'the evolutionary scapegoat'

[QUOTE][b]Its not life threatning so natural selection wouldnt eliminate it. But still our bodies only have the minimal necessities to allow us to function.[/QUOTE][/b]Adaptations that serve no purpose tend to be removed from the population. This is why cavefish and similar organisms tend to lack pigments (and vision).

If the absence of a feature does not reduce probability of survival and production of offspring, it is not needed.

[QUOTE][b]Your missing my point. These traits {spinal ridges, eyebrows, mens nipples} have virtually no effect in increasing the probability of reproduction. I know they serve an important purpose but they dont increase the probability of reproduction so how can they increase reproductive success?[/QUOTE][/b]You're overlooking something. If it serves "an important purpose" then it contributes to reprodution. Simply put, if it helps keep you alive or helps you in any way, it improves reproductive success.

[QUOTE][b]Keeping the hair out of my eyes is helpful, but its not going to win over the ladies.[/QUOTE][/b]I doubt someone who has shaved their eyebrows would agree. For one thing, it makes people look strange, thereby harming you in the mate selection department, and since people are social it could cause you even more trouble if you are ostracized all the time or even banished from the group. Another problem is that if you can't keep sweat out of your eyes, you can't see, so it can get difficult to flee from predators. When you get eaten, you cannot produce more offspring. Even a small disadvantage between you and your peers will harm the chances of a particular allele being propagated through a population.

[QUOTE][b]If you put two naked men in the forrest and one with shaved eyebrows is it fair to say that the one without is at a disadvantage? Come on now, lets be realistic.[/QUOTE][/b]Yes. We've already mentioned three different purposes for eyebrows, that is more than enough to demonstrate reproductive advantage.

[QUOTE][b]If natural selection works as well as you theorize then why do we have genetic predispositions towards obesity, poor eyesight, poor hearing even baldness? These traits have a much greater impact on their[/QUOTE][/b]I'm glad you asked. Obesity is such a problem today because people are now more sedentary than they are "supposed" to be (as they would be in nature, where we evolved) and eat fat-choked food that they were not supposed to. Our bodies store surplus calories from food because, in the wild, there would be times when food is not so plentiful. Now that most people in industrialized nations eat three times a day, our bodies store more fat than they should. The concept that we could be killed off by too much food just never manifested itself in nature so modern nations are victims of their own success.Eyesight, being something more likely to fail later in age, past the point of reproductive years, is not subject to strong selection pressures. Age 40 is usually the approximate life expectation in the wild (and in very poor nations today) so macular degeneration is rare, people just don't live long enough for it to happen often. That is why, when we live longer, we develop more medical problems in old age: we have genes that would have been better for us had our ancestors lived long enough for the negative effects to show, and therefore allowed the poorer ones to be weeded out. Same with hearing loss and baldness, both traits that are most common later in life. By the way, this also contributes to the high rates of cancer and heart disease in people who are no longer young. [QUOTE][b]Just because an individual has an improved design (tear duct, eye brow)over the others does not AUTOMATICALLY mean that he will have a reproductive or survival advantage over the others.[/QUOTE][/b]But we are dealing with statistics here, and yes, such a population will be at a disadvantage. And yes, you are being inconsistant in your arguments. See the other post above.

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[This message has been edited by gene90, 07-26-2002]