When Darwin was writing his book about his ideas, he came upon this conflicting facts of the oldest known layer of rocks have fossils that are much more diverse than the newer ones in comparison. For his idea to work there should be less diversity as all life originated from one(the tree of life). At the time he asked for later generations to look for more clues, for many years no one found anything on the Precambrian rocks. Originally, ppl thinks that the life forms predates the Cambrian explosion are all soft body type, and weren't preserved, but geologist were able to find microscopic fossil records in layers of rocks that predates the Cambrian explosion, and they shown the same trend, more diverse.
How can we explain this? well, could it be there were multiple origin of life, and each of these were very different from each other, the only similarities they share were the living environments. Adaptation of the most fit takes place, and instead of life diverging we have life converging dictated by the environment. Maybe that's why we have 5 different kingdoms in biology, just can't group all them shits together cause they are too different and originated not from the same life form. Anyone with any other ideas on how else to explain this ?
PS. I'm only debating evolution on the part where there is only 1 origin of life, i think there might be more than one.
There is some possibility (and I think it is somewhat likely) that life began a number of independent times on earth. In many of these cases, it probably died out entirely and then happened again. There may also be independent lines of evolution in some extremophiles. The cambrian explosion, however, has nothing to do with this.
The cambrian explosion is an example of punctuated equilibrium in evolutionary systems. The creativity of the system opens up new design space which then becomes rapidly filled. It's still an open question exactly why this happens; one of my professors in school was working on this problem and it's very interesting.
On February 23 2012 03:38 rei wrote: When Darwin was writing his book about his ideas, he came upon this conflicting facts of the oldest known layer of rocks have fossils that are much more diverse than the newer ones in comparison. For his idea to work there should be less diversity as all life originated from one(the tree of life). At the time he asked for later generations to look for more clues, for many years no one found anything on the Precambrian rocks. Originally, ppl thinks that the life forms predates the Cambrian explosion are all soft body type, and weren't preserved, but geologist were able to find microscopic fossil records in layers of rocks that predates the Cambrian explosion, and they shown the same trend, more diverse.
How can we explain this? well, could it be there were multiple origin of life, and each of these were very different from each other, the only similarities they share were the living environments. Adaptation of the most fit takes place, and instead of life diverging we have life converging dictated by the environment. Maybe that's why we have 5 different kingdoms in biology, just can't group all them shits together cause they are too different and originated not from the same life form. Anyone with any other ideas on how else to explain this ?
PS. I'm only debating evolution on the part where there is only 1 origin of life, i think there might be more than one.
We don't have 5 "kinbdom" in biology, the most "fundamentals" branches are eukaryotes/archeas/eubacterias. And we even have an idea of the relationships between these 3 "groups" (basically archeas (which are bacterias) are closer to eukaryotes,which includes us, than to eubacterias. If these life forms had different origins, why would they have similar ribosomial RNA, use DNA etc. ? The evidence for a unique origin to life are really overwhelming. It doesn't mean that the life didn't appear more than one team, all it means is that only one survived.
And also I don't get what you mean when you see that the oldest known layer of rocks have fossils that are more diverse than the newer ones... it's not true at all. There was a huge increase of diversity at this period, people think that this was caused by a big change in the environnement (it's all debated, even the notion of cambrian explosion is debated). We do have fossils of the precambrian era, but they are really different than current organisms (none of them have a bilateral symetry). What we call the cambrian explosion is this relatively short period where "modern" groups of animals appeared, and is a period that saw a huge diversification of macro life forms (we almost don't know anything about microorganisms at this time).
On February 23 2012 03:38 rei wrote: When Darwin was writing his book about his ideas, he came upon this conflicting facts of the oldest known layer of rocks have fossils that are much more diverse than the newer ones in comparison. For his idea to work there should be less diversity as all life originated from one(the tree of life). At the time he asked for later generations to look for more clues, for many years no one found anything on the Precambrian rocks. Originally, ppl thinks that the life forms predates the Cambrian explosion are all soft body type, and weren't preserved, but geologist were able to find microscopic fossil records in layers of rocks that predates the Cambrian explosion, and they shown the same trend, more diverse.
