Re: Apologetic Islamic take on Evolution … Or unkind dismissal?
There you go again..
Misconceptions about evolution
MISCONCEPTION: Evolution is not science because it is not observable or testable.
CORRECTION: This misconception encompasses two incorrect ideas: (1) that all science depends on controlled laboratory experiments, and (2) that evolution cannot be studied with such experiments. First, many scientific investigations do not involve experiments or direct observation. Astronomers cannot hold stars in their hands and geologists cannot go back in time, but both scientists can learn a great deal about the universe through observation and comparison. In the same way, evolutionary biologists can test their ideas about the history of life on Earth by making observations in the real world. Second, though we can’t run an experiment that will tell us how the dinosaur lineage radiated, we can study many aspects of evolution with controlled experiments in a laboratory setting. In organisms with short generation times (e.g., bacteria or fruit flies), we can actually observe evolution in action over the course of an experiment. And in some cases, biologists have observed evolution occurring in the wild. To learn more about rapid evolution in the wild, visit our news story on climate change, our news story on the evolution of PCB-resistant fish, or our research profile on the evolution fish size in response to our fishing practices. To learn more about the nature of science, visit the Understanding Science website.
…and to give you an observable instance of evolution in laboratory settings..
Time in a bottle: Scientists watch evolution unfold over 40,000 generations
Contact: Michael Steger, College of Natural Science, Office: (517) 432-4561, [email protected]; Richard Lenski, Microbiology and Molecular Genetics, [email protected]
Published: Oct. 19, 2009 E-mail Editor ShareThis
EAST LANSING, Mich. — A 21-year Michigan State University experiment that distills the essence of evolution in laboratory flasks not only demonstrates natural selection at work, but could lead to biotechnology and medical research advances, researchers said.
Charles Darwin’s seminal Origin of Species first laid out the case for evolution exactly 150 years ago. Now, MSU professor Richard Lenski and colleagues document the process in their analysis of 40,000 generations of bacteria, published this week in the international science journal Nature.
Lenski, John A. Hannah Distinguished Professor of microbial ecology, started growing cultures of fast-reproducing, single-celled E. coli bacteria in 1988. If a genetic mutation gives a cell an advantage in competition for food, he reasoned, it should dominate the entire culture. While Darwin’s theory of natural selection is supported by other studies, it has never before been studied for so many cycles and in such detail.
“It’s extra nice now to be able to show precisely how selection has changed the genomes of these bacteria, step by step over tens of thousands of generations,” Lenski said.
Lenski’s team periodically froze bacteria for later study, and technology has since developed to allow complete genetic sequencing. By the 20,000-generation midpoint, researchers discovered 45 mutations among surviving cells. Those mutations, according to Darwin’s theory, should have conferred some advantage, and that’s exactly what the researchers found.
The results “beautifully emphasize the succession of mutational events that allowed these organisms to climb toward higher and higher efficiency in their environment,” noted Dominique Schneider, a molecular geneticist at the Université Joseph Fourier in Grenoble, France.
Lenski’s long-running experiment itself is uniquely suited to answer some critical questions – such as whether rates of change in a bacteria’s genome move in tandem with its fitness to survive.
“The coupling between genomic and adaptive evolution is complex and can be counterintuitive,” Lenski concluded. “The genome was evolving along at a surprisingly constant rate, even as the adaptation of the bacteria slowed down a lot. But then suddenly the mutation rate jumped way up, and a new dynamic relationship was established.”
A mutation involved in DNA metabolism arose around generation 26,000, causing the mutation rate everywhere else in the genome to increase dramatically. The number of mutations jumped to 653 by generation 40,000, but researchers surmise that most of the late-evolving mutations were not helpful to the bacteria.
Gene mutations involved in human DNA replication are involved in some cancers. Many of the patterns observed in the experiment also occur in certain microbial infections, “and cancer progression is a fundamentally similar evolutionary process,” observed collaborator Jeffrey Barrick. “So what we learn here can help us better understand the course of these diseases.”
Barrick, a postdoctoral researcher in MSU’s Department of Microbiology and Molecular Genetics, developed computational tools to discover and validate often complex mutations. “We know an astounding amount about the details of evolution in these little Erlenmeyer flasks,” he said.
The Nature paper involved collaboration with scientists from South Korea as well as France and MSU. The research, said genomics team leader Jihyun Kim of the Korea Research Institute of Bioscience and Biotechnology, “is not only useful in understanding the tempo and mode of evolution, but can serve as a nice framework for practical applications in biotechnology, such as improving the performance or productivity of an industrial strain.”
Thousands of generations later, the MSU experiment continues to evolve. “Like a lot of science, our study answers some questions but raises many others,” Lenski said.
The research has been supported by the National Science Foundation and the Defense Advanced Research Projects Agency.