Evolution: The Scientific Evidence

[xilman]

Originally Posted by Wacky

I don't dispute the difference in diversity between the two groups cited. However, are you really comparing "apples and oranges"? For example, look at all of the diversity among the mammals.

The true grasses are monocotyledonous plants (Class Liliopsida) in the Family Poaceae. The bamboos to which you refer are not even in that Class, but they are still in the Family Poaceae.

Class Mammalia is a class of animal within the Phylum Chordata.
Hominidae are but a small portion of that Class.

Yes, I am comparing apples with apples.

Brief response: cladistics.

Longer response, grasses and bamboos are very closely related from an evolutionary and genetic standpoint. Classification into families and classes hasn't really caught up yet.



Paul

[xilman]

Originally Posted by ewmayer

And note that there is no small amount of evidence indicating that the changes in the 2 (e.g. by way of changes in the nature of the flora and fauna of the African savannah) may be interrelated. Fewer trees and more grass makes it advantageous for a bipedal-capable species to be able to stand and walk upright for long periods. You still have chimp-like and ape-like species inhabiting the the forested regions of the continent, but if the study of these processes has taught us anything, it's that when a new niche opens up, species will move (both in physical and evolutionary terms) to exploit it.

There is a very large amount of evidence that they are interrelated with respect to their co-evolution.

Wheat and maize, especially, have done very nicely indeed by co-opting Homo sapiens into their reproductive strategy.

The propensity of Homo sapiens for savannah-like conditions, even in sub-arctic ecologies, has greatly reduced tree-cover and greatly increased grasslands throughout the temperate regions over the last few millenia (though, to be fair, that period is rather too short to demonstrate radical evolutionary change amongst relatively long-lived species).


Paul

[xilman]

{ewmayer: Moderator's note - body of original message moved to...}

Hmm, perhaps this ought to be in a "Happy bamboo" thread.

Paul

[brunoparga]

Originally Posted by Fusion_power

Look back at Xilman's post which points out that the great apes have not changed significantly in that million years.

Originally Posted by xilman

To be completely transparent: I include humans in the collection of species which go under the name "great apes".

My claim is that we as a species have not evolved an enormous range of differences in the last few megayears. Neither have the other great apes.

Well, Fusion; let's track things down lest we get confused.

Throughout your four posts in this thread, you present a "basic premise":"humans have changed an awful lot in a very short time." Let me remind you that if your premise is wrong, then so is your entire argument. Also, you stated that against Ewmayer's excellent posts #1, 2, 4 and 5.

Up to post 18, we're discussing about whale evolution; instead of refuting my argument, you simply stated it didn't "hold water" (quite a pun, indeed).

The only piece of evidence you would have presented would be the quotation from Xilman; however, as we have seen, it's not evidence for your premise, it's actually against it.

To sum it all up: you've done nothing but petitions of principle. It's time to present some serious, reasonable evidence that humans have changed a lot. I think I'm not wrong in considering anything else from you as a waste of my time.

Not to forget your systematic avoidance of (trying to) refute others' arguments.

Bruno

[brunoparga]

Originally Posted by Jwb52z

Well, it wasn't for someone's disbelief, most of the time, but there are people, according to the Bible, who were killed for disobeying God at some point.

OK. Hippolytus, according to the eponymous play by Euripides, was killed by the goddess Aphrodite for preferring Artemis to her. His stepmother, Phaedra, who was an innocent and was used by Aphrodite in the plot, died because of that, too.

First, we'll put aside reasonings based on the idea of justice; one's argument that the Greek story ain't fair and mine that the Biblic story ain't fair either have exactly the (very weak) weight and cancel each other.

Now, can you give me a single reason for beliving in the Bible and not believing in Euripides or, say, any or all of the ancient or Eastern authors? Please note that since the end of this argument is belief, it cannot be its principle too ("You have to believe this and not that because you have to believe this and not that"). That was what I meant in my original post: the only reason one has for believing in God and not any other religion is the belief itself, which is a seriously flawed logic.

Originally Posted by Jwb52z

Well, I wouldn't really personally ask for proof because I would first kinda wonder if you were well.

Please bear in mind the belief question I told you, and think I could ask if you *are* well since you argue from a book which has internal inconsistencies (please refer to the Bible thread for that).

Originally Posted by Jwb52z

If I did ask for proof or evidence, for me it would only be because that would be an interesting thing to see. I never thought it was up to people to prove God's existence because the way I believe, it's impossible to prove it the way humans want to prove it because God wants Faith from humanity. If you have proof, you know for a fact that something is true. If you know something for a fact, you cannot have Faith.

