72 replies to this topic

[SteveT]

No, I'm not saying that at all.

In some situations, energy is released when molecules form. This increases the entropy of the universe, and therefore it can spontaneously happen. Otherwise, large amounts of energy are required to force the two particles to combine into one.

[Alakhriveion]

And all the particles are compatible, aren't they? As for large amounts of energy- there's plenty of that. Every been sunburned? Yeah, that's actually caused by energy. Oh, lighting! That's energy, too! The Earth's inside is very hot- heat, hey, that's energy too!

[SteveT]

Indeed it is. But...wait. Doesn't hte ozone layer block UV rays? And I've never seen something become a more complex species by being struck by lightning. And the funny thing about the Earth's core is that there's a nice layer of rock and magma to absorb all that heat. Otherwise it'd be warm at night.

And yes, the only reason there's any life at all on earth is because of the sun. However, that's not enough for anything more complex than plants, or we wouldn't need to eat. This begs to question of: where did the energy to jump from one-celled organism to multi-celluar organism come from, and the question become more and more difficult with each successive increase in complexity.

And no, not all the particles are compatable. You don't see Helium-Xenon molecules, do you?

[Alakhriveion]

I'm talking about becoming RNA, not becoming a more complex species. RNA leads to DNA. DNA leads to cellular life. This easily becomes multicellular and symbiotic life- that's evolution. Then, the ones that are bigger than the others survive longer, and reproduce more. Evolution. The question becomes easier and easier.

And no, not all the particles are compatable. You don't see Helium-Xenon molecules, do you?

No, nor do I require them to live. That's irrelevant.

[SteveT]

No, it's not easy. Each successive step in evolution brings the entropy of earth lower and lower unless you can account for where the energy is coming from.

[Alakhriveion]

The sun. If it can sustain life now, it could sustain life ten, twenty, a hundred, a thousand, three billion years ago. If life can be sustained, it can reproduce. If it reproduces, it'll mutate. If it mutates, it'll evolve.

[SteveT]

And what causes the mutation?

EDIT: Actually, you know what? Screw it. I'm gonna go hang out with Black Mage, who has recently been revealed to be my soulmate.

[Alakhriveion]

Originally posted by Wolf_ODonnell@Sep 26 2004, 11:11 AM
Heat energy. Electrons. Free radicals. Sometimes DNA bases get mismatched. That sort of thing. You'd be surprised how easily DNA "mutates", even just a regular dose of UV can cause mutations.

That's what most people forget. DNA isn't just floating around in relative safety. Even within a cell, it's being attacked by free radicals generated from regular respiration (not breathing, respiration as in the generation of energy from glucose).

There are DNA mechanisms to repair the DNA, not to mention that you always have two copies and each two copies has one strand. Well, the DNA repair proteins use one strand as a template. There's a 50:50 chance of it attaching to the mutated strand and using that as the template, getting rid of the normal strand and replacing it with the mutated strand.

Once you realise how fragile DNA really is, even within a cell, you realise how easy it is for mutations to occur.

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[arunma]

Originally posted by Alakhriveion@Sep 26 2004, 01:51 PM
Actually, we're not.  We synthesised polio, Summer '02 or '03.  It was in the Times.

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If you want to get technical, a virus isn't alive. People have been synthesizing viruses for years.

[Alakhriveion]

Regardless, where you can have it, you'll get actual cells- while the virus isn't alive, it has implications... That everyone's too lazy and underfunded to follow up on.

[Wolf O'Donnell]

[quote]Originally posted by SteveT+Sep 26 2004, 08:05 PM-->

You don't quite have the concept down.  That's the end point of entropy, but it does control pretty much everything.

The Second Law of Thermodynamics is that for something to spontaneously happen, the entropy of the universe must increase.  This means that overall, the universe becomes more disorderly.  By extension, things can happen that seem to make things more orderly, but overall, entropy still increases.

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Protein folding is spontaneous and does follow the Second Law of Thermodynamics. Granted, the protein itself becomes less entropic but the solution which it is in becomes more entropic and thus negates the problems of a protein becoming folded and ordered.

In the book, "Stardust: the cosmic recycling of stars, planets and people" by John Gribbin, it is mentioned how "in Janurary 2001, NASA's Ames Research Centre and the University of California, Santa Cruz, surprised many of their colleagues... by announcing the results of experiments carried out in laboratories here on Earth which produced complex organic molecules under conditions resembling those in interstellar clouds of gas and dust."

In the experiments, a mixture of the kind of icy material known to exist in these clouds (water, methanol, ammonia and carbon monoxide) was kept in a cold vacuum and dosed with UV radiation. Bingo. Hey presto, they got chemical reactions that ended up creating organic compounds which in water spontaneously created membranous structures resembling soap bubbles. That's membranous.

That's got nothing to do with evolution though. It's helping us get one step closer to understanding how life got on Earth in the first place, but has nothing to do with evolution.

[quote]Indeed it is. But...wait. Doesn't hte ozone layer block UV rays? [/quote]

Not all of them. Why else do you think you have to wear sun cream/sun block/sun screen when tanning on the beach? To protect you against UV rays, of course, which are also carcinogenic.

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[Alakhriveion]

No, he's right, virus are technically not alive for a slew of reasons. We're all decended from them, though, so let's not get too supercilious about it.

[Wolf O'Donnell]

Originally posted by Alakhriveion@Sep 27 2004, 08:17 PM
No, he's right, virus are technically not alive for a slew of reasons.  We're all decended from them, though, so let's not get too supercilious about it.

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Actually, you can't say that fully outright.

Some biologists see it as a non-living infectious particle like prion proteins. Others disagree and suggest they are alive because of what happens inside the host cell. They're kinda right on the border between living and non-living and the question, "Are Viruses alive?" is quite an open-ended one.

Ref: Are viruses alive?

So you see? We're not even sure what is alive and what isn't.

As human beings we like to define things and classify things to make things easier to understand. Yet in biology there are quite a few things that just plain resist to be classified, viruses being one of them.

The difference between species isn't clear cut either. We are the ones that defined what a species is.

1. Biology.
a. A fundamental category of taxonomic classification, ranking below a genus or subgenus and consisting of related organisms capable of interbreeding. See table at taxonomy.
b. An organism belonging to such a category, represented in binomial nomenclature by an uncapitalized Latin adjective or noun following a capitalized genus name, as in Ananas comosus, the pineapple, and Equus caballus, the horse.
2. Logic.
A class of individuals or objects grouped by virtue of their common attributes and assigned a common name; a division subordinate to a genus.

Some genuses, like the red wolf, have turned out to not be genuses after all but in fact, mongrels. The red wolf was found out to be a grey wolf that had bred with a coyote. We are the ones who said that the red wolf is different from the grey wolf and we tried to conserve both, whereas a recent study (which appeared in a copy of NewScientist way back) stated that there wasn't any point.

The definitions aren't as clear cut.

Take for example, bacteria. Compared to other organisms, they undergo orgies that would daunt even the most hedonistic of people. They transfer plasmids (small pieces of circular DNA) with any cell they can come across. Does that mean there is only one species of bacteria?

It's getting late and I fear that I continue I will start to not make sense. I bid you goodnight.