On Pond Scum

This past weekend, I took my kids to the Houston Museum of Natural History.  It was kind of a spur of the moment trip, and it was quite fortuitous that we took the journey.  We actually had planned to go to the zoo, but the Houston Zoo was having Zoo Boo and was packed to the gills.  Not wanting to fight crowds and spar for parking, we drove to the museum, parked in the parking garage, and enjoyed a much more serene day.

It was also an educational one for the kids and their parents.  The museum was having an earth science's day.  They had stations set up throughout the museum to teach kids about geology, chemistry, electricity, energy, and paleontology.  It was at the paleontology exhibit where I had a moment which made me go "hmmm."

The museum was offering guided tours of its paleontology exhibit given by paleontologists, and it was great learning about dinosaurs and geologic time from actual dinosaur diggers and experts.  Some of the lessons learned will not be forgotten.  Especially the presentation on "deep time" and pond scum.

As the tour began, we received a lesson on deep time and the history of the formation of life on this planet.  In the blink of an eye, we traversed five billion years of history--from the beginnings of our solar system to modern day.  What was most intriguing was the development of life.

The paleontologist spoke of how the earth formed and how for a couple of billion years nothing living existed.  Then, he explained how the first living organism was bacteria which formed in the water.  Essentially it was pond scum, and pond scum was the only form of life that existed on this planet for nearly two billion years.  That might be a rather hard figure to comprehend, but it's important.  For the vast majority of time on this planet, the only thing living was pond scum. 

Then something happened.  Something quite amazing, in my estimation.  Life took off.  In a relatively short amount of time--700 million years, we went from pond scum to human beings.  It was hard for me to fathom the rapid evolution of animals and the extinction of the dinosaurs and other creatures to lead up to the present where humankind can thrive.  After two billion years of hardly any evolution at all, what precipitated the change?  How did life go from being almost static to changing so rapidly that animals with brains large enough to comprehend themselves and contemplate the future came to exist? 

In my estimation, it should not have happened so fast.  It should have taken much, much longer. 

But it didn't.

Why?

(Actually, I've got a pretty good idea, and it doesn't rely upon chance.)