If by knowing things for a fact precludes having Faith and God wants people to have Faith, it follows that he doesn't want us to know things for a fact, right? This is fantastic, and I have to say it's coherent with the story of the Tree of Knowledge in Eden.

Now I take this as a principle: not knowing things we can know (e.g. that 2^32582657 -1 is prime) is simply unbearable. Not only that: is only by trying to know for a fact everything we can (=science) that we've improved our lives to an almost inimaginable standard. For instance, our very conversation, you being somewhere in the world and I in Brazil, is an example. I should infer that God wouldn't want us to be talking. Since people might get killed for disobeying Him, we're at risk, assuming everything above is true.

I hope I've made my logic clear - I probably haven't, since it's almost 2 AM here.

Bruno

[Jwb52z]

Originally Posted by jinydu

How can tell whether any system has a purpose or not?

Maybe I just thought I already answered this. There's no test that I know of that can be done to do that. That's the short version of what I thought I said already.

[ewmayer]

At Paul's semi-suggestion I split his longish bamboo-related post off from this evolution thread and put it here.

However, I noticed that the topic of pandas and their favorite food provides an excellent example of evolutionary adaptation:

One of the few known candidates for the root of the word panda is pónya, possibly derived from a Nepali word referring to the ball of the foot--perhaps a keen observation of how this bear eats bamboo with an adapted wrist bone that functions as an opposable thumb and sixth digit.

[Fusion_power]

Bruno, Look carefully at this thread and its mostly pointless posturing. Neither of us is gaining anything. To me, the holes in current evolutionary theory are significant. In the end, you will choose to believe what you see as valid and I will choose to believe what I see as valid.

Xilman makes a point that the "great apes" have not changed significantly in the last few million years and as he pointed out, he was including man in that grouping. Then he brings up the comparison of the divergence in grasses to demonstrate a family with greater diversity over the same time span. The comparison is not valid for the simple reason that a given grass species may be represented at a given time by trillions of reproductive individuals. Humans on the other hand show pretty conclusive evidence of going through an evolutionary bottleneck in the recent past. Translate that to mean that comparing divergence of a large population into multiple species is not completely comparable to the situation with humans. Its not an apples to apples comparison.

Rather than continue to post meaningless opinions, why don't we wait and see just how different the genes are that control the shape and function of man's brain compared to the chimpanzee. We should have the rest of the story within 5 years based on recent progress. Who knows? Maybe someday soon a scientist will extract your genes for brain size and function and graft them into a chimpanzee genome. Will we then have an intelligent chimpanzee or a more nimble Bruno? This is not meant to be critical, its a very very real possibility.

I won't be posting to this thread again so have fun.

Fusion

[ewmayer]

Originally Posted by Fusion_power

Bruno, Look carefully at this thread and its mostly pointless posturing.

Speak for yourself, please - aside from vague blather about the "holes" in evolutionary theory, I've yet to see one of you religionists make a coherent, logical argument backed up by empirical evidence that the basic tenets of evolution are "wrong." (I'm not even going to ask you to provide a noncircular line of reasoning that any of the major non-historical aspects of your religious beliefs are "right.") If there is pointless posturing, it is on one side alone.

To me, the holes in current evolutionary theory are significant.

Aside from your quibble about whether hominid evolution has been more or less in the past few million years, what holes, exactly? In response to your vague objections, I can say: we know for a fact, based on extensive DNA sequencing and functional genome analysis, that the human and chimpanzee genomes differ (in terms of base pair-by-base-pair differences) by only a few percent, although some of the specific "hotspots" of variation tell a quite interesting story about likely evolutionary and environmental pressures acting differentially on the 2 species. Here's an excerpt from the Wikipedia page on the Chimpanzee Genome Project (bold highlighting and inline notes in [EWM: ...] are mine):

Analysis of the genome was published in Nature on September 1, 2005, in an article produced by the Chimpanzee Sequencing and Analysis Consortium, a group of scientists which is supported in part by the National Human Genome Research Institute, one of the National Institutes of Health. The article marked the completion of the draft genome sequence. A database now exists containing the genetic differences between human and chimpanzee genes, with about thirty-five million single-nucleotide changes, five million insertion/deletion events, and various chromosomal rearrangements. Gene duplications account for most of the sequence differences between humans and chimps. Single-base-pair substitutions account for about half as much genetic change as does gene duplication.

Typical human and chimp homologs of proteins differ in only an average of two amino acids. About 30 percent of all human proteins are identical in sequence to the corresponding chimp protein. As mentioned above, gene duplications are a major source of differences between human and chimp genetic material, with about 2.7 percent of the genome now representing differences having been produced by gene duplications or deletions during approximately 6 million years since humans and chimps diverged from their common evolutionary ancestor.

