Archive for the ‘What Scientists Say’ Category

In The Origin of Species, Charles Darwin proposed that evolution proceeds by “slight, successive changes”. Although molecular biology was largely unknown by Darwin during the nineteenth century, “slight, successive” molecular changes have become a cornerstone in the study of biological evolution.

Since steroid hormones are known to perform sophisticated regulatory functions in microbes to man, the path of steroid evolution has entered center stage in the realm of investigative molecular biology.

Steroids hormones were first discovered in the mid-twentieth century by American chemist Edward Calvin Kendall while working at the Mayo Clinic. In 1950, Kendall and colleague Philip Hench, along with Swiss chemist Tadeus Reichstein were awarded the Nobel Prize in Physiology or Medicine for “their discoveries relating to the hormones of the adrenal cortex, their structure and biological effects.” Continue Reading

Charles Darwin never mentions the 1856 fossil discovery in the Neander Valley limestone quarry located in Germany in The Origin of Species in 1859 nor in any of the six subsequent editions. Even in The Descent of Man, Darwin did not endorse the Neanderthals as a potential ancestral transitional link to humans.

In fact, the discovery was a problem since the Neanderthal skulls are larger than human skulls. Darwin had argued that the advancement of evolution proceeded through “slight, successive changes”.

The Neanderthal fossils created a dilemma for Darwin, how could a larger brain precede a smaller brain? Darwin cautiously noted, that “it must be admitted that some skulls of very high antiquity, such as the famous one of Neanderthal, are well developed and capacious [large]”. For Darwin, the Neanderthal skulls were too large to have preceded humans. Continue Reading

In The Origin of Species, Charles Darwin agonized over the gaps in the fossil record. “Why then is not every geological formation and every stratum full of such intermediate links? Geology assuredly does not reveal any such finely graduated organic chain; and this, perhaps,” Darwin pined, “is the most obvious and serious objection which can be urged against my theory.”

To address and justify the “serious objection,” Darwin reasoned that “only a small portion of the surface of the Earth has been geologically explored.” However, in the wake of 150 years of unprecedented paleontological research since the publication of The Origin of Species in 1859, the gaps are even more glaring. Continue Reading

The fossil remains of Australopithecus sediba, nicknamed Karabo, has generated a frenzy in the evolution loving media following the publication of five papers in the journal Science on September 9, 2011. The intention of the papers was to finally resolving the long standing human evolution fossil record gap problem.

Using state-of-the-art radiological technologies, the papers focused on the comparing the shape and size of the cranium, pelvis, hand, and ankle & foot of Karabo to humans. The fifth paper estimated the date of the fossils mains using advanced Uranium-lead dating technologies. Continue reading

In this last week’s issue of Science, researchers present two remarkably complete and well-preserved partial skeletons of a species called Australopithecus sediba discovered 3 years ago in a South African cave. The new report extended a flurry of spinning speculations on the possible human “missing link” status of A. sediba.

National Public Radio (NPR) ran an article entitled “Examining Ancient Fossils for Clues to Human Origins”. The Wall Street Journal chimed in with “Fossil Trove Sheds Light on a Stage of Evolution”. The Boston Globe speculated with the title “Skeleton could be human relative”; TIME with “Rethinking Human Origins: Fossils Reveal a New Ancestor on the Family Tree”. Contniue Reading

In a letter to Hugh Falconer in October 1862, Charles Darwin wrote, “I look at it as absolutely certain that very much in the Origin will be proved to be rubbish.”

Since the publication of the first edition of The Origin of Species in November 1859, attempts over the past 150 years to avoid fulfilling Darwin’s own prediction have largely been a failure, according to an article in The New York Times —at least in the classroom.

In the Times article “On Evolution, Biology Teachers Stray From Lesson Plan,” free-lance writer Nicholas Bakalar notes “that only 28 percent of biology teachers consistently follow the recommendations of the National Research Council to describe straightforwardly the evidence for evolution and explain the ways in which it is a unifying theme in all of biology.”

While only 28 percent of the teachers consistently follow the recommendations, Bakalar was even more dismayed that researchers discovered that “13 percent explicitly advocate creationism, and spend at least an hour of class time presenting it in a positive light.” Continue Reading

Charles Darwin in The Origin of Species hoodwinks natural selection with alternating unlimited and limited power. Natural selection was Darwin’s “grand” natural law acting through the ages giving rise to ever increasing complex forms of life. This essence of the concept is captured in the title: The Origin of Species by Means of Natural Selection.

Natural selection, the proposed natural law driving the progress of evolution, was envisioned by Darwin, on the one hand, with powers like that of a deity: It has been said that I speak of natural selection as an active power or Deity; but who objects to an author speaking of the attraction of gravity as ruling the movements of the planets?
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Charles Darwin in a letter Joseph D. Hooker in February 1871 speculated that life might have originated in “some warm little pond, with all sorts of ammonia and phosphoric salts, light, heat, electricity, &c., present, that a proteine compound was chemically formed ready to undergo still more complex changes”. The search for the origin and essence of life continues.

Central to the origin of life issue is the question, what is life? The journal Astrobiology in December 2010 featured a collection of essays on the topic “What is Life?” organized by David Deamer of the University of California, Santa Cruz, by asking the question, “Can life be defined?” Continue Reading

In The Origin of Species, Charles Darwin explains how “external resemblances [of moths]… has been gained for the sake of protection” giving the moth “a better chance of escaping destruction from predaceous birds”… “So that we have an excellent illustration of natural selection.”

Bernard Kettlewell in the early 1950’s was the first to design an experiment to test Darwin’s “excellent example of natural selection” in two types of wooded areas in England—polluted and nonpolluted. Kettlewood demonstrated light colored peppered moths survived better than darker colored moths in areas where the tree trucks were of lighter color, and conversely— darker colored moths survived better than lighter colored moths in areas where the tree trucks were of darker color.

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In a letter to botanist Joseph Hooker in 1871, Charles Darwin attempts to explain how life originated from materials, “we could conceive in some warm little pond, with all sorts of ammonia and phosphoric salts, light, heat, electricity, etc., present, that a protein compound was chemically formed ready to undergo still more complex changes”

While not specifically address origin of life issues in The Origin of Species, Darwin clearly wrestled with the issue. At the time, concepts of spontaneous generation, the animate arising from the inanimate, dominated the evolution movement. Continue reading