Where'd all these eggshells come from?

Happy Sunday everyone! And wish me luck (I have a cumulative final on Wednesday, a Philosophy exam on Thursday and then another cumulative final on Thursday night. Some how The "Tao Te Ching", Archeology of the Chesapeake and a History of the Earth have to congeal in my head before then. The results have been interesting)

But I wanted to put up my environmental learning tale for the week. First though I have to give a shout out to Diana who correctly answered that a symbiotic relationship is an interaction between two species whereby both benefit. My favorite example is that of the ants in the acacia trees. The ants get to live in a convenient little home that comes equipped with thorns to reply ant eating animals, and the acacia gets the little ants to repel all acacia eating creatures of the buggy variety. Go Mother Nature!

And now...for my Environmental Learning Tale entitled...

Where'd All These Eggshells Come From?

Okay, recently the environmental community has gotten pretty riled up about the whole "Global Warming/Global Climate Change" thing. And thanks to Al Gore's "An Inconvenient Truth" (say what you will, we eco-geeks were having a field day. One of our own! On TV!) the general public has basically been apprised of the situation.

I believe that Global Warming is an issue.

No one panic, I am not about the brow beat you into accepting this idea (hence the idea of walking on eggshells conveyed by the title). I think one of the problems with this issue is that no one is giving any one the facts. The scientist have them, the media doesn't want to talk about them, and the general public doesn't really know them.

In the interest of raising public awareness (this is a revolution after all, facts are not just for scientists people!) I am going to give you one example of why I feel that Global Warming could become a problem. I am not going to touch human involvement in the development of this issue in this post (but be on the lookout! I'll happen when you least expect it!)

Here's what I will tell you. When the earth was formed during the Hadean era, about 4.5 billion years ago (oh man, maybe I won't fail my physics final) the atmosphere was mostly carbon dioxide. As a result of this, life took a darn long time to evolve, but eventually, during the Archean, some wee little protozoa popped up. They became cyanobacteria. These cyanobacteria set up shop and grew like crazy. However, things were about to change...

These cyanobacteria breathed in carbon dioxide and breathed out oxygen (think of them as little tiny trees) This went okay for a while, but eventually there were so many cyanobacteria that most of the carbon dioxide in the atmosphere wound up inside them. Consequently the air on earth became what it is today. Which was just great actually. Temperatures dropped (say what you will, Carbon Dioxide is a green house gas) and lots of little critters evolved, and now here we are. As a note, there is still carbon dioxide in our atmosphere and THAT IS A GOOD THING. In fact, its a great thing, because without it the earth would be too cold for any life at all to have evolved. So things are pretty good.

Basically to recap: Earth formed - CO2 atmosphere - cyanobacteria - O2 atmosphere - people

If I drew that outline on my test my teacher would go into cardiac arrest, but it serves my purpose. What I just told you actually happened, it is accepted as fact with in the scientific community. I even wrote a poem about it for my poetry class. Its all good.

That is my learning tale, and here is the question that goes along with it. Its a tough one, but I have faith in you all.

When did Homo sapiens sapiens evolve?

Have a wonderful week everyone. If you attend WaC, good luck on finals!