Which came first...the mutated jaw muscles, or the enlarged cranial capacity?

[ComeToTheDarkSideWeHaveCookies]

A very geeky attempt at a chicken vs egg…

Disabling jaw muscle mutation touted as possible pivitol transition in human evolution.

I’m inclined to favor the perspective that, while the discovery of any such mutation is facinating and important, that no single mutation (or consequence thereof) is the magic bullet responsible for the enlarged cranium and brain of the human.

I’m also curious as to why there is this pressure to find the singular reason? Is this pressure an artifact of the media? Isn’t the scientific community self-aware enough to know that there is never the singular reason for anything in the world of science? That we’re just always peeling back the layers of the onion of comprehension? Are we ever going to be able to write this short-sighted bias out of our scientific media?

[John_Mace]

I read about this today as well. I don’t know that scientists are looking for “the_single_reason” that turned us into what we are so much as that makes a good story when published in the popular press.

[laigle]

It’s human nature. We look for blatant oversimplifications. We try to draw nice clean lines around everything. History has to move in straight lines.

But was that true before the jaw thing, or was it a result thereof? Answers at 11!

[ComeToTheDarkSideWeHaveCookies]

Dr. Minugh-Purvis said it was unclear how the mutation could have become fixed in the species, considering its potentially deleterious effects on survival. Perhaps other agents of change were already at work, like the transition to a richer protein diet of meat. The heavier jaws were required for grinding the mainstays, nuts and plants, in their diets.

That paragraph had me nodding a bit more than some of the others. It seems a bit easier to swallow if the loss of functionality of the more powerful jaw was preceded by changes in diet and eating patterns, making the need for that power obsolete.

The first act (long removed) of the Agricultural Revolution?

I wonder how that would go over with teeming billions…We ate our way to global domination?

[II_Gyan_II]

@honeydewgrrl

I’m inclined to favor the perspective that, while the discovery of any such mutation is facinating and important, that no single mutation (or consequence thereof) is the magic bullet responsible for the enlarged cranium and brain of the human.

And the article doesn’t really say that.

From the article:

“We’re not suggesting that that mutation alone buys you Homo sapiens,” said Dr. Hansell H. Stedman, leader of the research team. “But it lifted a constraint that leads to brain growth.”

So, this mutation need not be even responsible for brain growth, just that it removed a constraint, that limited the direct factors from their potential.

[ComeToTheDarkSideWeHaveCookies]

@II Gyan II

And the article doesn’t really say that.

From the article:

“We’re not suggesting that that mutation alone buys you Homo sapiens,” said Dr. Hansell H. Stedman, leader of the research team. “But it lifted a constraint that leads to brain growth.”

So, this mutation need not be even responsible for brain growth, just that it removed a constraint, that limited the direct factors from their potential.

Some quotes that prompted me to post the OP:

…scientists say this could have made all the difference, leading to the enlarged brains of the lineage that evolved into modern humans…

…the gene mutation may represent the beginning of the ancestral triumph of brain over brawn…

“The mutation very possibly initiated an evolutionary cascade,” said Dr. Nancy Minugh-Purvis, a paleoanthropologist involved in the project.

I’m not saying that the article isn’t even-handed. They give sufficient copy to more cautionary views. I suppose I will never get used to complex scientific ideas reduced to soundbytes. I wish they’d at least throw another paragraph in articles like these to try and reinforce the scientific method…something a bit more than robust than:

Even so, the findings were expected to encourage other scientists to investigate a whole range of other genes that have decisive roles in making us distinctively human. This could enable molecular biologists to establish the chronology of important steps in human evolution with greater precision.

Am I being a whiney geek here? There’s gotta be a way to grasp the average joe’s attention without so much over-simplification of the scientific method.

Is it so much to ask for Hollywood (or the black sheep thereof) to produce some controversial blockbuster about evolutionary biology…just to get some water cooler buzz word exposure?

I look forward to the day when I’m just as likely to have a satisfying conversation on my commuter train about the fossil record as the upcoming election. Maybe someday…

[II_Gyan_II]

honeydewgrrl: I don’t understand. All of the initial quotes you present just rephrase what the last line in my first post says. As for the last quote, we share ~98.5% of our genes with the chimps (and most of the genome is “junk DNA”). It stands to reason, that of the 450 odd divergent genes, there will be a finite number of genes that conspire and collaborate in unique ways to make us human. As for the ‘singular reason’ part, there probably aren’t any direct & immediate singular causes, but there very well might be critical singular divergences, like this mutation, without which the crucial cascades might not occur in the same way.