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Author | Topic: How can evolution explain body symmetry? | |||||||||||||||||||||||
jar Member (Idle past 393 days) Posts: 34026 From: Texas!! Joined: |
if there had been any basis for what you propose.
You said
Take the human ear. If evolution is correct, then I suppose that sometime long ago, some sort of cells started developing that were sensitive to sound waves, and eventually they formed into an ear with the various organs. But two ears are better than one because they allow the animal to distinguish which direction the sound is coming from. So somewhere along the line, via a mutation, an additional ear appeared, and over time slowly migrated to the opposite side of the head where it was in optimal position for stereo hearing. But the ear would still be a copy of the original ear, and not a mirror image. How can evolution explain this? All humans should have one of their ears facing backwards, or maybe upside down if they evolved naturally by the above process. Nice thought but all of the indications and evidence is that is not at all what happened. Instead, the Ear appears to have come from jawbones. Jawbones already are symetrical, one on each side of the head. So forget all the migration around the skull. Never happened. Summary, symetrical ears do not present any problem and are certainly not any indication of intellegent design. Start you search for reasonable explanations of how the ear developed at TalkOrigins and then for more information (lots of it) simply Google +ear +evolution. Aslan is not a Tame Lion
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jar Member (Idle past 393 days) Posts: 34026 From: Texas!! Joined: |
First, for a trait to continue it must offer an advantage to the population for survival. It is not individuals that evolve but populations. There is no plan to it, no direction.
For what you describe to happen, some asymetrical mutations would have to give some advantage, reproduction, able to tolerate some changed environment, new food supply, something. That you do not see it simply means it didn't happen. That says absolutely nothing about Evolution. Aslan is not a Tame Lion
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jar Member (Idle past 393 days) Posts: 34026 From: Texas!! Joined: |
Unless it offers an advantage you will not see it. But the very things you have mentioned, that there is no symmetry internally, shows that there is no preference for either symmetry or asymmetry.
Plus, look at all the critters out their that are not symmetrical. Plants, are a great example. Look at handedness. Asemmetrical. Look at snail shells, look at fiddler crabs, look at trees, look at many spyder, bee and other insect's eyes. Often there are three of them, asymmetry. Aslan is not a Tame Lion
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jar Member (Idle past 393 days) Posts: 34026 From: Texas!! Joined: |
Cliff.
Evolution is evolution. There is not one set of rules for plants and another set of rules for animals. Aslan is not a Tame Lion
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jar Member (Idle past 393 days) Posts: 34026 From: Texas!! Joined: |
As a Christian I get really upset when people try to use Intellegent Design as a way to falsify Evolution.
There is no way anyone can look at the designs and say they were done by an Intellegent Designer. Maybe they were a Junior High Science Project but certainly not one the level that any mechanical engineer would hope to produce. Don't you realize just how incompetent that makes God look? Aslan is not a Tame Lion
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jar Member (Idle past 393 days) Posts: 34026 From: Texas!! Joined: |
The one eyed, one horned flying purple people eater?
Well I saw the thing coming out of the sky It had one long horn and one big eye I commenced to shakin' and I said oo-wee It looks like a purple people eater to me It was a one-eyed one-horned flying purple people eater Sure looks good to me Well, he came down to earth and he lit in a treeI said mr Purple People Eater don't eat me I heard him say in a voice so gruff I wouldn't eat you 'cos you're too tough It was a one-eyed one-horned flying purple people eater It sure looks strange to me Aslan is not a Tame Lion
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jar Member (Idle past 393 days) Posts: 34026 From: Texas!! Joined: |
of symmetry, it can easily be done.
