Evolution? How?

Hi CI,

Well, I guess we could all just assume that if two critters look enough alike then one MUSTA evolved from the other (or else they both evolved from a 'common ancestor' ) .

But that's all it is. An assumption.

Accepting assumptions such as this can condition one to accept all kinds of interesting gymnastics.

Like 'different species cannot interbreed, except when they can'.

And 'hybrids are sterile, except when they're not'.

Accepting assumptions such as this can condition one to accept all kinds of interesting gymnastics.

Like 'different species cannot interbreed, except when they can'.

And 'hybrids are sterile, except when they're not'.

Like 'different species cannot interbreed, except when they can'.

And 'hybrids are sterile, except when they're not'.

{Farmerman:Excellent post Today at four at the Frying Pan in New York City, Frank and I will lift a glass in your honor.}

Joe( )Nation

real life

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Accepting assumptions such as this can condition one to accept all kinds of interesting gymnastics.

Like 'different species cannot interbreed, except when they can'.

And 'hybrids are sterile, except when they're not'.

When evdence from DNA in existing species nicely complements fossil records, our findings are "conclusions" not assumptions .REmember, reproductive isolation is accomplished in many ways, only some of which are chromosomal incompatability (like most birds). Sterility, while most common is not necessarily the only "litmus test" Viable crosses between lions and tigers are quite a novelty in Asian zoos.
You should be more careful how you use these facts rl ,because the Biblical assertion that things reproduce "after their kind" loses its boundaries when we can demonstrate that many species and even geni and families can still interbreed actually is a "field" demonstration of common ancestry.

There is the fact that there is decreased genetic flow between speciating populations in sympatric populations like fish and plants, while most land animals speciate due to geographic or environmental changes. However some species disperse so easily that the entire species are panmictic throughout their ranges The evidence of each of these possibilities is demonstrable through paleo evidence. There is no evidence to support your working hypothesis that all things were "created " at the same time and just happened to be transported to new niches.

A major area where Creationism wants not to have any discussions is the evolution of angiosperm plants during the Cretaceous. The evidence for the appearance and development of angiosperms is strongly tied to the geologic record and occurs in such a short time span that the transition is still an argument that is short on detailed evidence of intermediate stages of development.

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Like 'different species cannot interbreed, except when they can'.

And 'hybrids are sterile, except when they're not'.

LIKE most other sciences , including quantum chemistry and cosmological phenomena, we have "bell shaped curves" of evidence. If you consider it carefully, speciation can be a gradually acquired characteristic that defines the diversion of the species themselves snd complete reproductive mixing is theoretically possible at the fringes of niches where two or more derivative species come in contact. While most evidence of interbreeding is artificial selection it does occur in nature and by so doing, will often imbue the resulting hybrids with even more genetic diversity. Think how quickly plants can hybridize in natural situations. Acquired characteristics in wild species is often a real pain for monoculture agriculture. Acquisition of traits by natural populations of plants gives us a clear demonstration of how evolutionary mechanisms actually work.

I love the DNA evidence argument. Two similar critters MUSTA evolved one from the other, so we check the DNA. And you know what? These two similar critters have VERY similar DNA. Well, no wonder they look so much alike. What a surprise. So we call it a conclusion.

The fact that two similar critters ALSO have similar DNA still provides no real support for the assumption that evolution MUST have occurred for it to be so.

However, when DNA is NOT similar enough (evolutionists expected a 1% difference in the DNA of humans and chimps, but found to their dismay a nearly 4% difference), then the DNA is not all that important after all.

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However, when DNA is NOT similar enough (evolutionists expected a 1% difference in the DNA of humans and chimps, but found to their dismay a nearly 4% difference), then the DNA is not all that important after all.

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No one said that. You're making assertions yourself without evidence to back it up.

While the results confirmed that single nucleotide substitutions did account for roughly 1.4 percent of the differences, in accordance with previous estimates, Britten also found that indels account for a further 3.9 percent of divergence. This gives a rough estimate of five percent difference, he said.

"There seems to be a deep interest in this question," of how genetically similar we are with chimpanzees, said Britten. "Increasing the number is mostly a technical matter though; we are still the same distance away as we were before, and that is about five million years," he said.

The new estimate could be a little misleading, said Saitou Naruya, an evolutionary geneticist at the National Institute of Genetics in Mishima, Japan. "There is no consensus about how to count numbers or proportion of nucleotide insertions and deletions," he said.

