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Experimental evidence for evolution

Discussion of everything related to the Theory of Evolution.

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Re: Experimental evidence for evolution

Postby Geokinkladze » Wed Sep 22, 2010 4:04 am

jevg wrote:
Yes there is empirical evidence


Now please don't bombard me with links and other data but can you succintly explain to me where the empirical evidence that supports your view* on speciation is?

You reject evidence on the basis that its not direct observation of speciation and then post links to experiments which are... you guessed it.. not direct observations of speciation.


* I don't know if you've actually explained your view. I think I've got it, reading between the lines but can you just come out and say it so we can all be clear where your coming from?
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Re: Experimental evidence for evolution

Postby jevg » Thu Sep 23, 2010 4:15 pm

The whole statement reads
Yes there is empirical evidence and NO it does not support “macroevolution”.


Now if that is not clear enough then may be it is the English language that has the problem :)

Look I understand your need to use rhetorical devices to veer away from what the evidence is revealing.

If it is your view (although I am not sure what your view is) that the Darwinian mechanism is real and explains speciation, then likely it is a very ingrained viewpoint.
This however is science and science requires evidence. The evidence I have repeatedly pointed to shows that the Darwinian mechanism does not explain speciation.

That is where I am coming from.

However, there is a more fundamental principle that Developmental biology raises against this mechanism.
Please bear with me, if only for the purpose of some education.

Embryological evidence has long shown that DNA does not wholly determine morphological form. This suggests that mutations/variations in DNA alone cannot account for the changes required to build a new body plan, which is what speciation requires.
( I can point you to the evidence both in the wild and experimental, but I wont push my luck :) )

DNA directs protein synthesis. It also helps regulate the timing and expression of the synthesis of various proteins within cells.

DNA alone though, does not determine how individual proteins assemble themselves into larger systems of proteins, still less does it alone determine how cell types, tissue types, and organs arrange themselves into body plans.

Other factors, such as the structure and organization of the cell membrane and cytoskeleton, play important roles in determining developmental pathways that give rise to body-plan formation during embryogenesis.

For example, the shape and location of microtubules in the cytoskeleton influence the shape and form of embryos. Arrays of microtubules help distribute the essential proteins used during development to their correct locations in the cell.

Now microtubules themselves are made of many protein subunits. These protein subunits in the cell’s microtubules are however identical to one another. But neither they nor the genes that produce them account for the different shapes and locations of microtubule arrays that distinguish different kinds of embryos and developmental pathways.

What matters in development is the shape and location of microtubule arrays, and (this is important) the shape and location of a microtubule array is not determined by its units.

An analogy may help explain

Electronic circuits are composed of many components, such as resistors, capacitors, and transistors. But these lower-level components do not determine their own arrangement in an integrated circuit.

Biological systems also depend on the hierarchical arrangements of parts.

Genes and proteins are made from relatively simple building blocks, nucleotide bases and amino acids, arranged in specific ways.
Cell types are made of, among other things, systems of specialized proteins.
Organs are made of specialized arrangements of cell types and tissues.
And body plans comprise specific arrangements of organs. ( I hope you can see the hierarchical nature of the cell arrangement.)

Clearly therefore the properties of individual proteins (or indeed the other lower-level parts in the
hierarchy generally) do not determine the organization of the higher-level structures and organizational patterns or forms.

It follows, then, that the genetic information that codes for proteins does not determine these higher level structures either.

James Shapiro uses the analogy of Lego-like assemblies regarding this arrangement.

The above consideration poses but just one challenge to the sufficiency of the neo-Darwinian mechanism.(there are others)

Why does this pose a challenge?

Because neo-Darwinism seeks to explain the origin of new information, form, and structure as the result of selection acting on randomly arising variation at a very low level within the biological hierarchy, namely, within the genetic text.

Yet major morphological (form and shape) innovations depend on the specific arrangement at a much higher level of the organizational hierarchy that DNA alone does not determine.

So if DNA is not wholly responsible for the body-plan ,(which is a fact) then DNA sequences can mutate indefinitely and still not produce a new body plan.
But speciation requires a new body plan.
These mutations could and do produce variations at the lower levels and that is what the experimental evidence I have referred to shows.

Thus, the mechanism of natural selection acting on random mutations in DNA cannot in principle generate novel body plans, including those that first arose in the Cambrian radiation.
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Postby Geokinkladze » Fri Sep 24, 2010 12:03 am

My view is quite simple.
Evolution has happened, and that is a fact.
Natural selection is happening, that is also a fact.

Whether natural selection alone explains new species is unknown, for the simple reason that observing new species is so difficult. Hey for all we know all this random mutation and natural selection may serve only to improve a species, maybe even to set the conditions for the creation of a new one, but maybe not create a new one.