Unfortunately, you are wandering down the wrong path to do so. If you will step back from living things for a moment, you will find that symmetry is a very basic result of some of the more fundamental laws. It is inherent in the basic facts of the three dimensional world we live in. Stop for a moment and consider crystals. They are all symmetrical because there is no way that the basic building blocks can combine without producing symmetry. The human body, in fact almost NO organisim beyond simple cellular forms, is symmetrical. Yet at the earliest stages we still find symmetry. And that is where your analogy totally fails. Look at any animal. You may find some symmetry from right to left, but then you will find the analogy fails when examined fore and aft or top to bottom. Look though at a crystal and you will find such symmetry. The only way that you can explain living creatures, and the fact that they, unlike crystals are not symmetrical, is that living creatures are not subject to the restrictions imposed at the lowest level. Living things do not follow the same set of basic rules laid down for crystals. They have evolved and differentiated based on random changes that allowed one set to reproduce while another failed. Aslan is not a Tame Lion
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jar Member (Idle past 393 days) Posts: 34026 From: Texas!! Joined: |
CrackerJack writes: I am making a case out of the general observed bilateral external symmetry of animals. Okay, let's look at that and see if there is anything reasonable there. First, since ALL life Evolved from something earlier, we can not seperate plants from animals. But to humor you as you begin your search for understanding, let's begin by looking at animals. The first step is to see if you agree that the basic symmetry was a result of life first appearing in a water environment. Do you agree with that as a starting point? Aslan is not a Tame Lion
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jar Member (Idle past 393 days) Posts: 34026 From: Texas!! Joined: |
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jar Member (Idle past 393 days) Posts: 34026 From: Texas!! Joined: |
Or that just stick around saying the same thing even after it's refuted and refusing to answer questions. It's sad.
Aslan is not a Tame Lion
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jar Member (Idle past 393 days) Posts: 34026 From: Texas!! Joined: |
Or possible Hydrodynamics.
Aslan is not a Tame Lion
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jar Member (Idle past 393 days) Posts: 34026 From: Texas!! Joined: |
C'mon, guys. "Aerodynamics" "Hydrodynamics"? I asked you about the insects. Hint: it’s the square of speed. What kind of aerodynamics is required for a Daddy longlegs? How about the mites or ticks? Actually, as I remember it, you wandered off into jumping plants and such and touched on the issue of flight and mobility as well. Frankly, I didn't bother responding to you because it was pretty obvious that you had no idea of what you were talking about and were just prattling. You took what might have been a good question and turned it into what may well be the most absurd paragraph I've seen yet at EvC in question #3
3) Are the symmetry and motion related? Anybody ever seen a walking tree, or a flying shrub, or a jumping flower? If the plants and the animals came from the same line, from the same mother-cell (should I call it "proto-euglena"?), how come at some point one daughter's off-springs are bound by the rule of a distinct shape, symmetry, and motion, while the other daughter's off-springs are bound by the rule of the absent distinct shape, non-symmetry, and lack of motion? We often get the drive by shooter here who comes sweeping in with the killer insight. They generally last a day or so, a few even as long as a week. Then they pass away into the fog bank they came from. For now, I'll continue to glance over your posts. When you finally explain why question #3 is totally absurd, I'll begin to read your posts in depth. When you start asking pertinent questions I'll try to respond. Aslan is not a Tame Lion
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jar Member (Idle past 393 days) Posts: 34026 From: Texas!! Joined: |
Welcome to EvC.
There is a bunch of information on the development of Starfish but I know of little that actually goes into what drives the change. One interesting observation I picked up from some biologists during my many yaers with the GA Department of Natural Resources was that starfish seem to have the ability to override their radial symmetry from a functional point of view under stimulus. One ray can take control and become the guiding or motivating ray for a given event or activity. I'll be interested in seeing what some of our biologists can offer. Aslan is not a Tame Lion
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jar Member (Idle past 393 days) Posts: 34026 From: Texas!! Joined: |
Yup, it's a Sea Squirt.
Aslan is not a Tame Lion
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jar Member (Idle past 393 days) Posts: 34026 From: Texas!! Joined: |
Is not ID in the similar David vs Goliath position that Darwin/Huxley et al found themselves in when they stood up with a mind-blowing idea against the mammoth-like orthodoxy of their time. Nope. There are several significant differences. The FACT of evolution was apparent long before Darwin. Just looking around anyone could see the variety of critters and things and that they varied from place to place, period to period. The question was, "How did all that variety come about?" The TOE has done a marvelous job of answering that question. It's been supported by every scientific development over the last 150 years. It's been show to be flexible enough to account for anything seen so far. ID on the otherhand is a theory looking for a question. It adds no new understanding, answers no questions that cannot be answered under conventional TOE models and is in fact, fruitless and pointless. Aslan is not a Tame Lion
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