ShakyJake

Since we take care of our sick and disabled, have we thwarted the process of natural selection?

If we were to fast forward a couple of million of years, and assuming the human race survives either self annihilation or some planetary calamity, would we be no different than we are now?

MrDarwin

I suspect humans will be very different. We like to think we're exempted from natural selection but nothing could be further from the truth. Humans are still under evolutionary constraints, and still subject to natural selection. We are still limited by resources (food, water, air) and are still subject to diseases that continue to mutate even as we devise new methods to treat them.

And natural selection takes many forms--one of the most effective (but commonly overlooked) selective filters is the weeding out of defective gametes, i.e., sperm and eggs (as well as genetically defective embryos), which is likely to continue as long as our species exists, and produces more sperm and eggs than viable embryos. Every time one sperm fertilizes an egg cell at the expense of all the other sperm cells, every time a fetus miscarries or a badly deformed newborn dies, natural selection is at work.

Jayhawker Soule

Less theism and body hair.

Skeptictank

I have to disagree with you Mr. Darwin. I believe we have overcome the major factors of natural selection that lead to speciation and adaptation. e.g. We do not let the sickly die out, but invest resources in keeping them alive and allowing them to reproduce and pass on their genes. While they would otherwise die out.
In addition, due to world transport, there is now no longer a real chance of some group being isolated and evolving to fit their new, unique environment. People cross oceans and breed with others from all over, in addition, we now adapt our environment to our needs (to a degree). Thus, while ancient humans adapted to their surroundings (e.g. dark skin in Africa, sickle cell; fair skin in Europe) we now rely on medicines and sunscreen. (If people from all over were to breed across cultural and racial lines I think we'd end up with a nice, olive tan coloring!)
In fact, society tries to correct for genetic "abnormalities" with surgery and gene therapy. If we change at all, it will be because we initiate it (e.g. we engineer our kids to have an extra liver, just in case), not because nature pushes it on us.

DRFseven

But we're just as isolated by cultural factors, such as economics and politics, as we were by oceans and mountains. Think of the medical implications of two groups widely separated by accessibility to medical and health advancements.

MrDarwin

The question was not about speciation. Evolution does not necessarily lead to speciation (although it commonly does). And natural selection is based, quite simply, on the tendency of populations to breed more individuals than the environment support. I don't see this fundamental fact changing for humans in the near future.

Go to any third world country and tell them that.

I believe you are overestimating this genetic mixing. In western countries like the U.S.A. or U.K. it's easy to think that humankind is a huge melting pot, but I suspect that this has little genetic effect on the populations in most third world countries, which remain quite isolated genetically in the sense that they may be exporting genes to the west, but the reverse is not true.

The flip side of greater mobility is the global distribution, often quite rapidly, of new diseases.

Unless gene therapy is made available to all 6 billion or so humans on this planet, it is unlikely to have a major effect on the long-term evolution of our species. (Although on second thought, it may actually lead to a speciation event of sorts: an affluent, western, genetically modified population, and the rest of the world which is left out.)

If anything, I think the still-growing human population of the earth, combined with environmental destruction, the exhaustion of natural resources, and the globalization of communicable diseases, will in a generation or three re-introduce us in a big and very unpleasant way to natural selection.

Jamie_L

I believe we are moving to a point where the human race as a whole will be generally isolated from many aspects of natural selection. Without medical care, childhood diabetes and asthma might eventually be weeded out of human genetics. That seems highly unlikely now, as these conditions are easily treatable.

However, the human race WILL be different in the future if only becuase of our own tampering with our genes. Biotechnology has the potential to become our new form of evolution - only a self-directed form. (Aside: biotech has the potential to really make ECONOMIC conditions into an evolutionary factor - the rich get the benefits while the poor lag behind).

Jamie

NialScorva

<a href="http://www.sciencedaily.com/releases/2001/04/010424073740.htm" target="_blank">No</a>

KeithHarwood

I have to agree with Mr. Darwin, but for slightly different reasons. Evolution occurs as species adapt to their environment. Now all that has changed is that we will adapt to the environment that we have created ourselves. In that environment genetic diseases aren't selected against, but running out into the road without looking is very strongly selected against. We could very well evolve into two species, those who look left before crossing and those who look right. And you may very well get reproductive isolation since neither could live long enough to reproduce in the environment of the other.

Skeptictank

What a disturbing article (but good). Essentially it says that uneducated, overreligious lemmings are going to out breed everybody. Ugly scenario..."and the stupid shall inherit the earth!"

To help reverse this trend, I think many, many attractive women should have sex with me. I am both an athiest and (to brag a bit) an Ivy League graduate. Help produce the attractive, smart, atheists of tomrrow! So do the species a favor ladies and mate with me today!