Creation vs. Evolution

[sandmanz32]

sharks and alligators, crocs have evolved very little in millions of years, birds on the other hand have changed drasticly over the fossil record.

 

[deco_martini]

I don't think you have the concept quite right. Your description ("needs to adapt to survive") makes it sound like a process guided by intent.

Maybe it isn't so obvious?

No, it really is obvious. Which is why people get it without understanding it fully. Indeed, nothing is "forced" to adapt in nature. Species die off without being forced to adapt to changing environments.

 

[sandmanz32]

I("needs to adapt to survive") makes it sound like a process guided by intent.

it IS guided by intent, the intent of lifeforms to survive the everchanging world. single species may not survive but the "family" typically does. like i said "im by no means a scientist", so i may be a little off on my explainations, but i did love science class, and im highly interested in anything scientific. [url]http://www.ucmp.berkeley.edu/diapsids/birds/birdfr.html
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[MikeFerrara]

it IS guided by intent, the intent of lifeforms to survive the everchanging world. single species may not survive but the "family" typically does.

One of the scientists can step in any time but I don't think any mechanism of evolution is driven by "intent". Changes take place by way of the various forms of mutation. Selection takes place simply by what works and what doesn't.

 

[MikeFerrara]

sharks and alligators, crocs have evolved very little in millions of years, birds on the other hand have changed drasticly over the fossil record.

Interesting point. Maybe there's more to talk about in the case of species that haven't changed over long periods? All this talk of mutation and genetic drift and so on makes change sound almost unavoidable as long as those changes don't make survival impossible. You would think that there are lots of changes possible that wouldn't be deselected so why haven't sharks or aligators changed? Are they really specialized and such a perfect fit that any significan't change is deselected?

 

[deco_martini]

Interesting point. Maybe there's more to talk about in the case of species that haven't changed over long periods? All this talk of mutation and genetic drift and so on makes change sound almost unavoidable as long as those changes don't make survival impossible. You would think that there are lots of changes possible that wouldn't be deselected so why haven't sharks or aligators changed? Are they really specialized and such a perfect fit that any significan't change is deselected?

Modern crocs resemble their ancestors more than some other species in their appearance. But, modern crocs are differentiated from them.

As a marine life enthusiast, we know that sharks go back a long way. We even still find megalodon teeth buried in river beds. However, modern shark is a far cry from the megalodon.

Mutation is an evolutionary factor, but the two main evolutionary levers are natural selection and genetic drift. You can look at the wikipedia page for modern crocodiles and find all sorts of interesting species large and small. You will find that large crocodiles live in areas where the prey is large. Small crocodiles species live in areas with smaller prey generally. Coincidence?

Evolution doesn't mean the modern crocodile should walk on two legs and wear a hat.

 

[Warthaug]

I disappear for two years and this thread is still going on?

Holy crap!

I have to do something while at work...

A two year gap though? I miss this thread after a weeks absence...

Bryan

 

[Warthaug]

Most church's avoid discussions of science altogether. Most understand they are there to teach about faith in God.
My whole purpose for posting on here is because I'm tired of the sanctimonious attitude of scientists that tout the theory of the day as fact.

And I'm here to try and correct the position you take above.

Evolution is an observed phenomena - meaning we see it happen in front of our eyes. You may as well be decrying scientists talking about sunrises. The theory of evolution is simply a scientific explanation of why we see evolution occurring.

EDIT: I think the above sentence may reflect where some of the confusion comes from - evolution and the theory of evolution are two different things. Most people don't know/realize that, hence some of the confusion...

The theory may have errors, but that doesn't change the simple fact that its describing an observed phenomena. A phenomena which humanity has been aware of for millennia (Aristotle wrote extensively about it).

You want us to pretend we don't observe evolution - sorry, that isn't going to happen.

Yet, even on here, you see they admit Darwin had it wrong.

You need to go back and read what was written. Darwin had the broad strokes right. He lacked details, so parts of what he wrote were incomplete. On a few small points he was wrong.

But the vast majority of what Darwin wrote is as true today as it was 149 years ago.

So if Darwin had it wrong and you guys have molded his theory into something more palatable, why stand there and say its indisputable fact?

To my knowledge, no one has claimed evolutionary theory is 100% correct on this thread; in fact, myself, thal, and many others have highlighted the continual "tweaking" of the theory as the key difference between it and religion - you know, improving as new data becomes available and all that.

But evolution is an indisputable fact - as in it is an observed phenomena. The Greeks provided us with the first written accounts of observing it, and further references to life changing can be found throughout medieval history (not to mention in ancient Chinese and other cultures texts). To deny that evolution doesn't exist is to deny our own eyes.

Its tantamount to denying gravity - except that we can explain why evolution occurs. Gravity is pretty much still a mystery.

Wouldn't it be more accurate to say, according to the evidence we have today this is what we believe?

No. It would be correct to say that based on current evidence, the theory of evolution is the best explanation as to why we observe evolution occurring.

