Posted on 01/18/2006 6:10:34 PM PST by PatrickHenry
Our ears could have started evolutionary life as a tube for breathing, say scientists, after examining the ancestral structure in a 370-million-year-old fossil fish.
Evolutionary biologists are intrigued by how complicated sensory organs evolved from structures that may have had completely different uses in ancestral creatures. The bony structures in ancient fish, which at some point turned into ears, for example, appear to have had mainly a structural function, bracing the cheek and holding up the jaw. How exactly they made the transition to their role in hearing has proved a bit of a mystery.
The ear is a relatively easy organ to study. Its evolving bones have been preserved as fossils, whereas the soft tissues of other specialized features, such as eyes and noses, have long decayed.
So Martin Brazeau and Per Ahlberg of Uppsala University in Sweden decided to take a close look at the ear-like features of an ancient, metre-long monster from the Latvian Natural History Museum in Riga. Panderichthys was a fish, but is thought to be closely related to the earliest four-limbed tetrapods that eventually climbed on to land and gave rise to modern vertebrates.
The researchers examined Panderichthys and found that the bony structures in its head combine features of fish and tetrapods, capturing a snapshot of evolution in action. "It's neat to see that transition," says Hans Thewissen who studies the evolution of the ear and other organs at Northeastern Ohio Universities College of Medicine, Rootstown.
Half-way house
Ancient fish have a narrow channel from the roof of the skull into the mouth, known as a spiracle, which is bounded by a long bone known as the hyomandibula that braces the cheek. In tetrapods, the equivalent bone is stubbier, a step towards the stirrup-like stapes bone that helps to transmit sound waves into our skulls.
The team found that Panderichthys has a wide, straight spiracle rather than a narrow one, and a shortened hyomandibula. They report their findings in Nature1.
Some have previously speculated that our ancient ears may have had a role in breathing.
On the basis of this new fossil evidence, the team speculates that the widened spiracle may have served Panderichthys much like the breathing holes used by modern-day sharks and rays. These allow the fish to inhale water over their gills while lying on the seabed, and avoid gulping in grit through the mouth.
| The demonstration of an organ evolving provides tangible evidence against the idea, put forward by some proponents of creationism, that sensory organs are so intricate that they must have been designed by a higher being. Brazeau says: "It's a slap in the face to that kind of thinking." |
Oh ouch, that really hurt. You're opinion meant so much to me too!
Your!
The best argument that there is a GOD - and it often moved me deeply - is this one that he proves from generation of species: a cow always bears a cow, a horse a horse, etc. No goldfinch produces a siskin. Therefore it is necessary to conclude that there is something that directs everything thus. ---Martin Luther (350 yrs. before Darwin).
Try People magazine?
Ah yes. That eminent scientist Martin Luther.
Didn't he discover that the Earth revolved around the Sun? No?
Pity.
Why are you continuing to make the dishonest claim that evolution is somehow equivalent to atheism? Does it not bother you that you are lying?
we are the special product of a God who created us in His Own Image, and breathed life into us?
What if God looks like a Gorilla? That would definately throw a 'Monkey' wrench into these discussions, wouldn't it?
I never read (or look at the pictures) People. National Inquirer maybe...
That's the best argument that there is a God?
Produce some evidence that statement was made the doesn't trace back to David Menton
My Buick Regal evolved into a Ford Truck F150. I don't know how it happened, but there are many similarities. They both have engines that work on the same principles, both have four wheels and steering wheels, so it must be true.
Your truck is an imperfect self-replicator? Or are you just making an inane and totally invalid analgy in abscence of any real arguments?
It was a funny,PEOPLE, you know? Those are the pics you requested. That all came from an article I read in Playboy.
What exactly is your point?
Hey, you've got your two center lines for a limerick!!
Opra won't approve of that 'loopy' business, lol.
A sligh quibble. This was so only in Christian (and, AFAIK, Muslim) countries. The Hindus believe in a **much** older universe than science does.
Well, yeah, they believed in an oscillating universe come to think of it. But I was talking about countries whose religions were based on the Bible. I was arguing against the contention that idea of a young earth arose about the same time that Darwin came onto the scene. That is of course the opposite of what happened.
That is quite a leap to imagine that a fossil fish means that we once breathed through our ears. It is as absurd as concluding that my Buick evolved into a Ford truck because there are some similarities.
But, as you bring up the subject--has time always and behaved the same? That is, a billion years ago--was a day still 24 hours? Our notions of time are like our notions of speed--dependent on a paradigm.
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