How can we explain this? well, could it be there were multiple origin of life, and each of these were very different from each other, the only similarities they share were the living environments. Adaptation of the most fit takes place, and instead of life diverging we have life converging dictated by the environment. Maybe that's why we have 5 different kingdoms in biology, just can't group all them shits together cause they are too different and originated not from the same life form. Anyone with any other ideas on how else to explain this ?
PS. I'm only debating evolution on the part where there is only 1 origin of life, i think there might be more than one.
We don't have 5 "kinbdom" in biology, the most "fundamentals" branches are eukaryotes/archeas/eubacterias. And we even have an idea of the relationships between these 3 "groups" (basically archeas (which are bacterias) are closer to eukaryotes,which includes us, than to eubacterias. If these life forms had different origins, why would they have similar ribosomial RNA, use DNA etc. ? The evidence for a unique origin to life are really overwhelming. It doesn't mean that the life didn't appear more than one team, all it means is that only one survived.
And also I don't get what you mean when you see that the oldest known layer of rocks have fossils that are more diverse than the newer ones... it's not true at all. There was a huge increase of diversity at this period, people think that this was caused by a big change in the environnement (it's all debated, even the notion of cambrian explosion is debated). We do have fossils of the precambrian era, but they are really different than current organisms (none of them have a bilateral symetry). What we call the cambrian explosion is this relatively short period where "modern" groups of animals appeared, and is a period that saw a huge diversification of macro life forms (we almost don't know anything about microorganisms at this time).
You got a couple of the details wrong, but your argument makes sense (there is overwhelming evidence that eukaryotic mitochondria arose from a symbiotic relationship between an ancient prokaryote and a eukaryote "see Lynn Margulis' Endosymbiont Theory, super fucking interesting".
I think its most likely that all eukaryotes evolved from a common ancestor, but there might be a slightly greater chance that some eukarya/prokarya came into being separately?
I'm just thinking out loud, if there's some fundamental thing I've overlooked, enlighten but don't skewer me.
On February 23 2012 03:38 rei wrote: When Darwin was writing his book about his ideas, he came upon this conflicting facts of the oldest known layer of rocks have fossils that are much more diverse than the newer ones in comparison. For his idea to work there should be less diversity as all life originated from one(the tree of life). At the time he asked for later generations to look for more clues, for many years no one found anything on the Precambrian rocks. Originally, ppl thinks that the life forms predates the Cambrian explosion are all soft body type, and weren't preserved, but geologist were able to find microscopic fossil records in layers of rocks that predates the Cambrian explosion, and they shown the same trend, more diverse.
How can we explain this? well, could it be there were multiple origin of life, and each of these were very different from each other, the only similarities they share were the living environments. Adaptation of the most fit takes place, and instead of life diverging we have life converging dictated by the environment. Maybe that's why we have 5 different kingdoms in biology, just can't group all them shits together cause they are too different and originated not from the same life form. Anyone with any other ideas on how else to explain this ?
PS. I'm only debating evolution on the part where there is only 1 origin of life, i think there might be more than one.
We don't have 5 "kingdom" in biology, the most "fundamentals" branches are eukaryotes/archeas/eubacterias. And we even have an idea of the relationships between these 3 "groups" (basically archeas (which are bacterias) are closer to eukaryotes,which includes us, than to eubacterias. If these life forms had different origins, why would they have similar ribosomial RNA, use DNA etc. ? The evidence for a unique origin to life are really overwhelming. It doesn't mean that the life didn't appear more than one time, all it means is that only one survived.
And also I don't get what you mean when you see that the oldest known layer of rocks have fossils that are more diverse than the newer ones... it's not true at all. There was a huge increase of diversity at this period, people think that this was caused by a big change in the environnement (it's all debated, even the notion of cambrian explosion is debated). We do have fossils of the precambrian era, but they are really different than current organisms (none of them have a bilateral symetry). What we call the cambrian explosion is this relatively short period where "modern" groups of animals appeared, and is a period that saw a huge diversification of macro life forms (we almost don't know anything about microorganisms at this time).
