Transterrestrial Musings

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Speaking of 700 million years. This reminds me of a conversation I had with my brother. Why, if the earth is over 4 billion years old did life arise only 700 million years ago? Did life exist here on earth before that time and was destroyed? Was it like life on earth today or something else altogether?

Posted by Jardinero1 at September 5, 2006 12:33 PM

The prevailing theory was that it took the first few billion years for the earth to cool and develop an environment in which life could form/flourish.

Posted by Rand Simberg at September 5, 2006 12:48 PM

Why, if the earth is over 4 billion years old did life arise only 700 million years ago?

It did not. The oldest known fosslizied bacteria date 3.5 billion years ago or more. What arose 700 million years ago is multicellular life. Actually, "multitissue" seems a better description. Things like sponges, which are technically multicellular but not much more than a colony of single-cell organisms, seem to have been around since about 1 billion years back.

Posted by Ilya at September 5, 2006 01:06 PM

Well, there seems to be some evidence that life is older than 3 billion years old. So even more time to do whatever was done.

Posted by Karl Hallowell at September 5, 2006 01:30 PM

While it's true that many (if not most) 'evolution skeptics' often (yeah, sometimes it seems like always and it's embarrassing) don't have the scientific or mathmatic background to make a good argument against evolution; Richard Dawkins' jumps to conclusions by way of weak arguments himself. It's a human trait to see things as obvious that you already believe. For example, in this article about junk DNA what conclusion might there be?

As a programmer, my belief is you can't draw too many conclusions regarding code that hasn't been decyphered yet.

What I do know is that when you do look into the mechanism for evolution you will be struck by the fact that it works in the opposite way that it's popularly characterized. As you say Rand, 'it is directed' but against evolution happening at all!

700 million is a big number, but if the life of the universe is not long enough, then 700m isn't either (and this has nothing to do with monkeys and typewriters.) Regards, ken.

Posted by ken anthony at September 5, 2006 01:42 PM

There's another difficulty with disproving evolution via this "I think it's unlikely" argument. Not only do you have enormous difficulty quantifying exactly how likely evolution would be, we also don't have any way of knowing how many worlds like Earth have the conditions Earth started with, but where evolution never got started. Is it only one chance in a million that evolution would produce what we see on Earth? Okay, but maybe evolution DID only work on one world out of a million eligibles. We won't know that until we've explored the galaxy a lot more.

Posted by Mark at September 5, 2006 01:45 PM

Those who look for science to back up their religion (like Cramer), or for an irreligion to back up their science (as many do) - are doomed to disappointment, IMHO.

No amount of science will ever explain WHY the reality we inhabit came to be, only how. Even that "how" depends on a underlying assumption that the rules of this reality have not changed over the period covered by that hypothesis.

Most religions (including mine) take on faith that our reality was created/designed by some intelligence beyond our knowledge and comprehension. Any intelligence this powerful can easily hide its tracks from our science, much less perform child's play such as raising Jesus from the dead.

Just my $0.02

Posted by Hunter McDaniel at September 5, 2006 01:46 PM

Several years ago I attended a lecture by Sir Fred Hoyle. (It was in the Space Science Lab auditorium at NASA MSFC) He argued that life did NOT originate on this planet, but that viruses and bacteria have been raining down through the atmosphere from extraterrestrial sources. Multicellular life here evolved from that rain. If you accept his arguments for interplanetary; possibly interstellar transportation, then you have many orders of magnitude more opportunity for the first self-replicating organism to start. Personally, I am not convinced of the viability of the transport mechanism, but I do think this is something that NASA could/should be looking for.

Posted by Dan DeLong at September 5, 2006 02:44 PM

Three different comments:

= = =

First, one of the arguments Zubrin makes for going to Mars is to look for bacterial fossils which (if DNA based) would be a large piece of evidence for panspermia (bacteria crossing through space).

= = =

Second, there is some evidence we humans learned to read and write more or less around the time calculated for the Garden of Eden in Genesis. Give or take a few thousand years, but in geologic terms, that is less than an eye blink.

= = =

Finally, perhaps this day (October 26th) should be celebrated as a global holiday:

In 1645 Bishop Usher from Ireland painstakingly studied the family lists in the Bible and stated that the Earth must have been created on October 26th 4004 BC. This detail, he felt, would stop the arguments once and for all.

