The Evolutionary Hotseat

[extro...*]

I think a person covered in fur gives the impression of being more primitive, perhaps less intelligent - more like other animals. Intelligence, and many other advantageous traits, make us unique in the animal world, and sexual selection for mates with these traits is advantageous to the long term genetic reproductive prospects of the one doing the selecting. One possible way to select a mate having many of these traits to a greater degree might be a general preference for individuals that are less like "all the other animals", i.e. more distinctly human. Being less furry might just accidentally appeal to that general preference.

I think the animal world is full of examples of sexual preferences that are hard to logically explain. The plumage of a peacock evolves because the lady peacocks (peahens?) like it. Why do they like it? They evolved that preference. Why do some birds remain dull, and not evolve similar preferences for colorfulness? The ability to maintain bright plumage can be an indicator of general fitness, which it helps to be able to select for in ones mate, yet not all birds develop this mechanism. Similarly, the ability to see a mate's skin can give insight into its health, and similarly, not all mammals go that route. If it's a mystery, it's not unique to humans.

[Quailman]

[Chuck]

Maybe the peacock had no predators while evolving and could go all out in trying to get attention since there was no unwanted attention.

[Jack_Ian]

The resources that a bird uses for feather pigmentation are the same resources that are used to fight infection.
By displaying a good set of plumage, a bird is saying that they have been free from disease for a year.
Your offspring will therefore be more likely to be immune to any of the prevalent diseases in the area. This is why many birds of this type have a harem of many females. They are trying to wipe out disease and parasites.

Of course saying "trying" etc. is incorrect as it really only says that this random sexual selection actually had a benefit that increased the offspring's chances of survival and propagation.

[Chaz]

Peacocks use nano technology to make their colors.
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[Chuck]

[Chuck]

[Chuck]

[Chuck]

[Chuck]

[Chuck]

[Jack_Ian]

If it looks like a duck, swims like a duck, and quacks like a duck, then it probably not a duck.

[Chuck]

[extropalopakettle]

I found this kinda surprising: Apparently, tunicates (aka sea squirts) evolved from a hybrid between some sort of chordate and some sort of echinoderm - completely different phyla.

http://www.newscientist.com/article/mg20327246.300-13-more-things-hybrid-life.html

[Chuck]

[Zag]

One of the more interesting arguments against purely random evolution is that the amount of information in human DNA is more than could be accounted for in the number of generations (of whatever) since life first appeared on Earth. Those making this argument are, of course, pushing (again) for "Intelligent Design," but many are willing to accept a deity-guided evolution model. They make the assumption that each generation can only introduce one "piece" of information, and they further assume that all the "pieces" of information in human DNA are absolutely necessary to be in their current state in order to be a human. Both these assumptions are wrong, of course, but it's hard to convince them of it.

This article, however, shows a very interesting experiment in evolution. Music is created from random noise, using the "survival pressure" of consumer choice and the musical equivalent of sexual reproduction. In only 600 generations they have created music which is quite good and rather complex. It clearly has way more than 600 pieces of information in it, and, equally clearly, there are many different variations that would have been similarly good.

[Jack_Ian]

I've been considering writing an App that would evolve a birdsong chorus.
Male birds would defend a territory from similar sounding birds and would produce a song based on some seeding parameters (no pun intended). Similar seeds should produce similar songs.
While involved in disputes, they do not produce a song and disputes are settled by stronger birds pushing other birds away. Larger territories produce more offspring, but also require more dispute resolution.
Essentially a song would need to be easily heard by a similar female among the cacophony of other songs produced in the vicinity..
Birds could only mate if they could find each other and their offspring would produce similar sounds to the parents.
I have no idea how to recognise a sound amongst noise and I would also need to do some research regarding merging sounds or generating sounds from a "seed", but I expect the eventual songs produced might be pleasant to the ears.
I would also need to take account of how far individual tones would carry etc.

The App should allow the user to start with random input and perhaps adjust the seeding algorithm and then let it run for a few hundred generations. You can then listen to the chorus or examine individual evolved species.
The more thought I give it, the more interesting it becomes, but I don't think I'll ever find the time to devote to actually coding it. ~*sigh*~

[Scurra]

Yeah, but the conclusion that the article comes to is also valid - that composers write music and if people don't like it then they don't necessarily feel the need to evolve into something that people do like. Unless they are not composers but merely crowd-sourced commodity brokers. <cough Simon Cowell cough>
I have to say that I thought the final result was truly terrible as actual music though. Compared to the start, it was indeed marvellous, but in its own right it had no, well, "soul".


But yes, the assumption that only one thing changes at a time during the evolutionary process is clearly ridiculous. I do agree that trying to get people to understand that is surprisingly hard.
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[extropalopakettle]

[Chuck]

[Jack_Ian]

A simple evolution demonstration.

Try to trace the previously drawn line

[Jack_Ian]

[extropalopakettle]

I saw a hummingbird moth a few weeks ago. I watched it closely for probably a minute before I concluded it was some species of hummingbird I hadn't seen before. Only recently did I see a pic of a hummingbird moth. The degree of convergent evolution is just astonishing.