You got a couple of the details wrong, but your argument makes sense (there is overwhelming evidence that eukaryotic mitochondria arose from a symbiotic relationship between an ancient prokaryote and a eukaryote "see Lynn Margulis' Endosymbiont Theory, super fucking interesting".
I think its most likely that all eukaryotes evolved from a common ancestor, but there might be a slightly greater chance that some eukarya/prokarya came into being separately?
I'm just thinking out loud, if there's some fundamental thing I've overlooked, enlighten but don't skewer me.
Could you point out the details that were wrong? Evolution is not my specialty but I'm in 4th year of biology, my specialty is neurosciences but I took a good number of classes on evolution. I must admit that my knowledge of the Cambrian explosion is not that good, i'm not really into fossils ^^. I'm well aware of the endosymbiotic origin of mitochondrias, as well as chloroplast (the organist used for photosynthesis) that's indeed really fucking cool. I had a seminar recently on that, and when you go in the details it's actually horribly complicated ...
By the way you're talking about procaryotes and eucaryotes, it was actually proven (by Carl Woose, compairing ribosomial RNA) that this division is not correct. As I said the 3 "fundamental" branches ar: - eukaryotes (basically cells that have a nucleus, including animals, plants and a lot of microorganisms) - eubacterias: basically most bacterias - archaeas: these are bacterias as well, a lot of them live in really extreme environnements (temperature, pressure acidity etc... they're pretty sick ^^)The funny thing is that there is an enormous amount of evidence showing that they are fundamentally different than bacterias (it was done at first with ribosomial RNA, but we also have a lot of evidence).It's currently thought that archaeas are closer to eukaryotes than to eubacterias. Therefore it doesn't make any sense to group eubacterias and archaes into "procaryotes", it's really a completly outdated concept. Unfortunately even among biologist (that are not specialized in evolution) it's hard to make people change their habits...
Concerning this hypyothesis that current lifeforms would have more than one origin it's really really unlikely. As I said we use almost the same DNA code, most biological molecules have the same chirality (left for amino acids, right for sugars), similarity between certain proteins/genes etc.. All these evidences mean that eucaryotes having a completly different origin than eubacterias and archaes is really unlikely. For those who don't have a background in chemistry or biology and don't know what chirality means and why it's relevant wikipedia explains better than I would on a forum :p .
I was tempted to make a conspiracy Keanu meme for this but the fact is, I've wondered about this too. Not about the "five kingdoms" or anything concrete really - I don't know enough about biology. But what if life emerged multiple times in different ways, but didn't all survive?
On February 23 2012 06:30 Failsafe wrote: rei i'm terrified like hell that i'll ever figure out anything you say
Yeah i should probably have PMed that, I do realize that it's going to be complete gibberish for almost everyone probably, including the guy I responded to ^^.
On February 23 2012 06:30 Failsafe wrote: rei i'm terrified like hell that i'll ever figure out anything you say
Yeah i should probably have PMed that, I do realize that it's going to be complete gibberish for almost everyone probably the guy I responsded to as well ^^.
On February 23 2012 06:30 Failsafe wrote: rei i'm terrified like hell that i'll ever figure out anything you say
Yeah i should probably have PMed that, I do realize that it's going to be complete gibberish for almost everyone probably the guy I responsded to as well ^^.
rei is the OP not you (afaik anyway!)
Oops nevermind... I thought for some reason that "rei" was some kind of noise, I forgot that it was the name of the OP ^^.
You know, you can just go on wikipedia and educate yourself. Here, let me link you.
On February 23 2012 03:38 rei wrote: When Darwin was writing his book about his ideas, he came upon this conflicting facts of the oldest known layer of rocks have fossils that are much more diverse than the newer ones in comparison. For his idea to work there should be less diversity as all life originated from one(the tree of life).
This is simply not true on a very basic level. Let me show with shitty paint:
This type of phylogeny is perfectly fine within the scope of evolution. While it is generally true that diversity increases with time, loss of niches and extinction events can remove variation, lineages are more likely to dead-end than keep going on. So even if diversity in the "cambrian explosion" was higher than that of a time later on it doesn't mean that there were multiple origins of life.
