GGR101H1F – Ancient Civilizations and Their Environments
- Environment covers all of ambient influence in the physical, biological and human world
o Physical environment includes characteristics of
Biosphere constrained by elements of physical environment & interactions
- Atmosphere composed of nitrogen (78%) & oxygen (20%)
o Produces greenhouse effect b/c of small concentrations of CO2, CH4, etc.
o Without greenhouse effect: -50 degrees C (not completely man-made phenomenon)
How stable is this composition?
Addition of CO2 due to natural and human activity
How much has it changed through time?
Substantially; climate changed due to proportions of greenhouse gases
What are the consequences of changes in atmospheric chemistry?
- Hydrosphere: unique in solar system
o Water exists as a solid, liquid or gas (readily exchanges between states) energy
exchanges accompany changes in state (evaporation & condensation & precipitation)
70% globe water-covered – how has that changed through time?
More land above water than there has been in a long time
Changes in the amount of water on the earth = shape and size of the
What roles do oceans play in forcing environmental change?
Huge role in climate change intersection between hydrosphere &
atmosphere (energy exchanges occur)
- Lithosphere: dynamic w/ hot differentiated interior that drives plate tectonics
o How long has plate tectonics been going on?
As long as the earth has had a crust (~3.5 billion years)
Continents constantly moving and changing in location
o How does it determine environmental change?
Volcanism = effects global climate, etc.
- Biosphere: comprised of plants & animals as well as microbes (most successful of earth’s biota)
o Essential to biogeochemical cycles (e.g. The N cycle)
o Directly & indirectly influence climate
How to biota influence global environments and what role do they play in
- Evidence from past earths and enviroments from geologic record earth is old (4.5 billion yrs)
o Environmental change for most of time
Record is thin for 85% recycled
Most record from marine sediments; most of global surface covered by water
(marine env. depositional; land erosional records don’t persist for as long)
Only 0.6 billion years provide details (time with hard bodies developing at this time
fossils to make statements of envir