Is Evolution Over In Humans? 761
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.'"
Re:Blending (Score:2, Informative)
you tend to see the most extreme specialization in places where populations are cut off.
Ie, take the galapogos (spelling?) islands where Darwin first got his ideas. He noticed how specialized the birds of these islands had become, in comparison to their main-land brethen. The idea being that given a population that is isolated, certain charactistics can be more easily selected for , instead of having to try to select it out of much bigger population. Of course, the problem with this guy's (the article) opinions is that it does smak of segregation and other asty thoughts, but he should be given a fair consideration
Thanks all!
Re:Blending (Score:3, Informative)
For evolution to stop (Score:3, Informative)
(an allele is one varient of a gene, like some people have the blue eye allele, some have brown eye allele, while almost all of us have the genes for eye).
1. random mating (i.e. people will randoming mate with any other person)
2. constant sized society (no one leaves or enter, everytime someone is born, someone dies)
3. large society (a group of 50 people, even isolated, will still evolve, while a group of 5000, if the rest of these condistions are met, wont)
4. No selective pressure (favoring one type of allele vs. another)
These were all learned in a basic biology class, btw.
Re:Blending (Score:2, Informative)
Random read errors in transcription also leads to mutation, as well as ionizing radation. Ionizing radiation leads to DNA breaks in your cells, your cells try to "fix" the breaks by re-reading dna and reassembling, or by the other method of randomly recombining segments. All of which leads to errors, possible mutations, and maybe cancer if you're lucky. But mutation of individual cells is NOT EVOLUTION. Mutation of zygotes allows for introduction of new traits. Most detrimental mutations cause abortions, as "natural" abortions are much, much common than commonly believed, as the ovums machinery effectively self-destructs.
Re:Evolution is a fairy tale (Score:3, Informative)
"This elephant though, like the one with the missing tail gene does not express it, and natural selection does not come into play. 5 generations down the track, two close relatives have a child with this super spit power. Unfortunately, because of the second fact I listed above, this child also has a missing tail, one leg that can't move properly, a reduced brain size, and a bad back meaning it has difficulty feeding in hard to reach places. The problem here is that along with the beneficial mutation there came a host of harmful mutations."
This is an interesting concept mind you but as usualy happens when people have a counter argument to something fairly complicated you sometimes miss fairly obvious mistakes. For one your concept of mutations is driving how you evaluate evolution. Elephants don't suddenly evolve the ability to spit acid and therefore have some sort of evolutionary advantage. In fact the reality is in this case unless the elephant was in a highly isolated enviroment the mutation would get blended into the gene pool as background noise and never remanifest EVER. That kind of mutation is far too severe to really take hold at all. The community would have to be so isolated that inbreeding would kill them off almost. To understand evolution you have to really really concentrate on the time scale involved. As we are short lived beings this is sometimes hard for us to concieve.
For example one of the favorite arguments against evolution is flying. How could anything ever evolve something so complex by just mere natural selection. They think "gee how could such a complext mutation happen no matter how much randomness was applied". The answer is quite simple. We in fact know now the highly likely reason why beings evolved the ability to fly. There is a bug (forget what its called sorry) that skates on water. It uses its extreme light weight (note how low weight is important to flying beings) to float ontop of water without breaking its surface. To move around it kind of hops and skates along the water with its long almost flight capable wings. Scientist took these bugs and did studies on them. They cut the wings smaller and smaller till they were practically nubs and the bugs could STILL jerk around quick as heck with them. They did a documentary on it even the video was quite interesting. Obviously the amount of time it takes for a water organism to evolve into something that floats on the water is astronomical and then who knows how long it goes from floating to skating to jumping and finally flying. It's almost inconceivable but when laid out its obvious to see how it works. Thats how evolution is though unless you know what happened its just almost impossible to imagine how BIG changes happened.
So in conclusion while I it's good to question scientific concepts I think your arguments are fairly uninformed here. "Macro-evolution" as you put it just dosn't even exist. It's a word created by people who can't comprehened that small changes are all that are required to reach huge differences in gentic diversity.
I dont want to ruffle religious feathers but perhaps evidence for your creation theories would be more proper? I've noticed religious people tend to try and discount other concepts instead of promoting their own. Usually they believe that if everything else is discounted then creation must simply be how things happened. This is a futile goal because if you did convince people that evolution isn't true they'd no sooner believe in "creation" than they did before. They'd just go searching for another solution with founding in the physical laws which they can observe. In something like this the observable laws of the universe are the status quo. You'd have to first determine exactly what every law of the universe is then point out how they don't explain EVERYTHING for you to have proof. Even then though the point of faith is to believe without proof though isnt it?
Jartan
Re:Evolution is a fairy tale (Score:3, Informative)
A Brief History of the Evolution and Creation Science Conflict [religioustolerance.org]
Many claims of evidence against evolution are in reality pseudo-science, and are easily refuted. [religioustolerance.org]
Six Flood Arguments Creationists Can't Answer [lhup.edu]
Is Creationism a viable scientific hypothesis ? [hem.hj.se]
Re:This is the most ridiculous article... (Score:4, Informative)
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 (Score:4, Informative)
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.
Re:Evolution is a fairy tale (Score:3, Informative)
> Harmful mutations far outnumber beneficial
> mutations
No, relatively meaningless mutation far outnumber both of these. Look at the people around you. Most of their differences are minor -- different hair, different complection, some are a little stronger, some shorter, some smarter. Everyone has lots of little, largely meaningless variations. (These can be both recessive or dominant traits.) Relatively rare is the person with a deeply serious genetic variation, good or bad.
> Evolution is impossible as beneficial recessive
> mutations could never have arisen.
This isn't how evolution works. Keep in mind that every population has a good deal of variety in it. When that population is put under stress (say, there's a flood and all the short people die), individuals whose genetic traits give them an advantage for dealing with that specific stress have a better chance of survival.
> Natural selection requires a genetic mutation
> to express itself in order for the selection to
> work
No, no, no. Evolution doesn't take place when an organism inherits some magical mutation, which allows him to eat more, which is somehow magically linked with having more children. Evolution is the result of stress on a large and diverse population -- limited resources, predators, oil spills, et cetera. When that stress occurs, the various weird traits that had always been occuring (different hair, different skin, whatever) give some of those organisms a better chance.
> We have evidence that close relations have
> cumulatively worse of children than average
> partners.
Again, this is a too-shallow analysis of complex systems. Your model (that any one beneficial trait is virtually always accompanied by at least one harmful trait) ignores the way these systems actually behave. Traits are meaningless until stress is put on the population, thus there is little correllation between them.
Anyway, there's a counter-argument; post up what you think its flaws are. Hopefully the moderators will de-lodge their heads from their collective asses, shake their heads vigorously, and mod your post back up.
Re:immune system evolution (Score:2, Informative)
While the majority of HIV infected people in those places are homosexual or IV drug users, the majority of new infections happen through heterosexual transmission. Aids is no longer a "gay plague".
(Source: UK phls ( http://www.phls.org.uk ))