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question for evolutionary biologist.

Discussion of everything related to the Theory of Evolution.

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question for evolutionary biologist.

Postby searchfortruth » Sat Aug 18, 2012 4:23 am

Can someone explain to me how evolution supports the following;
I am not a biologist or trained scientist so i do not understand .
How if the code for the protiens required for DNA formation are contained in the DNA/RNA system did the protiens form to begin with? does this question make sense?

in other words protiens must have come first in order to create the DNA but the code for that protien is contained in the DNA that hasnt been formed yet.

i guess you could liken it to the chicken or the egg argument.

thanks,

Rick
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Re: question for evolutionary biologist.

Postby wbla3335 » Sat Aug 18, 2012 5:31 am

No one knows. Do a search for "abiogenesis" for some current ideas, but stay away from the creationist sites. They have nothing to contribute to a rational search for truth.
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Re: question for evolutionary biologist.

Postby Rap » Sun Aug 19, 2012 7:06 pm

The answer is much like the answer to the chicken-and-egg answer, which is that the egg came first, and it was laid by something that was not a chicken. Evolution is continually producing "new" organisms with never-before-seen DNA.

As far as which came first, the protein or the DNA, early life might have used molecule that reproduced itself, no distinction between protein and DNA. Then maybe a mutation occurred which two forms alternated back and forth. Then maybe a mutation in which the two forms stayed separate, with one more in charge of reproduction than the other, and these two molecules evolved into DNA and proteins. Maybe.
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Re: question for evolutionary biologist.

Postby scottie » Tue Aug 21, 2012 5:03 pm

Rick
There are two ways you can address this issue.
The first is to look at it in a scientific way as you appear to be doing, however it is often mistaken as a chicken and egg argument.

The reality is that the Cell is the basic unit of life, therefore it was the Cell that had to have been in existence before anything else could have happened, biologically speaking that is.
Why? Because it is the cell that contains the translation machinery that allows the DNA to code for proteins. It is the cell that contains the machinery that allows for duplication, and so on.

DNA outside the cell environment is an inert molecule. It will just sit wherever it is, doing nothing but deteriorate into it's basic constituent parts.

In very basic terms the cell contains machinery that takes a coded sequence of DNA and Translates that coded sequence to produce a protein. The type of protein made is determined by this coded sequence. This new molecule is then folded in a very precise way into the 3D shape we recognise as a protein. Different proteins have different shapes and coded sequences. Indeed one coded sequence can produce different proteins depending on the way these molecules are folded.

The question that therefore arises is; How does the DNA get into the cell.

This is where Real Scientists of the ilk of Craig Venter and his colleges have provided a proof of concept experiment.

This is what they did and announced in 2010
http://www.jcvi.org/cms/research/projec ... ell/video/

Spend time with this video which is about one hour in length. The question and answer session at the end is very helpful.
Hopefully at the end of this instructive video you will appreciate the biological engineering that is needed just to transplant a new chromosome into an existing living cell. This of course does not take account as to how the genetic code underpinning the translation system could have originated.

Now for the other way.

You can indulge yourself, as is suggested, and go down the speculative route of “abiogenesis” which has absolutely no scientific foundation. In fact even NASA has recognised that there is no plausible route that these molecules can come together randomly. A fact that the Venter team has demonstrated in a very practical way.

Abiogenesis is the stuff of fairies at the bottom of the garden. If people wish to research this subject then that is a personal choice.
However scientific research is another matter.

To me the beautify in biology is getting an understanding of how life processes work. The more scientists discover the more questions surface.

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Re: question for evolutionary biologist.

Postby wbla3335 » Tue Aug 21, 2012 6:55 pm

scottie wrote:Abiogenesis is the stuff of fairies at the bottom of the garden.

The only alternative to abiogenesis is creation, which is not exactly free of fairies. As I said, no one knows. The documentary crews weren't around, so all we can do is surmise. Some of us choose to believe in gods, some don't.
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Postby Rap » Wed Aug 22, 2012 1:42 pm

Venter et. al. mention a number of times how his group is the "top down" approach, while those searching for a plausible mechanism for the development of early life (the "bottom up" people) may have something to contribute to each other and will hopefully meet in the middle some day. Ventner et. al. clearly don't thing that abiogenesis is the "stuff of fairies".
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Postby JackBean » Wed Aug 22, 2012 3:26 pm

scottie: so, because we can grow plants in garden, no plants are able to grow without us?
http://www.biolib.cz/en/main/

Cis or trans? That's what matters.
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Postby Darby » Thu Aug 23, 2012 3:02 am

One of the main theories is that the first main metabolic molecules were RNAs, which can template proteins as well as be active themselves. How you get from such a start to the system seen now hasn't, so far as I know, been worked out.
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Re: question for evolutionary biologist.

Postby scottie » Sat Aug 25, 2012 10:40 pm

wbla3335

The only alternative to abiogenesis is creation, which is not exactly free of fairies. As I said, no one knows. The documentary crews weren't around, so all we can do is surmise. Some of us choose to believe in gods, some don't.


You are quite right in that the only alternate to abiogenesis (ie non science)is creation.
Venter and his team created a new species without any biological precursor.
This is what is referred to as “a proof of concept.”

Who is arguing that Venter is a god?
Certainly not me.
You continue to confuse religion with science.