Anyone who holds a view that something causes new species does so on a basis of faith because, to quote one of your favourite lines, "the evidence is simply not there".
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Postby Julie5 » Fri Sep 24, 2010 8:15 am

Hi, not sure if this has been discussed here, but cancer provides a compelling demonstration (even if not proof!) about how mutations in DNA can create a new 'surviving unit' (ie, cancer cell/tumour) which evolves by continuing mutation, so that a 'late cancer cell' can be considerably different in genome from an early one, and which, moreover, has spread into other eco-niches (ie, metastasised), and which also demonstrates survival of the fittest, as chemo will kill off vulnerable cancer cells, whilst some, with different genotypes, will survive to continue to increase their population in the host body and colonise more and more habitats (lungs, bones, brain, liver, peritoneum etc etc etc....)(until the host dies, of course....)

The only evolutionary barrier cancer faces is, of course, the death of the host, except starting again from scratch in a new host for those particular cancers that are familial and inheritable.

But, in a microcosm, each patient's cancer does seem to demonstrate rather a lot of the tricks and traits that evolution uses to increase populations, colonise new habitats, and improve fitness (ie, survivability).

By the way, the death of the host situation that limits cancer could also be a pretty good mirror of the death of the host situation that global warning/earth destruction by humans presents as a grim limit to our own species....
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Re: Experimental evidence for evolution

Postby jevg » Fri Sep 24, 2010 4:46 pm

Geokinkladze
Evolution has happened, and that is a fact.
Natural selection is happening, that is also a fact.


I fully agree with you and it is good to be at one on this.
This is something that both empirical evidence and research supports and is good sound science.

There are things that science is unable to answer and it becoming clear that species origin is one of those things.
Science however can and often does show what cannot be.

Species origin by the Darwinian mechanism of random variation and natural selection cannot be, and I hold that the accumulating and now indeed the overwhelming evidence of actual science, demonstrates this. The last two of my posts simply summarises that evidence.

Anyone who holds a view that something causes new species does so on a basis of faith because, to quote one of your favourite lines, "the evidence is simply not there".

Nice to have agreement again.

What is very problematic though, is the reality in the scientific community that Darwin’s Origin of Species hypothesis which is a faith based view (and it is) is paraded as fact, to the point that any other faith based view is regarded as unscientific (which they are) and considered irrelevant and often ridiculed.

Julie5 » Fri Sep 24, 2010 8:15 am

What you say is demonstrably true.
Remember though that there is a great deal of difference between the concept of “survival of species” and the “arrival of species”

The full Title of Darwin’s publication is very revealing.

“On the Origin of Species by Means of Natural Selection, or the Preservation of
Favoured Races in the Struggle for Life.”

Darwin himself recognized that he was using one hypothesis (preservation) supported by observable evidence to support his philosophical view of an entirely different process (origin).
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Re: Experimental evidence for evolution

Postby Geokinkladze » Sat Sep 25, 2010 1:37 am

jevg wrote:
Species origin by the Darwinian mechanism of random variation and natural selection cannot be, and I hold that the accumulating and now indeed the overwhelming evidence of actual science, demonstrates this. The last two of my posts simply summarises that evidence.


Not quite.. when you say
This suggests that mutations/variations in DNA alone cannot account for the changes required to build a new body plan, which is what speciation requires.


That is indeed a fair point of view to take, however you then shift your viewpoint without any further prompting towards...

So if DNA is not wholly responsible for the body-plan ,(which is a fact) then DNA sequences can mutate indefinitely and still not produce a new body plan.
But speciation requires a new body plan.


in order to conclude...

Thus, the mechanism of natural selection acting on random mutations in DNA cannot in principle generate novel body plans


So firstly you interpret data to support a viewpoint (A suggests B is not true), but then suddenly state that viewpoint as if it were a fact (ie B is not true).

jevg wrote: What is very problematic though, is the reality in the scientific community that Darwin’s Origin of Species hypothesis which is a faith based view (and it is) is paraded as fact, to the point that any other faith based view is regarded as unscientific (which they are) and considered irrelevant and often ridiculed.


Darwin's hypothesis was that evolution has happened and that natural selection drives it. Whether natural selection drives alone is the debateable point, but the amount of evidence in support of natural selection's role means that anyone who suggests it isn't even in the car is being unscientific.

I don't think that the scientific community regards faith based views as irrelevant and I certainly don't see any ridicule that isn't justfied. Examples of justified ridicule would be the conservapedia/Lenski dialogue, demanding samples of E Coli was just plain asking to be ridiculed. On the other hand Shapiro's treatment by some members of the scientific community is unwarranted, but these people represent a minority and certainly don't represent the science community in the same way that Conservapedia don't represent people of faith.

