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Author | Topic: Question on evolutionary Rates | |||||||||||||||||||||||||||
Chiroptera Inactive Member |
quote: Even assuming that the 200,000 year per speciation is correct (and I doubt that it is), then what is the problem with 7500 "levels"? Actually, if their god makes better pancakes, I'm totally switching sides. -- Charley the Australopithecine
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RAZD Member (Idle past 1433 days) Posts: 20714 From: the other end of the sidewalk Joined: |
If they could have provided a detailed trail with the formas forking off and becoming some other family of creature they would have been heros. Why? There is plenty of evidence for this happening, so it would not add anything new to the concept of evolution or the evidence for it. The foraminifera are also an order not just a species, so there are changes at the family level too (between species and order). If you want an example of species evolving into a substantially different species try horses. Part of this depends on what you think is distinctive enough of a difference ...
abe: this is copied from another thread that is not open to general discussion. We can talk about horses and the distinctive development of the modern horse and single-toe hoof from the splayed toed dog sized "eohippus": http://www.flmnh.ufl.edu/...ci/vertpaleo/fhc/relatives10.htm (2)
quote: Check the above link to see images of the legs of four different horse ancestors. You can see a splayed toe stance for Hyracotherium and Miohippus but a single toe stance in Merychippus and Equus. http://www.geocities.com/...rk/7841/horse_evol/eohippus.html (1)
quote: The coloration is pure speculation, of course, but the size and stance are based on the physiology of the skeleton. Now lets also look at the Condylarth: Paleocene mammals of the world (3)
quote: This is the most "horse-like" image from this site, and it looks much more like a dog than a horse eh? Of course the coloration and fur are speculation, but the size and stance are again based on the physiology of the skeleton. To see what the skeletons looked like for the four species used for the leg examples at the start we go to: http://www.flmnh.ufl.edu/natsci/vertpaleo/fhc/Stratmap1.htm (2)
quote: I selected the same species as were listed for the legs above for convenience here - on the original link you select by clicking on the skulls. So we have a sequence of species that starts with one standing on the fleshy pads of several splayed toes to the modern species that stands not just on one toe but on the toe-nail of that single toe. But that is not all: http://muextension.missouri.edu/...agguides/ansci/g02740.htm (4)
quote: This is much more difference in a feature than "just an increase in length" (as in an elephants trunk), it is a totally different structure to stand on (eohippus stood on his toes pads, equus stands on a hoof which not only is not a toe pad, but a feature that wasn't present in the eohippus) and it incorporates a new {added\changed} structure to increase blood flow by acting as a secondary pump. Not only that the effect of changing the foot structure from a flat footed splayed toed eohippus to the single toed equus also involves standing the foot up on the tip of the toe and using each of the bones between the tip and the heel to effectively make the leg longer for faster running while also making it more flexible than just adding length to the bones of the leg. Probably useful for getting through tight spots and to keep from tripping ... it certainly helps horses jumping in shows from hitting that top bar. Totally different foot structure, coupled with totally different leg structure (with some ex toe bones now effectively used as leg bones). The question again is how much change is enough? Try walking around the house on the tip of one toe, then compare your foot to that of eohippus. Enjoy. References:
Edited by RAZD, : abe compare Fiocruz Genome and fight Muscular Dystrophy with Team EvC! (click) we are limited in our ability to understand by our ability to understand RebelAAmericanOZen[Deist ... to learn ... to think ... to live ... to laugh ... to share.
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crashfrog Member (Idle past 1495 days) Posts: 19762 From: Silver Spring, MD Joined: |
What I am saying at the 200,000 year rate you could only have 7500 levels. Sure. At the bottom level, though, you'd have 2^7500 different species. It's all but impossible to imagine how many species that is. That's more species than there are atoms in the entire visible universe. That's more than the number of atoms in 100 visible universes exactly like ours. Is it really so unreasonable to believe that Homo sapiens would be just one of those species? I don't see that it is. It's more unreasonable to believe that Homo sapiens wouldn't be one of those species.
