Humans have undoubtedly been a major environmental disaster. We have driven numerous other species into extinction. We have destroyed enormous sections of habitat. We've polluted the air, the land, and the sea. We are on the verge of permanently altering our planet's climate.

Another major environmental disaster of even more enormous proportions took place roughly 2.5 billion years ago. A small fraction of existing organisms began producing a poison that was deadly to 99% of existing life. The poison also eliminated existing energy supplies for many of those organisms by reacting chemically with them.

The poison was oxygen, and the process that produced it was photosynthesis. Oxygen is a highly a reactive molecule. That's why it burns, and that's why it makes such a good source of energy for those organisms that can tolerate its presence. There are still primitive organisms that can't survive in oxygen. They are called obligate anaerobes. All other forms of life have developed special proteins to scavenge for dangerous oxygen bi-products. Without those proteins, oxygen would still be poisonous.

The presence of oxygen from photosynthesis, while poisonous to the existing life forms 2.5 billion years ago, also created the opportunity for a great expansion in the nature and diversity of life. The trees in our forests, the grass in our fields, the algae in the sea, and the plants and animals everywhere exist in their beauty and their complexity exist because of the introduction of oxygen.

We humans are a biological phenomenon. We are the result of the emergence of a new form of evolutionary replicator that changes more rapidly than DNA. We are more than another form of primate. Humans are the carriers of thoughts that can be passed from individual to individual, and which undergo variation and selection. The emergence of this new replicator has the potential to be as important event for the planet as the introduction of photosynthesis. More so because while photosynthesis was the result of a the DNA replicator producing a new form of life, human thought is a new replicator, with a potential to produce even greater than that of DNA.

And as a person who studied biology for four years, I can say that what DNA has produced is pretty amazing. A human body contains roughly 10,000,000,000,000. Each cell is amazing piece of machinery, sophisticated and intricate beyond belief, and each cell contains a blue print for the organization of the entire 10,000,000,000,000 cells. Look at the brain. 1,000,000,000,000, neurons each with on average five thousand connections to other neurons. And that's just humans. We are just one of hundreds of thousands of species interacting together.

Yet, the new system of evolution is only a couple hundred thousand years old. It's one ten thousandth of the age of the DNA system. Think about the potential of the new system. Give it another 100,000 years and where it will be? I look at what DNA has done, and I think of it as example. I look at the oxygen catastrophe and the human impact on the environment, and I think how amazing our future will be.