What are the limitations of early methods used to study ancient conditions?
Lack of historical data, limited reliability of proxy data, lack of coordination among researchers, and inadequate measurement equipment
These limitations hindered the understanding of early Earth conditions.
What improvements have been made in studying ancient conditions?
Long-term data collection, electronic monitoring, gas analysis of ice cores, isotope analysis
Enhanced methods allow for more accurate measurements and better understanding of historical conditions.
What abiotic factors are essential for life on Earth?
Water, temperature, ambient gases, light and radiation
These factors are crucial for creating a habitable environment.
What is the significance of water’s high specific heat capacity?
Acts as a buffer against temperature variations, stabilizes aquatic environments
This property is vital for maintaining suitable living conditions for organisms.
How does water’s polarity affect its properties?
Water is a polar molecule, allowing it to dissolve ionic compounds and polar molecules
This property is why water is often referred to as the universal solvent.
What is the ecological importance of ice floating on water?
Prevents lakes and ponds from freezing solid, provides insulation for aquatic life below
The floating ice layer allows life to persist during cold seasons.
What is surface tension in water and why is it important?
Cohesion of water molecules creates a strong film on the surface, allowing some organisms to walk on water
Surface tension supports various life forms and ecological interactions.
What is the greenhouse effect?
Trapping of heat in the lower atmosphere, essential for maintaining suitable temperatures for life
Without the greenhouse effect, Earth would be too cold for most life forms.
What percentage of oxygen and carbon dioxide is present in Earth’s atmosphere?
21% O2 and 0.035% CO2
These levels support aerobic respiration and photosynthesis without causing a runaway greenhouse effect.
Fill in the blank: Water is the universal _______.
solvent
This property allows water to facilitate numerous biochemical reactions.
What is the main reason water’s solid form is less dense than its liquid form?
Hydrogen bonds create a crystalline structure in ice, making it less dense
This allows ice to float on water, which is critical for aquatic ecosystems.
True or False: The speed of Earth’s rotation contributes to temperature stability.
True
The rotation creates day and night cycles, preventing extreme temperature fluctuations.
What is the percentage of oxygen in today’s atmosphere?
21%
This allows plants and animals to carry out aerobic respiration.
What is the primary use of nitrogen in living organisms?
Protein synthesis
Nitrogen is a key element in amino acids, which are the building blocks of proteins.
What role does sunlight play in photosynthesis?
Provides energy
Sunlight drives the process of photosynthesis in plants.
What is transpiration?
Movement and loss of water by plants
This process returns water vapor to the atmosphere.
What were the major gases in the early atmosphere?
- Carbon Dioxide (86%)
- Ammonia (10%)
- Methane (4%)
- Nitrogen (< 1%)
- Water Vapour
These gases were prevalent before life began to alter the atmosphere.
What are the major gases in today’s atmosphere?
- Nitrogen (78%)
- Oxygen (21%)
- Noble Gases (1%)
- Carbon Dioxide (0.04%)
- Methane (< 1%)
- Ozone
The composition has changed significantly due to biological processes.
