Radical Revisions

I pointed out in Genesis and Genes that occasionally, there are discoveries that upset the standard teaching. Standard teaching refers to scientific matters that are considered to be settled. One example of a standard teaching being revised was the discovery by Drs. Robin Warren and Barry Marshal that bacteria can survive the acidity of the stomach and that most peptic ulcers are in fact caused by bacteria, not lifestyle factors as was previously thought. Standard teachings are conveyed to the public as fact, and challenging the standard teaching often incurs ridicule.

Another example of this phenomenon that I discussed briefly had to do with snake reproduction. I referred to a report published in Biology Letters, a Royal Society journal. A summary of the journal article was provided by Science Daily (4th November 2010). It begins:

In a finding that upends decades of scientific theory on reptile reproduction, researchers at North Carolina State University have discovered that female boa constrictors can squeeze out babies without mating. More strikingly, the finding shows that the babies produced from this asexual reproduction have attributes previously believed to be impossible.

Notice that this research upends decades of scientific theory. Before this research was published, anyone who suggested that certain snakes can reproduce asexually would quite likely be ridiculed. The report continues,

This is the first time asexual reproduction, known in the scientific world as parthenogenesis, has been attributed to boa constrictors, says Dr. Warren Booth, an NC State postdoctoral researcher in entomology and the lead author of a paper describing the study. He adds that the results may force scientists to re-examine reptile reproduction, especially among more primitive snake species like boa constrictors.

Here is a more recent example of this phenomenon, in which the standard teaching turns out to be subject to radical revision.

According to standard evolutionary teaching, it was tetrapods – four-limbed creatures – that made the transition from living in the sea to terrestrial life less than 400 million years ago. For the past 150 years, it was believed that the construction of the tetrapod backbone was understood. A new report in Nature[1] radically revises the picture. The researchers used X-ray scans of fossils of tetrapods to study the structure of tetrapod backbones. The synopsis of the study notes that,

This study fundamentally revises our current understanding of vertebral column evolution in the earliest tetrapods and raises questions about the presumed vertebral architecture of tetrapodomorph fish.

The fundamental revision concerns the fact that parts of the tetrapod backbone oriented back-to-front turn out to have been front-to-back and vice versa.

A BBC report, entitled Tetrapod anatomy: Backbone back-to-front in early animals, included an interview with one of the researchers, Professor John Hutchinson of the Royal Veterinary College, and reported that[2]:

Textbooks might have to be re-written when it comes to some of the earliest land creatures, a study suggests. Researchers have found that our understanding of the anatomy of the first four-legged animals is wrong. New 3D models of fossil remains show that previous renderings of the position of the beasts’ backbones were actually back-to-front… The scientists looked at a group of animals called the tetrapods, examining three creatures called Ichthyostega, Acanthostega and Pederpes…

RVC’s Professor John Hutchinson said: “Their vertebrae are actually structurally completely different from what everyone for the last 150 or so years has pictured. The textbook examples turn out to be wrong.”

The scientists found that parts of the spine thought to face the front of the animal, in fact faced the back – and vice versa.

Informed consumers of science understand that even when scientists claim that something is known, we must differentiate between various realms of science. As we move further away from repeatable, observable and limited phenomena, the claim of scientific knowledge becomes weaker and weaker.

References:

[1] http://www.nature.com/nature/journal/vaop/ncurrent/full/nature11825.html
Retrieved 31st January 2013.
[2] http://www.bbc.co.uk/news/science-environment-20987289
Retrieved 31st January 2013.

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One Response to “Radical Revisions”

  1. Matt Says:

    Hi, I have a few questions for you:

    Could I ask you to clarify your point in why you included the anecdote about tetrapod anatomy in your article? Is it because you claim it to be a finding that “upsets the standard teaching”?

    If so, could you please clarify what you think the “standard teaching” is and how you think that this finding “upsets it”? Could you also clarify the big picture for me? What is the importance of Ichthyostega? Why do researchers care about it’s anatomy?

    Also, you ended your article, “As we move further away from repeatable, observable and limited phenomena, the claim of scientific knowledge becomes weaker and weaker.” I agree with the pshat of this statement, but I feel like there is implied subtext in your article. Are you referring to anything in particular?

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