About 600 genes have been identified that may have been undergoing strong positive selection in the human and chimp lineages; many of these genes are involved in immune system defense against microbial disease (example: granulysin is protective against Mycobacterium tuberculosis, see: Entrez PubMed 9756476) or are targeted receptors of pathogenic microorganisms (example: Glycophorin C and Plasmodium falciparum) [EWM: malaria]. By comparing human and chimp genes to the genes of other mammals, it has been found that genes coding for transcription factors (such as forkhead-box P2 (FOXP2), mentioned above) have often evolved faster in the human relative to chimp; relatively small changes in these genes may account for the morphological differences between humans and chimps. A set of 348 transcription factor genes code for proteins with an average of about 50 percent more amino acid changes in the human lineage than in the chimp lineage.

Six human chromosomal regions were found that may have been under particularly strong and coordinated selection during the past 250,000 years. These regions contain at least one marker allele that seems unique to the human lineage while the entire chromosomal region shows lower than normal genetic variation. This pattern suggests that one or a few strongly selected genes in the chromosome region may have been preventing the random accumulation of neutral changes in other nearby genes. One such region on chromosome 7 contains the FOXP2 gene (mentioned above) and this region also includes the Cystic fibrosis transmembrane conductance regulator (CFTR) gene, which is important for ion transport in tissues such as the salt-secreting epithelium of sweat glands. Human mutations in the CFTR gene might be selected for as a way to survive cholera (see: Entrez PubMed 15905150).

Another such region on chromosome 4 may contain elements regulating the expression of a nearby protocadherin gene that may be important for brain development and function. Although changes in expression of genes that are expressed in the brain tend to be less than for other organs (such as liver) on average, gene expression changes in the brain have been more dramatic in the human lineage than in the chimp lineage. This is consistent with the dramatic divergence of the unique pattern of human brain development seen in the human lineage compared to the ancestral great ape pattern. The protocadherin-beta gene cluster on chromosome 5 also shows evidence of possible positive selection (see: Entrez PubMed 15777644).

Results from the human and chimp genome analyses should help in understanding some human diseases. Humans appear to have lost a functional caspase-12 gene, which in other primates codes for an enzyme that may protect against Alzheimer's disease.

Thus, there *has* in fact been recent evidence that genes which specifically correlate with brain size and defense against various human-specific pathogens have changed more than most others. Interestingly, note that unlike the Alzheimer's gene, there would be strong selective pressure for resistance to pathogens like malaria and TB since (unlike Alzheimer's) those strike people at all stages of life, i.e. severely impact reproductive capacity.

So, how do uncertainties in the details of the human/ape divergence qualify as a hole in the theory? You're using the standard creationist/ID canard: scientists don't know everything and disagree on some things, so it all must be a bunch of hooey. That same reason can be turned against the bible-thumpers, you know, except in that case there was never any empirical evidence to support any of the major tenets (God, the biblical creation, divinity and resurrection of Jesus, etc.) to begin with - in other words, there folks are squabbling about how many angels can dance on the head of a pin, as it were.

In the end, you will choose to believe what you see as valid and I will choose to believe what I see as valid.

...the difference being that "valid" means completely different things in the realms of science and religion. Your "valid" leads inevitably to circular reasoning: "It's valid because I have faith in its truth, its truth is proven by this book here, which is valid because it's the word of God, which we know is true because we believe it to be so - and He appeared to me in a dream last night, so there's your empirical evidence." Worse than being completely illogical, your "valid" is not open to question, even on points where it clearly flies in the face of what those "god-given" senses we are endowed with tell us is so. In other words, what you're really saying is that you embrace willful ignorance.

Xilman makes a point that the "great apes" have not changed significantly in the last few million years and as he pointed out, he was including man in that grouping. Then he brings up the comparison of the divergence in grasses to demonstrate a family with greater diversity over the same time span. The comparison is not valid for the simple reason that a given grass species may be represented at a given time by trillions of reproductive individuals. Humans on the other hand show pretty conclusive evidence of going through an evolutionary bottleneck in the recent past. Translate that to mean that comparing divergence of a large population into multiple species is not completely comparable to the situation with humans. Its not an apples to apples comparison.