You have previously likened neo-darwinism to being a sinking ship, one only has to type the following words "neo darwinian sinking ship" in to a search engine to see the types of unscientific people who hold those views. Only you will really know whether your part of that community or the scientific one.
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Re: Experimental evidence for evolution

Postby jevg » Sun Sep 26, 2010 6:33 pm

When I stated
So if DNA is not wholly responsible for the body-plan ,(which is a fact) then DNA sequences can mutate indefinitely and still not produce a new body plan.
But speciation requires a new body plan.


I was stating a fact. I resisted the urge to provide evidence simply because of your stated request for me not to keep referring to evidence
However may I repeat
Changes in DNA alone do not produce new body plans. That is a fact supported with evidence.
I also stated that the Darwinian mechanism of random mutations/variations and natural selection can and do produce variations at levels lower than speciation.

From your comments I rightly or wrongly assumed that we are in agreement

However if I assumed wrongly and you have evidence to challenge that view then please present it so that a rational debate can continue.

However I am not going to engage with you on peripheral issues. If you disagree with me on the matter of ridicule then that is ok with me.
We are dealing with opinion on this matter and it’s always good to have variety, so long as it does not lead to animosity.
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Re: Experimental evidence for evolution

Postby Geokinkladze » Mon Sep 27, 2010 1:14 am

jevg wrote: Species origin by the Darwinian mechanism of random variation and natural selection cannot be, and I hold that the accumulating and now indeed the overwhelming evidence of actual science, demonstrates this.


I guess the only explanation for my failure to be overwhelmed by such evidence is that I can't see the wood for the trees. Seriously though, you can hold whatever opinion you wish, but know this; if what you say were true then I'm sure we wouldn't be having this debate because it would be accepted by major sections of the scientific community.

The way I see it, one small but growing section of the scientific community (evolutionary developmental biology, a relatively new field) is currently undergoing a debate over interpretation of it's own findings. You seem to liken this to the sinking of the darwinian ship, whereas I suggest it's merely a few raised voices in one corner of the foredeck. I guess what I'm saying is that I think you're overreacting.

jevg wrote: Changes in DNA alone do not produce new body plans. That is a fact supported with evidence.


There is evidence in support of this viewpoint but of course this is down to interpretation. There is overwhelming evidence that genes are responsible for body plan changes, such as the loss of limbs that lead to snakes. Darwins own observation of the beaks of finches was later confirmed to be the result of genetic expression alone.

Whether you believe that phenotypic evolution conflicts with neo darwinism or extends it is a point of view. I guess I take the view that it extends it (rather like Einstein extended Newton). But then again, I believe in the evidence which supports natural selection and the extension of that viewpoint is that DNA, whether directly or indirectly, is responsible for embryological development.

Well we've had Darwinism and Neo-Darwinism, I guess "Post Modern Darwinian Development" might be the new watchword in years to come. :D
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Postby Julie5 » Mon Sep 27, 2010 8:53 am

This is probably a can of worms, but I've personally never really undrestood why some faiths don't like evolution. Huge numbers of religious people have no problem with E by NS (eg Catholics, Anglicans), and simply reconcile the science with their theology - ie, that God used the mechanism of E by NS to produce the living world, and good old Homo.sap to do whatever He/She are here to do.

If some religious people say they don't like E by NS because it implies that it's chance alone that produced Homo sap, then they don't really get the concept of divine omniscience and omnipotence. If they seriously think God can't set up a universe in which particular genes are subjected to particular mutuations by particular mutagenic events at particular times which eventually result in Homo sap, then they believe in a pretty puny God to my mind! (When you are God, random doesn't exist!)

As for the moral objection to E by NS, that species come and go without any divine care of them, well, Nature, like it or not, is red in tooth and claw, and no amount of Creationism is going to get round that moral problem.

Finally, it is my personal belief that the reason dinosaurs came and went is because God thought they were a pretty neat idea, and got a lot of fun out of them (After all, we already know He/She has an inordinate fondness for beetles....). More utilitarianly, of course, He/She needed dead dinosaurs to form our modern oil reserves, which are necessary to get Homo Sap into a state of civlisation where we are wealthy enough so we can FINALLY sort ourselves out and put a stop to poverty, illness etc etc, and built that City of God that is our Divine Task (ie, for those who are of a religious disposition.)

