Intelligent design / creationism

[Tormod]

Please tell me, how would you have said what I said in a non-hostile manner? :xparty:

 

I simply think you have come to the wrong place. We are here to discuss evolution, not bash it. If you think the teaching of evolution is a social problem, then back your claims up with evidence from scientific studies which show that A) children are in fact choosing to turn away from the church, and :D what this social cost is.

 

Just because you are against the teaching of evolution does not mean that everyone is, nor that your claims are correct.

 

I suggest you read around our site a bit before you post any more, so that you can get a feel for how we discuss things here. It simply is not a good idea to come in yelling at us. This is a science site - read our FAQ so you understand who we are a little bit better.

 

By the way, where I come from has no effect on this discussion.

[TeleMad]

Do you truly believe that blind, chance mutation; followed by natural selection is responsible for the integration of your brain, optic nerve, pupil, cornea, rods, cones, etc?

 

Yes (or to be more technical, I believe they are all the product of evolution).

 

A pupil is not a thing: it's a lack of a thing: it's a "hole".

 

The optic nerve is ... a nerve. There's nothing really outstanding about it compared to other nerves.

 

Rods and cones are found in other animals' eyes: it's not like we alone have rods and cones. So why couldn't our rods and cones have come from a common ancestor we share with them? And by the way, even some bacteria have the rudimentary basic molecules of sight: a form of rhodopsin called bacteriorhodopsin.

 

And here are some indicators that the various eyes from widely different species are related. I have the underlying details but won't post those unless asked.

 

(1) Expression of Pax-6 (or one of its homologs) has been detected in various structures of developing eyes in all animals examined.

 

(2) Not only has Pax-6 (or one of its homologs) been detected in developing eyes, but it also has been shown to be necessary: “no Pax-6 = no eye”.

 

(3) Not only has Pax-6 (or one of its homologs) been detected in developing eyes, and also been shown to be required for eye development, but it also has been shown to actually cause eyes to form, as demonstrated in the formation of ectopic fruit fly eyes caused by the relocating of the eyeless gene within the fly’s genome (thus, Pax-6 also must reside at the highest levels of the hierarchy in the genetic cascade).

 

(4) True functional homology exists between Pax-6 and its homologs. Pax-6 has been taken from two very-distantly-related organisms (a mouse and a squid) and spliced into the genome of a third very-distantly-related organism, the fruit fly, at locations that always direct the formation of structures other than eyes. The insertion of the Pax-6 homologues at those locations caused “functioning” fruit fly eyes to develop on the wings, legs, and antennae. The similarity of Pax-6 and its homologs goes beyond sequences to actual function.

 

(5) At 422 amino acids in size, the protein encoded by Pax-6 is fairly large and it shows a great deal of homology – over 90% - across even only-very-distantly-related phyla (with some of the members of these diverse phyla being mice, humans, squid, fruit flies, lancelets, ascidians, nematodes, chickens, etc. – all of which currently have eyes). This strongly implies that Pax-6 – and some form of primitive eye - was present in the common ancestor of all these organisms.

 

(6) Pax-6 is not the only gene conserved in eye development. Two genes (sine oculis and eyes absent) that are regulated by Pax-6 and that operate further downstream – at the intermediate level – are also conserved between (the very distantly related organisms) mice and fruit flies.

 

(7) The “high-up” Pax-6 and the two intermediate-level genes sine oculis and eyes absent are not the only genes conserved in eye development of both mice and fruit flies. Other genes operating at the lower levels of eye differentiation are also conserved. For example, the genes that code for opsins are found in all the distantly-related phyla (again, with some of these diverse members being mice, humans, squid, fruit flies, lancelets, ascidians, nematodes, chickens, etc. – all of which have eyes).

 

(8) The Pax-6 gene, the two intermediate-level genes, and the lower-level genes are not the only genetic entities conserved across different phyla. In addition, splice sites have been conserved in Pax-6 and its homologues in mice, humans, squid, ascidians, nematodes, etc.

 

(9) Also conserved among vertebrates and fruit flies in relation to eye development are the two genes Rx and Tbx5.

 

(10) All photoreceptors use the seven-transmembrane proteins known as opsins – and they all contain a vitamin A-derived chromophore that absorbs light – and they all use G protein-mediated signal transduction.

 

(11) All photoreceptors either have cilia throughout their “lives”, or possess them transiently during development, thus providing a very plausible commonality between the two apparently distinct types of photoreceptors (ciliated or rhabdomeric).

[TeleMad]

Shouldn’t we have a right to expect some quantity of ... current species in transition...

 

This is analogous to Zeno's paradox of motion. In more modern terms, an arrow is in flight through the air and you take a snapshot with an incredibly high speed camera at a particular instant: what do you see? The arrow will be in only one place, perfectly stationary. If it's not moving at that instant, or any other instant one might have chosen to take a picture, then it's not really in motion and motion must be an illusion.

