Questions about evolution

Discussion in 'Biology & Genetics' started by Cyperium, Dec 9, 2008.

  1. Cyperium I'm always me Valued Senior Member

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    Hello, there are a couple of questions that I'm interested in.

    1: How long - approximately - does it take for an organ of average complexity to evolve from its simplest form?

    2a: The environment is complex, sometimes more variables than one need to be addressed so that the creature can continue living the way it has done before, what is the chances that a creature will evolve in two ways simultaneously?

    2b: I guess that the evolution of the brain might be one of the solutions to multiple survival scenarios, does that mean that we will eventually be the only species left as we have the highest survival chance because of the way we can adapt?

    2c: Were other species more abundant before, so that we have decreased their chances of surviving a environmental change? (as we constantly shoot animals so that they are kept at a constant rate - even kill insects that are deemed a threat to us)

    2d: How many of a species is needed for evolution to occur - generally?

    2e: Could we become a concurrent to evolution of other species, as we will build tools and keep a species alive if they were to be threatened by environmental change?

    3: If I were evolution then the first thing I would change - if there were a environmental change - would be what attracts females (or what attracts males) so that the attraction would lead evolution towards the desired change. Could that be a quick fix in reality? (I would think that it would need less generations to complete the change, than would it not be directed)
     
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  3. spidergoat Liddle' Dick Tater Valued Senior Member

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    1. Impossible to say. When was the first organ seen? 2-3 billion years?
    2.a. It is certain that more than one trait will evolve simultaneously.
    2b. We do not inhabit all environments, also, other animals are suited to human environments (rats, crows, squirrels, dogs, cows, etc...)
    2c. Yes, we have decreased genetic diversity in many species.
    2d. One.
    2e. Domestic animals are an example of this.
    3. Males and females are already attracted to indicators of health.
     
    Last edited: Dec 9, 2008
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  5. Cyperium I'm always me Valued Senior Member

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    ok, I'll rephrase the question; what is the number of individuals of a species required to survive a environmental change if the common individual have traits that it would not survive as it is. Or rather; what is the odds for a species to survive a fatal environmental change?

    Also, how many would have to survive that change in order to successfully continue their existence?
     
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  7. Crunchy Cat F-in' *meow* baby!!! Valued Senior Member

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    Don't know.

    100%

    Nope, we're dependent on a wide variety of species to survive (bacteria, plants, mammals, you name it). We are however, the best chance for life on Earth to survive past the death of our planet.

    Yes.

    Don't know, but I'll speculate one.

    Yes.

    Males and females are often attracted to the opposite sex that is surviving the best in the present environment and therefore more likely to pass on the better traits.
     
  8. James R Just this guy, you know? Staff Member

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    Not good. Far more that 99% of species that have ever lived are extinct.

    Not too many. For example, I believe that cheetahs are thought to have gone through a bottleneck at one stage, with perhaps only 20 or so individuals living at one particular time.
     
  9. EntropyAlwaysWins TANSTAAFL. Registered Senior Member

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    Only 20? would really be a viable breeding population?
     
  10. Pandaemoni Valued Senior Member

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    It varies. Random mutation is random, and natural selection can occur rapidly or slowly depending on the environment. Evolution through natural selection is not a process to get you from simple to complex, it is a process that gets from not well adapted to reasonably well adapted. Sometimes complexity cobnfers an advantage and is perpetuated, sometimes it is a disadvantage and the complex line dies out.

    I point out that for 75% of the history of life on Earth, only single celled organisms existed, and they are still by far the most successful lifeforms by any biological measure.

    Evolution is constant and is not confined to one trait at a time. But your question is flawed. If the environment changes so that an organism cannot live the way it has in the past, then evolution does not "compensate" sio that it can go back to doing things the way it used to. Evolution does not care about the way things used to be done or the form and function a species had in the past. if the environment changes so that a lifestyle or feature is now maladaptive, those features will disappear and the organism will either adapt to a new way of living that works with the new environment or die out.

