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." |
It sounds like you have the right idea. I like the way you put that, bioligical change over time. I would like to see evolution taught in religious schools. And I am sure it is, because there are some really good parochial schools out there.
Oh? I've never heard a mathematician state that 2 plus 2 might equal 4. Or a chemist say that a water molecule MIGHT contain two parts of hydrogen and one part oxygen. But maybe they're not real scientists.
1.9999999999 is deducted 2 and 1.9999999999 plus 1.9999999999 is 3.9999999998. 3.9999999998 is is deducted 4
H2O is water H3O is heavy water and exists in bodies of H2O. Both are water but heavy water is so named because of molecular weight difference.
Check out my post: 200.
I think it's bedtime now. %-)
Me too. No new revelations today.
check your html
There are times when my ears plug up so bad I feel like I can't breathe.
http://69.64.39.6/cgi-bin/ImageFolio3/imageFolio.cgi?action=view&link=Humor_and_Quirkyℑ=951203D.jpg&img=60&tt=
My IE interprets the "&image" part as some kind of HTML character & mucks it up. In fact, if you're using IE, all you see in the url above after "Humor_and_Quirky" is the unprintable character block! But Firefox, OTOH, handles it correctly.
Oh well. Here's the tinyurl for it. (That was a long walk for a short payoff, I'm sure. :-)
I went to school with some other chemists who claimed did not accept evolution in ANY way. I then asked them if they understood the principles involved in the process of bacterial resistance, and if so, whether they wanted to change their claim a little ;) Got alot of 'er..um..er'...
H2O is water, and also heavy water. In ordinary water, the hydrogen atoms are almost entirely the light isotope of hydrogen, 1H, occasionally called protium. In heavy water, they are a heavier isotope of hydrogen, 2H, also called deuterium. The chemical formula of both, however, is the same.
From the article:These allow the fish to inhale water over their gills while lying on the seabed, and avoid gulping in grit through the mouth.
I've kept rays in aquariums. In addition to moving water over their gills, they'll also squirt it out of their mouth to stir up the sand/gravel to find food.
Ever seen a shark or a ray?
It's the only crap she's got ...
Let me translate the article for you:
I don't want there to be a God. I don't want to be responsible to a God. I don't want to think that maybe I'm not the highest thing in the Universe. But more than anything, I don't want you to think that their is a God who is smarter than we scientists because in our little world, WE ARE GOD.
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And I will now translate the above posting, showing all the relevant and truthful parts:
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