Even if evolutionary theory was found to be 100% wrong, we'd still be stuck with explaining why we see evolution occurring in nature.

I also find it ironic that science uses so many static models to represent a dynamic equation.

Strange, that as a scientist, I cannot think of any static models that we use. Perhaps an example is in order...

Time itself is not even a constant and is relative.

Time, in the same reference frame, is constant.

Doesn't Hawking discuss the tearing of the space-time continuum?

No, he doesn't. Unless you're making an odd reference to his writings about singularities (black holes); which, of course, has no bearing on the universe in which we live.

I see science today as a lot like fudging the answers to the pre-determined result that I already "know" instead of approaching that data with a more open mind.

No, that would be religion. Science constantly changes - evolutionary theory is quite a bit different today than 5 years ago, and 50 years in the future will be different from what we have today.

There are no pre-determined outcomes - PE didn't turn out the way most of us expected, likewise the selfish gene hypothesis has legs no one expected. At the end of the day your problem is simple - you have a pre-determined outcome, and you're desperate to explain away everything which disagrees with your beliefs. And since you cannot do it on an evidence-based basis, all you can do is libel those who've spent their lives trying to figure out how this universe of ours works.

I know this challenge has been made before, but since you have a more "open mind" then the millions of scientists around the world, perhaps you could tell us about the alternative theory that you have which explains all the evidence...

...or maybe you'd rather keep pretending that anything which disagrees with your faiths dogma is a product of "closed minds".

Bryan

 

[Warthaug]

One of the scientists can step in any time but I don't think any mechanism of evolution is driven by "intent".

"Intent" usually implies a guiding intelligence with a predetermined goal. That would be incorrect. Evolution does not have a goal or "final target design". Species have the drive to reproduce, which is about as close to "intent" as you're going to get.

Changes take place by way of the various forms of mutation. Selection takes place simply by what works and what doesn't.

Aside from selection, there is also drift and perhaps species-level selection.

Bryan

 

[Warthaug]

Interesting point. Maybe there's more to talk about in the case of species that haven't changed over long periods?

Not really. Take sharks as an example; early in their evolution they've hit on a few important adaptations - anti-marine growth skin and a streamlined form. Any mutation which changes those features would be detrimental, and therefore be selected against. Based on what we know of hydrodynamic drag, there aren't many shapes better for moving through the water than the shape of a shark - and those which are more efficient would not be compatible with the way sharks swim.

But that said, I think its far more important to point out that the idea that sharks, turtles, alligators, etc, haven't evolved for a long time is an urban myth. The fossil record is filled with all sorts of different species which are clearly different from what we have today. At different times in the past there have been examples of all those species many times larger than the ones around today - Megalodon as an example. Likewise, many bizzar species are to be found - Stethacanthus being a prime example. Even today oddly shaped sharks abound - Chlamydoselachus being a prime example.

Long story short, a common body plan - which evolved to a highly optimized state a long time ago - has been used in the case of sharks, turtles and alligators. But within those basic plans a huge amount of change has occurred over time.

Saying sharks haven't evolved would be like saying land animals haven't evolved, because we all have a spine and four limbs...

All this talk of mutation and genetic drift and so on makes change sound almost unavoidable as long as those changes don't make survival impossible.

This is only the case if there is no selection. In the absence of selection accumulation of mutations and drift is inevitable.

But in the real world - where "holidays" from selection don't exist, selection limits evolution. Even beneficial mutations can be lost, through competition by better mutations and plain bad luck.

The world is ever-changing, so change is inevitable. But change itself is not unlimited - the amount of change possible is limited by time, mutation rate, and the strength of selective pressure.

You would think that there are lots of changes possible that wouldn't be deselected so why haven't sharks or aligators changed?

As pointed out above, this is an urban myth. Sharks, turtles and alligators have undergone extensive evolution. The underlying body shape has remained the same, but within those limitations the degree of change has been astounding.

This is a common theme in biology - the skeletal form of humans is nothing more then a modified form of what you find in lobe-finned fishes. The four-chambered heart appeared soon after amphibians and has stayed in that form ever since. The reason for this is simple - once an effective "platform" has evolved most mutations which result in fundamental changes are detrimental.

Its been nearly a billion years since we've seen a new, basic body plan evolve. It may be billions more before we get another.

Are they really specialized and such a perfect fit that any significan't change is deselected?

But significant change has occurred. The number of extinct species is enormous, and among those you'll find thousands of examples of how things changed - both over time, and in comparison to today. Some of those changes have been profound; so profound that many of those species would be hard to identify (by sight) as being sharks, turtles or alligators...

On the topic of sharks, discovery channel has released a shark week box set, of the "best" shark week documentaries from the last 25 years. I'd argue a lot of the documentaries aren't "best" and instead are nothing more than examples of how ignorant we were of sharks upto the late 1990's, but none-the-less, the 2 or 3 documentaries on extinct sharks are excellent.

Bryan