Posted by Bill White at September 5, 2006 03:18 PM

The flaw with the million monkeys argument is that the goal is not to reproduce a particular work, but to produce any work that meets a predefined standard. For example, something that could pass as having been written by Alan Ginsberg or Margaret Atwood or Maya Angelou.

When I was just out of college, I wrote a simple computer program that could analyze a chunk of text (including punctuation and spacing). In effect, I was createing a template for what constituted a work by that author. Then, by randomly stringing together text in the proper proportions, create new text. When you analyze in twelve character overlapping chunks, what comes out almost looks like it should make sense, because it uses real works separated by commas and periods. It just lacks any grammar.

Posted by Raoul Ortega at September 5, 2006 03:39 PM

The real question is not how did we evolve, but what happened that caused some single-cell green slime bacteria mats, after being around for something like 3 billion years-the most successful lifeform on earth, in terms of longevity) to suddenly develop in to multi-cellular and complex forms in a geological blink of and eye half an million years ago. Snowball Earth? An asteroid impact? Increased volcanism? That is an interesting question...

Posted by Greg at September 5, 2006 04:55 PM

"The flaw with the million monkeys argument is that the goal is not to reproduce a particular work, but to produce any work that meets a predefined standard."

The only predefined standard is survival. Anything that survives, lives. If it doesn't survive, it meets the dodo bird and the passenger pigeon. These are very broad standards, which is we have such divergent life on the planet (from spiders to dogs).

I guess the only real template is the laws of physics. Everything else just kind of fell into place. This is why I've always thought the evolution vs. creationist arguments were garbage. There's room for both. God created the rules (only so many keys on the typewriter) and everything else happened randomly according to those rules (monkeys can only hit those keys). Why does it have to be one or the other?

Posted by CT at September 5, 2006 06:52 PM

Well I would say specifically the 2 things that direct evolution are Sex and Food. Recent research in Proteomics indicate that nuclear cell receptor interactions are primarily linked to Sex and Metabolism.

It could be reasoned that early cells naturally formed these networks to help elevate their reproductive and metabolic activities through increasingly more efficient metabolic activities. It could be tied into the fact that the cells evolved into ever more complex organisms to improve the rhythm of metabolic activity. In fact our enhanced intelligence and dexterity could be Altruistic means to a end for our cells in our bodies to have the best odds at continued sustenance and survival.

Posted by Josh Reiter at September 5, 2006 09:19 PM

what happened that caused some single-cell green slime bacteria mats, after being around for something like 3 billion years-the most successful lifeform on earth, in terms of longevity) to suddenly develop in to multi-cellular and complex forms in a geological blink of an eye [?]

You're giving too much weight to gross morphology and too little to the evolution -- within the cell -- of biochemistry and of the genetic system itself. The "green slime bacteria mats" just before the Cambrian may have looked like their predecessors three billion years before. But I'm betting that under the hood, they had incorporated far more of the interlocking biochemical cycles of metabolism, and developed far more sophisticated hierarchical code to support and regulate them. In terms of evolutionary "work to be done," the difference between the first shakily replicating proto-mRNA (or whatever it was) and a eukaryotic cell is greater than the difference between that cell and you, or a sequoia, or a blue whale.

My guess is that the Cambrian "explosion" reflects an internal threshold rather than an environmental change such as you propose. Maybe something like the homeobox (the "object oriented" module of developmental genetics), or the beginnings of the positional information signaling system that tells a cell it's in a muscle rather than a membrane, and adjusts its gene activity accordingly. Once that came into play, getting from slime to Angelina Jolie was just a matter of networking :-)

Posted by Monte Davis at September 5, 2006 11:10 PM

You probably know this via Dawkins et al, but the best metaphor I know for the mechanism that freezes the "right" letter in the sonnet -- or preserves the favorable mutations -- is the ratchet and pawl.

In a self-winding mechanical watch, random motions are converted into winding of the mainspring: no violations of thermodynamics, no mystical tendency to winded-ness, just a structure that accumulates "memories" of certain random jiggles while discarding the rest. That's exactly what the cycle of mutation, selection/differential reproduction, and changes in gene frequency does.

Posted by Monte Davis at September 6, 2006 09:42 AM

Rand,
Take a few minutes to look at the following website and read through the article there. As pointed out, 700 million years is not nearly long enough.

http://www.uncommondescent.com/index.php/archives/100

Posted by John F. at September 6, 2006 01:10 PM

Take a few minutes to look at the following website and read through the article there.