Then when they started to mate you have the added problem of mating. Sexuality, as near as we can tell, emerged quite early in evolutionary history, so I don't see how it's a problem. We have so many sexual organisms because they're all the decendants of the first sexual species, not because they all evolved sexuality independantly. (It's possible, now that I think about it, that sexuality may have evolved two or three times independantly, since there's at least two or three different chromosomal schemes for sex determination that we know about.)
That problem had to be solved along the way somewhere. It's not a hard problem to solve. Consider a genetic factor that's passed on only 50% of the time. If you have it, you're Sex A. If you lack it, you're Sex B. Of course, that's not the only way to do it. You can have more than 2 genders, and many species do. But specialized sex structures and body types come long after the genetic basis for sex in evolutionary history. It's interesting but it's not a major problem.
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jar Member (Idle past 422 days) Posts: 34026 From: Texas!! Joined: |
Of course, that's not the only way to do it. You can have more than 2 genders, and many species do. But specialized sex structures and body types come long after the genetic basis for sex in evolutionary history. It's interesting but it's not a major problem. And you have species where sex is determined by external conditions and species where sex changes with maturity and species that change sex and species were a single organism is both sexes and ... Aslan is not a Tame Lion
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Wounded King Member Posts: 4149 From: Cincinnati, Ohio, USA Joined: |
Foraminifers are sexual and asexual, but not conscious (so sexual selection not a factor). This a contentious issue, some people argue that plants can have sexual selection, so I can't imagine they would except Foraminifers. TTFN, WK
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ICANT Member Posts: 6769 From: SSC Joined: Member Rating: 1.6 |
It's all but impossible to imagine how many species that is. Number reaches Infinity.
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Dr Adequate Member (Idle past 312 days) Posts: 16113 Joined: |
A while ago you didn't believe that speciation didn't happen at all. Now you think that the number of species should "reach infinity".
Here's a tip: try relating your statements to reality.
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ICANT Member Posts: 6769 From: SSC Joined: Member Rating: 1.6 |
Here's a tip: try relating your statements to reality. Do the math yourself start with 2 double for 7500 times.
A while ago you didn't believe that speciation didn't happen at all. ????
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NosyNed Member Posts: 9004 From: Canada Joined: |
Do the math yourself start with 2 double for 7500 times. And if I put a grain of rice on the first square of a chess board, two on the next; 4 on the third ....but what does that have to do with reality?
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Zucadragon Member Posts: 72 From: Netherlands Joined: |
ICANT its not so much a number issue really, what you're doing now is saying that the change from the first eukaryotic organismen to a human is a more complicated one then the change from a prokaryotic organism to an eukaryotic one.. Or atleast on the same level.
But that original statement is wrong in a very important way. And I'll provide a little example to explain it. The Drosophilia fly is a bug of which we know all genetic information, we also know that (and this is well known for anyone dealing with the fly, ask around biologists and they'll explain it to you) the fly has many genes that are closely related to human genes, around 78% I hear and read in a lot of places. Yet if you look at it, it still looks like a simple bug. And thats where the point lies, you can think about the first multicellular organismes and say "those would be so simple". But those first multicellular organismes would already have many of the genes that the humans would have in the future as well, minus and plus extra changes.. Just like the fly now, would those first organismes have many of the basic genes.. Which would take it less time in "speciation events" to get to the stage of what we call a human now. Does that make sense ? Add to this one more bit of information.. The genes from a prokaryote to an eukaryote was a big change, it wasn't something present in the organism and thus had to be created during a long process.. When the genes were there, you'd have eukaryotes, it is ofcourse a smaller step to go from one eukaryote to a different one..
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RAZD Member (Idle past 1433 days) Posts: 20714 From: the other end of the sidewalk Joined: |
This a contentious issue, some people argue that plants can have sexual selection, so I can't imagine they would except Foraminifers. True. And one could argue that sexual selection also goes on in mosquitoes and the like via variations in the sexual organs\fit. Perhaps what I mean is conscious\unconscious selection - based on some mental perception. So the question is where does run-away sexual selection fit on the conscious\unconscious scheme of things? This would represent the fast-tracked selection process that, imh(ysa)o, would show a faster than normal rate of fixing selected mutations. Thanks. compare Fiocruz Genome and fight Muscular Dystrophy with Team EvC! (click) we are limited in our ability to understand by our ability to understand RebelAAmericanOZen[Deist ... to learn ... to think ... to live ... to laugh ... to share.
