This is the sort of thing I think about while in the bathroom
We all know a little bit about how chaos theory works – the weather is impossible to accurately predict because it is so complex that we cannot keep track of every variable.
Our predictions become worse over time because that missing variable has affected it’s surrounding elements, and over every second those elements do unpredicted things to their surrounds, until your perfect equation becomes an utter mess. Even overlooking a single molecule will, over a significant length of time, alter the outcome of weather prediction drastically.
The typical scenario is, “A butterfly flaps its wings in Vegas, and there is a hurricane in China.” It’s kind of bunk, because with billions of butterflies out there, constantly altering the speed and direction of air molecules, they’re -all- causing and cancelling these potential effects, all at once. Until you start considering what might be if you could look at two realities – one where the butterfly flapped, and one where it didn’t.
This concept is used well in some time-travel books, where a figure travels far into the past and makes one minor change (killing an insect, perhaps), and that change folds and multiplies exponentially, like a snowball, to create a present-day world incomprehensible to the traveller. … frankly, most fiction concerns itself with one person’s life, such as Sliding Doors.
What would our society be like if, at some point, we had evolved better vision? Say, a few thousand extra rods, perhaps, or a double foveae (like eagles) to focus on more than one thing at the same time.
Not only would there be major changes (people that might have survived if they’d seen danger, or people who would have died if their attacker had seen them), but think of all the terribly minor differences – contests won, conversations altered – even the avoidance of poison ivy by a sharp-eyed child a thousand years ago could have changed our society today as they interact with their environment differently than before.
It’s simply fantasy to consider, if a protein altered ever so slightly, a hundred thousand years ago, we might have had WWIII and our generation might never have been born, or kingdoms could have risen and fallen completely differently, with totally different dictators and governments. If any. If you go back far enough in our evolution to add this ever-so-slight advantage, it might have helped or hindered other evolutionary changes, either by structure or coincidence. Far enough back, and the advantage might have been enough to make brain size and usage not such a big deal.
Which brings me to wonder if, in the scope of evolutionary biology, two advantageous traits ever duked it out, as one might say, as owners of one advantage outbred the other, or if they were easily interbred.
Okay, back to work :D
Man, that’s pretty deep. You musta been in that bathroom for a while.
Also very, very bolded. (ouch)
Fixed.
And I elaborated some after I got out :D
well, ya know, better evolution than horses’ butts and contemplating the proper use of good samaritans I guess.
XD
A trait is never advantageous by itself, it is advantageous in a particular circumstance. Selective pressure. Selective pressure can select for more than one trait at a time, for sure, but I wouldn’t say they duke it out, exactly.
Something along the lines of improved vision would have an advantage in many diverse circumstances, wouldn’t you think?
I wasn’t trying to be literal in the fighting sense. My question was whether it would make sense that there may be two different advantageous traits bred at the same time, would one outbreed the other, or would they intermix rather seamlessly? Could some unrelatedly advantageous trait be bred out?
Also, I do wonder how much coincidence plays a role in natural selection. A major forest fire? The death what might have been a prodigious breeder? Hmm.
improved vision is kind of nonspecific terminology. being able to see farther? not so good if it’s more important to be able to see up close. It just depends.
There are very few random mutations that actually make us better, but there is no reason for those traits to be selected if it’s not better for any of a multitude of specific environments. So yes, in sense what may seem advantageous to us now, would not have been at some time in the past, and so it didn’t get passed on. But nothing is an advantage by itself. There has to be a reason it’s an advantage.
Mutations happen all the time in the absence of selective pressure, and whether or not they get passed on is pretty much a random event, that much is true. Good or bad.
Well, I was extremely specific in my original post, actually. You picked a specific way in which seeing better has an exact downside, however there are actual ways in which our eyes could be improved upon that would not be so easy to prove have a direct downside. What if we had developed muscles that change the shape of the eye, as some animals do, and thus would have, essentially, telescopic eyes, good for a variety of distances? What if we simply had an abundance of cones and rods?
