Evolution: the Facts.

[Lukraak_Sisser]

Yes, but some cells are programmed for cell death (such as those between the fingers when the hand is just a club). Apparently the rest of our cells are also programmed for cell death at our old age. I stand to be corrected.

The apoptosis mechanism evolved in single celled organisms, probably as a response to deal with accumulating DNA damage in older genomes.
But once the mechanism is there, evolution can co-opt it to do all sorts of neat things, like the mentioned controlled cell death to from fingers.

 

[steenkh]

The apoptosis mechanism evolved in single celled organisms, probably as a response to deal with accumulating DNA damage in older genomes.

Can you explain? Accumulating DNA damage would probably lead to cell malfunction in any case. Is this a sort of mercy killing?

 

[Dessi]

Ok darwinist ape people, if evolution is true, why are homosexuals so attractive?

 

[Dinwar]

Can you explain? Accumulating DNA damage would probably lead to cell malfunction in any case. Is this a sort of mercy killing?

This is all squishy, so outside my area of expertise. However, I do know that there are organelles (lysosomes) that act to remove other cellular structures that are no longer necessary or which are damaged somehow. This is rather necessary in order to keep the cell operational--ask any factory manager or construction worker why housekeeping is important ($50 says "Slips, trips, and falls" comes up!). Nonfunctional cellular structures get in the way, and disfunctional ones can actually kill a cell, so cells evolved a way to eliminate them. Apoptosis may be an extension of that.

If this is right, it's another example of evolution definitively NOT making something good, only making it good enough. Cells evolved a mechanism that's critical, but has the annoying side-effect of eventually killing them.

 

[Dinwar]

Ok darwinist ape people, if evolution is true, why are homosexuals so attractive?

Well, as many women in my alma matre learned, if two girls make out they can basically pick which guys they want that night. Makes selecting a mate pretty easy.

 

[PartSkeptic]

Ok darwinist ape people, if evolution is true, why are homosexuals so attractive?

Some homosexuals, not all - I have seen quite a few that are downright scary. But I think most die out from lack of procreation.

Besides, when it comes to men attracting women, I am told that women find the most attractive feature is the bulge in the back pocket - and that (in the modern world) fits right in with evolutionary theory.

 

[Diogenes]

...

The theories to explain how unicellular organisms may have evolved into multicellular ones are very logical, but I have yet to see anything to demonstrate why I should believe that what the theories say is what had actually occurred.....

http://www.pnas.org/content/109/5/1595.long

abstract:

Multicellularity was one of the most significant innovations in the history of life, but its initial evolution remains poorly understood. Using experimental evolution, we show that key steps in this transition could have occurred quickly. We subjected the unicellular yeast Saccharomyces cerevisiae to an environment in which we expected multicellularity to be adaptive. We observed the rapid evolution of clustering genotypes that display a novel multicellular life history characterized by reproduction via multicellular propagules, a juvenile phase, and determinate growth. The multicellular clusters are uniclonal, minimizing within-cluster genetic conflicts of interest. Simple among-cell division of labor rapidly evolved. Early multicellular strains were composed of physiologically similar cells, but these subsequently evolved higher rates of programmed cell death (apoptosis), an adaptation that increases propagule production. These results show that key aspects of multicellular complexity, a subject of central importance to biology, can readily evolve from unicellular eukaryotes.

That was a direct experiment. There are also complex prokaryotic community interactions where an individual cell's position in the community (be it with its own species or a mixed organism environment) determines its physiological state. Heterocysts in cyanobacterial mats, for example.

 

[Lukraak_Sisser]

Ok darwinist ape people, if evolution is true, why are homosexuals so attractive?

It's evolution's way to counteract the human nature to select mates purely on looks. This way, after having been rebuffed by attractive homosexuals for a while those that have to reproduce learn to look at inner beauty

 

[Lowpro]

Yes, but some cells are programmed for cell death (such as those between the fingers when the hand is just a club). Apparently the rest of our cells are also programmed for cell death at our old age. I stand to be corrected.

Almost all cells have the genes to induce apoptosis so it's a matter of expression. Apoptosis is a major factor in embryonic development, it's a semi-major factor in inflammation response and immune system response. Old age cell death makes no sense, that's a consequence of telomere reduction.