On February 23 2012 03:38 rei wrote: When Darwin was writing his book about his ideas, he came upon this conflicting facts of the oldest known layer of rocks have fossils that are much more diverse than the newer ones in comparison. For his idea to work there should be less diversity as all life originated from one(the tree of life). At the time he asked for later generations to look for more clues, for many years no one found anything on the Precambrian rocks. Originally, ppl thinks that the life forms predates the Cambrian explosion are all soft body type, and weren't preserved, but geologist were able to find microscopic fossil records in layers of rocks that predates the Cambrian explosion, and they shown the same trend, more diverse.
How can we explain this? well, could it be there were multiple origin of life, and each of these were very different from each other, the only similarities they share were the living environments. Adaptation of the most fit takes place, and instead of life diverging we have life converging dictated by the environment. Maybe that's why we have 5 different kingdoms in biology, just can't group all them shits together cause they are too different and originated not from the same life form. Anyone with any other ideas on how else to explain this ?
PS. I'm only debating evolution on the part where there is only 1 origin of life, i think there might be more than one.
We don't have 5 "kinbdom" in biology, the most "fundamentals" branches are eukaryotes/archeas/eubacterias. And we even have an idea of the relationships between these 3 "groups" (basically archeas (which are bacterias) are closer to eukaryotes,which includes us, than to eubacterias. If these life forms had different origins, why would they have similar ribosomial RNA, use DNA etc. ? The evidence for a unique origin to life are really overwhelming. It doesn't mean that the life didn't appear more than one team, all it means is that only one survived.
And also I don't get what you mean when you see that the oldest known layer of rocks have fossils that are more diverse than the newer ones... it's not true at all. There was a huge increase of diversity at this period, people think that this was caused by a big change in the environnement (it's all debated, even the notion of cambrian explosion is debated). We do have fossils of the precambrian era, but they are really different than current organisms (none of them have a bilateral symetry). What we call the cambrian explosion is this relatively short period where "modern" groups of animals appeared, and is a period that saw a huge diversification of macro life forms (we almost don't know anything about microorganisms at this time).
I remember, I once read something about the Cambrian explosion. If I remember correctly, that was the time when animals evolved shells and claws, thats why we have more fossils after that period than before that (bone fossilizes better than just cell walls/membranes). Is that about correct? I'm not quite sure but I believe the article said that animals before the Cambrian explosion had a lot larger cells and not so many of them, so they kinda looked like giant pillows or something flat like that. Wouldn't they have bilateral symmetry then? I'm not sure about all this. It's been quite a while since I read about this but I'm still interested. Would you enlighten us a bit more, please?
On February 23 2012 06:30 Failsafe wrote: rei i'm terrified like hell that i'll ever figure out anything you say
zomg it's failsafe, wear a smi shirt to the next lan event.
I only made this blog cause someone show me this video, and I went digging for the things they talked about in it. Turned out to be truth, but I am still skeptic about this. Here is the video,
On February 23 2012 03:38 rei wrote: When Darwin was writing his book about his ideas, he came upon this conflicting facts of the oldest known layer of rocks have fossils that are much more diverse than the newer ones in comparison. For his idea to work there should be less diversity as all life originated from one(the tree of life). At the time he asked for later generations to look for more clues, for many years no one found anything on the Precambrian rocks. Originally, ppl thinks that the life forms predates the Cambrian explosion are all soft body type, and weren't preserved, but geologist were able to find microscopic fossil records in layers of rocks that predates the Cambrian explosion, and they shown the same trend, more diverse.
How can we explain this? well, could it be there were multiple origin of life, and each of these were very different from each other, the only similarities they share were the living environments. Adaptation of the most fit takes place, and instead of life diverging we have life converging dictated by the environment. Maybe that's why we have 5 different kingdoms in biology, just can't group all them shits together cause they are too different and originated not from the same life form. Anyone with any other ideas on how else to explain this ?
PS. I'm only debating evolution on the part where there is only 1 origin of life, i think there might be more than one.
We don't have 5 "kinbdom" in biology, the most "fundamentals" branches are eukaryotes/archeas/eubacterias. And we even have an idea of the relationships between these 3 "groups" (basically archeas (which are bacterias) are closer to eukaryotes,which includes us, than to eubacterias. If these life forms had different origins, why would they have similar ribosomial RNA, use DNA etc. ? The evidence for a unique origin to life are really overwhelming. It doesn't mean that the life didn't appear more than one team, all it means is that only one survived.
