By Brook Stallings.
In a speech that spanned 10 billion years and disciplines as diverse as agriculture and computer science, Dr. Leroy Hood explained Darwin’s theory of natural selection and what it tells us about who we are, how we came to be, and where our shared journey may take us in the far future.
Hood spoke at the Carlson Theater at 2:30 on Feb. 12 to a packed auditorium for an hour, taking questions from the audience at the end. Thursday was the 200th anniversary of famed English naturalist Charles Darwin’s birth.
Hood is the inventor of the automated gene sequencer, which made it possible to read the human genome. The event was sponsored by BCC and the Foundation for the Future, a non-profit formed in Bellevue to spread knowledge about humanity’s future.
The common thread of Hood’s talk was complexity, how simple things give rise to more complex things in nature. Hood attributed to Darwin an insight about complexity that profoundly changed biology in the 20th century, and which is now changing other sciences as well.
When Darwin began his famous four-year voyage on the Beagle, people knew that life evolved, but no one knew how or why. Darwin’s voyage changed that. He knew how to observe nature, and how to take knowledge from many fields and use it.
So, when Darwin came home, he took lots of time to think about what he had seen. In fact, he thought for 22 years before Alfred Wallace’s independent discovery of natural selection forced him to publish his theory. Evolution is a simple idea, but a deep one, Hood said.
Evolution happens when natural variation (individuals in a species differ) and natural selection (these differences keep some from reproducing) work together over time to make a species better able to survive. It turns out that this idea is useful in many sciences. The immune system uses natural selection to rapidly adapt to new diseases. Computer scientists use it to find new ways to teach computers to do complex tasks. Financial theories are being built around evolutionary principles.
Hood went on to discuss how life evolved. Four and a half billion years ago, when the earth formed, it was too hot to support life. As the earth cooled, life became possible. Early life evolved into more complex bacteria, then multi-celled life.
Things really took off when symmetry evolved. For the first time, a single change in a single gene could give a creature an extra set of wings, or legs, for instance. This can make a huge change in how well creatures survive, which helps drive evolution.
Finally, Hood spoke of his ideas about the future. He said that biology will be the dominant science of the 21st century, and will transform our understanding of everything.
We now know that different human peoples differ by less than one gene in a thousand. The Neanderthal genome is being sequenced now, and only differs from ours by 5 genes in a thousand. We are using genetic diversity to track human migrations throughout history.
The lessons that Hood draws from this are that we are connected to all life, and that we are all one race. He wants to see us use science to push towards a better understanding of the human condition.
In 5 billion years, Hood said, the sun will expand and the earth will die. He said he hopes that before then, we will use genetic science to adapt our bodies to new planets orbiting other stars.
The question and answer session opened with a man who asked if scientists had an explanation for how the first life forms arose.
“One of the great arguments that creationists use is that there are gaps in evolutionary knowledge
By Brook Stallings.