    No. Evolution of the human brain is an adaptation to be sure, but it is not the end all be all adaptation that make us the best survivor. The brain is expensive, it uses up a huge number of calories per day and requires difficult to obtain protein to grow and sustain it. In a severe environmental cataclysm, there's good reason to believe that the large thinking brain would be a disadvantage because it is a resource hog.

    Even assuming that the environment never changes it is unlikely that we'd become the only species left in any reasonable time frame. We eat other species opf plants and animals. It is hardly reasonable for any animal to allow a Soylent Green situation to develop when it can foresee the trouble in advance.

    Much like wolves and mountain lions (superior killing machines) did not come to kill off all the herbivores in North America, though, we would not be able to entirely destroy our food supply before that fact negatively impacted our own numbers. As with a predator-prey interaction, one can expect a certain dynamic equilibrium to form.

    Yes, certain other species were more abundant in the past. Mountain lions and wolves to return to those. By thinning their numbers we have made it less likely their populations would survive a serious environmental change. Insects are harder to judge. Those that feed off humans are (like roaches) far more common that they were in the state of nature). Roaches, despite out trying to kill them, thrive more than ever in the human fiulled world because they can live off our detritus.

    There is no number. A single organism that reproduces asexually can evolve For those who believe that life has a chemical origin likely evolution started with chemical evolution, before there were any real "species".

    I do not follow. But look, evolution is not conscious it does not think or hope or design or plan or want. Anything that alters the mix of factors that make to reproductive success can affect evolution, including mankind's actions. Natural selection no more wants to use one species to change another or wants to change a species than a river wants to make rough stones smooth or gravity wants to make ripe apples fall.

    Again, desire is irrelevant. Evolution was not trying to produce humans, humans are simply what happens to have resulted from evolution. Evolution also has no plan for what we will evolve into. That too will be just something that happens and it is something that could happen in millions of ways. We could all evolve back into isingle celled organisms. It is unlikely, but evolution doesn't care.
     
  11. Enmos Valued Senior Member

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    There are no set rules. It all depends on chance.
     
  12. Cyperium I'm always me Valued Senior Member

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    But I think there are rules. The chance part is just the push forward, the rest is governed by rules. I even think there are long-term rules that has an effect in millions or billions of years.

    For example, the DNA code can be made so that it is more likely to evolve (by chance) in a less dangerous way, if there were alternative paths to take. I think it's more complex than most people seem to think.

    There is of course a bottleneck in how complex the DNA structure can become, but perhaps there are methods like encryption or that one thing can have two meanings (or perhaps alot of meanings) - if there is a genius way to do it, nature has done it (or even above genius, with nature and chance you never know).
     
  13. spidergoat Liddle' Dick Tater Valued Senior Member

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    Yes, there is a limit to the information that DNA can encode. I suppose that's why we have brains and culture that led to computers, which can store far more information.
     
  14. Cyperium I'm always me Valued Senior Member

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    Yes, I think it's amazing that DNA can produce something as complex as the brain. That's kind of what I mean with encryption, and I think that it might be applied to it's own structure as well.


    To Pandaemoni - I will reply to you later, I have limited time right now

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    (same to Crunchy Cat and James R)
     
  15. Enmos Valued Senior Member

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    What do you mean 'made' ? DNA has come into existence by chance and it changes by chance. The only 'rules' are the laws of nature.
     
  16. Idle Mind What the hell, man? Valued Senior Member

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    Yes, exactly Enmos. That is exactly what Cyperium has stated. Chemistry is not random.
     
  17. John99 Banned Banned

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    Does nature have laws? Can you please elaborate.
     