And also I don't get what you mean when you see that the oldest known layer of rocks have fossils that are more diverse than the newer ones... it's not true at all. There was a huge increase of diversity at this period, people think that this was caused by a big change in the environnement (it's all debated, even the notion of cambrian explosion is debated). We do have fossils of the precambrian era, but they are really different than current organisms (none of them have a bilateral symetry). What we call the cambrian explosion is this relatively short period where "modern" groups of animals appeared, and is a period that saw a huge diversification of macro life forms (we almost don't know anything about microorganisms at this time).
I remember, I once read something about the Cambrian explosion. If I remember correctly, that was the time when animals evolved shells and claws, thats why we have more fossils after that period than before that (bone fossilizes better than just cell walls/membranes). Is that about correct? I'm not quite sure but I believe the article said that animals before the Cambrian explosion had a lot larger cells and not so many of them, so they kinda looked like giant pillows or something flat like that. Wouldn't they have bilateral symmetry then? I'm not sure about all this. It's been quite a while since I read about this but I'm still interested. Would you enlighten us a bit more, please?
As i said i don't really know that much concerning the diversification at this period, I would advise you to read the wikipedia articles on the cambrian explosion, as usual it is very well done. http://en.wikipedia.org/wiki/Cambrian_explosion#Dating_the_Cambrian Just a small clarification: a bilateral symetry means that you can define a front and a back as well as a upside and downside. If something has a circular shape (like a pankake for example) you can usually define an upside and downside, but not a front and a back, therefore they are not bilaterians.
for rei Concerning the video I tried to watch it, I don't have time to watch it entirely though so my opinion on it might not be 100% accurate. What you learn in high school is a highly simplified version of what we currently know of evolution (and science in general), and some historical evidences that are traditionnaly used were proven to be false and should not be used any more. (for example Heckel drawings, as well as some studies on the color of butterflies etc), so these are good points. Evolution could be taught better, however the teacher talking seemed to want to use these to push his agenda that evolution was not a valid theory.. it would be really dishonest to pick old and outdated evidences that are not relevant any more to our vision of evolution to try to attack the validity of the theory. If he honestly wants to show more up to date evidences of the theory of evolution, then that's good but I don't feel like it was his goal..
By the way everthing you learn in high school, and even the first years of college is completly outdated science, especially in biology. Genes are much more complicated that what you learn in high school. Even Newton theory is only an approximation of Einstein's relativity theory. It doesn't mean that Newton's theory is worthless, on the contrary most of the time it would be absolutely stupid to use Einstein's theory of gravity to solve a problem. I feel like it's the same with Darwinian evolution: the 'simple' version can explain a lot, and therefore should be taught (not with evidences that were proven false of course), and what researchers do is pushing the theory to its limits. For example darwinian evolution can not really be applied easily to bacterias, partly because bacterias are able to exchange genes between them. It doesn't mean that Darwinian evolution is not the best way for us to understand how life evolved and is still evolving .
I read a book a couple years ago that shows how our body kept hints of our evolutionnary history, if you curious about this kind of thing it's a pretty good read (it's not something for specialist and it's easy to read) http://www.amazon.ca/Your-Inner-Fish-Journey-3-5-Billion-Year/dp/0375424474 (maybe you can find it in a library or cheaper somewhere else, I just googled 'fish evolution' because i couldn't recall the name of this book, and found it with the amazon link). That's a really good book .
Overall i'd just like to say that it's good to be critical of what you're being taught in school and it's even better to be curious. It's just important to remember that what is taught in high school is not an accurate representation of what is known, and that if you really want to have an educated opinion on something, you need to put much more time into it that going to a few classes in biology :p.
On February 23 2012 06:41 Djzapz wrote: I was tempted to make a conspiracy Keanu meme for this but the fact is, I've wondered about this too. Not about the "five kingdoms" or anything concrete really - I don't know enough about biology. But what if life emerged multiple times in different ways, but didn't all survive?
What do I know.