So because Paul's comparison was not perfect, you dismiss his entire argument - and I'm sure you'll have some similarly "compelling" reason to dismiss the detailed genetic studies on the page I cite above. You use your misunderstanding of the scientific process and vague, ill-founded quibbles to dismiss a truly massive body of evidence that evolution is occurring all around you - like I said, willful ignorance. To again turn the tables: the biblical ten commandments include one that says "thou shalt not kill." The bible - especially the old testament - is full of killing, much of which is clearly described as righteous. That's a contradiction, hence the ten commandments have "holes,", hence the entire book they appear in is completely bogus, hence God doesn't exist, Jesus never lived, et cetera.

Rather than continue to post meaningless opinions, why don't we wait and see just how different the genes are that control the shape and function of man's brain compared to the chimpanzee. We should have the rest of the story within 5 years based on recent progress.

I find your word choice quite revealing here. Guess where that, yes, actual honest-to-goodness progress is going to come from? (Hint: not from the theological side of the ledger, nor from the camp of the ID propagandists.) Regarding "meaningless opinions," I again say, speak for yourself.

[xilman]

Originally Posted by Fusion_power

Xilman makes a point that the "great apes" have not changed significantly in the last few million years and as he pointed out, he was including man in that grouping. Then he brings up the comparison of the divergence in grasses to demonstrate a family with greater diversity over the same time span. The comparison is not valid for the simple reason that a given grass species may be represented at a given time by trillions of reproductive individuals. Humans on the other hand show pretty conclusive evidence of going through an evolutionary bottleneck in the recent past. Translate that to mean that comparing divergence of a large population into multiple species is not completely comparable to the situation with humans. Its not an apples to apples comparison.

I chose grasses as an example because they show great diversity and because, being a bamboo enthusiast, it's something I've looked into in some detail. Whether or not they are "completely" comparable, they are surely comparable. Indeed, each of us has made the comparison in this thread.

However, I can provide other examples. Equids, for example, have evolved quite markedly in the last few dozen megayears.

Another, probably better, example is the Felidae. Consider the differences and similarities between the house cat and the tiger. This grouping of species even contains one which has been through an evolutionary bottleneck at least as severe as Homo sapiens. I refer, of course, to Acinonyx jubatus, commonly known as the cheetah. The evidence suggests that some time in the past the species very nearly went extinct.

Either of these group meets your "trillions of reproductive individuals" objections. The cats, being largely hunting carnivores, have always had quite small populations compared to their prey and compared to their prey's food supply.

Originally Posted by Fusion_power

I won't be posting to this thread again so have fun.

Fusion

Well, if you want to run away without presenting your arguments, that's your prerogative. I'll continue to post while I have something to say which I believe will help others to understand the subject and to prompt them to conduct their own investigations.


Paul

[Jwb52z]

Originally Posted by brunoparga

Now, can you give me a single reason for beliving in the Bible and not believing in Euripides or, say, any or all of the ancient or Eastern authors? Please note that since the end of this argument is belief, it cannot be its principle too ("You have to believe this and not that because you have to believe this and not that"). That was what I meant in my original post: the only reason one has for believing in God and not any other religion is the belief itself, which is a seriously flawed logic.

No, I can't with those conditions or guidelines and your opinion as you have said it here.

Originally Posted by brunoparga

Please bear in mind the belief question I told you, and think I could ask if you *are* well since you argue from a book which has internal inconsistencies (please refer to the Bible thread for that).

Ok, I'll just refrain from commenting on that because there's another thread.

Originally Posted by brunoparga

If by knowing things for a fact precludes having Faith and God wants people to have Faith, it follows that he doesn't want us to know things for a fact, right? This is fantastic, and I have to say it's coherent with the story of the Tree of Knowledge in Eden.

Now I take this as a principle: not knowing things we can know (e.g. that 2^32582657 -1 is prime) is simply unbearable. Not only that: is only by trying to know for a fact everything we can (=science) that we've improved our lives to an almost inimaginable standard. For instance, our very conversation, you being somewhere in the world and I in Brazil, is an example. I should infer that God wouldn't want us to be talking. Since people might get killed for disobeying Him, we're at risk, assuming everything above is true.

I hope I've made my logic clear - I probably haven't, since it's almost 2 AM here.

Bruno

I've always looked at it as "If we're not supposed to know it, we never will, or there's no way to know it, unless it is a matter of free will and temptation to doing wrong and then we'll be able to know it. Knowledge and education can, when combined with the human tendency toward self-importance and arrogance, be the very thing that leads a person down the wrong path as I think Christianity would think of it, so you have to be careful and keep all the "things you learn" in a proper perspective and framework or whatever you want to call it. As you know, science has led to some great advances, but also, because science has no moral compass or limits of its own, it has led to some very agregious things, even if sometimes they turned out to have a beneficial effect in the future in some way by using the same knowledge.