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ICANT Member Posts: 6769 From: SSC Joined: Member Rating: 1.6 |
Hi RAZD in your earlier post you gave a chart on the horse.
It shows 15 different species within 8 levels. The time frame for this was 55 million years. Now this was after science says we have a horse. The average speciation rate per level would be 1 every 550,000 years. Almost 3 times as long as the Foraminifers. Merychippus 17 - 11 million years ago
Pliohippus 12-6 million years ago. Update: Over the years, refinements in our understanding of the Pliocene have resulted in the shrinking of that epoch. It is now believed to have covered a period ranging from about 5.3 to 1.75 million years ago.Dinohippus appears to be the closest relative to Equus. It seems to be an intermediate between Pliohippus and Equus. In fact, the genus was established from species that were initially included in Pliohippus (e.g. P. leidyanus). I have a problem understanding how Dinohippus can be an intermediate between Pliohippus and Equus when Pliohippus didn't exist until 5.3 million years ago. If he is then we have an unaccounted for time period of 5.7 million years.
would show a faster than normal rate of fixing selected mutations. It does not appear that the horse went very fast. The question remains with only 7500 levels how did modern man evolve from the Eukaryotic Cells. If he did, how did he do it without leaving a lot of fossils?
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fallacycop Member (Idle past 5548 days) Posts: 692 From: Fortaleza-CE Brazil Joined: |
I have a problem understanding how Dinohippus can be an intermediate between Pliohippus and Equus when Pliohippus didn't exist until 5.3 million years ago. If he is then we have an unaccounted for time period of 5.7 million years.
How is the 5.3 million date a problem? Intermediate simply means in between.
The question remains with only 7500 levels how did modern man evolve from the Eukaryotic Cells.
I don`t think this counting of levels make any sense, but even assuming the method has something to it, how isn`t 7500 levels enought?
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RAZD Member (Idle past 1433 days) Posts: 20714 From: the other end of the sidewalk Joined: |
It shows 15 different species within 8 levels. It shows 15 different genera (several species). That's why the different first part of the scientific names. Look at Equus: http://www.flmnh.ufl.edu/natsci/vertpaleo/fhc/equus1.htm
quote: And there are extinct species within Equus. One within modern times (recorded history). Not all genera represented by multiple species (eg - man) but most are (else why create a different genus? It's an arbitrary distinction).
It does not appear that the horse went very fast. When you include the species within the genus categories then it does appear that horse was faster than shown here, though the chart isn't detailed to the species level (the way foraminifera were, nor is the foraminifera data broken down by genera). It does not appear that horse ancestors engaged in the type of run-away sexual selection for specific traits that I was talking about either -- there is no sexual dimorphism beyond a slight difference in size (and that is due to dominant male herding behavior) -- and no "peacock tail" features. When we look at man we do see sexual dimorphism and "peacock tail" features: bare-appearing skin, long head hair, large creative brain, large sexual organs, and the like -- more extreme than in any other ape or primate, and some (bare skin, long hair, large brain) extreme to the point of threatening survival of those with the features. This to me is a significant element of human evolution since the common ancestor with chimps.
The question remains with only 7500 levels how did modern man evolve from the Eukaryotic Cells. The Abbott and Costello (and 3 stooges, and other vaudeville acts) way Step by step, slowly he turns .... Enjoy. Edited by RAZD, : fix quote and plural compare Fiocruz Genome and fight Muscular Dystrophy with Team EvC! (click) we are limited in our ability to understand by our ability to understand RebelAAmericanOZen[Deist ... to learn ... to think ... to live ... to laugh ... to share.
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Allopatrik Member (Idle past 6215 days) Posts: 59 Joined: |
Just a gentle point: the plural of genus is genera.
A Natural Selection is not Evolution-- R.A. Fisher
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