And, whether or not we are religious, making people happier and healthier is a clear moral imperative for all of us.
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Re: Experimental evidence for evolution

Postby JackBean » Mon Sep 27, 2010 8:58 am

jevg wrote:When I stated
So if DNA is not wholly responsible for the body-plan ,(which is a fact) then DNA sequences can mutate indefinitely and still not produce a new body plan.
But speciation requires a new body plan.


I was stating a fact.


That's definitely not true. You can have plenty of mutations causing basically nothing, but you can have like one mutation, which changes "everything"
http://www.biolib.cz/en/main/

Cis or trans? That's what matters.
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Re: Experimental evidence for evolution

Postby jevg » Fri Oct 01, 2010 1:30 pm

JackBean
You can have plenty of mutations causing basically nothing, but you can have like one mutation, which changes "everything"

When you say “everything” I have to assume you mean “speciation or novel body plan” because that is what this question is all about.

Can you therefore point me to evidence that shows how one mutation, as you put it, can change “everything”.

Julie5
There seems to be a problem here in separating science from religion.

This question is about whether there is any experimental evidence that supports speciation.
It has nothing to do with faith or religion. That said though, peoples faith can and often does impact on their world view.
In a book review by Danny Yee on the book
Bones of Contention:
Controversies in the Search for Human Origins Roger Lewin, he made this comment.

“And anyone who still holds to a naive belief in the clear-cut objectivity of science and scientists will find it an eye-opener.”

That comment carries a lot of merit.

Geokinkladze
May I remind you what you yourself wrote on the Fri Sep 24, 2010 12:03 am

Whether natural selection alone explains new species is unknown, for the simple reason that observing new species is so difficult. Hey for all we know all this random mutation and natural selection may serve only to improve a species, maybe even to set the conditions for the creation of a new one, but maybe not create a new one.


You now write

There is overwhelming evidence that genes are responsible for body plan changes, such as the loss of limbs that lead to snakes. Darwins own observation of the beaks of finches was later confirmed to be the result of genetic expression alone.


You appear to be (and I would conclude unintentionally) blurring the distinction between variation within species (ie darwin@s finches) and speciation.

You also refer to the loss of limbs in snakes as overwhelming evidence for body plan changes by genes.

This of course raises quite a controversial topic on the origin of the snake. However whichever side of the argument you are on, none of the discussions address, what to many is the fundamental question about snake evolution in the first place:

Why should an animal with legs evolve into one without them?
Legs seem to be quite a useful bit of equipment; every other terrestrial vertebrate has them.

The Darwinian hypothesis of natural selection rests on the selective advantage for survival. The snake seems to me to be disadvantaged by the removal of it’s limbs.

Now a biblical scholar pointed me to the Genesis account Chapter 3 verse 14, which reads in reference to the serpent.
“Because you have done this you are accursed more than all the cattle and all wild creatures. On your belly you shall crawl……”

So the account states that all the animals were put into a state of disadvantage (cursed) but the snake more than the rest, in that it lost it’s limbs.

Now I may not be a creationist, but this explanation has more logic to it than Darwinian selectivity.

What do you think?
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Re: Experimental evidence for evolution

Postby canalon » Fri Oct 01, 2010 1:59 pm

jevg wrote:Why should an animal with legs evolve into one without them?
Legs seem to be quite a useful bit of equipment; every other terrestrial vertebrate has them.

The Darwinian hypothesis of natural selection rests on the selective advantage for survival. The snake seems to me to be disadvantaged by the removal of it’s limbs.

Now a biblical scholar pointed me to the Genesis account Chapter 3 verse 14, which reads in reference to the serpent.
“Because you have done this you are accursed more than all the cattle and all wild creatures. On your belly you shall crawl……”

So the account states that all the animals were put into a state of disadvantage (cursed) but the snake more than the rest, in that it lost it’s limbs.

Now I may not be a creationist, but this explanation has more logic to it than Darwinian selectivity.

What do you think?


The fact that you do not see the advantages of the loss of limbs does not prove anything. Maybe it makes it easier to crawl into small holes/spaces, or maybe something else that cannot be seen but was advantageous for the snake's ancestor. Remember that reversion is not always possible, and once something is lost, it might not be possible to get it back. So the evolution has to work on what is there now, not on what was previously there.
The famous example by S.J. Gould is the Panda's thumb. Bear lost it, but a thumb is useful to eat bamboo shoots, but the thumb structure cannot be recreated, however another solution emerged (i refer you to the book, he writes better than me).
And the "curse" solution however better it looks to you have so much implicit complexity (necessity of a creator, possibility of curses etc...) that I suggest that you take Occam's razor and use it. But once again remember the implicit assumptions behind your scenarii.
Patrick

Science has proof without any certainty. Creationists have certainty without
any proof. (Ashley Montague)
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