 

Same kind of thing with evolution. You are in the middle of species transitions but you see no transition because you are looking at only a particular instant in time. You are being misled by the apparent lack of transtion seen in the snapshot.

[Lolic]

As for transitional fossils, according to the current evolutionary ideal (punctuated equilibrium) specieation occurs very quickly (geologically) when stress are put upon a population. The odds of fossilization are very low, and with the trunckated time period true "transitional" organisms are unlikely.

 

thank you for your kind response. I do appologize if I offended you or anyone else.

I do have two questions regarding your mention of PE.

Please tell me, in your opinion, how "quickly" would specieation occure?

 

Also, what are some examples of "stress" that are put upon the population that would cause the cycle of mutation and natural selection to occure more rapidly?

 

thank you and appreciate your input! :o

[TeleMad]

Shouldn’t we have a right to expect ... some evidence of species mating and creating new species ...

 

We do have such examples. Here's one:

 

"The mechanism of sympatric speciation has been experimentally verified for many plants. One example is a group of species, collectively called hemp nettles, that occurs in temperate parts of Europe and Asia. One hemp nettle, Galeopsis tetrahit (2n = 32), is a naturally occurring allopolyploid thought to have formed by the hybridization of two species, G. pubescens (2n = 16) and G. speciosa (2n = 16). This process occurred in nature but was experimentally reproduced. Galeopsis pubescens and G. speciosa were crossed to produce F1 hybrids, most of which were sterile. Nevertheless, both F2 and F3 generations were produced. The F3 generation included a polyploid plant with 2n = 32 that self-fertilized to yield fertile F4 offspring that could not mate with either of the parental species. These allopolyploid plants had the same appearance and chromosome number as the naturally occurring G. tetrahit. When the experimentally produced plants were crossed with the naturally occurring G. tetrahit, a fertile F1 generation was formed. Thus, the experiment duplicated the speciation process that occurred in nature." (Biology: Fifth Edition, Eldra Pearl Solomon, Linda R. Berg, and Diana W. Martin, Saunders College Publishing, 1999, p411-412)

[C1ay]

Tormod

In America I’ve seen the social effect of evolution being taught in our schools. Children or young adults who once believed in God, are taught evolution in school, and then feel there is no God or no need for God.

 

I live in America too and I haven't witnessed any church going children that were brought up to believe in God that lost their faith when they had evolution in biology class. Now that you have given us your hypothesis on this can you provide us with some scientific proof of your claims. FWIW, both of my children live with an agnostic that believes strongly in evolution yet, at this point in their lives they tend to believe in God. This is their belief based on their own experiences and conjecture without any influence from me one way or the other. How does this fit your claim?

[BEAKER]

... both of my children live with an agnostic that believes strongly in evolution yet, at this point in their lives they tend to believe in God. This is their belief based on their own experiences and conjecture without any influence from me one way or the other. How does this fit your claim?

 

Jesus said: "allow the little children to come to me and do not forbid them, for of such is the kingdom of God."

 

...then they went to school and learned about all the alternative viewpoints that sinful man has concieved (- few of which even agree in any other area than supposing there is no God), in an attept to escape their inevitable end; facing their creator on judgement day.

 

...Unless of course their parrents intentionally made it a point to teach and nurture their childrens faith by believing themselves, and living in such a way as to honor God; by loving each other "...till death do them part", etc.

 

But I know I don't have enough scientific evidence to substantiate my claim.

 

I wonder how many people believed the Earth was round when everyone else said it was flat; there just wasn't enouigh scientific eidence - yet. - or more to the point; it was simply being erroneously interpreted.

[IrishEyes]

Good to see you again, Beaker!

You need to PM me with your postal address, as I have a box sitting on a shelf in my front closet with your winnings from the avatar contest...

[jp3089]

This is analogous to Zeno's paradox of motion. In more modern terms, an arrow is in flight through the air and you take a snapshot with an incredibly high speed camera at a particular instant: what do you see? The arrow will be in only one place, perfectly stationary. If it's not moving at that instant, or any other instant one might have chosen to take a picture, then it's not really in motion and motion must be an illusion.

 

Same kind of thing with evolution. You are in the middle of species transitions but you see no transition because you are looking at only a particular instant in time. You are being misled by the apparent lack of transtion seen in the snapshot.

 

That's a good analogy. You do have to admit that it wouldn't hurt evolution to have a few more "snapshots" that showed some better transitionary fossils to better illustrate divergence.

 

Do you think there are more "snapshots" yet to be discovered? Or are we going to be left with what we have right now?

 

-jp

[Aquagem]

Please tell me, in your opinion, how "quickly" would specieation occure?

