Can you show any circular reasoning? 1. nature produces variation. 2. nature produces too much progeny. Not all can live and reproduce. 3. variations that are favourable have a higher chance of leaving progeny. Variations within a population that are not favourable have a lesser chance. It is a description of a process.
Perhaps so. Obesity is an adaptation to famine, so that when times are plentiful, you can store up energy. Modern agriculture and transportation is making this adaptation counterindicated, but in the long term it could still be beneficial.
Oh, what, and the belief that some random-assed magical force created everything isn't? Please Register or Log in to view the hidden image! Evolution's premise has evolved along with the evolution of species, and Darwin's original thinkings are now somewhat simplified. Evolution as a whole, however, is not just so simple, and is far more complex than even Darwin could've imagined.
Hapsburg, You might be surprised to know that I believe that evolution does indeed happen at the species level, but that is about as far as I go with it. The only point I'm making is that the "cause" of evolution is not really known.
Woody says: #1 is a statement of the odvious --no two things are exactly alike, and everything changes with time. #2 Is not necessarily true. What about when a new species is just starting out? It's chances of survival increase as its numbers increase. Its hard to find a mate in sparse populations. What is "too much progeny" who is to decide when we are overpopulated? "Not all can live and reproduce." There are lots of reasons for this which include accidents, acts of nature, and other things that have nothing to do with heredity. #3 "variations that are favourable have a higher chance of leaving progeny." It could very well be true, but is the "higher chance of leaving progeny" enough to make a difference? Additionally it could make sense if you defined "favorable." Then a controlled experiment could be designed to test the hypothesis, to see if indeed, the "favorable trait" makes progress in the test population. It would need to be repeated to verify the results and eliminate "luck of the draw" -- in other words, use standard hypothesis testing methodology. Perhaps someone has done a controlled experiment like this. I'd like to see it.
Sure it is. Evolution requires only 3 things: 1. Competition for limited resources. 2. Random variation in characteristics of organisms. 3. Difference in reproductive or survival success, depending on adaptation to the competitive environment. What don't you understand?
Damn! I didn't read spurious's post, which says exactly the same thing I jsut wrote. In response: When there are not enough resources, such as food, for all the individuals in the population, or competition increases to the point where some miss out. Correct. And so? Easily. Take 10 individuals. Give each a 5 in 10 chance of survival, and designate one as having a "more favourable variation" which gives it a 6 in 10 chance of survival instead. Randomly determine which individuals survive. 4 times out of 10, the more favourable variation will die out. The other 6 times, it continues. For the next generation, assume that each surviving individual will have 2 offspring, say. Offspring inherit the survival ratios of the parents. Repeat the process over many generations. You will rapidly find that the entire population becomes dominated by individuals who have the "favourable variation". This is really obvious. If you seriously think about it, I don't see how you can deny that the process works. I've just given you such a method. Try it!
Arrogant twat. Obviously it is obvious now. Do you think you could have thought of it 150 years ago? No fucking way. You think Darwin wrote a hole chapter on variation in domestic breeding because it was all so obvious? He made it obvious for you to see. Get of your religious high horses already. Nobody decides anything. EVERY organism produces more progeny that can survive. If nothing killed bacteria the world wouls be covered with them 10 km up in no time. Nobody decides anything. Get that in your head. Nobody.
Woody: Darwin essentially said 'Variation leads to differential rates in survival and reproductive success." How is that circular reasoning, nitwit? Do you even actually have an argument, or just more of your ignorant hand waving?
James R: When there are not enough resources, such as food, for all the individuals in the population, or competition increases to the point where some miss out. Woody says: Isn't that exactly what's happening with humans in the third world countries? S/M says we can't include humans -- I say why not? Didn't humans evolve too? When did it stop? Are they evolving in the third world countries? After all human starvation is nothing new in those countries. We should expect to find humans that can survive on less resource shouldn't we? Perhaps pigmies? Once again you are "just assuming" and this is how a circular argument begins. --------------------------------------------------------------------- M/H says: Darwin essentially said 'Variation leads to differential rates in survival and reproductive success." How is that circular reasoning, nitwit? Do you even actually have an argument, or just more of your ignorant hand waving? Woody says: Circular reasoning is based on a dogmatic assumption that is not proven true and therefore begs the question. In short you say variation leads to evolution because of different probabilities of success (the same old worn argument). There are two problems here so would you please clarify -- are you saying variation is the "cause" of evolution. If so then we have already covered this base -- all nature varies therefore -- I can say anything I want and appear to be correct as long as it includes variation -- this is a false logical basis for a "cause." F=ma is a cause. "Survival of the fittest = survival of the survivors" does not identify a cause. Secondly,you have not defined "reproductive success," Would you include spinal bifida as a reproductive success? Probably not. It appears you are assuming that just because something survives it is a success. Once again if you can propose the cause(s), you can set up an experiment to test it. I'd like to see the results of an actual test performed on a hypothesis. I am an engineer -- I require data -- this is how I make decisions. ---------------------------------------------------- S/M says: You will find many programs that similate evolutions and do exactly that. Woody says: I'm not interested in a simulation. A video game is also a simulation. I'm interested in a factual test -- there is enough time to test a hypothesis so don't give me the way back time machine argument (where we can't live long enough to witness the results in our lifetime). Let's see a factual test.
