Here’s a great one. Here’s another good one.
I wonder how long it will take to find some of these space seeds, if they exist. I hope soon!!!
DaLovin’ Dj
DJ, in Great Debates you’re supposed to post an opinion, tell us what you think, so we can have a debate. Otherwise, this is just MPSIMS material, babe. 
We can’t really debate “how long do you think before we find some space seeds?”
But I do like their motto: “Life comes from space because life comes from life.”
Right.
Duck Duck Goose wrote:
Uh … huh.
Hmmm. Where do the people who thought up this motto think that the first life came from, anyway? The Big Bang?!
Space is life, because it’s full of spores, which are alive. See?
And as to where the spores came from, well, obviously, they came from the same place that spores always come from–from fruiting bodies of some kind. So obviously there was no Big Bang, but instead there were Primeval Extraterrestrial Fungi somewhere on an alien planet, which produced spores.
It’s not that difficult, Tracer. Sheesh.
Cthulhu fhtagn! Iaaeeh! Iaaeeh!
Duck Duck Goose wrote (and I’m quoting completely out of context here):
Aha! I knew it! Panspermia advocates are all secretly Creationists!
I shoulda known when I saw Duane Gish, Philip Johnson, Ken Hovind, and Ken Ham on the Board of Directors…
All you’ve done is doubled (or at least procrastinated) your problem.
Where did the original life come from? Panspermia or seeding or whatever is an interesting idea, but doesn’t really explain anything or answer any questions. Your website freely admits that. All panspermia does is add another link in the chain in the question “Where did life come from?” And that site has wacky points about the Big Bang theory and wormholes and other stuff.
What I find more interesting is the theory that oil is not necessarily a by-product of surface life, but indeed is a natural feature in planets, and can be created and maintained by a deep, hot biosphere. This means after suns burn themselves out, planets or planetismals that remain warm can transport life from system to system. This theory has been forwarded by Thomas Gold, the guy who postulated and then helped discover quasars (argument from authority, I know). Described as a “world-class contrarian”, he may be just your type, dalovindj.
Here is a nice Wired interview with him.
One of my all time favorites, good ol panspermia
While it doesn’t answer the question as to the ultimate origin of life, it does have some utterly fascinating effects. First and foremost, at least to my mind, it opens up more time. I have always been troubled by that.
Suppose you take all the cogs, wheels, gears, transistors etc. in the world, and rolled them down a ten-thousand mile slope, then scooped them up and rolled them again, as many times as one wished. Sooner or later, those pieces will accidentally assemble into a self replicating robot, which, is a rather crude but effective metaphor for DNA. But your going to need lots of time, the Saganesque “billions and billions and billions”. But our recent studies seem to indicate that Earth became infested with DNA at a very early point in time, perhaps only a few millions of years after it cooled enough to be a solid. This contradiction is neatly solved by panspermia. Also, its really cool.
More interestingly, it implies that life, rather than being delicate and unlikely, is sturdy and damn near inevitable, it will exist so long as conditions do not absolutely prohibit it. When you look up into the night sky, you are seeing billions of stars, and gigazillions of living things. More importantly, DNA based living things, like ourselves!
We could eat them! Chicken-fried bandersnatch, anyone? Tribble sushi?
To paraphrase St. Pogo, “We are either the most intelligent beings in the Universe, or we aren’t. Either way, its a mighty sobering thought”
Gonna nitpick here. By all estimations, we don’t need more time. There has been between 2 and 3 billion years since evolution began on this planet. 545 million since the Cambrian explosion. We have diverged from mice in 60 million.
Your robot example is also relatively meaningless. At all points in evolution, there has been selection. Your example has no selection. At all times in evolution, the most evolved organisms passed their genes on most frequently. So instead of a truly random process resulting in a robot, you have a process at which each step is regulated, but there is no clear endpoint.