Sigh...

This has been debunked many times, in many places. I haven't the time, or gumption, to do it again.

Posted by Rand Simberg at September 6, 2006 01:34 PM

People tend to believe that 700 million years is a short time to evolve complex life forms because they 're thinking sequentially, but evolution is not sequential. The genetic operations of crossover, competition, selection, and mutation are massively parallel. They should be asking why it took as long as it did.

Steve

Posted by Steve Rogers at September 6, 2006 07:13 PM

But what are the chances that all of these complex mechanisms managed to develop in less than 700 million years?

1:1.

Posted by Chris Mann at September 6, 2006 09:05 PM

Here's the question I keep coming back to when considering the origin of life: Is there any completely neutral reason to think that everything that happens occurs only as a mechanistic result of what we would normally call "natural causes?"

This is an important question for the following reason. If you start with the assumption that everything is mechanistic, you will interpret evidence based on that assumption (e.g. 700 million years is plenty of time); if you start with the assumption that some things might not be mechanistic, you will interpret evidence based on that assumption (e.g. 700 million years isn't nearly long enough).

If you start with the assumption that everything is mechanistic, interpretations of the evidence showing otherwise will seem foolish; if you start with the assumption that some things are not mechanistic, interpretations of the evidence showing otherwise will seem foolish.

In a theoretically perfect situation, we would start with neither assumption, examine the evidence, and decide which assumption (mechanistic only or some non-mechanistic) better fit the evidence. Then we would decide if the evidence better fit one assumption or the other, or was indeterminate.

A difficulty here is that we don't generally have a theoretically perfect situation. Most of us (me included) seem to have pretty dearly held assumptions about the purely mechanistic or partly non-mechanistic nature of the universe.

Posted by Jeff Mauldin at September 7, 2006 11:24 AM

If you start with the assumption that everything is mechanistic,

If you start with any other assumption, you're not doing science.

Posted by Rand Simberg at September 7, 2006 11:27 AM

Is there any completely neutral reason to think that everything that happens occurs only as a mechanistic result of what we would normally call "natural causes?"

If by "natural causes" you mean "causes that are ameanable to formulation of theories that make testable predictions", then the reason is that it would be a waste of time to investigate any other explanation, since you could never reach an objective conclusion, and never achieve any knowledge that could be used for an objectively useful purpose (if you could, that use would constitute a test of the theory!)

Note that gods, demons, angels, etc. would fall under this definition of "natural causes" if you could make testable predictions about them.

Posted by at September 7, 2006 12:46 PM

"If you start with any other assumption, you're not doing science."

I have two completely different reactions to this comment.

The first is to observe that if you define science as assuming, a priori, that everything is mechanistic (a definition I don't instantly buy into, but one I won't immediately disregard either), then you can't prove that the origins of life and species are mechanistic in nature. You can certainly theorize as to how life came into existence assuming mechanistic processes, but you will not have proved that there were only mechanistic processes involved in the creation of life--you assumed that a priori.

The second reaction I have is to the definition of science such that if it doesn't assume mechanistic causes it isn't science. I'm not wholly adverse to this definition. Momentarily ignoring the issue of the origins of life, science by this definition is incredibly powerful. In fields such as physics, chemistry, medicine, and in engineering fields as well, science has given us a great understanding of and ability to use nature.

However, doesn't this definition also eliminate many other things we'd normally consider science? Take for example archaeology and anthropology. We actually start by assuming that people lived and did things in certain places and cultures in the past, and we try to gain understanding of the things they built, the things they used, and the way they lived. In those fields we start by assuming the causes were human rather than mechanistic, and then we study what we find in a "scientific" manner.

Posted by Jeff Mauldin at September 7, 2006 03:36 PM

You can't "prove" anything in science. You can only disprove things.

In those fields we start by assuming the causes were human rather than mechanistic, and then we study what we find in a "scientific" manner.

For the purposes of science, humans are assumed to be mechanistic at some level. At any rate they're a known quantity. What science can't consider is supernatural forces, or untestable ones.

Posted by Rand Simberg at September 7, 2006 03:55 PM

The fight is really not between mechanistic and non-mechanistic worldviews, but between empiricism and faith.