  18. Fraggle Rocker Staff Member

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    "You can never do just one thing." -- The Law of Unintended Consequences

    By killing off most of the cougars and nearly all of the wolves in the USA, we have perpetrated an explosion of the deer population. There are cities in the Northeast, like Buffalo, where it's almost impossible to have a garden, because the deer will come and eat everything down to the ground by morning. In Washington DC the deer have very nearly self-domesticated, like pigeons and squirrels. I've seen them (literally) stand patiently on the curb and walk across the street with the pedestrians when the light turns green. They're a little more wary out in the Maryland suburbs where there are some big dogs, but in urban Washington they've realized they have no predators.

    But by eliminating the apex predators, we've left a giant territory full of succulent prey animals up for grabs. What second-tier predator is going to accept that challenge? One who is quite a bit more gregarious, curious and tolerant than the wolf and the cougar. One who has happily adapted to the life of a camp-follower since the first paleo-Indians arrived and started leaving perfectly good food lying around their sites. One who already knows his way around the fringes of civilization. One who is flexible in temperament and can hunt singly to scavenge a ripe trashcan, or in a pack to bring down deer.

    The coyote.

    Coyotes are steadily spreading out to take over the former range of the wolf, focusing on populated areas where there are pets and vermin and garbage to eat, rather than hunting for scarce game. Coyotes have lived among us for so long that they've learned all the right tricks. They've become diurnal, because there's a lot more food running around in the daytime, nobody's home to guard their pets and their garbage, and if we are out and about we're way too busy to pay them any attention. In Los Angeles they've even learned to carry their tails up over their backs instead of down between their legs, so at a casual glance people just think they're stray dogs.

    And what an unexpected bonanza. Our populated areas are now teeming with tasty deer! We've created a new ecosystem!

    Of course there's a twist to all this. Some of the coyotes made it all the way to eastern Canada, where there's still a wolf population. But not very many, so it was getting a little hard to find a mate. So they mated with the coyotes. Now we've got coyote-wolf hybrids coming back across the border with the coyote pack. Sixty-pounders, twice the size of a normal coyote.

    The deer are in trouble!
     
  19. Cyperium I'm always me Valued Senior Member

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    I do think that there are higher probabilities that weaker parts of the DNA is changed, and by knowing the probabilities even chance can be managed to some degree.

    Also, any changes are a result of something, the "hardest to know" result might be from a random decay of something, but the "easiest to know" result might be simply from a chemical reaction where the end results could be somewhat limited (and thus known - and potentially can have solutions - this may lead to the possibility that changes can be directed in a favourable way (for instance if there are parts of the DNA that does the function but not perfectly then that part might be made weaker or that part is more directed in other ways to change)).

    What makes you think that I don't mean the laws of nature?

    I think that there are more laws of nature than you or I can imagine.
     
    Last edited: Dec 10, 2008
  20. Enmos Valued Senior Member

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    So who governs it ? Surely the characteristics of the various elements are not determined by some being beforehand ?
    Eventually it all comes down to chance. Admittedly, that is somewhat of a belief perhaps..
    'They' don't know what caused the characteristics the various elements exhibit.
     
  21. Enmos Valued Senior Member

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    Are we talking about evolution or selective breeding ?

    The fact that you called them rules. Rules are there to keep entities from moving beyond arbitrary boundaries i.e. rules can be violated by definition.
    The laws of nature cannot be violated.

    Such as ?
     
  22. Fraggle Rocker Staff Member

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    If we can't imagine them, then that would be a rather difficult question to answer, wouldn't it?

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    Still, I don't find that hypothesis remarkable. We discovered new ones in the last 100 years. There could easily be a few more that we haven't found yet. We still haven't been able to find a relationship between gravity and the other three fundamental forces; there might be a new law lurking in there. Ditto for string theory, or whatever is taking its place. Which I suppose will include gravity, won't it?
     
  23. Idle Mind What the hell, man? Valued Senior Member

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    The laws of thermodynamics and other physical laws dictate how chemicals interact with one another. We can predict what the outcome will be, based on those laws, when we mix two substances together. We can predict the products of the reactions. All chemicals, even in biological systems, obey these laws. So, I'll state again: Chemistry is not random.
     

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