To borrow an analogy from Richard Dawkins, your example is like monkeys randomly banging on typewriters to create Shakespeare. Everything is discarded, except that which is Shakespeare. (It can’t be off by even one letter.) Evolution is like starting with a random string of letters, keeping only the ones which resemble Shakespeare, and then resubmitting the blanks between those letters for more random monkey trials:
TQWIO UJENASLKD HA
TOIUM AKANWLAJS SK
TOTND HRYN JMTT NT
TOLDE TRBNJDVTY UK
…selection…
TO BE OR NOT TO BE
This is obviously the shorter route to take when generating Shakespeare. Of course evolution has no definable end point, but it is still a useful analogy to show that evolution can move quickly.
Entirely valid. However, the processes of selection and the resulting acceleration, can only come into play after DNA based life exists. The “self-replicating robot” I’m talking about is the DNA molecule itself, which apparently I did not make clear. There is no real evidence to bring to bear on this issue, but my guess is that there isn’t enough time between the point at which the Earth became less than totally hostile to life and the first clear evidence of life for DNA to happen if we are positing strictly random chemical interaction.
If we have, however, the life-span of the Universe rather than the (comparatively short) Earth, it becomes at least that much more feasible.
IMHO, not really. All you really need for selection with replication is an RNA molecule. DNA is a relatively unnecessary second layer of complexity. Even something like classical RNA is not really necessary, one can evolve to that point. All that is needed is a nucleic acid like substance that can replicate itself. While this sounds complex, we have made RNA which comes close – it can polymerize RNA and partially replicate itself. Give us a few years and we can, in 20 years of PCR, replicate what nature had around a billion to do.
…and it seems, I would say, logically questionable.
Southern cuisine comes from Zeus because southern cuisine comes from southern cuisine.
Geena Davis impersonators come from Belgium because Geena Davis impersonators come from Geena Davis impersonators.
Gasoline comes from smegma beca
Well, it does seem questionable. Although IIRC most Geena Davis impersonators are Belgian.
Bandersnatch are not based on DNA. They are massive single-celled organisms with chromosomes so big they can be seen with the naked eye.
edwino
Well, as long as we’re nitpicking… Unless you are privy to some knowledge that seems to have escaped the rest of the scientific world… we don’t KNOW if we need more time or not. No one has successfully calculated all of the probabilities to know whether or not there was enough time for abiogenesis. No one even knows what all of the degrees of freedom are in this probability equation. Also, the point that elucidator was making was not about the 2-3 billion years to evolve from the first organism, but the 300-500 million years for the first living, self-replicating organism to appear.
But then, you did use the word “estimation” so I guess that let’s you off the hook. Great word. It carries with it an implication of actual information without requiring all that pesky data…
What I was trying to say was that the theories of evolution and abiogenesis are based on data. These data include things like probable composition of Earth’s early atmosphere based on planetary modeling , how much time there was for the stuff to go on based on radioisotope dating, biological data on the reactivity of particular types of molecules, for instance the ability of RNA to catalyze an RNA polymerization reaction. The theory has to fit the data, so any theory of abiogenesis without panspermia has to fit the observed time scale. Since in my readings, time scale has never been an issue, I assume that scientists theorizing about abiogenesis are not too concerned with it. Certainly the ones theorizing about evolution are not terrifically nervous about cramming all of observed life into the 3 billion years that they probably have to work with.
Well continuing to nitpick:
(1) The formulation of the theory of evolution (AKA Darwinian evolution) was not based on data. It was based on some basic observations and some deductive reasoning. Most of the supporting data came after the theory (which is, incidentally the way it usually works in science).
(2) I do not share your assumptions about the data.
First we may need to define what you mean by “the theory of evolution”. If your definition is that evolution is a change in the genetic characteristics of a population over time, there’s plenty of data to support that.
If your definition of evolution is that natural selection is largely responsible for the transition from the first theoretical single celled organisms into all of the known lifeforms that ever have and ever will inhabit this planet… well, there’s significantly less data to back that up. In fact, some of the data seems to be contradictory to that theory.
Because I know many of the scientific processes and techniques employed in data gathering in this field, and recognize that most of the analysis is done in an environment that assumes that the central premise is true, I don’t “assume” that the supporting “data” is not worthy of question.