Apoptosis response to DNA damage isn't as common as general DNA repair expression and to some degree senescence. Apoptosis also usually occurs in bursts because adjacent cells signal for it so you'll get cells communicating and many just induce apoptosis together within inflammation response.

I wouldn't say any cell is "programmed" for cell death, but they have the genes on hand to express them if they need to. They also have robust DNA repair genes to reduce the effects of DNA damage. Their entire cell cycle actually hinges on it.

 

[Dessi]

Ok nerd burglars, if evolution is true, why is it so much fun to kill and eat other humans?

 

[Mister Earl]

Ok nerd burglars, if evolution is true, why is it so much fun to kill and eat other humans?

I know we tangled before regarding your pet organization. But this?

I genuinely fell sorry for you. I absolutely hope for your sake you're trying to invoke Poe's law.

 

[sphenisc]

Ok nerd burglars, if evolution is true, why is it so much fun to kill and eat other humans?

Eating humans is fun because they contain exactly the right balance of nutrients required by humans. Killing them first is fun because it makes them easier to eat.

 

[Dinwar]

Ok nerd burglars, if evolution is true, why is it so much fun to kill and eat other humans?

I know that you're either being completely off-the-wall or completely disengenuous here, but let's examine this with the seriousness it doesn't deserve.

Who has fun eating other humans? There are easier ways to get meat. There are some cultures that eat humans for various reasons, and you'd have to examine each of them to determine why. But you'll need to provide data showing that humans consider eating other humans is fun; most that I know of do it for religious or cultural reasons completely divorced from the concept of entertainment.

As for why it's so much fun killing other humans, until extremely recently other humans represented a threat. Any other humans not in your group would be likely to kill you for your resources, or enslave you, or kill you because you were trying to take their resources. We went through a period lasting over a hundred thousand years where the tribe (more or less) kept you alive and the rest of humanity was a threat. This is basic evolutionary theory; more similar organisms necessarily have more overlaping resource needs than less similar organisms, and no organism is more similar than two members of the same species. Humans who couldn't kill other humans, due to psychological, technological, or numerical issues didn't survive to reproduce. After a few tens of millenia of this, it's hardly surprising that some humans enjoy killing others. The surprising thing is that some of us DON'T enjoy it.

There's also the sex aspect. Being able to defeat all other men wins you the most women. As a woman, being able to defeat men means you get to keep them (what are they going to do? fight you?). Thus, there's sexual selection as well. Playgirl doesn't show pale, lanky folks like myself, after all. While the killing doesn't hold true, contests of strength certainly do have impacts on mate selection. Any high school demonstrates that quite clearly. Though to be fair, my school was different--some of the hottest girls in the school during my time there weren't the chearleaders, but the people in the trivia game (Quize Bowl).

As for PETA's nonsense, other animals aren't humans. Simple as that. We enjoy killing and eating them because we're omnivores. Humans have always killed and eaten meat (I've seen the remains, including burned bones and spearpoints in fossil bones). Our ancestors killed and ate meat (some of our cousins didn't). THEIR ancestors killed at ate meat. While there is of course variation (this is biology, after all), humans by and large continue to eat animals.

 

[Acleron]

I know that you're either being completely off-the-wall or completely disengenuous here, but let's examine this with the seriousness it doesn't deserve.

Who has fun eating other humans? There are easier ways to get meat. There are some cultures that eat humans for various reasons, and you'd have to examine each of them to determine why. But you'll need to provide data showing that humans consider eating other humans is fun; most that I know of do it for religious or cultural reasons completely divorced from the concept of entertainment.

As for why it's so much fun killing other humans, until extremely recently other humans represented a threat. Any other humans not in your group would be likely to kill you for your resources, or enslave you, or kill you because you were trying to take their resources. We went through a period lasting over a hundred thousand years where the tribe (more or less) kept you alive and the rest of humanity was a threat. This is basic evolutionary theory; more similar organisms necessarily have more overlaping resource needs than less similar organisms, and no organism is more similar than two members of the same species. Humans who couldn't kill other humans, due to psychological, technological, or numerical issues didn't survive to reproduce. After a few tens of millenia of this, it's hardly surprising that some humans enjoy killing others. The surprising thing is that some of us DON'T enjoy it.

