Is Evolution Over In Humans?

BrianGa writes: "Is evolution over? Are current humans the final version? This article presents a number of interesting theories, including the theory that 'Our species has reached its biological pinnacle and is no longer capable of changing.' Professor Steve Jones believes this, in part, because 'human populations are now being constantly mixed, again producing a blending that blocks evolutionary change.'"

Comments

Re:This is the most ridiculous article...

[brunes69]

The problem with modern society is that evolution has no CHANCE to take its course. Let's use your Sickle-Cell gene as an example. In any other species on the planet, Sickle-Cell genes would be gradually phased out of the population, as people with them died at an earlier age, and thus having less offspring than those that don't. The same rings true for basiclly all genetic diseases; the reason evolution takes care of them IN THE FIRST PLACE is beacause they kill the animals with the defects off.

The same rings true for animals born with advantagous mutations. They have a greater chance of survival, and thus, for producing offspring. Over generations, the breed with the mutations is so much more likely to survive than those that won't, that it eventually takes over, and the inferior breed dies off.

Human's don't follow this trend any more. People with genetic diseases are given drug treatments and so forth to prolong their lives as long as possible, often far beyond what they would achieve otherwise. And they definitly mate as well, thus passing the defective gene along.

Without the threat of extinction, evolution falls apart. When a species becomes as dominant over its environment as humans have, how can its environment have any impact on it? It is totally illogical.

I think that, unless we move in with some other alien species and start cross-mating, physical evolution by humans has indeed come to an end. As for cultural evolution, that is a never ending process that has nothing to do with external environmental factors.

Re:It's worse than that

[xigxag]

There is no such thing as "de-evolving."

The whole point of the theory of evolution is that it describes an inevitable one-way process, like entropy. Due to random errors in DNA replication, mutations are produced all the time. Some of those mutations are more suited for the environment they are in, some of them are less suited. The mutations which are more suited tend to out-produce the others (natural selection), and over time, evolution occurs. The genius of Darwin was in recognizing that the ones who survive, by definition, are the fittest, and vice-versa.

Are selective processes still at work today? Yes, of course. So what if 20-20 vision is no longer a fitness trait? It used to be that having gills made us more fit for our environment, some hundreds of millions of years ago. Now it's not longer to our advantage to have gills, nor to have perfect vision. Our environment continues to change, and so must we. Perhaps we now live in an environment where it is more important to be able to play dirty pool than to be able to swim in a dirty pool. Maybe we're evolving into a nation of smooth-talking baby-daddies. More seriously, there are other elements in our changing environment that people are evolving in concert with. It seems increasingly common for people to develop diseases like asthma and bizarre autoimmune disorders which may be related to synthetic chemicals in our environment. Those unfortunates who can't live in a plastic, super-medicated society are dying out -- but the rest of us are evolving into Homo Artificialis, if you will.
Also, a disease like AIDS which is cutting great swaths of death through the developing world will inevitably lead to populations which are largely resistant to its modus operandi. (In fact, some Europeans already are immune to HIV, a genetic gift conferred upon them by surviving the Black Death, scientists surmise.)

The evolution happening now may not seem "higher" on some kind of eugenic scale, but nature works in its own way. Alligators survive but the dinosaurs are long gone. And we all know that after every mammal has perished, bacteria will still remain, deep within the crevices of the Earth, adapting.