 

Also, what are some examples of "stress" that are put upon the population that would cause the cycle of mutation and natural selection to occure more rapidly?

 

Speciation is widely misunderstood, a fact that allows room for creationists to claim that there are no evidences of its occurrence. The problem is that speciation is not a single event. No matter how much you know about the world system (which is never much, in comparison to everything that's going on), you could not, for example, look at a litter of puppies, coyotes, say, and be able to point to one and say, "Here's our new species!" Instead, if you could follow all members of a single litter through all their many generations for thousands of years, or thousands of generations, you might finally be able say, based on genetic and behavioral evidence, that a new species, worthy of the name, had arrived.

 

Let's say one of the pups had a mutation, one that, like many, go unnoticed because they don't show up in any obvious way (i.e., genetic "drift"). Genes like these may disappear by chance or competition in later generations, or just lurk around in the genome with nothing to do and with no outward expression that would cause them to be selected out.

 

Much later, something changes. Maybe a volcano chokes the atmosphere with dust and the temperature drops; maybe rainfall patterns shift; or UV radiation increases because another species is so shortsighted and so deep in denial that it won't believe good evidence when it's available to help them guide their behavior... As this change manifests, the rules are modified for the coyotes in this corner of the world, e.g., food sources diminish. Starvation encroaches, and social groups of these predators have to change their habits to survive.

 

This stressor may decimate the population as a whole, but under these conditions, the mutation that came about a hundred generations back may prove to be advantageous in subtle, indirect, and unexpected ways. Maybe the animals with this gene pattern need a bit more sleep and save a tiny increment of energy by not wasting on fruitless hunts (now that prey are less common). Maybe they are less susceptible to a disease and manage therefore to propagate more reliably (the sickle-cell example, which brings about earlier death, but increased reproduction).

 

It's not that an animal is necessarily better adapted at the time a mutation occurs, and it's a known fact that we carry huge amounts of seemingly redundant information in our DNA. Typical of our immature view, we call it "junk DNA". But if there's one thing we can say about evolution, it is that it is productive of diversity, and by time something new hits the fan, there's a pretty good chance that there will be pre-adaptations galore in the genome to foster survival for at least some of the members of a species. (In this, I'm thinking about less drastic events than a major comet collision, which I call a "lawnmower" event, effective, but not particularly selective.) Preadapted genes would, and probably do, speed the process up by orders of magnitude over sitting around waiting for cosmic rays to do the work. The accumulation of diversity may be the most vital aspect of evolution, paired with the blade-edge of selection.

 

This picture of speciation, which has risen out of our new understanding of the complex interaction of genetics and environment, replaces the narrow and simplified picture of a new species popping fully formed from the head of Zeus. Now, in answer to the question, "Where are all the intermediate species?" you can say, "They're all around us; the world teems with them. You may be one of them!"

 

And, to your question about how fast speciation can occur, I don't think anyone has offered a simple, or even a complicated, answer. Too many variables; not enough solid genetic evidence quite yet. A massively disruptive event like the comet that deposited iridium around the globe about 65 million years ago might hasten speciation for some and destroy it completely for others. Animals and plants have very different habits and habitats, and based on the stressor, might drive many to extinction and offer up new opportunities to survivors that will change their reproductive success (Darwin's finches; isolated populations; epidemic diseases, and on and on). I'd expect the time span to be at least thousands of years, but I know of one ancestral fish species that was blocked into a limited area no more than four thousand years ago and has blossomed into many new, very different species (cichlids, as I remember).

 

So, this is a long post with an easy summary: :(

 

:(

[TeleMad]

Do you think there are more "snapshots" yet to be discovered? Or are we going to be left with what we have right now?

 

We already have plenty of fossil evidence showing snapshots in the overall evolutionary "motion" across the age of the Earth. The first snapshot shows only single-celled bacteria, somewhere around 3.5 billion years ago. A later snapshot in the series shows simple worm-like eukaryotes, at somewhere around 700 million years ago. A later snapshot shows eukaryotes with exoskeletons, such as trilobites, around 540 million years ago. A later snapshot shows fish; then there's a snapshot of amphibians; then there's a snapshot of reptiles; then there's a snapshot of mammals; then there's a snapshot of primates; then there's a snapshot of humans. At any particular snapshot, no motion is seen, but when all of the frames are viewed in sequence, then the larger motion picture can clearly be viewed.

 

And our snapshots continue to be filled in more and more. For example, many fossils related to bird evolution have been found in China over the last decade.

[jp3089]

We already have plenty of fossil evidence showing snapshots in the overall evolutionary "motion" across the age of the Earth. The first snapshot shows only single-celled bacteria, somewhere around 3.5 billion years ago. A later snapshot in the series shows simple worm-like eukaryotes, at somewhere around 700 million years ago. A later snapshot shows eukaryotes with exoskeletons, such as trilobites, around 540 million years ago. A later snapshot shows fish; then there's a snapshot of amphibians; then there's a snapshot of reptiles; then there's a snapshot of mammals; then there's a snapshot of primates; then there's a snapshot of humans. At any particular snapshot, no motion is seen, but when all of the frames are viewed in sequence, then the larger motion picture can clearly be viewed.

