Oldest vertebrate fossil found in Australia, scientists say

farmerman wrote:

... the need for further sequencing to draw the conclusions tha ican wants

Has enough of any genome (e.g., CA or intermediate genomes between CA and H) been retrieved from the fossil record to sequence it?

0 Replies

ican711nm wrote:

It has been alleged that natural selection is the cause of procreating genomes NOT surviving.

It has been alleged that chance is the cause of the edits of procreating genomes. In particular, it is alleged that these edits of procreating genomes are the cause of genetic-drift.

It's called natural *selection*, not natural *chance*. If there was no non-randomizing factor in the process then evolution would not happen.

ican711nm wrote:

Regardless, what do you think caused the physical differences to evolve?

Amidst the variation within the genome there is an imbalance in the probability of any particular genome accumulating in a population. There is a bias against those genes which are not replicated (due to a range of conditions).

There are two forces at work: Variation and Selection.

Variation is relentless and results from many different causes (every single individual is unique, even if its uniqueness is only slight). Some of the gene sequences duplicate the previous generation, and some do not.

Selection is a result of events or conditions which limit or benefit the replication of any given gene sequence.

Usually the selection occurs against genes which are expressed in the organism (not dormant).

Some selection events can have a random effect by being so devastating that nothing survives (adapted or not). But most selection conditions are passive, like mountains being snowy and cold, and beaches being wet. As populations expand into differing environments, their genetic structure flows through generations like fluid into the new environments, form fitting the organisms into the environment. Over time, the populations diverge, or they may be suddenly isolated by geologic events.

This is the standard theory, and it has proven to be extremely accurate by test and prediction. There may yet be additional pieces to the process, but there is not yet sufficient evidence to indicate that there *must* be additional pieces. As far as we know, the model as it exists today may be sufficient to produce the results we see.

.

0 Replies

A very elegant summary, rosborne.

Thanks for the article, farmerman. Found out today that I missed a chance to see Craig Venter speak yesterday on "Our Genomic Feature." Bummer. (This is the guy who left NIH to try and map the human genome, racing against the human genome project -- a race which ended up in a dead heat despite the Project's considerable head start and budgetary advantage. Granted, when Venter started computers had gotten a whole lot better...)

0 Replies

yeah venter took a real creative step in beating the nIH (to me a dead heat with a mega funded agency is a win)

ROSBORNE_APPLAUSE APPLAUSE< EXCELLENT ,

Patiodog, what texts are you now using in ecology? Youre at Wisconsin right?

0 Replies

ican, they have not been able to do much sequencing beyond the limits that one can extract osteocalcin, which is derived from the bone and consists of proto amino compounds as silicate replacement. Its a tricky bit of magic but it has enabled some sequencing as far back as the Miocene (15 my)

0 Replies

Quote:

Patiodog, what texts are you now using in ecology? Youre at Wisconsin right?

Excerpts from various texts, and even those are largely skippable. It's a dismal, elementary, 2-credit couse (probably better back when Aldo Leopold started it) that I enrolled in on recommendations from some previous folks, and to satisfy a requirement. I've read enough (not much, but enough for this course) that it's a minimal-effort kind of thing.

Was excited to find I was walking through a copse named after John Muir (an alum) on my way to the first lecture, though...

0 Replies

Acquiunk wrote:

"What Evolution Is", by Ernst Mayr., Basic Books, 2001.
"Evolutionary Analysis" by Freeman and Herron, Prentice Hall, 2001. It is an introductory text.

I've taken Amazon's cheap-ship approach, so I won't receive these two books until after Thanksgiving.

In the meantime, I'll explore the proper distinction between what is a cause of an evolution event and what is a consequence of an evolution event.

I define a genome edit to be at least one change to the content of a base position in a germline genome.

I define an evolution event to be the first procreation of a genome edit.

I define a selection event to be the termination of one or more genome edits.

IT IS CURRENTLY ALLEGED
An human genome consists of a sequence of 3 billion base pairs.
Each side of the human genome consists of 1.5 billion bases.
There are 4 different kinds of bases.

Germline ( hereinafter, GL) genomes are found in EACH of the eggs and sperm of those species containing individual female and male organisms.

GL genomes consists of exactly one side of a non-GL genome.
Only human GL genomes participate in procreation of human genomes and humans.

The average human GL gene contains 27,000 bases or 9,000 codons.

Thus, 300 GL genes contain approximately 2,700,000 codons.

A codon consists of 3 bases.

WHAT CAUSES

an evolution event?

a selection event?

Genetic drift?

0 Replies

ican711nm wrote:

What causes... an evolution event?

[based on your definition of "evolution event"] Reproduction.

ican711nm wrote:

a selection event?

