e15.    What was early life like?

By bombarding the paleoenvironment with electricity and ultraviolet rays, amino acids formed into proteins and other complex organic molecules formed.  This may have been the beginnings of organic life on earth. The first organisms were most likely anaerobic bacteria because they do not require oxygen for their functioning.  They were also most likely prokaryotes that did not eat other prokaryotes.  Eventually, they adapted to making their own food through photosynthesis.  This produced large amounts of oxygen, allowing for evolution toward aerobic bacteria.  Eukaryotes evolved because some prokaryotes formed symbiotic relationships.

g03.    How did the atmosphere change after the Precambrian?

g07.    How did plate tectonics affect the diversity of ecosystems?

g13.    What makes up earth's climate?

g20.    What is the theory of plate tectonics?

m21.    Why is there controversy over old-growth deforestation?  

m29.    How is oil recovered?

m30.    How is natural gas used?

m33.    How does global warming affect climate?

m39.    How does ozone affect life?

m47.    When did we begin using pesticides?

m74.    How is soil important in the environment?

m78.    How do droughts and floods impact populations?

m79.    Where are our water supplies?