Do you not consider it time to start presenting some science to this forum instead of your religious bias.

Rap
Venter et. al. mention a number of times how his group is the "top down" approach, while those searching for a plausible mechanism for the development of early life (the "bottom up" people) may have something to contribute to each other and will hopefully meet in the middle some day. Ventner et. al. clearly don't thing that abiogenesis is the "stuff of fairies".


If you read my postings you will realise that the top down approach is precisely what my position is.
Design is exactly what a top down approach is. Venter and his team designed the new chromosome
and then engineered a way (using the already existing machinery in yeast) to insert it into the recipient cell thus creating a new species.
The “stuff of fairies” I refer to, is what exists in peoples imagination and especially so when it is disregards scientific evidence.

Many people believe in many things, but belief isn't reality unless it is accompanied by evidence, and there is no evidence that life can arrive from non life. All the scientific evidence shows that life can only come from another life. Venter himself acknowledges that.
Indeed Darwin himself (maybe unwittingly) acknowledged this fact because he postulated his hypothesis based on common decent, ie one life from another life.

Jackbean

scottie: so, because we can grow plants in garden, no plants are able to grow without us?

Sorry I have no idea what your point is? What your statement has to do with my posting is really beyond me.

However we have been down this road before, so perhaps a refresher might be in order.
The Ribosome is the translation system for the manufacturing of proteins.
This process starts with Transcription.
This is the first step in decoding a cell's genetic information. During transcription, Enzymes called RNA polymerases build RNA molecules that are complementary to a portion of one strand of the DNA double helix.
Now what is an enzyme?
Guess what? It is a protein.

This basic refresher tell us that a Protein is required at the start of a process to make (guess what?)another Protein.
That is why I argue that the Cell is the basic unit of life. I really don't see what the difficulty is in understanding such a simple concept.
Unless of course some pre conceived philosophy is coming in the way.
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Re: question for evolutionary biologist.

Postby scottie » Sat Aug 25, 2012 10:50 pm

Darby

One of the main theories is that the first main metabolic molecules were RNAs, which can template proteins as well as be active themselves. How you get from such a start to the system seen now hasn't, so far as I know, been worked out.

I agree with you about the RNA world having been one of the main theories.
In 1968 Sir Francis Crick argued that RNA must have been the first genetic molecule. He went on to suggest that RNA, besides acting as a template, might also act as an enzyme and, in so doing, catalyze its own self-replication.

The problem now is that, as knowledge has accumulated, his idea has become obsolete.
Challenges to this idea have been many and various (I refer not to any creationist literature).
NASA has discounted it.
One of the latest studies published in March this year can be found here:-
http://news.illinois.edu/news/12/0312ri ... olles.html
Study of ribosome evolution challenges RNA world hypothesis

Here is what the lead researcher had to say
“This is the crucial piece of the puzzle,” Caetano-Anollés said. “If the evolutionary buildup of ribosomal proteins and RNA and the interactions between them occurred gradually, step-by-step, the origin of the ribosome cannot be the product of an RNA world. Instead, it must be the product of a ribonucleoprotein world, an ancient world that resembles our own. It appears the basic building blocks of the machinery of the cell have always been the same from the beginning of life to the present: evolving and interacting proteins and RNA molecules.

 
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Re: question for evolutionary biologist.

Postby wbla3335 » Sun Aug 26, 2012 3:44 am

scottie wrote:Venter and his team created a new species without any biological precursor.
This is what is referred to as “a proof of concept.”

Venter has not created life. No "proof of concept" here.

scottie wrote:You continue to confuse religion with science.

Not me. Look in a mirror.

scottie wrote:Do you not consider it time to start presenting some science to this forum instead of your religious bias.

I have no religious bias. Look in a mirror.

scottie wrote:Many people believe in many things, but belief isn't reality unless it is accompanied by evidence, and there is no evidence that life can arrive from non life.

And there's no evidence that life was created by a supernatural entity. As I've already said (twice) before, no one knows how life on Earth, or in the universe, began. If you believe that life on Earth was created by some advanced being (which no one can discount), then how did this advanced being originate? Pushing back creation to earlier sources must have an end (i.e beginning), and that end can only be abiogenesis or creation by a supernatural entity.

Your continual appeals to your faith in science are becoming tiresome. You have done nothing in your posts but misunderstand or misinterpret the findings of science. If you do not wish to accept the findings of science, then that's OK. Just don't be a hypocrite. All science has been able to do, all it is able to do, is to try and test what might have been possible. No more. If you feel that science has found evidence that life was created by a supernatural entity, please present it. Be specific.
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Re: question for evolutionary biologist.

Postby JackBean » Sun Aug 26, 2012 8:52 pm

scottie wrote:Venter and his team created a new species without any biological precursor.
This is what is referred to as “a proof of concept.”


Seriously? And I thought they used bacteria into which they put artifical DNA. However, still molecule, which is found everywhere around us. Thus, still nothing new.

And even if they have created something new, that doesn't mean it had to happen that way in nature. Just because we are able to grow trees in gardens, does that mean they do not grow in wildness? Only because we can grow them artificially, they cannot grow naturally (without any help)? After we will be able to produce meat in Petri dishes, will that mean, that no meat is produced by Nature?
http://www.biolib.cz/en/main/

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