Archive for the ‘Miscellaneous’ Category

Biology Textbooks Get It Wrong on Life’s Origin

Thursday, August 2nd, 2007

Photo of Fazale 'Fuz' RanaChemist Stanley L. Miller died in late May (March 7, 1930-May 20, 2007).

If you don’t recognize the name, you are probably familiar with his famous experiment. Virtually every high school biology text describes the work Miller performed in the early 1950s. He filled the confines of a carefully assembled glass apparatus with methane, ammonia, and hydrogen after diligently excluding oxygen from the system. At that time, scientists thought the gases Miller used in his experimental setup had existed in early Earth’s atmosphere. A boiling flask of water connected to the glassware introduced water vapor into the headspace and simulated early Earth’s oceans. Miller passed a continuous electric discharge through the gas mix and showed that the primitive atmosphere of the early Earth could, in principle, generate amino acids, one of the key building blocks of life.

Miller’s work was the first experimental validation of the Oparin-Haldane hypothesis. This model, based on the principles of chemical evolution, was one of the first scientific models to describe a mechanistic pathway to life from simple chemical compounds.

Stanley Miller’s experiment launched origin-of-life studies as an exciting area of experimental research. His success has prompted scientists over the course of the last 50+ years to conduct similar experiments seeking chemical routes to other critical biomolecules.

Status of the Miller-Urey Experiment

Today, the Miller-Urey experiment is considered to be irrelevant to the origin-of-life question. Current understanding of the composition of early Earth’s atmosphere differs significantly from the gas mix used by Miller. Most planetary scientists now think that the Earth’s primeval atmosphere consisted of carbon dioxide, nitrogen, and water vapor. Laboratory experiments indicate that this gas mixture is incapable of yielding organic materials in Miller-Urey-type experiments.

In May 2003 origin-of-life researchers Jeffrey Bada and Antonio Lazcano, long-time associates of Miller, wrote an essay for Science (May 2, 2003, pp. 745-746) commemorating the 50-year anniversary of the publication of Miller’s initial results. They pointed out that the Miller-Urey experiment has historical significance, but not scientific importance in contemporary origin-of-life thought. Bada and Lazcano wrote:

Is the “prebiotic soup” theory a reasonable explanation for the emergence of life? Contemporary geoscientists tend to doubt that the primitive atmosphere had the highly reducing composition used by Miller in 1953.

In his book Biogenesis, origin-of-life researcher Noam Lahav passes similar judgment:

The prebiotic conditions assumed by Miller and Urey were essentially those of a reducing atmosphere. Under slightly reducing conditions, the Miller-Urey reaction does not produce amino acids, nor does it produce the chemicals that may serve as the predecessors of other important biopolymer building blocks. Thus, by challenging the assumption of a reducing atmosphere, we challenge the very existence of the “prebiotic soup”, with its richness of biologically important organic compounds.

For many people, the generation of amino acids from simple chemical compounds thought to be present in early Earth’s atmosphere meant that life could originate all on its own without the need for a Creator. Work done on the early planetary conditions of Earth in the intervening decades between Miller’s famous experiment and his death, however, have invalidated this famous experiment and its support for an evolutionary explanation for life’s origin, in spite of what textbooks report.

For more detailed discussions on other problems confronting the evolutionary paradigm for the origin of life see the article “Origins-of-Life Predictions Face Off: Evolution Vs. Biblical Creation” and the book Origins of Life: Biblical and Evolutionary Models Face Off.

Ingenious Discoveries

Wednesday, June 6th, 2007

Photo of Jeff ZweerinkI often marvel at the discoveries scientists make and the ingenuity employed in making those discoveries. For example, a year ago on Creation Update I discussed a Science article where researchers used neodymium concentrations in fossil fish teeth to date when the Drake passage opened, allowing circumpolar ocean currents around Antarctica.

A Nature article describes another example where scientists discovered two supernovae in the Large Magellanic Cloud (LMC). Remarkably, the supernovae in question occurred over 400 years ago (not including light travel time from the LMC to Earth). While the original light from the supernovae has long since passed Earth, some light reflected off clouds in the LMC back toward Earth. From this light, scientists determined the location and nature of supernovae and are attempting to pin down what type of supernovae occurred.

Astronomers used another ingenious technique to measure the temperature of the universe in the past. The cosmic microwave background (CMB) provides abundant information on many important characteristics of the universe. While the CMB detected on Earth measures only today’s temperature of the universe, we see distant galaxies as they appeared in the past. Taking advantage of this fact, a team of scientists describe in the Astrophysical Journal how the state of carbon in distant galaxies tells the temperature of the CMB at earlier times in the universe. The temperature extracted matched the value predicted from big bang cosmology.

On the subject of dating, recent developments show how cave formations provide some of the most precise methods for dating geological history. As annual layers in deep ice cores from Antarctica provide dates to a few hundred thousand years, cave formations called speleothems provide dates in the same range but with much higher precision. Additionally, since caves are found throughout the world, speleothems give more complete and more easily accessible data.

One last example shows how scientists use asteroid material to reconstruct events during the formation of the solar system. Different kinds of stellar environments are required to produce all the elements naturally occurring on Earth. All stars heavier than the Sun produce many lighter elements like carbon, nitrogen, and oxygen, but elements heavier than iron are produced only in cataclysmic stellar explosions like supernovae. Different types of supernovae produce different heavy elements. Additionally, novae and asymptotic giant branch stars form elements not produced in abundance any other way. A Science article described how asteroids record the signatures of these stellar processes during the formation of the Sun, thereby giving detailed information on events that occurred over 4.5 billion years ago.

Scientists make numerous rational, scientific inferences about creation. Arguing that those inferences correspond to reality is troublesome from a naturalistic perspective but flows naturally from a Christian worldview. Ken Samples, my colleague at Reasons To Believe, develops this point further in this article.