Indels are common in the non-functional sections of the genome, said Peter Oefner, a researcher at Stanford's Genome Technology Center in Palo Alto, California. Scientists estimate that up to 97 percent of DNA in the human genome has no known function. However, he added, indels are extremely rare in gene sequences.

"We haven't observed a single indel in a [gene] to date between human and chimp," said Oefner. Therefore, the revised estimate doesn't alter the amount of DNA that holds information about our species. "Humans and chimps still differ by about one percent in gene sequences", he said.
Source

Eichler and his colleagues found that the human and chimp sequences differ by only 1.2 percent in terms of single-nucleotide changes to the genetic code.

But 2.7 percent of the genetic difference between humans and chimps are duplications, in which segments of genetic code are copied many times in the genome.

"If genetic code is a book, what we found is that entire pages of the book duplicated in one species but not the other," said Eichler. "This gives us some insight into the genetic diversity that's going on between chimp and human and identifies regions that contain genes that have undergone very rapid genomic changes."

Mutations

Humans and chimps originate from a common ancestor, and scientists believe they diverged some six million years ago.

Given this relatively short time since the split, it's likely that a few important mutations are responsible for the differences between the two species, according to Wen-Hsiung Li, a molecular evolutionist at the University of Chicago in Illinois.
Source

I love the DNA evidence argument. Two similar critters MUSTA evolved one from the other, so we check the DNA. And you know what? These two similar critters have VERY similar DNA. Well, no wonder they look so much alike. What a surprise. So we call it a conclusion.

The ID-iots have gotta put some effort into improving their collective reading comprehension skills.

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While the results confirmed that single nucleotide substitutions did account for roughly 1.4 percent of the differences, in accordance with previous estimates, Britten also found that indels account for a further 3.9 percent of divergence. This gives a rough estimate of five percent difference, he said.

"There seems to be a deep interest in this question," of how genetically similar we are with chimpanzees, said Britten. "Increasing the number is mostly a technical matter though; we are still the same distance away as we were before, and that is about five million years," he said.

The new estimate could be a little misleading, said Saitou Naruya, an evolutionary geneticist at the National Institute of Genetics in Mishima, Japan. "There is no consensus about how to count numbers or proportion of nucleotide insertions and deletions," he said.

Indels are common in the non-functional sections of the genome, said Peter Oefner, a researcher at Stanford's Genome Technology Center in Palo Alto, California. Scientists estimate that up to 97 percent of DNA in the human genome has no known function. However, he added, indels are extremely rare in gene sequences.

"We haven't observed a single indel in a [gene] to date between human and chimp," said Oefner. Therefore, the revised estimate doesn't alter the amount of DNA that holds information about our species. "Humans and chimps still differ by about one percent in gene sequences", he said.
Source

Quote:

Eichler and his colleagues found that the human and chimp sequences differ by only 1.2 percent in terms of single-nucleotide changes to the genetic code.

But 2.7 percent of the genetic difference between humans and chimps are duplications, in which segments of genetic code are copied many times in the genome.

"If genetic code is a book, what we found is that entire pages of the book duplicated in one species but not the other," said Eichler. "This gives us some insight into the genetic diversity that's going on between chimp and human and identifies regions that contain genes that have undergone very rapid genomic changes."

Mutations

Humans and chimps originate from a common ancestor, and scientists believe they diverged some six million years ago.

Given this relatively short time since the split, it's likely that a few important mutations are responsible for the differences between the two species, according to Wen-Hsiung Li, a molecular evolutionist at the University of Chicago in Illinois.
Source

Then, there's that whole human/chimp interbreeding thing ... it appears, that while Scopes of Tennessee trial fame may not have been a monkey's uncle, a monkey somewhere is uncle to all of us.

How funny.

Your source cites a 5% difference.

But since , (as one of your sources states) , up to 97% of the genome has no known function, then we can just discount about 3/4 of that 5% difference and call it less than 2%

Hey, if we don't know what it does, then it probably doesn't do anything, right? Cause we would know, right? Seeing as how we know everything......right?.

Keep 'em comin' timber. You are doing great. I hope you never start reading these things before you post 'em.

Most Human-chimp Differences Due To Gene Regulation -- Not Genes

The vast differences between humans and chimpanzees are due more to changes in gene regulation than differences in individual genes themselves, researchers from Yale, the University of Chicago, and the Hall Institute in Parkville, Victoria, Australia, argue in the 9 March 2006 issue of the journal Nature.

The scientists provide powerful new evidence for a 30-year-old theory, proposed in a classic paper from Mary-Claire King and Allan Wilson of Berkeley. That 1975 paper documented the 99-percent similarity of genes from humans and chimps and suggested that altered gene regulation, rather than changes in coding, might explain how so few genetic changes could produce the wide anatomic and behavioral differences between the two.

