THE WORLD is very old, and human beings are very
young. Significant events in our personal lives are measured in years or less; our
lifetimes in decades; our family genealogies in centuries; and all of recorded history in
millennia. But we have been preceded by an awesome vista of time, extending for prodigious
periods into the past, about which we know little -- both because there are no written
records and because we have real difficulty in grasping the immensity of the intervals
involved. - Carl Sagan, Dragons of Eden
Wooly Bear Caterpiller
In his landmark book and TV series Cosmos, Carl Sagan introduced the world to the Cosmic Calendar. This is a calendar that plots the life of the universe on a calendar year with the Big Bang happening at midnight on January 1st and the current time being just before midnight on December 31st. The cosmic calendar allows us to have a chance of understanding just how much time the universe has existed for, how really really old the it is. Our sun doesn't even form until September. The autumn is a bit more busy with the first life on Earth showing up in late September and photosynthesis developing in mid October. Things really pick up in December but everything ever done by a human being happens in the last ten minutes before midnight on December 31. Really puts things in perspective, doesn't it?
On the Cosmic Calendar, December 5th is when single celled organisms first started banding together to form multicellular life. No one is sure exactly how this revolutionary leap forward happened so it is an area where scientists are still asking and answering really interesting questions. It seems that working together, symbiosis, is a really useful thing for living creatures even when those creatures are yeast cells or bacteria. Lynn Margulis was a biologist who made a career out of emphasizing cooperation in nature and evolution. She claims that the bodies of complex organisms are in fact the result of symbiosis and cooperation among different kinds of bacteria. The mitochondria that create energy in our cells and the chloroplasts that make energy in plant cells are actually "captured" bacteria who work together with the host cell, trading protection and an increased chance of survival for the energy they can create. Similarly, many single cells can join together to form a multicellular organism cooperating to increase their chance of survival. Sponges are an excellent example of this. Each cell in a sponge is essentially its own living being but they join together to create an environment where each cell can better survive. Some kinds of soil amoebas actually spend a part of their life cycle as independent single celled organisms but in times of drought or low food, they band together into a super amoeba that can move quickly to find a more suitable habitat.
Trillium
When we think about life, we are almost always imagining multicellular organisms. Dogs, oak trees, mushrooms, dolphins and ants are all complex systems of cooperating cells. Nature may still be red in tooth and claw, but it is also very willing to work together to make life easier for the entire community. That is a very uplifting thought to me - at every level, from cells up to ecosystems, living things are cooperating and living in symbiosis and through that cooperation have developed into the grand array of living things we see around us today.
What is your favorite multicellular living thing? When have you seen surprising examples of cooperation, either in nature or in humans society? What science PB&J (passion, beauty and joy) are you in awe over these days?
Around Town: Zoolights!
Go see some amazing multicellular life at the Oregon Zoo and stay for the holiday light show. Zoolights is open every night this month and is a family friendly fun time for all. Plus, soon you might get to see the new baby lions or the new baby otter!
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