[based on your definition] Death before reproduction.

ican711nm wrote:

Genetic drift?

http://www.talkorigins.org/faqs/genetic-drift.html

In general, the talkorigins archive provides a wealth of information on evolution.

Have fun Smile

0 Replies

Ican and farmerman,

I am enjoying this thread immensly. For that I thank you both. Very Happy

As a Mechanist I "believe" that everything can be explained in some sort of mechanical context. Shocked

I am not qualified to comment on any part of the subject so I won't, but this does not prevent me from hoping that farmerman keeps it up. You (farmerman) seem like a person who "knows" something about something. This is not a universal trait amongst humans in general, and is much to be commended. :wink:

Thank you for sharing. Best wishes of all the worlds to you and yours, Mech.

Dog,

As you run through this world you will run across a lot of people who will profess to know something. Query them closely. Many people have a view of the world which does not seem to be in accordance with facts.
Unfortunately some of them have been granted tenure, respect, and adulation.
To "know" something is very different from "thinking" something or "believing" something.

Another, perhaps unfortunate fact --- is, "Should have" "Could have" and "did" are three very different possibilities describing a course of action, all of which seemed reasonable at the time! Good luck, M.

0 Replies

akaMechsmith wrote:

I am enjoying this thread immensly. For that I thank you both.

Mech,
Currently, I'm working to understand the optimism among many evolutionists that the evolution events and selection events that have occurred are caused by chance and not by any mechanistic synthesis influences, influences which I have included in a group I've labeled, 2ndI.

My probability model is rejected by many but I do not understand why. The reasons they have given appear to me to not be relevant to the validity of my model.

My probability model might be likened to a variation of the lottery model.

P = the probability of the occurrence of any specific one of a large set of numbers, within a given time, at a given number pick rate.

S = the total number of numbers that are possible to occur.

I = the total number of winning numbers.

M = the total quantity of numbers picked within a given time period.

The probability of the occurrence of a winning number with one pick = I/S

The probability of a winning number being picked within a given time period containing many picks is P = M x I/S.

The issue being discussed is whether this model is applicable to the standard evolution model.

It is alleged that there are many kinds of pick-events that occur in evolution. Picks of whole numbers generally get picked implicitly via picks of numbers in relatively small segments of a whole number. Some picks result in the deletion of whole numbers from the list of possible whole numbers because of certain segment picks. More about all this later.

0 Replies

Quote:

Dog,
As you run through this world you will run across a lot of people who will profess to know something... Unfortunately some of them have been granted tenure, respect, and adulation.
To "know" something is very different from "thinking" something or "believing" something.

Thanks, sir. Duly noted. My feeling (for what those are worth) on this topic is that very, very little is known, and so the opportunities it offers for thinking (and believing) are incalculable.

ican --
My quibble with the lottery thinking is that, for any given generation, "S" is limited by the previous generation's "I," so to speak, by virtue of the fact that they survive (if I'm understanding the model correctly). Does this make sense? (That's an honest question, not a smug rhetorical challenge.)

0 Replies

ican-sorry, I just saw this in que and I must have missed it.
While your total distribution is understandable, the number of total expressions of effective gene sites, actually decreases with each throw. In our world then it would be as if, for every time a lottery number is picked, a cerstain protion of that sequence gets transferred into the next set of l;ottery numbers. So if we are dealing with , say 1 billion sites (divided by 3, 6 9, or 12 since some amino acids are expressed as MULTIPLES of 3 codons,) then the placement of these sequences , or protein sequences, once expressed as a feature in aphenotype and it leads to an increased fitness in an individual , for that moment in time, then if that trait is far up in the phylogenetic chain , such as legs or eyes, it gets transfered to next and next generations .
The point is that randomness is not defined as all the possibilities that could be expressed, as in your lottery simile., because each event of draw in a lottery is independent of those previous.
There is an inherent declining variability in genomes because the previous expressions of phenotype limit the next expressions of genotype. Now if the environment changes completely, the path of evolution and selection usually takes a different route. Like in The Cretaceous, the Birds were just a minimal order, like mammals. Once the big predators (dinosaurs) were gone, both birds and mammals evolved to fill dinosaurs niches in the Tertiary. Mammals won because the birds that evolved into large meat eaters were flightless and were less able to compete with mammals for a number of reasons.None of which I have a clue about.

That talk origins site is a good one and has , lately, been altering itself to discuss and refute the arguments of Intelligent Design and Irreduceable Complexity etc..

0 Replies

An interesting article on the probability of evolution: http://www.findarticles.com/cf_0/m2379/4_40/63787448/p1/article.jhtml

0 Replies

Rosborne, that was a very interesting and informative article.