The theory of abiogenesis has even less to go on. Many of the experiments that produce “data” to support the theory (such as Miller-Urey) are based on other theories, about the nature of the early Earth, for instance. These theories, also have little or no supporting data and, in fact, some rely on still other unsupported theories.
In fact, there are many scientists and mathematicians that have serious concerns about the time scale. Attempts to calculate the basic probabilities of even the most basic steps have come up with improbable numbers. Actually, some of these numbers exceed the age of known universe, but that doesn’t bode well for panspermia, either.
Personally, I’m betting on abiogenesis, but I think there must necessisarily be catalysts, chemical principles, and other processes that we have yet to discover (and perhaps never will) which led to that “blessed” event. However, until I know with greater certainty, I leave room in my philosophy for other theories, including, but not limited to panspermia.
OK, I’ll bite ACoverOfNoise. WHAT data contradicts the idea that all life on earth comes from a common ancestor? Are you talking about extremophile bacteria? But as far as I know, every organism on planet earth uses the same amino acid codon sequences. I can see no objective reason to link any codon to any amino acid, so the only explanation is that all life has a common ancestor.
You can’t just toss out casually that all our evolutionary theories are wrong without doing some backup work. Of course we don’t have any good theories of biogenesis. This disproves evolution…how?
I will bite, too, Cover, with two preconditions:
- I will not hijack this thread any further after this post. If you want to debate faulty science behind evolution, start a new thread to do it, and I will gladly be there.
- Since I am a molecular geneticist, the organic synthesis of proteins, lipids, and ribonucleic acid in abiogenesis interests me, but I have little knowledge in the region. I am interested in the world after selection with descent started, and that is where I will begin. I will say that our body seems to synthesize ribonucleic acids and proteins every day from 2 and 3 carbon substrates. It seems likely to me that in the correct environment, given a few hundred million years, similar things could happen.
I don’t know how you define data, but in my lingo, observations are data. I agree with your next sentence – deductive reasoning and observations behind the hypotheses, continued observation of new data to form a theory.
I will disagree with you about their being “less data to back that up.” There are reams of comparitive genomic analyses, protein homology studies, mitochondrial and Y chromosome DNA analysis, and observations of speciation in fruit flies. The molecular analyses by-and-large agree with the general taxonomic pattern established by fossil morphology. This all points to a continuum of descent with modification. This all points to common ancestry, for instance the striking 98% homology between histone H4 in E. coli and humans. One data point in a huge field, though. I’ll invoke Ben here and say that there is little reason for the pattern of protein homology unless you accept a descent with modification origin of species.
As do I. I work on a highly conserved network of genes in the fruit fly Drosophila melanogaster. Some of the genes are so highly conserved that mouse and chicken homologs can rescue Drosophila mutants. I read my papers with a critical eye, and I can recognize when pieces of the puzzle don’t fit together. That seems not to be the case with evolution, as almost all observations from numerous areas of science – geography, paleontology, anatomy, genetics, ecology, and biochemistry to name a few – all support evolution.
I do find the evidence of an RNA world compelling. Self-polymerizing and partially self-replicating RNA has been made in the lab with techniques less than a decade old. The intron/exon structure of genes somewhat supports an RNA origin of life. More than that, RNA forms the key catalytic components of many of the key reactions in the cell – namely splicing and protein synthesis, as well as parts of DNA replication (telomere extension). While I cannot safely conclude that this is how life began, I can say that the data are compelling, the story is interesting, and the experiments are for the most part sound.
I have seen no such calculations, and in my experience, trying to make the calculations are nearly pointless. We don’t know the environmental changes occuring on the early earth, we don’t know the migration patterns, we don’t know which species survived and which didn’t. We can estimate general trends perhaps, but evolution is based on improbable events occuring over large time scales. To estimate the amount of time needed to within 2 orders of magnitude is a task which I would think next to impossible.
Natural selection can be a powerful impetus, leading to rapid species change. Also, Gould may be right about punctuated equilibrium – we have lots of evidence for events that lead to quick genomic instability and fast change in populations. This only serves to speed things up.
