Evolution!? - (Mar/16/2006 )
There are many examples that suggest humans are not yet fully evolved for bipedalism. Flat feet, back problems, varicose veins, and hemorrhoids are just a few examples of common maladies that suggest we're not fully evolved for upright posture.
Also, consider our rib cage. It is superbly designed to protect vital organs from attack if one assumes quadrupedalism -- the top (our back) is protected, as are the sides. However, from an erect posture, we are pretty susceptible to extensive damage from frontal attack, at least to the abdomen.
Of course, there are other areas in which we are evolved for bipedalism (lower spine curvature, an angled femur, broadened pelvic bone, knee joint development, musculature, etc.).
Will human be extinct one day?
as we know us, probably. but supplanted by more evolved form (next step, then next...).
slowing? or moving it in another direction?
OR is it that since mutations occur & accumulate.. we change and because some mutations make us survive the conditions better.. we are said to be evolved.. !? what im saying is.. its the other way round.. not that evolution makes us adapt. And hence i think evolution has no aim.. mutations occur at random.. and may or may not help survival. whenever we see the outcome as a better survivor we call the group as an evolved group.. is it?? (and also.. when we use the term evolution we dont mean an individual.. we mean a large population.. and that's why we can only see better survivors in a population)
this is waht i need to know.. if u can tell me:)
...OR is it that since mutations occur & accumulate...
Beneficial and null mutations accumulate, detremental mutations (lethal and otherwise) do not.
...we change and because some mutations make us survive the conditions better...
Conditions can change, too -- a mutation that is beneficial under a given condition may no longer be so if the conditions change.
...we are said to be evolved.. !?
We are said to have become better adapted to current conditions.
...i think evolution has no aim.. mutations occur at random.. and may or may not help survival.
Correct.
...whenever we see the outcome as a better survivor we call the group as an evolved group.. is it??
We say the group is better adapted to current conditions.
(and also.. when we use the term evolution we dont mean an individual.. we mean a large population.. and that's why we can only see better survivors in a population)
Correct.
I dont think its a matter of us contolling our environment, certainly certain areas of the environment become for favorable, but other areas change at an increasing pace. Its seems that we change our environment to suit our physical conditions, yet our environment is constantly shifting in relation to our mental conditions (computers, etc) - so maybe our evolution is shifting away from morphological changes and more towards cerebral changes.
But this type of evolutionary step is a lot harder to judge than those of standard morphology, but I think personally we are becoming smarter and developing better cognitive abilities - well some of us at least!
I wouldn't be so certain. Less educated people simply outbreed us. I don't know if it doesn't form some sort of negative selection against the smart ones.
dont think that is even an argument, i meant the average intelligence. I mean what kid learn in school today is vastly more complex than 30 years ago.
and what you do in a PhD will (hopefully) be tough to pre-grads within 5 years.
Overall the average intelligence seems to be increasing
The News Just in
Fossil discovery fills gap in human evolution : http://www.msnbc.msn.com/id/12286206/
Beneficial and null mutations accumulate, detremental mutations (lethal and otherwise) do not
Detremental mutations can accumulate in "bottleneck passages" (when only a small part of the entire gene pool is transferred to a new habitat) as exampled by serial passaging of small fractions of viral supernatans (RNA virusses) leading to severe fitness losses (due to non-lethal detremental mutations). If the "nummber" of the passaged virusses increased, no fitness loss was observed (articles of esteban domingo). The theory is called "muller's ratchet".
We are said to have become better adapted to current conditions.
This is what the "Red Queen hypothesis" suggests (and has been proven in viral passages in vitro).
(RNA virusses replicate extremely fast when compared to mammals like ourselves and have very high mutation rates and therefor are very easy 'organisms' to study evolution. They have no sexual reprodution, but they ofthen have recombination events between different genomes).