0 Replies

As a result of the past Nova program on Rosalynd QWilkinson, I just finished reading James Watsons new book DNA. Its really a marvelous compendium of this molecule, even to a section on sequencing .
of course, his words make it sound that anyone would have found out that Wilkinsons xray diffraction pix of the DNA lattice, when actually she broke the code. The only reason that she wasnt named for a NOBEL Prize, he said, was that she died early.
One of my earliest jobs in p chem was xray of xls, scary beams

0 Replies

Ican
I think that I understand your hypothesis, particularly in light of Farmermans post. I suspect that some modification of the rules to "Evolutionary Bingo" may get your "2ndI" a bit closer. Perhaps it would be helpful to your expression of it.

Dog, Yes they are. Isn't it wonderful, in both senses of the word?

Rosborne, I second Acquiunk. Thanks.

0 Replies

patiodog wrote:

ican --
My quibble with the lottery thinking is that, for any given generation, "S" is limited by the previous generation's "I," so to speak, by virtue of the fact that they survive (if I'm understanding the model correctly). Does this make sense?

First, check rosbourne's referenced article and acquiunk's reaction. Then check farmerman's last post. Yours is no quibble -- no quibbles in any these.

Second, I think in our discussion we have finally reached "the core" of the issue.

What must be done to the lottery model to make it completely analogous to the standard evolution model?

Let's start with CA, the genome that was common ancestor to M, the genome of mice, and H, the genome of humans. But let's limit our attention to the evolution of those alleged 300 genes in H that are not found in M

ALLEGATIONS (i.e., from stuff I've read)
1. The evolution of M and H from CA started about 100 million years ago.
2. M evolved about 60 million years ago.
3. H evolved about 0.15 million years ago.

4. In that interval of time, there were three major extinctions: 53%@99 million years ago; 75%@70 million years ago; 35%@40 million years ago.
5. CA and its progeny were edited multiple times over that 100 million year period.
6. An edited GL, germline ,genome may or may not survive and enconter an opportunity to procreate; even if it does, its progeny may or may not survive to procreate.
7. The 300 gene sequence found in H that is different than M can be represented by a sequence of base-four numbers: 0, 1, 2, 3.
8. This sequence is 300 x 9000 = 2,700,000 base-four numbers long.

ASSUMPTION
None of this sequence existed just before the time CA began to evolve to M and H.

QUESTIONS
1. How many separate edits of CA were required to evolve CA to M and to evolve CA to H.?
2. What was the average rate at which these edits occurred?

0 Replies

Quote:

1. How many separate edits of CA were required to evolve CA to M and to evolve CA to H.?

What is defined as an edit? The addition/alteration of one base, or an event that changes a base of indeterminate number? A frameshift mutation can effectively alter several hundred bases at a swoop, though if this occurs in the only copy of a gene that is expressed it can't be passed on unless its complement is continually expressed.

0 Replies

Acquiunk wrote:

Rosborne, that was a very interesting and informative article.

My pleasure. I liked many points in the article, but this one was particularly noteworthy:

[Evolution by natural selection, however, is a cumulative process, and that makes it a very different matter. Think of the coin game, and suppose it is played in a cumulative fashion. That is, suppose that you get to throw the first coin until it comes up heads. Then you set that coin aside and flip the second coin until it, too, comes up heads. If you continue in this fashion, it will surely not be long before all one hundred coins are facing heads up.

Likewise, evolution builds incrementally, from one stage of development to the next. The evolution of human life did not require the simultaneous appearance of self-replicating molecules and vertebrae and a gift for language; rather, the more complex systems could wait until the simpler systems were in place. Playing a game of accumulation shortens the odds considerably.]

The article as a whole reminds us that probability mathematics even by itself can be a challenging endeavor, without even adding in the remaining mysteries and details of the evolutionary process.

Best Regards,

0 Replies

patiodog wrote:

Quote:
What is defined as an edit? The addition/alteration of one base, or an event that changes a base of indeterminate number? A frameshift mutation can effectively alter several hundred bases at a swoop, though if this occurs in the only copy of a gene that is expressed it can't be passed on unless its complement is continually expressed.

Think of an edit as a variable number of changes to a GL gene-codon sequence within a genome. Simple mutations change very few codon positions. Gene substitutions change a great many gene-codon positions. An extinction deletes a great many GL genomes, but not necessarily the extinction of all occurrences of a specific gene-codon sequence. When I asked how many edits, I was really asking how many editing events. I was ignoring the variation in the size or complexity of editing events.

Suppose each and every edit event successfully substituted,say, one whole, 2,700,000, not previously occurring, gene-codon sequence for another such sequence. More than 10^93 such edits would be required to generate 10^100 different sequences. If such edits occurred at the rate of say 10^8 per second or about 10^16 per year, then 10^77 years would be required.

0 Replies

Oldest vertebrate fossil found in Australia, scientists say

Related Topics

Quick Links

My Account

able2know