While I can’t rule panspermia out, I find no evidence to support it. Therefore, since abiogenesis and evolution IMHO seem to be working adequately, I will stick with them. As is the nature of science, if I see valid contradictory data, then the theories will change. I do have to say that the probability of finding valid contradictory data about evolution is exceedingly small, as it would have to overwhelm an enormous set of data which support it.
Lemur866
I didn’t say that, and I wouldn’t say that. A thesis that all life does not come from a common ancestor is no more provable than the thesis that all life did come from a common ancestor.
The “data” that I was speaking of “seems” to be “contradictory” to natural selection as the principle mechanism in evolution. I couldn’t possibly list all of the seemingly contradictory evidence, but perhaps a few examples will suffice?
(1) The “explosive” growth in the number of new species and animal groups in the Tommotian stage of the Cambrian period. That period of only about 5 million years seems to throw a big monkey wrench in the slow gradualistic process of natural selection.
(2) On the other hand, we have the so called “living fossils”, animals that remain virtually un-evolved from their ancestors of 200-300 million years ago. Why do some creatures exhibit this evolutionary stasis if, as natural selection suggests, random naturalistic processes should drive change?
(3) Touchy ground here, but doesn’t it seem ironic that all known, observed cases of speciation have resulted from artificial selection (specifically hybridization) rather than natural selection? Doesn’t it also seem ironic that after thousands of years of selective breeding of cats, dogs, etc. that no new species has accidentally been created?
Now I’m not saying these things disprove that natural selection could be the sole agent of evolution, only that they tend to weaken the argument.
No. That illustrates the problem. That is not the only explanation - it’s merely the only one you can think of. There are certainly others - another explanation might be intelligent design. [No. I’m not making an argument for intelligent design, but it can’t be ruled out… scientifically - of course, you are free to rule it out philosophically]. There could be others that we’ve not “thunk” of yet.
Who’s tossing them out? I’m merely pointing out that they are not beyond reproach. Good scientists will not simply believe a theory simply because someone else says it’s so… where would we be if Einstein, Feynman, Hawking and others didn’t question conventional wisdom?
You’re quite adept at placing words in my mouth… I made no such claim. In fact, I think it’s pretty clear that these were separate thoughts.
However, let me say for the record that I believe in the theory of evolution and even in the process of natural selection, to a limit. I’m just careful not to cast my beliefs as fact and/or natural law.
In the immortal words of Sir Karl Popper:
edwino:
I agree with you, we’ve already started to diverge from the intent of this thread, so I’ll try to avoid serious hijack, but still answer a few of your questions, as long as they seem reasonably relevant.
By the way, my only intent in joining this thread was to state that throwing out the theory of panspermia is purely a dogmatic reaction. Panspermia actually does allow more time for biogenesis to occur, it may provide for “happier” environments, and it could be used to explain certain other events, such as the Cambrian explosion.
I’ll quote from “The American Heritage® Dictionary of the English Language, Fourth Edition” because it suits me:
Observations, in and of themselves, are not data (according to my definition). Observations can be used to collect and assess data.
If you don’t mind, I won’t continue to argue the point about evolution in this thread. Let’s stick to abiogenesis and panspermia. Therefore, I’ll leave your next couple of paragraphs unanswered, but let me reiterate, I’m not arguing against evolution anyway.
As do I. However a compelling argument does not a fact make.
Slight tangent here. Check me if I’m wrong, but these RNA sequences were made from other RNA sources (ribozyme engineering), were they not? The missing key seems to be getting that first RNA molecule right.
Agreed, but does this necessisarily preclude the possibility of panspermia? Again, I prefer abiogenesis over panspermia, but my preference is not based on science.
Can’t imagine that in your field… I’ve seen many versions, most are lame and assume that we went spontaneously from a pool of amino acids to the first proto-bacteria. Some, however attempt to calculate the intermediate probabilities of amino acids into polymers, then from polymers into self-replicating polymers, and so on. They also try to assess probable generation rates and survival rates. Of course, as you point out there’s so many assumptions as to make the whole process nearly pointless. However, it does raise valid questions about whether or not 200-300 million years was long enough for the process (whatever it was) to occur, which in turn makes the question of panspermia a valid one.