Of course each evolutionary bonus is useless without a circumstance with which to apply it – that’s the very definition of advantage. But every trade-off is not necessarily even. Which is beside the point, because my question was about two advantageous traits. Pick your own circumstance that humans struggled or struggle with and a way that we could have evolved to better handle that circumstance. Now pick another, for a different circumstance, but equally capable of providing us with a better capability of survival and breeding. Now have these two occur at the same time. Both of them have the bonus of selective pressure.
Even -with- that advantage, I do wonder what possible evolutionary bonuses we (or any species) MIGHT have had, had a given circumstance not wiped out the owners of said genes.
I mean, just because group of creatures have evolved a trait that allows them to forage for food better doesn’t mean they couldn’t be completely wiped out by a pack of predators with a stroke of luck.
I don’t know. I think we ended up how we did because it really was the best combination so far. That’s all I’m saying.
From my understanding . . .
Rods and cones need a specific distance between them, to handle the nerve-interfaces that handle them. So more rods / cones means a bigger eye, more risk of damage, greater rate of casual blinding, etc. Further, a more sensitive set of rods / cones would make one more sensitive to glare blindness, from sudden illumination changes. . . And as a guy who has that problem daily, it could be Very Lethal to suddenly not be able to see, just because you eyes were more sensitive.
What one must remember is, EVERY “advantage” has a cost. More complexity leads to greater rates of breakdown. More mass means more food, and a possible greater starvation rate. Extra muscles means againg more food, even seemingly small ones around the eyes. Our brain, which is a great advantage to us, uses up an EXTREME amount of food, Oxygen, Learning time, Etc, and leaves us vulnerable to a range of problems that many other creatures don’t have.
Now, if a major event happened, darkening the entire world (say, constant cloud cover) then it might make a lot of sense to adapt with better eyes. . . But if that cloud cover clears up a hundred thousand years later, the more sensitive eyes may be a lethal problem. . . And that branch is lost to predation.
And, as you have pointed out. . . .It’s a random mutation dance, and catastrohpies abound. . . Great adaptations may have been lost. But, as I recall heinlein saying, If you were designing a electric motor, would you add a kitchen sink, just because you had one, and you liked them? Nope, you would go with what worked, and nothing else, except perhaps redundancy. Our bodies are like that, in a lot of ways. They don’t have every possible advantageous mutation. . . But they have enough to get us to where we are, without crossing over that perilous line of supply and demand.
I don’t disagree with much of this, except two things: First, birds have hundreds of thousands more rods and/or cones than us, depending on what was more advantageous for them – hummingbirds can see the color red from miles away, and owls have an order of magnitude more rods than we do, and their eyes are not an order of magnitude larger.
Second, I just don’t believe that physiologically EVERY mutation that produces a beneficial change has a equal cost. Certainly, an increase in muscle mass requires an increase in food, but I think that one is ignoring the random nature of, well, nature to say that ALL benefits have a (less than negligible) cost.
As I understand it, some traits have far more cost than their value to the creature (and thus don’t survive), and some have far more value than their cost. Sure, one could say, “Ha! what if the atmosphere boiled away, you lung-breathers would sure be some trouble then!”
By the way, if it isn’t clear, I’m definitely enjoying this conversation. :)
I think ‘battle’ between any two genetic traits entirely depends on many circumstances… whether there’s a genetic overlap in which one can only exist without the other; whether the host’s environment is more favourable (or hostile) to one over the other; whether the effects of one are detremental to the other; coincidence definitely plays a role in the survival of one trait over another I think; and so on… but I do think two genetic alterations can co-exist if there’s no conflict between them, in that I don’t think the host as a whole would see two mutations and only allow one to exist, just for the sake of it. Plus, we all experience some level of genetic drift anyway, even after our parents’ genetics combine; just to much smaller degrees than the kind of mutations you’re referring to, like extra organs and such.
slightly OT, but I’ll risk it :)
it is actually interesting, because even from my belief, having extra (or a lack) of what we already have genetically is entirely possible – what if a mutation gave us extra rods, or an extra hearing organ, or other things which enhance certain abilities? That actually does happen today all the time… There would be tradeoffs for more of extremethese ‘gifts’, and it really is within the capability of our genetic drift (you could even say all of our gifts and characteristics are slight mutations), and the mutation would need to be sufficiently existent within enough breeding couples for it to ‘stick’ within the population, but what if something like that had happened in the past? Or on the flipside, what if Beethoven wasn’t deaf? What if Einstein wasn’t a genius? What if Andre the giant wasn’t a giant? What if Terry Fox didn’t have cancer, and always had two legs?
