Natural selection, my ass AchillesSinatra: Not one of you fanatics ever gets this. HERE'S the point!!! So, you've told me about polar bears and their white fur that helps them to creep up on unsuspecting seals? Fine, might be true for all I know. And you've told me about poisonous frogs in green jungles with yellow skin that warns predators? Might also be true for all I know. What you have NOT told me is the overarching principle that unites both these, and all other similar cases. Let me try ... "Those things with stuff that helps them survive well... tend to survive well"? This is what you frothing Darwinians NEVER get. (yes, a little provocative, I grant) Pertaining to specific organisms in specific environments, it's perfectly respectable. When generalized, it becomes vacuous shite. You don't have to leave your armchair to know that dudes who have what it takes to get laid tend to get laid more than those specky wee gadges who don't. Geddit? I thought not. Otherwise, I challenge you to give me an encapsulation of your powerful theory of natural selection that I need to buy binoculars to confirm.  (Edited by AchillesSinatra) AchillesSinatra: Go ahead and make a general principle of natural selection that is not utterly devoid of empirical content. I'm off to bed. How about "Those organisms that sleep well tend to sleep better than those with insomnia"? Gosh, I might be due a Nobel prize.  AchillesSinatra: Well, any good polemicist is supposed to anticipate his critics. "How can 50000 Parisians possibly be wrong?"  Because as history shows, they almost always are. See ya  Angry Beaver: This is pretty much what i learnt in school and it works for me, if it ain;t good enough I don;t care lol Natural Selection Natural selection is the term that's used to refer to the natural evolution over time of a species in which only the genes that help it adapt and survive are present. This idea was reported by Charles Darwin, the researcher behind many of our modern concepts of evolution. In natural selection, a population will show genetic traits over many generations that help it remain best suited to its environment. These can be physical, structural traits like a skeleton or musculature that helps it live in that setting, or can even by physiological traits such as the presence of an enzyme in the digestive tract to help it break down the available food sources. Examples of Natural Selection: 1. Skeletal Adaptations Giraffes, lizards, and many other known species adapted to their environments through genetic changes to their skeletons. This form of natural selection meant that members of the population who didn't develop and present these skeletal changes died out. For example, giraffes developed long necks to reach food sources higher up in trees, so members of the giraffe population who didn't develop a long neck died out. At the same time, certain lizards in one region developed longer leg bones to help it climb up during periods of flood and to escape predators in the ground; shorter legged lizards of the same population died out until only the lizards with the long legs survived.. 2. Coloration Many species have been studied who've adapted to their environment through adaptions in coloring. Once the optimal coloration is present, natural selection occurs when members of the species without the adaptive coloring died out more quickly and therefore didn't reproduce as abundantly. Some example include the deer mouse, the peppered moth, and the peacock. 3. Bacteria Bacteria are a common research subject when studying evolution and adaptation because some colonies of bacteria can produce several generations in one day, letting researchers see a "fast forward" version of evolution and natural selection. Some observed bacteria have included some who've adapted to new food sources that were previously unusable, as bacteria that have adapted to the presence of deadly antibiotics and exhibited traits that let them not only survive, but reproduce to generate offspring that are also resistant to the antibiotic. 4. Physiological Different species go through changes over time that help them adapt to different environments, and humans are no different. One of the physiological changes that different groups of human beings have made involves the ability to digest cow's milk. In regions where cattle are not raised, the human population is often lactose intolerant, lacking the enzyme to break down the milk. However, in regions where cattle are grown domestically and their milk is used as a chief part of the food supply, those humans as a whole produce the enzyme needed to digest milk. AchillesSinatra: Beaver, none of the above is disputed. Yes, white moths turn black and all that. But you miss the point. It's a subtle one, I grant you. What is the overarching principle which unites what is going on in all those moths, lizards and giraffes? If you can state it without circularity, I'll marry you. And before you say "50000 brilliant scientists can't be wrong"... 1. Yes, they can (it happens a lot actually) and 2. I'm hardly the first person to point out the tautologous nature of natural selection. Some of the finest biologists of the 20th century did, too. It's just that these days, they either don't see it, or DO see it and try not to draw attention to it. After all, who wants an empty theory? (Edited by AchillesSinatra) AchillesSinatra: Can all the above stuff be described as nature selecting? I suppose so, but it adds absolutely nothing to our stockpile of knowledge. People die all the time. Can this be described as a "death force" at work? I suppose. How about "All people with conditions susceptible to death tend to kick the bucket faster than those without". Happy now? AchillesSinatra: Take a look at what you typed, Beaver: "Natural selection is the term that's used to refer to the natural evolution over time of a species in which only the genes that help it adapt and survive are present." So what you're telling me is: those populations of organisms which have genes that help them to adapt (i.e. survive) will tend to, er... do what? Survive and transmit their genetic material more successfully than those without? You mean to say the winners tend to win? Nice n comfy here in ma armchair.  AchillesSinatra: Again, if you can define "adaptability" (or "fitness" ) without reference to survival and reproduction, the loop is broken and we have a perfectly respectable empirical scientific hypothesis. Be my guest Until you do, all we have is "Those best able to survive tend to survive better than those less able to survive". AchillesSinatra: I believe it was Thomas Henry Huxley who, upon first hearing of Darwin's theory, said something like "How incredibly stupid of me not to have thought of that". Doesn't this give you a clue? Why is it so obviously true? Ans: Because it's a truth of language; not how the world is. (cf. "Winners tend to be winners". The circularity of natural selection is just a little better concealed, that's all.) No one ever said to Einstein, "How incredibly stupid of me not to have thought of that". And why not? Ans: Because Einstein's theories were empirical. Their truth or falsity requires more than an armchair to ascertain. | Science Chat Room 3 People Chatting Similar Conversations |
