The missing link has been found! Options

[False Dude]

Scientists have previously been able to trace the transition of fish into limbed animals only crudely over the millions of years they anticipate the process took place. They suspected that an animal which bridged the gap between fish and land-based tetrapods must have existed - but, until now, there had been scant evidence of one.

That is why there is a big deal about the animal.

[Jwilly]

i thought the missing link was forsaknr

[Mommy]

to be very honest and I dont care what you people think of me, I dont think we evolved from apes. A lot of evolution just seems like total bullshit to me. Im not saying I believe the bible, but I do believe that something had to start such an evolutionary chain if it were true. The big bang theory is so stupid. I dont know what I believe, but I can say that a lot (not all) of these "missing link" fossils seem totally bogus

This post has been edited by Jessica: Apr 6 2006, 04:48 PM

[Seeker]

to be very honest and I dont care what you people think of me, I dont think we evolved from apes. A lot of evolution just seems like total bullshit to me. Im not saying I believe the bible, but I do believe that something had to start such an evolutionary chain if it were true. The big bang theory is so stupid. I dont know what I believe, but I can say that a lot (not all)  of these "missing link" fossils seem totally bogus

aliens genetically engineered all humans and seeded earth with all the plants/animals

something like 95% of DNA is unused, right now i'm working on cracking the code in the DNA that the aliens left for us to find whenever we were advanced enough

i'm hoping the code tells me the meaning of life and how to build a huge alien spaceship

[Mommy]

aliens genetically engineered all humans and seeded earth with all the plants/animals

id believe that before I would believe most evolutionary ideas. Yes, evolution exists in a small sense, but not in the sense that fish became amphibians and amphibians became reptiles and yadda yadda yadda

[Seeker]

if evolution does exist then it's not a gradual process, it happens in jumps
like from dinosaurs to mammals

and my theory is that some sort of global catastrophe that occurs every million or so years causes the jumps for some unknown reason or another

scientists are just now figuring out that the sun regulates fertility in women and without it they wouldn't be fertile, so if that's true i'm sure some other galactic event could affect genes etc.... like a huge radiation burst from a quaser or some shit

[zetec]

Not gonna change anybody's opinions.

Whatever comes along, christians will have an excuse for it.

I'd just like to see them fanangle their way out of Aliens

they'd hire ripley

[Spectatrix]

scientists are just now figuring out that the sun regulates fertility in women and without it they wouldn't be fertile,

What? I'd like to see a source for that, actually...

[Mommy]

scientists are just now figuring out that the sun regulates fertility in women and without it they wouldn't be fertile,

so that would explain why i feel like doin the nasties when its sunny outside.

[Seussninja]

not necissarily true, most of the women i've known have wanted to play "hide the penis" when stomes were a brewin

[FORSAKENR320]

not necissarily true, most of the women i've known have wanted to play "hide the penis" when stomes were a brewin

that's because you have a thing for witches and voodoo priestess's

[Seussninja]

that's because you have a thing for witches and voodoo priestess's

[Spectatrix]

not necissarily true, most of the women i've known have wanted to play "hide the penis" when stomes were a brewin

Mmmmm.... stomes.

[zetec]

scientists are just now figuring out that the sun regulates fertility in women and without it they wouldn't be fertile

without it they wouldn't be alive.

so yeah, i guess you're technically right

[fingercuffs]

As someone who's taken a lot of molecular biology and organic chemistry at a rigorous institution of nerd-dom, I feel like I should dispel some "facts" about evolution that seem to have been ingrained in some of us.

I sincerely don't mean to call anyone out because many people certainly believe this, but it has been implied in this thread that the theory of evolution holds that humans evolved from apes. This is not true. All chemical systems that replicate using DNA (read: all life) are constantly evolving because of transcription/translation errors. Humans and apes are relatively new creatures in the world, and neither evolved from each other. However, they did originate from a common ancestor (CA). This is what evolutionary theory implies. It may seem like I'm splitting hairs here, but there really is a huge difference. To say that we evolved from apes implies that apes were running around on earth, and then we *poof* evolved from them as they continued to exist unchanged until today. Since everything is always evolving, apes as we know them didn't actually exist in the time of the CA. In fact, it was the CA running around on earth when some of its population evolved into the direction of humans while others evolved differently, in the direction of modern apes. (There was more than one fork in this path, to be sure, but this is just to illustrate.)

Next, the big bang theory came up. I hate when that happens in a discussion about evolution. The two have nothing to do with each other. The big bang theory attempts to explain the origin of the universe. Evolution does not. Rather, evolution is simply the net effect of a mix of random beneficial and harmful transcription/translation errors introduced to a population over an extremely long period of time. Evolution is not an attempt to explain the origin of the universe or life. It explains how new species evolve from existing ones. This is why Darwin titled his work "On the Origin of Species" and not "On the Origin of Life."

It was also mentioned that it's hard to imagine evolution without some sort of spark to start it. You may have no idea just how right you are, but first, a bit about oil and water:

Why don't oil and water mix? Bueller? Bueller? Water molecules are polar and have partial charges at different locations along the V-shape. The large electronegativity of oxygen pulls the shared electrons toward it, away from the hydrogens, creating a partial negative charge on the oxygen and partial positive charges on the hydrogens. In a cup of water, all of the water molecules are slightly attracted to each other because of the partial charges: the slightly negative O of one molecule will associate with the slightly positive H of a neighboring molecule, and so on. Oils, however, are altogether different because they don't have the same polar qualities as water. Long chains of saturated carbohydrates have practically no polarity because there's almost no difference in electronegativity between carbon and hydrogen. The chains are basically neutral in charge all over. For this reason it won't associate with a water molecule the way two water molecules will. Polar molecules crowd out nonpolar ones, causing the effect of water and oil not mixing. In addition, nonpolar molecules have a thing called the van der Waals force that helps them associate with one another, intensifying the separation between polar and nonpolar molecules.

