Oxygen in the atmosphere...?

Question

what was the result of the oxygen that accumulated in the atmosphere from 2.5 billion years ago to present????

Answer 1

In short, the world that we know....

The early atmosphere of the earth was a reducing environment with little or no free oxygen.

Anaerobic photosynthetic cyanobacteria produced oxygen as a byproduct.

Over time, this toxic gas accumulated and made the atmosphere an oxidizing environment.

organisms then evolved that used this toxin as an electron acceptor for respiration.

And thus, we have a world that is full of aerobes (at least on the surface!)

Answer 2

Ancient Global Pollution

The first "pollution crisis" hit the Earth about 2.2 billion years ago. Several pieces of evidence -- the presence of iron oxides in paleosols (fossil soils), the appearance of "red beds" containing metal oxides, and others -- point to a fairly rapid increase in levels of oxygen in the atmosphere at about this time. Oxygen levels in the Archaean had been less that 1% of present levels in the atmosphere, but by about 1.8 billion years ago, oxygen levels were greater than 15% of present levels and rising. (Holland, 1994) It may seem strange to call this a "pollution crisis," since most of the organisms that we are familiar with not only tolerate but require oxygen to live. However, oxygen is a powerful degrader of organic compounds. Even today, many bacteria and protists are killed by oxygen. Organisms had to evolve biochemical methods for rendering oxygen harmless; one of these methods, oxidative respiration, had the advantage of producing large amounts of energy for the cell, and is now found in most eukaryotes.

Answer 3

Many anaerobic organisms were killed off, complex animals arose and a great deal of rusting happened.

Answer 4

Accumulated?  It is used and rebuilt over and over.  Repsiration sound familiar?  Breath in air out air with less O2 and more CO2?

Answer 5

i dont know?

Answer 6

Oxygen stayed the same. We are probably breathing the same oxygen that the "dinosaurs" breathed. The oxygen comes from trees that helps us give carbon dioxide to them.