There's also the sex aspect. Being able to defeat all other men wins you the most women. As a woman, being able to defeat men means you get to keep them (what are they going to do? fight you?). Thus, there's sexual selection as well. Playgirl doesn't show pale, lanky folks like myself, after all. While the killing doesn't hold true, contests of strength certainly do have impacts on mate selection. Any high school demonstrates that quite clearly. Though to be fair, my school was different--some of the hottest girls in the school during my time there weren't the chearleaders, but the people in the trivia game (Quize Bowl).

As for PETA's nonsense, other animals aren't humans. Simple as that. We enjoy killing and eating them because we're omnivores. Humans have always killed and eaten meat (I've seen the remains, including burned bones and spearpoints in fossil bones). Our ancestors killed and ate meat (some of our cousins didn't). THEIR ancestors killed at ate meat. While there is of course variation (this is biology, after all), humans by and large continue to eat animals.

Competing for mates explains the reason why we can kill each other but it's a large risk to self to pick a fight with one of the most dangerous animals on the planet, there will be a balance. But eating each other is an equally risky occupation. Eating the one food which is most likely to contain pathogens evolved to infect us just isn't one of the best ideas.

 

[Safe-Keeper]

Ok nerd burglars, if evolution is true, why is it so much fun to kill and eat other humans?

Mind. Blown.

ETA:

As for PETA's nonsense, other animals aren't humans. Simple as that.

Oooooooh, PETA. That explains everything.

 

[Dinwar]

Competing for mates explains the reason why we can kill each other but it's a large risk to self to pick a fight with one of the most dangerous animals on the planet, there will be a balance. But eating each other is an equally risky occupation. Eating the one food which is most likely to contain pathogens evolved to infect us just isn't one of the best ideas.

The thing is, until recently we WEREN'T the most dangerous animals on the planet. Not in terms of one-on-one combat, anyway. Remember, humans evolved in a time when short-faced bears, dire wolves, and a whole bunch of other predators were running around. Even the prey consisted of monsters--you ever see a ground sloth claw? I've got daggers that aren't as long. And our weapons consisted of sharpened rocks on a stick. I agree that fighting for mates is risky, but it really wasn't any more risky than hunting for food.

Also, it's not unusual in the animal kingdom for males to engage in high-risk activities to win females. Many species engage in combat. A lot of it is ritualized to avoid killing off half the species, but not all of it. It's weird, but logical: nature is a horrifyingly dangerous place, and for many species only the strong are goinig to survive. And in some species, females find it sexy. Once sexual selection gets mixed in, very strange things almost inevitably happen.

As for eating humans, agreed that there's no evolutionary push in terms of natural selection. Every example of canabalism I know of is culturally driven. That's why I asked for proof from Dessi.

 

[jimbob]

Bump


Check out their video (and I gather there is some open source software available from Cornell atoo.
Unshackling Evolution: Evolving Soft Robots with Multiple Materials

Why did you choose your criterium to be locomotion speed and not anything else?

This is an excellent point, and clearly an aspect in which evolutionary algorithms diverge from biology. In natural selection, the driving force is the ability of oneself to reproduce -- a survival of the "fittest". Through this pressure, and the complex interactions that take place within the rich environments on earth, we see pressures to create complex, adaptive features like arms or legs, eye or ears, and even planning or communication. In this work, we use a single measure of an individual organism as it's measure of "fitness." Then the "fittest" individuals in our population of soft robots are more likely to mate, reproduce, and create the offspring that make up the next generation of robots. This allows us to abstract away from the rich ecosystems, which we would absolutely love to simulate - but at this point are largely computationally intractable. It also allows us to define the measure of what our robots are to evolve towards. This allows us to use evolutionary algorithms as an engineering tool to optimize towards specific goals. In this case we chose locomotion as that goal because -- in addition to being a commonly accepted goal in the field and a simple task that can lead to the evolution of complex behaviors and morphologies -- it creates creatures whose abilities and behavior are visually interesting, and easily deciphered -- creating cool visualizations like the video you've seen, which can provide a proof-of-concept of these behaviors to scientists and curious onlookers alike.

and this article about it

The results, displayed in the video using softbody simulation software called VoxCAd are not only amusing, but actually a good representation of how much more diverse the evolved creatures when given soft body pieces to use. It's at this point that you probably should forget about getting any real work done and clear your schedule for the day to play with VoxCad, a free download.