Posted by Paul Dietz at September 8, 2006 07:35 AM

"The fight is really not between mechanistic and non-mechanistic worldviews, but between empiricism and faith."

I think this is probably accurate. But I also think that some of what is claimed to be "empiricism" in the theory of origins is not empiricism. And this gets back to my original somewhat philisophical question: is there some completely neutral reason (I think philosophers would say "ontological" reason, but I've never been able to figure out exactly what that word means) to assume that everything that ever happened is the result of natural mechanistic processes? Or, for that matter, is there a neutral reason to believe that this is not the case? I'm willing to say that given the starting assumption that everything is mechanistic, mutation and natural selection is the best explaination we've got for how life as we know it came to be. But the question I'm asking is "is the evidence for natural selection and mutation as being the source of all life as we know it so overwhelming that the assumption must be valid?" Certainly many people will answer yes to that question, but others will answer no.

Here is a side issue, which I present in what is hopefully not a too confrontational manner. I recently read the following interesting claim: at the time of the "Scopes Monkey trials," those who argued in favor of natural selection and mutation as the force behind the origin of life and origin of species believed a certain set of facts about life. As a specific example of one of these facts, they believed that cells were very simple blobs of protoplasm. Since then we have discovered that every fact or almost every fact those people believed to be true is in fact false. Again, in the specific example, cells are extremely complex rather than fairly simple. So the logical grounds that these people were using--the assumptions--were in fact incorrect. On the one hand, I'd say that we should discard the opinions and arguments of those people because it turns out their reasoning was not based on sound assumptions. On the other hand you could certainly argue that the process of mutation and natural selection simply turned out to be much more complex than those people imagined. But shouldn't we discard a theory if it keeps needing to be changed as new observations are made? I don't think we can put this in the same category as, for example, the distinction between newtonian physics and quantuum physics, where we made additional discoveries which did not contradict previous discoveries, but gave broader and more general results of which previous discoveries were a special case--the old theory was not actually changed, it was just subsumed as part of the new theory. Or does it somehow go in that category as well?

Posted by Jeff Mauldin at September 19, 2006 10:26 AM

'In those fields we start by assuming the causes were human rather than mechanistic, and then we study what we find in a "scientific" manner.'

'For the purposes of science, humans are assumed to be mechanistic at some level. At any rate they're a known quantity. What science can't consider is supernatural forces, or untestable ones.'

Aha. Another philosophical question! Are we simply natural mechanisms going through the motions of existence? Do we have any free will? Are all these thoughts in my head the inevitable result of natural processes which were put in motion at the big bang? Where shall I have lunch? It was determined at the dawn of time!

I read an interesting and disturbing sci-fi short story a month or two ago. A lady toy inventor had gone crazy. She had been making artificially intelligent dolls that would talk to their owners in a realistic manner. She made better and better algorithms for response until the dolls were actually able to fool people for extended periods. Then she found out that she could predict exactly how real people were going to react to anything because she now understood all the artificial intelligence algorithms. She was going crazy because she was stuck wondering if all of us are really intelligent, or if we were just blindly and incomprehendingly following a set of algorithms. (I think it was called "The Algorithms of Love" or something with algorithms and love in the title. It was in a best-of-the-year type anthology.)

Ignoring the whole issue of free will, however, I think that anthropology generally doesn't make any assumptions whatsover about the mechanistic or non-mechanistic origin of humans. It starts with the assumption that there were humans doing things and making things, and that they lived in some kind of culture that had its own particular quirks. We don't care how the ancient ancestors of these humans came into existence originally, or if these humans are mechanistic or have free will. We are just investigating how they lived, what artifacts they left, and what they built. We call it science and we don't really care how the humans came to exist originally. The assumed cause is "human" not "mechanistic" and we don't care about the cause behind "human."

Here is an interesting parallel: when we do chemistry experiements, we usually could care less how the original atoms came into being. We take amout A of substance X and react it with amount B of substance Y, and we get such-and-such a reaction which is endothermic or exothermic and which yields these products, which have thus-and-thus properties. We are indeed assuming there is no "supernatural" intervention in the process, and that we will get the same results every time, assuming sufficient control. I am doing science whether I assume the atoms or their underlying components were originally created "naturally" or "supernaturally."

Posted by Jeff Mauldin at September 19, 2006 10:50 AM

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