And now we transition from oil and water to cell walls. There are some larger naturally-occuring molecules in our grand world that are polar at one end and nonpolar at the other. One class of these molecules in particular is known as the glycerophospholipid (I promise to not get too technical). The glycerophospholipid has two long carbohydrate "tails" that are nonpolar and a phosphodiester "head" that is polar. These molecules contain a ton of atoms, so a simple representation of them is often used. I drew one in Paint for you:



Now, remember oil and water. Polar associates with polar and nonpolar associates with nonpolar. Therefore, glycerophospholipids aggregate in the following way:



I know these aren't works of art, but let's press onward. The reason they aggregate this way is simple: each head is polar, so it wants to touch other polar heads, as well as the polar water molecules. The nonpolar tails are excluded from the polar heads and water. The tails associate with each other through van der Waals forces.

What happens when this structure, often called the phospholipid bilayer, forms a sphere? There would be an aqueous (water, polar) environment in the center, closed off by a nonpolar region (the tails), which separates the center from the rest of the environment. These structures occur in nature because of the propensity of oppositely charged species to associate and exclude uncharged species.

Could evolution have been a truly a random event? The odds of biological macromolecules and nucleic acids staying in close proximity to each other in the vast ocean of earth is next to zero, even if given trillions of years. Sometimes I get the feeling that some anti-evolution people believe this is what evolution is. However, what would happen if some key elements were trapped in the center region of the phospholipid bilayer? Evolution would happen a hell of a lot quicker for two reasons: 1) The concentration of key ingredients is MUCH greater. In such a small volume, the contents are constantly colliding and reacting with each other. 2) The phospholipid bilayer provides excellent protection from the outside environment. Not many substances could traverse the bilayer: a potentially threatening polar molecule would have to cross the nonpolar tail region. No thoroughfare, buddy. And a nonpolar substance? Good luck finding that in the ocean surrounded by polar WATER. As you can see, the phospholipid bilayer is the perfect "womb" in which to foster the development of sophisticated biological molecules from a few basic ingredients.

As you may have guessed, glycerophospholipids are the major components of real biological cell membranes. There's plenty of actual evidence for it, but you can see just by this that it's pretty logical that membraneous bilayers preceded living cells and are the precursors of modern cell walls and membranes.

So, the idea that evolution required some kind of "jump start" to get going is correct when you consider the fact that bilayer enclosures were required to get the ingredients concentrated enough. Whether or not you want to believe that God created the atoms and wavefunctions that allowed for differences in electronegativities and eventually the creation of phospholipid bilayers is your choice, but, as I said before, evolution makes no attempt to answer that question.

But wait! We've made a cell-like thing with some biological molecules and maybe organelles inside, but it's not actually made into life, or really evolution, yet. We're missing the ability to self-replicate. That's the one big step where there's still some real contention within academia. Today we need DNA and an elaborate manner of transcription and translation to replicate. The problem is how even an "evolution friendly" environment like the interior of the bilayer could foster the creation of such huge, complex molecules. Many wondered if it was possible. That is, until...

...the Miller-Urey experiment! Yay! Back in the day a grad student with cajones showed that in an environment similar to that of the harsh environment of early Earth, such molecules could absolutely have evolved. Basically he took some methane, ammonia, hydrogen, and water (which were all supposed to be very abundant in early Earth), put them in a flask at low heat, and shocked the flask with electricity every now and then (to simulate Earth's lightning). This was left to sit for a week or two. When he examined the contents, he found some amazing shit. Not only were there organic compounds, but there were entire nucleotides and amino acids! These are the building blocks of DNA/RNA and proteins, respectively. This was only 1-2 weeks; the possibility of a self-replicating cell doesn't seem so unlikely anymore when given millions of years to develop. So, as it was suggested, evolution may very well have required a "spark" to begin.

There has since been much controversy and criticism of this experiment. The most obvious point of contention is the assumption of what early Earth was like. So many other similar experiments were subsequently conducted using different possible starting materials. Most of them also had exciting results including amino acids; the only substance that seems to prevent this is oxygen. That's okay though, since it's a practically proven point that Earth began without oxygen in its atmosphere and that it was a heavily reducing (in redox terminology) environment.

I could go on, but I really should get to bed. I guess all I'm trying to get at is that evolution is not simply "humans evolved from apes" or something that some dude named Darwin came up with one day and the rest of the scientific community just decided to go along with it obstinately for the rest of eternity. Nor is evolution easily understood, and that's the biggest problem of all. Too many people in positions of power are concluding strange things about evolution and enacting public policy with their inaccurate assumptions coloring their decisions. It is painfully obvious that most people who have an opinion on the subject of evolution do not truly understand it, even at the most fundamental level.

I didn't get into how micro-organisms evolved into larger forms like birds and fish, but suffice it to say that individual cells aggregated often and localized certain functions to certain cells, the earliest form of symbiosis. Specialized aggregates of particular cells were the precursors of tissues and organs in modern animals. Diversification and evolution of species into new species is caused by built-in sloppiness and random mutations caused by the sometimes-faulty transcription/translation process. Anyway, I'm not here to teach anyone science, so I'll take my leave of this thread. Just know that even though I'm going because I'm tired, there's a ton more to it.

Here are some good links for further thinking:

Miller-Urey Experiment

Evolution Blog

Five Major Misconceptions About Evolution

If you wanna talk some more about it, I'm always up for an intellectual exchange. Hit me up on the PM.

Jesus Christ, I contributed something to a thread about evolution. I am soooo Internet right now. As soon as I cover abortion and the war in Iraq, I will have earned my e-wings.