What is the definition of life?
"a biological system which has the ability to reproduce, mutate and evolve in response to changing environments"
"a material system which has the ability to self-replicate, mutate and evolve in response to changing environments"
"a material system which has the ability to reproduce, mutate and evolve in response to changing temperatures"
"a Biological system which has the ability to self-replicate, mutate and evolve in response to changing temperatures"
What is the second law of thermodynamics?
The entropy of an isolated system not in equilibrium will tend to increase over time, approaching a maximum value at equilibrium.
As temperature approaches absolute zero, the entropy of a system approaches a constant minimum.
What are Advantages of Carbon in the evolution of complex life?
Strength & Quantity
Size & structure
Mass & Volume
Speed and Velosity
which element has the greatest ability to bond with itself creating greater variety and long Chains?
Carbon
Oxygen
Potassium
Hydrogen
The element silicon has similar chemical properties to carbon – it can form four separate chemical bonds, and has been suggested, particularly by science fiction writers, as a basis for life forms, why is it not such a likely candidate as carbon?
Chemical bonds are not as strong, cannot form double bonds & and is more likely to bond with Oxygen to for smaller molecules rather than long chains.
Chemical bonds are not as strong, it always forms double bonds & and is more likely to bond with Oxygen to for smaller molecules rather than long chains.
Chemical bonds are too strong and will not break
Of all the requirements for life, almost all biologists would agree that water, or some other liquid, is the most important. Complex chemistry is not likely to develop far in the rigid structure of a solid; nor is it likely to develop in a vapour as it would be hard to keep all the working components together.
Why is water "Stable"?
Water exists as a liquid over a very broad temperature range. At atmospheric pressure this range is 0 to 100°C, whereas at higher pressures the range extends upwards to 363°C. There is no other abundant molecule which significantly overlaps this stable range.
Water exists as a liquid over all temperature ranges. There is no other abundant molecule which significantly overlaps this stable range.
Water is very unstable.
Why is water so abundant?
It is composed of H (Hydrogen) which is the third most abundant element in the universe.
It is composed of O (Oxygen) which is the third most abundant element in the universe.
There it a lot of H2O on earth thus abundant.
Why is Oxygen Chemistry very active?
lot of energy is available in chemical reactions involving free (molecular) oxygen
lot of energy is available in chemical reactions involving fixed (molecular) oxygen
Oxgyen emits lots of energy
What are Environmental Conditions?
Temperature, atmospheric composition, mass and age
Time & Water present.
What other conditions are necessary to protect life?
Protection from radiation, Moderate and stable temperatures & Atmospheric recycling mechanisms.
Protection from solar winds, Moderate and stable temperatures & Atmospheric recycling mechanisms.
Protection from solar winds, Moderate and water source & Atmospheric recycling mechanisms.
Is Short wavelength radiation is damaging to biological tissues?
On Earth we are protected from the malign effects of UV radiation by a thin layer of ozone. Which atom makes up the ozone?
OZone, a molecule composed of three oxygen atoms, which absorbs the radiation.
OZone, a molecule composed of three hydrogen atoms, which absorbs the radiation.
OZone, a molecule composed of three carbon atoms, which absorbs the radiation.
OZone, a molecule composed of three nitrogen atoms, which absorbs the radiation.
What is the The Habitable Zone?
0.6 to 1.5 astronomical units from the sun
1.5 to 3 astronomical units from the sun
3 to 6 astronomical units from the sun
6 to 9 astronomical units from the sun
What will happen if the planetary surface is too close to the star?
Too much heat / Radiation
Not enough heat and too much radation
Not enough radiation to hot
What happens to water the surface of a planet if its too close to the surface of a star?
Liquid water will not exist, the surface will be too warm, ultraviolet radiation from the central star may dissociate the water, breaking H2O into its constituents H and O.
Water is permanently frozen.
What other factors determin whether a planet can maintain liquid water
Mass of the planet
Geothermal activity
Shape and density
Atmosphere
What is the greenhouse effect?
The presence of "greenhouse gases" in the atmosphere of a planet leads to warming of the surface
A planet being close to the sun thus being very hot
The Ozone layer stopping heat escaping the atmosphere
The Earth’s crust is broken up into large rigid plates, which move slowly across its surface, riding on a hotter deformable layer. This is called?
plate tectonics
Movable plates
Floating Plates
Tectonic ridges