Using novel gene-array technology to measure the extent of gene expression in thousands of genes simultaneously, this study shows that as humans diverged from their ape ancestors in the last five million years, genes for transcription factors -- which control the expression of other genes -- were four times as likely to have changed their own expression patterns as the genes they regulate.

Because they influence the activity of many "downstream" genetic targets, small changes in the expression of these regulatory genes can have an enormous impact.

"When we looked at gene expression, we found fairly small changes in 65 million years of the macaque, orangutan, and chimpanzee evolution," said study author Yoav Gilad, Ph.D., assistant professor of human genetics at the University of Chicago, "followed by rapid change, along the five million years of the human lineage, that was concentrated on these specific groups of genes. This rapid evolution in transcription factors occurred only in humans."

"For 30 years scientists have suspected that gene regulation has played a central role in human evolution," said Kevin White, Ph.D., associate professor of genetics and ecology and evolution at Yale and senior author of the study. "In addition to lending support to the idea that changes in gene regulation are a key part of our evolutionary history, these new results help to define exactly which regulatory factors may be important, at least in certain tissues. This helps open the door to a functional dissection of the role of gene regulation during the evolution of modern humans."

To measure changes in gene expression from different species, White and Gilad developed the first multi-species gene array. This allowed them to compare the level of expression of more than 1,000 genes between humans, chimps, orangutans and rhesus macaques -- representing about 70 million years of evolution. To make the samples comparable, the researchers studied tissue from the liver -- one of the most homogeneous sources -- from five adult males from each of the four species.

They focused their search on expression levels of two sets of genes, those that remained largely unchanged across all four species, suggesting that there was little room -- or need -- for improvement, and those that changed most dramatically, usually in the human lineage -- an indication of powerful incentives to adapt to a changing environment.

Of the 1,056 genes from all four species, 60 percent had fairly consistent expression levels across all four species. "The expression levels of these genes seem to have remained constant for about 70 million years," the authors wrote, "suggesting that their regulation is under evolutionary constraint."

Many of these genes are involved in basic cellular processes. The authors suggest that altering the regulation of these fundamental and ancient genes may be harmful. In fact, five of the 100 most stable genes have altered expression levels in liver cancer.

When they also looked for human genes with significantly higher or lower expression levels, they found 14 genes with increased expression and five with decreased expression. While only ten percent of the genes in the total array were transcription factors, 42 percent of those with increased expression in humans were. None of those with lower expression were transcription factors. This pattern, the authors note, is consistent with "directional selection."

Previous studies have found that many of these same genes have also evolved rapidly in humans, accumulating changes in their coding sequence as well as in expression rates. "Together," they add, "these findings raise the possibility that the function and regulation of transcription factors have been substantially modified in the human lineage."

This is a very efficient way to make big changes with very little effort, according to Gilad. By altering transcription factors, the entire regulatory network can change with very few mutations, increasing the impact and minimizing the risk.

"The big question," he said, "is why are humans so different? What sort of changes in the environment or lifestyle would drive such a rapid shift in the expression of genes -- in this case in the liver -- in humans and in no other primate?"

Part of the answer, he suspects, is rapid alterations in diet, probably related to the acquisition of fire and the emerging preference for cooked food. "No other animal relies on cooked food," he said. "Perhaps something in the cooking process altered the biochemical requirements for maximal access to nutrients as well as the need to process the natural toxins found in plant and animal foods."

This is just the first of a series of similar studies, said Gilad, that will look at changes in gene expression over evolutionary time. The next steps are to look at larger arrays of genes and to focus on other tissue types.

###
Additional authors include Alicia Oshlack, Gordon Smyth and Terence Speed from the Hall Institute in Parkville, Victoria, Australia. This study was supported grants from the Keck Foundation, the Beckman Foundation and the National Human Genome Research Institute to Professor White.

real life wrote:

How funny.

Your source cites a 5% difference.

But since , (as one of your sources states) , up to 97% of the genome has no known function, then we can just discount about 3/4 of that 5% difference and call it less than 2%

Hey, if we don't know what it does, then it probably doesn't do anything, right? Cause we would know, right? Seeing as how we know everything......right?.

Only an ID-iot could come up with that bit of twisted, straw man argument.

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Keep 'em comin' timber. You are doing great. I hope you never start reading these things before you post 'em.

My reading skills are not called into the least question, rl, whereas yours apparently are non existant.