while selective human breeding may produce offspring of superior quality;

1. our genetic knowledge is not good enough to ensure this "smaller, leaner gene pool" have a good enough defence against future desease.

2. humans are not mindless machine that act purely on logic. if your you dont like your partner despite s/he having the most compatible genetic material, you dont proceed.. and vice versa.

3. and no; while religious text may suggest inbreeding (starting population=few). this does not happen with evolution. as evolution is not discrete. during speciation, neighbouring branches are still fertile with each other and with the source branch, providing ample variation until the new species have a big enough population size.

does freedom of choice/human right include the freedom/right to marry your own sibling if both party consent?

by saying "there are only few humans last time, therefore they inbreed" it shows you do not understand evolution.

understand this.

EVOLUTION IS NOT DISCRETE.

and at present, since human and ape are separate species, they will not produce any fertile offspring (if they produce any at all)

look at it this way, science and technology are the something like the "NEP of evolution" they artificially protect us. now, for any reason if these technology is removed from our daily lives, imagine how vulnerable we will be to the elements and disease.

some individual are more resistant to disease than others. some people seemed to catch whatever sickness thats the flavor of the month. others rarely even get a sore throat. and some community in africa is highly resistant to malaria. etc etc.

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Added on January 12, 2010, 8:58 amnot really, if you look at male preference, it has gone from plump female circa 1500 to slim female circa 2000. so if there are evolution, where would the selection pressure be? towards plump or slim individuals? and you cannot tell what the preference will be at 2500. the period is also too short to produce any meaningful results

This post has been edited by lin00b: Jan 12 2010, 08:58 AM

A being the dominant allele will suppress the recessive a. so Aa while carrying bad genes, the bad quality is not express and the individual live a healthy life.

so as far as quality of life is concern, Aa and AA has no difference. while aa is catastrophic. in case of a large population, the chance of aa being expressed is significantly lower than AA or Aa as opposed to a small sample size of inbreeding.

as shown in the your example, by the third generation, 3/8 has aa. (1/8 at 2nd)

comparatively in crossbreeding, the chance of aa being expressed is significantly lowered.

not not neccessary all a is bad, there is a possibility that ou have some recessive genes that are good. but life prefer to err on the side of safety. its basic instinct. you prefer to take a risk if its to protect something you already have rather than to take a risk to get something that may benefit you.

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Added on January 13, 2010, 12:51 amsee difference from renaissance to present day

also

some article

now, i am not saying plump women are unattractive or vice versa, but society in general views slimness (hour glass) as the ideal female figure now, versus the plumpier version as the ideal 500 years ago.

there are numerous psychological and economical reasoning into why this happened, if you are interested in learning more.

yes, current age with medicine and technology is too short to produce any significance in evolution pressure, but if the current trend continues, we will see human as a species rely more and more on technology and medicine, and less on any evolution that occur (ie, the one that is more susceptible to illness get more or less the same chance to reproduce as the healthy one)

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Added on January 13, 2010, 1:04 amnaturally occuring medicine dont usually have as wide and deep effect as artificial medicine. and knowledge of medicine is not genetically passed on (at least not for human)

lamarckism does not play any role in species survival, because it does not happen. it is not an "alternative" path of evolution, it is a mistaken path of evolution.

you have thick pads on your fingers and feet because your body has the ability to develop harder skins at places where more stress is applied. your fingers are more flexible because you practise it more and your muscle and tendons did not harden. these are naturally occuring adaptation that you as an individual can perform. at no time is this information passed on to your offsprings. a baby is always born is soft smooth soles even though their parents are hard laborers with calloused feet and hands.

AND, grass is not "medicine" to dogs, at least not in the sense you are implying.
dog eat grass


This post has been edited by lin00b: Jan 13 2010, 01:11 AM

result of evolution is not to reduce bad genes, it is to reduce the expression of bad genes.

if bad genes are dominant - hence frequently expressed, that particular community will eventually be dead. if the bad genes are recessive, hence seldom expressed, the community will survive. if this surviving community resort to interbreeding, the odds of these bad genes being expressed is increased, and that is bad.

an interesting point is that majority of our genes are actually not expressed in any way. they may be junk, or extremely recessive

while you are referring to protecting the individual, i'm referring to protecting the species and community. the whole community suffer if the quality of the offspring produced is of frequently low quality. it is arguably better to allow only the better/fitter individual to reproduce and increasing the quality of the output. at least that's nature's way.

all those other "counter point" you use are actually true. although the exact line can be blurred. whatever artificial tools we make is not a result of our evolution. and by continuing to use them, we are in a sense limiting whatever natural selective pressure on use to be better biologically.

not to say tools are bad, but looking at a strictly evolution point of view, it is creating a weaker species biologically.

passing of knowledge is not lamarckism in any sense. say engineering parents, son may grow up to a profession that does not use engineering skills at all. whatever skill that the parents frequently use and depend upon is not transferred on to offspring

the passing of community-wide knowledge is good, but is fragile. knowledge is easily lost during catastrophes. after which the community has to start from a lower knowledge level, this is because those information is not guaranteed to pass on to future generation, unlike evolutionary genetic information.