Evolution, works like instant coffee right? Remove food for a hundred years, stir and watch pygmies evolve. Please Register or Log in to view the hidden image! Yes humans are evolving but its unlikely to be at the same rate as before, but then we'll find out in a million years time right? You wont find people evolving to survive on less food because the starved die out, the ones with enough food survive so why evolve to need less? In a natural habbitat the competition would be thus, the fastest would reach the food first, the strongest would carry more food home, the slow and weak would reach the food after its all gone and die out, hence will not breed and pass on these genetics, this really is the most simplistic way of putting it, it takes a million or so years to notice a difference. The problem is applying this to modern humans, we share resources(occassionally), the fastest may bring food back for the slow, the strongest may share with the weak, we also have medical technology, and some very compassionate people who look after the sick and lame who would under natural circumstances be unable to survive, we no longer live the same way as before. The more educated amongst us may feel free to correct me where im wrong or expand on this(as im sure you all will). Please Register or Log in to view the hidden image!
I'm waiting for a factual test report from somebody that tested Darwin's theory based on a cause and result experiment. And Alas, the drama department shows up. OK then, I can adapt to humor too, I like this picture of Piltdown man: Please Register or Log in to view the hidden image! Reminds me of an old biology professor.
It's not humour Woody: its sarcasm. You don't merit humour. By the way, if you'll compare your old biology professor with one of the current ones, I think even you will be able to see how much they have evolved.
A factual test? Is that something related to 'genome theory'? State your criteria for the test first, because I am sure if I give you some data you will say it isn't good enough. Therefore I want in black and white the criteria for the test so you can't back out like a little weasel.
There have been tests of evolution using fruitflies. If the definition of a species is that it is sufficiently different so that it can no longer reproduce with it's source population, then they created a new species. This was done, and it doesn't take millions of years, since fruitflies reproduce rapidy. This also tells us that there are environmental checks on the pace of evolution, otherwise it would happen very quickly. This is exactly what we see in the AIDS virus, and certain bacteria that have developed resistance to anti-bacterial agents.
Woody says: OK 1) Apply Darwin's theory to define an environment that causes a "life struggle" -- such as cold temperatures. Propose this to be the cause of change for hypothesis testing purposes. 2) Identify "potential good traits" on an a priori basis -- these traits could hypothetically increase the chances of survival -- traits such as higher metabolism, more body hair, more body insulation, etc, etc. A Post priori basis (after the fact) won't get it -- we are doing a hypothesis test here. 3)State your hypothesis. For example: Cold weather causes animals to genetically change so they grow longer hair, have more body fat, have higher metabolism, etc. 4) Choose a species that has a short reproduction cycle -- such as a mouse. 5) Control the test, and account for the causes of all the mortalities (the best you can). This step is optional, but could provide insight on how your test is proceding. 6) Continue the test until it appears you have statistically significant data. 7) If you think you have statistically significant data do the appropriate analysis to determine if it's just a random drift in the population (noise factors), or if there is a direct cause-and-effect relationship as stated in the hypothesis. 8) Repeat the test to verify the cause and effect relationship -- (this could also be done by running another test in parallel). 9) If any "surprise traits" come about that you have not postulated, then change your hypothesis and run another test.
Woody, even a mouse has far too long a reproductive interval to be of any reasonable use. We're talking millions (on the low end, tens of thousands) of years here. We just found out about evolution - and I can't say this enough - <b>less than two hundred years ago</b>. Give us a moment before you burn us at the stake, will you? Now, if you want to try the same experiment as above, you ought to use an organism with a <i>much</i> shorter 'reproductive' interval - say, a bacterium. Perform steps 1-8 as above. Then see if you produce bacteria with different morphologies, to say nothing of other ways in which they might diverge, such as physiology. Seem as far-fetched as the mouse example? It shouldn't. It's been done. Chance mutation - producing the variation - coupled with natural selection - which drives such variants to fixation or near-fixation - produces all kinds of bacteria with different morphologies and physiologies. Now, of course, bacteria don't "breed" per se and can transpose DNA from all kinds of sources - hell, so can bloody <i>flatworms</i>. But consider: cats and dogs are quite morphologically similar, really (our mammal-centric thinking only rates them as different because of our discernment within our Class - which is really only a subclass of Osteichthyes, anyway - and because of Tom & Jerry cartoons) yet they cannot breed. (Although, horrifyingly, they can do other things best not thought about. Anyway. Whatever.) Morphologically, they're extraordinarily similar. Tetrapedal, furry (not all), tails (not all), cute (cats only), teeth, large numbers of offspring (with associated machinery), susceptibility to football kicks when they're tearing at the carpet - hell, they even have the same placental type (I think...uninformed guess, really. Bah.). But they cannot breed. No matter how hard one might try...shudder...they cannot reproduce. And yet, they're ridiculously similar both externally and genomically. So extrapolate the argument. Minor morphological change = no crossbreeding = speciation. I like the old "Biological Species Argument", and all of you bloody Daphnia clone workers can go to hell as far as I'm concerned. And take your namby-pamby "oooh, but <i>my</i> organism is clonal and doesn't <i>have</i> sex, boo hoo hoo hoo" whining with you. Geoff