I'm thinking a Giorgio A. Tsoukalos meme (the guy from the aliens show with the crazy hair).
Cambrian explosion has many hypothesis, but multiple origin of life is not one of them. a particular one is the oxygenation of the atmosphere from the glaciation that occured near that time. with little to no ozone, uv interaction helped to oxygenate the atmosphere which (as with other oxygenation events) might have helped to kill off anaerobic organisms, and allowed the rapid evolution of survivors from the new energy source.
Jetaap I'm science teacher, my undergraduate back ground is in geology, and I know what you mean by "our body kept hints of our evolutionnary history" I remember someone a few year ago posted some video about the permian extinction and as one of the evident supporting his theory is that there is a gene in living things of today that is the aftermath of that extinction.
Here is the post I made to summarized the video for the ppl in TL as most of them are hot heady and didn't analyze what the video was really talking about. The whole reason for this thread is that one of my colleague that i work with is showing this video to his students to raise skepticism of what they are being taught. and i'm skeptic about the facts in the video in the same time i completely agree with the need for all learners to be skeptic about what they are being taught.
Honestly it's a terrible video .. I'm watching the part 20min and 28min and... sorry i'm just facepalming >_<. Wow actually I watched it till the end and it's really some creationist propaganda...
That's really frustrating to see how deceitfull and hypocritical this video is. It's a perfect example of what you can do when you carefully select what you present, put valid arguments among bullshit and things that not accurate. What's really annoying for me is that this video obviously push an agenda : "teach both side of evolution theory" and try to hide it. The problem that the other "side"they are pushing for is not scientific ... they try to make you think that the argument that they represented at the beggining were arguments that supported "creationism" or "inteligent design" (whatever you want to call it)... they are not. Of course the origin of life is complex, of course we don't know everything, of course our knowledge of it changes over time. It doesn't mean that non scientific approaches to evolution are more valid >_<. I don't know what's your opinion on that, but that's so... infurriating to think that teachers would show things like that in a classroom ...
These things make me really sad and angry at the same time ;(.
On February 23 2012 03:38 rei wrote: When Darwin was writing his book about his ideas, he came upon this conflicting facts of the oldest known layer of rocks have fossils that are much more diverse than the newer ones in comparison. For his idea to work there should be less diversity as all life originated from one(the tree of life). At the time he asked for later generations to look for more clues, for many years no one found anything on the Precambrian rocks. Originally, ppl thinks that the life forms predates the Cambrian explosion are all soft body type, and weren't preserved, but geologist were able to find microscopic fossil records in layers of rocks that predates the Cambrian explosion, and they shown the same trend, more diverse.
How can we explain this? well, could it be there were multiple origin of life, and each of these were very different from each other, the only similarities they share were the living environments. Adaptation of the most fit takes place, and instead of life diverging we have life converging dictated by the environment. Maybe that's why we have 5 different kingdoms in biology, just can't group all them shits together cause they are too different and originated not from the same life form. Anyone with any other ideas on how else to explain this ?
PS. I'm only debating evolution on the part where there is only 1 origin of life, i think there might be more than one.
The Cambrian explosion isn't a dilemma. It's not surprising to us that things become different as they spread out over the whole earth over billions of years. Also, the most obvious theorem of evolution (all extant life is from a common ancestor) isn't synonymous with saying life only originated once. Natural selection doesn't speak to how many times abiogenesis occured in history. For instance, the margins of error for molecular clocks are such that it's possible life is older than the Earth. And it's possible self-replicating molecules arose various times in the early Earth. It's logically possible that some life was seeded from space and some originated on Earth. We're also always looking for extremophiles. But your "hypothesis" isn't needed to explain the diversity of the kingdoms.
The reason we still have prokaryotes even though humans exist is analogous to the joke of a creationist being rebutted: If humans came from apes, why are there still apes? - If Americans and Australians came from British people, why are there still British people (not to compare British to prokaryotes, <3 limeys)? The diversity after the Cambrian explosion is because of the huge number of niches that popped up for multicellular life once it emerged.
EPT
(afaik anyway!)![[image loading]](http://img29.imageshack.us/img29/1236/70654857.png)
.