It’s interesting how both negative and positive mutations can really have an effect on the world. Trying to imagine what might have happened if anything even so seemingly insignificant had happened to anyone, especially who we know has affected the world, is staggering.
That’s a good post… very deep, too much for a bathroom break :)
Never a wrong time to think (or to provoke) deep thoughts. :D
Okay, that’s not entirely true, but I’m gonna go with it.
There are two reasons why individuals with different advantageous traits might not interbreed. One is that there is some biological incompatibility between the two (ie, can’t physically mate, or has very different chromosome biology, making any offspring nonviable). The other is that there is sexual selection at work, which has been demonstrated with the males of certain species of birds developing hugely long tails – sometimes at the cost of their mobility – because the females like it better that way.
Consider this: an individual is highly intelligent, but sucks at the war/hunting games of his/her tribe; advantageous for figuring out problems and making strategies, not so much for physically carrying out those plans. Another individual of the opposite sex is not so smart, but extremely good at the physical activities, can run fast, has quick reflexes, great aim, the whole bit.
What would keep these two individuals from breeding? Presumably, they’re still of the same species, so there shouldn’t be some huge biological or cytogenetic reason why they can’t mate. But what if Individual A decides that he/she hates jocks? Or if Individual B thinks that he/she can’t stand to be with a nerd? In that case, even though these traits are advantageous in their niches, they are decidedly disadvantageous for the most important thing ever: getting teh sex.
Then again, what if Individual A takes all the rest of the smart individuals, goes far far away and breeds, while Individual B takes all the athletically gifted individuals and breeds, creating two divergent populations? Over time, they could become two different species, unable to mate with one another; however, that would likely take a long damn time of separation and no interbreeding.
Of course, this is all speculative. It’s likely that the advantageous traits we have as species emerged one at a time, in one individual at a time, and got bred into the general population after many generations. I think it’s possible that we as a species lost some advantageous traits over the years due to sexual selection and behavioral biases that led to exile/war/genocide. However, I also think that we’re still evolving, and that anything truly advantageous that came around once will show up in the population again, given enough time and the appropriate conditions to let it flourish.
Nerds are hot. Thanks for growing my brain. You’re my hero!
I adore Sliding Doors.
lovin’ evolution
“Also, I do wonder how much coincidence plays a role in natural selection. A major forest fire? The death what might have been a prodigious breeder? Hmm.”
I can really only comment on this right now because I’m only allowing myself to partially procrastinate as I’ve got a paper due today (but hey, we’re talking science here..this is an allowed pause, right?!).
So, in my final semester of college, I took an evolution course that actually talked about eyesight and vision…if I can find the article that we had to read (I think it was really a chapter from a book, or something), I’ll pass it along to you…it went into awesome understandable detail about human eyes versus, say, a snail’s eyes, and why it’s believed that they evolved the way they did. But anyway, we were talking about exactly what you were talking about up there with the random bad luck of a forest fire.
So there’s a real-life extreme example of this happening, I believe sometime in the early 1900’s. There was an island (I think it was one of the pacific tropical islands, but not sure since the details are a bit fuzzy) where a fairly large population of hunter/gatherers were living, untouched by whities. When they were discovered, it was also discovered that almost the entire population of people on this island had the eye disease where they only see in shades of grey. The whities were perplexed by this, thinking “how could this be?! did they have some advantage to seeing only in black and white?!” but it turned out that when they learned the native language, they found out that about two generations ago, there had been a major earthquake on the island that literally killed almost everyone…who was left was old men who could no longer procreate, one guy who had a dominant form of the sight mutation, and a couple of ladies primed for baby-making. Seriously, this is a crazy example considering that things usually don’t happen this way, but this is a documented case of what you were saying up there. So, even though the sight was shite (as my irish professor said..funny I remember his crazy cursing antics, but don’t remember the name of the eye disease or the location or name of the island), life carried on and babies were made. When they were discovered, something like 78% of the population had that eye disease.
Wow. Thanks!