[Chuck]

[Jedo the Jedi]

What do most evolutionists (namely the Big Bang variety) believe about Pangaea?
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[Zag]

I don't understand the question. Yes, I believe that the current continents were once much closer together, until around 200 million years ago when they drifted apart. This theory is well-supported both by tectonic evidence and by evolutionary evidence.

Also, I'm not sure that there is distinction among evolutionists of "Big Bang Variety" and another sort. The concept of the Big Bang has very little to do with evolution, other than a Creationist philosophy opposes both.

[Jedo the Jedi]

Forgive my classification. I have never cared much to debate evolution vs. not evolution, so I don't know what variance there is in the evolution camp. I thought it was possible that there are some evolutionists who believe in the Big Bang and some who don't (though that's probably just projecting the divisiveness seen in almost every other camp of a given topic).

The question was really to see if there was anybody who doesn't believe in the theory of Pangaea. Again, it's another thing to which I've never cared to apply thought. You've informed me only religious nuts believe the continents were not once closer than present. That's what I was curious about.
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[Zag]

I do, however, have an outlier belief concerning Pangaea, which totally doesn't belong in this thread, but might be worth discussing.

It seems to me that the center of mass of all the water in the oceans should naturally be coincident with the center of mass of all the rest of the Earth. If they aren't, that represents some potential energy and the water still has some "downhill" it could flow.

Therefore, if the continents were all piled up on one part of the Earth, then there should have been land on the other side of the Earth also sticking out of the water. Otherwise, the water would flow over the piled-up continents until a point of zero potential energy is reached.

The arguments against this position are pretty easy. 1. Just look at the existing earth from the direction of mid-Pacific ocean. It's almost all water. My theory would have some of this water flowing away from it. 2. The Earth is not uniform density. A higher concentration of iron and lead in one section would mean that the center of mass of the land is not where the center of the volume is.

I have counters to these arguments, but they're a little weak. The second point is part of the counter to the first point (though Antarctica is the rest of it. Remember that Antarctica looks like water, but it's land.) The counter to the second is that the difference in concentration can't be that much. Remember that the crust of the Earth is just "floating" on the liquid core, so the same argument has to hold for the relationship of the crust to the core.

Anyway, that's the argument I've had with myself about Pangaea, for a while, now. I haven't resolved it. The people I have mentioned it to just wave it off as silly.

[Jack_Ian]

Not sure if it's related, but given that the moon was formed from debris after the glancing collision of a planetoid with earth, it's quite likely that Earth was not spherical for some time afterwards and that might have accounted for a single continent in the early stages of the Pangaea formation.
The separation of Pangaea into several individual structures could just be the evening out of that anomaly.

[extropalopakettle]

[Zag]

My assumption is that the water is free-flowing over the surface of the Earth, and that the Earth is basically a sphere. extro, your example has the water not flowing freely, so it isn't relevant. Jack_Ian, while I think that's reasonable, it still would imply that there would be another land mass on the far side of the earth from Pangaea. Of course, maybe there was, but it was wiped out by flood as the Earth's center of mass shifted as the existing continents separated.

[extropalopakettle]

[Elethiomel]

To scale, the Earth's crust is very thin. Like the skin of an apple. Relatively speaking, the mass of the oceans is minuscule. The surface is also smoother than that of a billiard ball, relatively speaking. (The maximum deviation from the reference spheroid is around 0.17%.) Furthermore, the oceans flow on the crust, which is rigid, and again "floats" on the mantle.

Not sure exactly what your theory entails, to be honest, but I figured these facts might be helpful to puzzle things out.

[Thok]

[Quailman]

Don't forget the force (the name escapes me) that causes the Earth to be wider at the equator as a result of its rotation. Then there's the tides (that force is called gravity, I think) that shift the water's center of gravity each day.

[Zag]

Thok, I'm talking about water flowing to the lowest point (i.e. reducing its potential energy). Activating that is pretty easy. In fact, preventing it from happening is pretty hard -- water is very good at penetrating stuff, eventually.

Q, I considered both those, even though I hadn't mentioned them. The first is just inertia, but is commonly (incorrectly) referred to as centrifugal force. However, it operates on the land and water equally, and wouldn't affect the center of mass of either.

The effect of the moon does, in face, have an effect, because the water moves more than the land does in response to it. However, two points: 1. The effect is only about two meters total. 2. The effect on the center of mass of all the free water is even less, because the water on the far side of the planet moves away from the moon when the water on the near side moves towards it. That's why there are always two high tides per day. The low tides are on the sides of the earth where a tangent line from moon to earth would touch.

Let me repeat that this is not a generally accepted concept -- at least, I've never heard anyone else, never mind anyone with any position within the scientific community say it. So keep the criticisms coming. But, so far, I've considered all these.

[extropalopakettle]

Do you not agree this makes the case that there can be a single continent on one side of the planet?

[Elethiomel]

Seems like you're postulating that the oceans have the ability to (significantly) alter the shape of the earth's crust, through some kind of erosion?

If not, then the shape of the earth's crust will just be decided by whatever decides that (mainly plate tectonics, I guess?), and the water will seek the lowest points of that shape, whatever it may happen to be.

If the water did over time alter the shape of the crust, why would it converge towards two continents? Why not zero continents, with a completely smooth crust and water covering everything?

I don't know how to refute your theory because it's very unclear what the actual theory is.

[Zag]

[extropalopakettle]