Skip to comments.Evolution moves more quickly than scientists thought
Posted on 11/19/2006 1:00:27 PM PST by DaveLoneRanger
ST. LOUIS - Evolution happens. But it can also stop and turn on a dime.
A new study of lizards in the Bahamas shows that the natural selection pressures that drive evolution can flip-flop faster than previously thought - even in months.
"Darwin was right about so many things," said Jonathan Losos, a former Washington University biologist who led the study. "In this case he was wrong. He thought that evolution must occur slowly and gradually."
The lizards and their changing leg lengths are yet another case of evolution occurring in real time. From finches that evolve longer beaks in a few years to bacteria that adapt to strange feeding regimens in days, evolution, as a science, has leapt out of musty museums and into the field.
Scientists say that, from a political perspective, the cases offer a vivid reminder of the continuous process that some people imagine proceeding only in fossilized fits and starts: First monkey, then man.
But for the scientists themselves, the cases show that evolutionary biology has, well, evolved into a predictive, experimental science like any other.
Losos had the perfect Petri dishes: 12 tiny islands in the Bahamas with small populations of insect-eating Anolis sagrei, six-inch long lizards that normally live on the ground but can adapt to life in trees.
On six of the islands, Losos introduced a predator, a large curly-tailed lizard that can gobble up the lizards. He theorized that at first, the fastest prey would survive as they ran for the trees. Natural selection would reward long legs. Then, as the little lizards adapted to life in trees, nimble twig maneuvers and shorter legs would be rewarded.
At the start of the experiment, the scientists, using dental floss nooses on the ends of 10-foot poles, caught all lizards and carefully measured their hind-limbs. After the first six months, their predictions held up. The average leg length of survivors was 2 percent longer than those that were killed. After a year, leg length was 3 percent shorter. The changes were small in absolute terms but statistically very large, said R. Brian Langerhans, a graduate student with Losos.
The study appeared Friday in the journal Science. Losos did the research while at Washington University, but left for Harvard University in June.
The lizard study echoes one of the classic cases of evolution-in-action: Darwin's finches on the Galapagos Islands. For more than 30 years, Princeton University biologists Peter and Rosemary Grant have measured changes in the finches' beaks. After extended droughts, small seeds became more scarce. In a few years, the finches evolved longer beaks to crack the larger, tough seeds that remained. Then as more plentiful times returned, the bird beaks got smaller again.
At Michigan State University, Richard Lenski is studying evolution in test tubes. For almost 20 years, he has reared 12 colonies of E. coli. They have divided more than 30,000 times - which, in terms of human generations, is longer than Homo sapiens has been around. Lenski has challenged the bacteria with strange feeding patterns - feeding them sugars, then starving them.
The colonies all adapted, quickly. But they used different genetic tricks to get there. Their DNA is now remarkably different: an example of parallel evolution.
It's difficult to know how an organism will adapt, and also how subtle environmental changes will kick evolution off in a striking new direction, said Ken Petron, a University of Cincinnati ecologist who worked with the Grants on their finches.
For example, on one trip to the Galapagos during a time of seed scarcity, the Grants expected to find the trend toward larger beaks. But a new, larger finch had colonized the island and was eating the larger seeds, Petron said. It was no longer an advantage for the smaller finches to grow larger beaks.
"It's very difficult to predict the outcome of evolution before it happens," he said.
But if biologists can get better at predicting evolution, it could have applications for areas in which humans are altering the environment and causing evolutionary pressures themselves, Langerhans said. Stanford University ecologist Stephen Palumbi has estimated a $50 billion "evolution bill" associated with the antibiotic and pesticide resistance that bacteria, weeds and insects have evolved in medicine and agriculture.
Had the experiment continued, Losos expected the lizard legs to get even shorter with successive generations. But two hurricanes in quick succession submerged the little islands. "All the living lizards were washed away. Bummer," Losos said.
Some eggs survived, however, and hatchling populations are growing. Losos plans to start the experiment over.
Isn't this just more evidence for "Intelligent Design"? Increasing and greater complexity among life forms, etc. Confusing... my head hurts. heh, heh. [sarcasm/]
As an atheist, I just love 'South Park.' Even the recent episodes bashing atheist groups' zeal have been superb. What a great show! Go, South Park! I'm sure they are working on a new episode as we type.
And that is why this story, like the long frog leg story, will quickly die. Neither had anything to do with evolution, but the use of the E word in the article will cause attrition.
Zero to sixty is just an expression.
As I've pointed out frequently, the 99% number is inaccurate and misleading, and even when it's just mildly distorted, was usually cast as 98%.
The article is written for our dumbed down public school students and general population: no creationist would argue with it..it's just the spin and attributing this to a macro evolutionary spin.It's laughable if one knows the issues
The lizard changed to a different species? If not, it's not evolution as the brain-warped Darwinists would have us believe.
If there's no increase in genetic information, it's not "evolution."
So basically you're an evolutionist. You just believe that evolution takes place for a while and at some point somebody hits a giant red "Off" switch, preventing further evolution from taking place. A bizarre belief, certainly.
Yep. From the beginning of evolution.
That's a bad definition of the term.
Evolution, as Darwinists proclaim, is the increase in transimissible genetic information. It's not "evolution" to go from a dog to a worm -- that would be devolution or entropy or something.
We just don't see "evolution" as Darwinists preach it.
No more than wanting a peanut butter sandwich today means you now hate hamburgers.
It only indicates that change can occur in the short term.
The natural extrapolation is that if the forces that influenced the change continue in the long term the changes will be set into a new evolutionary path.
Obviously this is not evolution of any kind; its a creature adapting to the environment for which it was designed, within the limits prescribed by said design.
"A bizarre belief, certainly."
Its not a belief, but simply an incisive observation of real life.
I contend that a better example of a short species evolution is the Democrat of 1942 and the Democrat of 2006.
Their brains and spines have shrunk perceptibly. We soon believe they will stop breeding altogether
They are much more clever than that, the ones that do breed will have abortions, and ones who might breed will join in civil unions, and the ones that avoid civil unions will think that they are homosexual and the ones that....
Well, being anti life does come at a price.
Dave -- I'd have to agree with Alter Kaker on this one. You either believe evolution or don't. "Micro-evolution" is still evolution.
I, for one, don't believe in evolution (defined as an increase of genetic information transmitted through generations) at all.
Yes, you are missing something.
When these little changes pile up over millions of years they can become big changes and they we get to call the resulting organisms by a different name.
And that is indeed an excellent point.
In favor of abandonding scientific research altogether then?
Sorry, but you don't get to re-define evolution in order to oppose it.
It is most specifically not defined as an "increase in trasnmissible genetic information"