 

And our snapshots continue to be filled in more and more. For example, many fossils related to bird evolution have been found in China over the last decade.

 

Are there any hypotheses as to why there are such large gaps in the snapshots?

 

-jp

[Buffy]

Are there any hypotheses as to why there are such large gaps in the snapshots?

Check out Chapter 21 in Bill Bryson's "*A Short History of Nearly Everything" for a good synopsis in layman's terms. Here's a very brief excerpt:

It isn't easy to become a fossil. The fate of nearly all living organisms--over 99.9 percent of them--is to compost down to nothingness. When your spark is gone, every molecule you own will be nibbled off you or sluiced away to be put to use in some other system. ... Even if you make it into the small pool of organisms, less than 0.1 percent, that don't get devoured, the chances of being fossilized are very small...First you must die in the right place...the fossil must somehow maintain an identifiable shape. Finally...after tens of millions or perhaps hundreds of millions of years hidden away, it must be found and recognized as something worth keeping.

Absence of evidence is not evidence of absence...

 

Cheers,

Buffy

[jp3089]

Check out Chapter 21 in Bill Bryson's "*A Short History of Nearly Everything" for a good synopsis in layman's terms. Here's a very brief excerpt:

It isn't easy to become a fossil. The fate of nearly all living organisms--over 99.9 percent of them--is to compost down to nothingness. When your spark is gone, every molecule you own will be nibbled off you or sluiced away to be put to use in some other system. ... Even if you make it into the small pool of organisms, less than 0.1 percent, that don't get devoured, the chances of being fossilized are very small...First you must die in the right place...the fossil must somehow maintain an identifiable shape. Finally...after tens of millions or perhaps hundreds of millions of years hidden away, it must be found and recognized as something worth keeping.

Sounds interesting... maybe the book adds more to it, but the excerpt isn't really a hypothesis about the gaps. It's more of a lesson on how fossils are formed.

 

Absence of evidence is not evidence of absence...

You are very right, and I wasn't saying it was... I was merely wondering if there were any hypotheses floating around.

 

-jp

[Buffy]

Sounds interesting... maybe the book adds more to it, but the excerpt isn't really a hypothesis about the gaps. It's more of a lesson on how fossils are formed.

 

You are very right, and I wasn't saying it was... I was merely wondering if there were any hypotheses floating around.

Uh, actually it is a hypothesis about gaps: gaps exist because its hard to become a fossil, therefore we don't have an example fossil of every intermediate change in the evolution of species. If its really hard to become a fossil, the gaps can be *very* large. Now if I misunderstood your question, and you were really asking "why are there large gaps in certain places and smaller ones in others" then that is partly explained by the quote (if you have gaps and few datapoints, the random distribution of them could have very large standard deviations in the "average" time between datapoints), and partly explained by what data you want to included. If you are looking only at human fossils, there's a large variability because there are a smaller set of datapoints, on the other hand if you expand it to include all fossils, you start to get much smaller gaps because the datapoints are randomly distributed.

 

Cheers,

Buffy

[jp3089]

Uh, actually it is a hypothesis about gaps: gaps exist because its hard to become a fossil, therefore we don't have an example fossil of every intermediate change in the evolution of species. If its really hard to become a fossil, the gaps can be *very* large. Now if I misunderstood your question, and you were really asking "why are there large gaps in certain places and smaller ones in others" then that is partly explained by the quote (if you have gaps and few datapoints, the random distribution of them could have very large standard deviations in the "average" time between datapoints), and partly explained by what data you want to included. If you are looking only at human fossils, there's a large variability because there are a smaller set of datapoints, on the other hand if you expand it to include all fossils, you start to get much smaller gaps because the datapoints are randomly distributed.

 

Cheers,

Buffy

 

I can concede that it may be a hypothesis, but I'm not sure it's a very good one.... Let's say for example that someone was trying to prove that computers improved gradually over time. If someone showed me an old Commodore 64 computer and then showed me a brand-new top of the line Dell without any intermediate computers to show the improvement, the hypothesis "there are gaps because computers are hard to make" would not be a good hypothesis at all.

 

-jp

[Buffy]

the hypothesis "there are gaps because computers are hard to make" would not be a good hypothesis at all.

You're right, that's because the relevant hypothesis would be: "Everyone throws out their computers and they disintegrate when thrown in the landfill." A hypothesis which in this case unfortunately isn't true, but its the parallel of the "hard to become a fossil" hypothesis.

 

Cheers,

Buffy