is this as good as it gets

[Guest]

Are humans still evolving?
is this as good as it gets?
how can natural selection be working when IVF and medical advances give everyone the chance of reproducing?
If we have stoped evolving what will happen to us?

[munchingfoo]

One theory that hit the headlines not so long ago was that we would end up evolving into two different species. Modern people seem to be more open to reproduce with people who are intelligent, rich or both. Someone suggested that this will cause an "elite" higher species that is fitter and more intelligent, leaving the rest of the species become less fit and more stupid. The reason for this is, as you say, there' are no pressures, for the most part, on who can and can't breed anymore so the only factor left is "who they breed with".

[Guest]

So do you think that intelligence is the most important thing for our evolution? Some of the most intelligent people are famed for lack of social/practical skills. Also intelligent/career focused people tend to have less children
One idea is that we might "de-evolve" as the sort of people you expect to have the most childen aren't what you would call the "fittest".

I think that until there is more enviromental instability such as an epidemic there is very little selection pressure. surely evolution (as oppose to intelligent design) only pushes species to be "good enough", not perfect and as long as the human race is "good enough" very little will change.

[Humphrey]

Love the picture

http://news.bbc.co.uk/1/hi/uk/6057734.stm

The descendants of the genetic upper class would be tall, slim, healthy, attractive, intelligent, and creative and a far cry from the "underclass" humans who would have evolved into dim-witted, ugly, squat goblin-like creatures.

This is already happening. By way of illustration simply compare Orange County California to Calton or Dewsbury.

[RedCelt69]

Evolution requires bottlenecks; either in population size or geographically. Along with IVF treatment and gene manipulation, you need to factor in transportation. The human species is effectively one giant gene pool of over 6 billion (and rising). For our species to evolve (even slightly) it requires one mutant gene to become dominant in the species and for that gene to be adapted by the whole species. Not very likely at the moment.

If technology collapses and inter-continental travel ceases, each pocket of population will eventually evolve to the point where they are no longer able to reproduce with other humans (the definition of a new and distinct species).

It isn't a case of whether evolution can some to a stand-still. It is more a case of the pace of the evolution.

As for an "elite" sub-species branching off... that might feasibly happen. At which point the majority species wipes the sub-species out. In the race for survival, numbers matter.

[Guest]

isn't it a good thing to say that we have stoped evolving so that the question of different human species doesn't come up?

[munchingfoo]

Why? Should we just bury our heads in the sand every time difficult questions arise?

[Frank]

STOMPY ROBOT BODIES



Evolved or not, we've got one hell of a lot of technology to be getting on with and applying our 'selective pressures' to. Once wetware's more common, evolution will be an afterthought. 'Species' will become brand-names and 'defects' or 'mutations' will be entirely optional, but at ludicrously inviting prices!

Hooray!

[jollytiddlywink]

Only very recently, and in select parts of the human population, can anyone have cause to ask if evolution has stopped. Antibiotics are scarcely more than 50 years old. Effective public health measures (quarantine, mass inoculation/vaccination, provision of clean drinking water, sewers) began to appear in Europe after 1800, but were only widespread by 1900. The NHS only came into being after the Second World War. Prior to that, medical care for the poor and even the middle classes could be patchy at best.

Its important to remember that evolutionary pressures continue to run rampant over wide areas of the plant. Malaria is endemic in large areas of the globe, killing roughly 1 million a year. Tuberculosis kills 1.5 million yearly. Cholera and other water-borne diseases are widespread wherever modern sanitation and waste-treatment are not in use, or where such systems have broken down (Zimbabwe). Malnutrition or outright starvation kill too. Large areas of the world live under much the same burden of disease, hunger, deprivation and occasional violent conflict that would be familiar to mankind over the last 100,000 years.

Even the western world, with vaccines, antibiotics, doctors and sewers is still prone to viral threats: A flu pandemic swept the globe from early 1918 to mid-1920, and killed anywhere from 20-100 million. Antibiotics, too, are no sure thing, as through mis-use or overuse they become useless. Drug resistant TB is causing epidemiologists no end of worry. It is very rare in developed countries now, but there were times in Scotland in the 1800s when TB was the cause of nearly 1/5th of all deaths. Its just as lethal now as it was then.

The modern world has also developed new and interesting ways to kill off people: cars, for example, kill 400,000 worldwide each year, directly or otherwise. So I think it is premature, or maybe even silly and dangerous, to consign evolutionary pressures to the dustbin of history.

[Thalia]

That article by the political theorist trying to pretend he knows something about evolution is awesome. For one thing, there would have to be hugely strong sexual selection pressures at both the upper and lower end of the scale that completely differ from each other, to the extent that anyone in the middle (either not attractive and smart or short and dim-witted enough to fit into either group) ends up dying out. I don't think there's any particularly strong sexual selection pressure in western society - while we have our ideals of beauty and intelligence, those who aren't beautiful and/or intelligent are still able to find someone if they want to. Although it's maybe true that career-minded 'intelligent' people have less children, not all intelligent people follow this pattern and even if they did they still have enough children for their genes to remain in the mix. I think the problem is when people look at these things in terms of poles of smart - stupid, tall-short, pretty- ugly, when really the majority will fall somewhere in the middle and only pressures that result in an unfavoured pole dying out would lead to the middle being moved to somewhere else along the scale.

One thing i think we might find, at least in western society where there are no strong selection pressures, is an increase in variability. There are no traits that are particularly beneficial to our society and so variations on all traits survive. This could be a good thing in the long run if there ever is a change in selection pressures as it increases the likelihood of some of the population having the traits needed to survive.

On a more entertaining note though, I once watched a funny movie called Idiocracy where stupid people basically outbreed smart people, resulting in society pretty much falling apart. It's gained a bit of a cult following despite not having a wide release - worth checking out

[Haunted]

As long as there is reproduction, evolution will not cease.
Yes, it is selection pressure that drives evolution in only certain directions, but genetic drift occurs regardless of whether there is any pressure or not.

In order for the human race to speciate there must be mutually exclusive populations. In nature this usually takes the form of geographical separation however, due to our technology, this is not available to us (until we start colonising other planets that is).

What has been suggested is social exclusivity, however even this would take several generations before there were any difference and even a little exchange of humans across the divide would prevent such changes. Even if there is no exchange and that the system remains stable it would still take many hundred's of thousands of years before the descendants of each population were unable to interbreed.

[LonelyPilgrim]

If technology collapses and inter-continental travel ceases, each pocket of population will eventually evolve to the point where they are no longer able to reproduce with other humans (the definition of a new and distinct species).

Why should we assume this is even possible in theory? How long has humanity been around? How many millenia were the American populations divided from the European? And yet... while contact resulted in serious disease resistance issues, I can assure that inter-racial reproduction was not a problem. I wouldn't be here if it had seeing as my great great something or other was a Cherokee woman.

I suppose, if intercontinental travel were impossible for long enough - longer than humanity has currently existed, at least - the changes you mention would be possible, but how likely is that? Are we really going to have a cataclysym so overwhelmingly bad that we will manage to survive and yet be unable to cross an ocean for several million years? I don't think it would take us ten years before someone was adventurous enough to try to reestablish intercontinental contact on a small boat. With our education and our plethora of basic written material lying around we aren't going to forget a) the shape of the Earth or b) rudimentary shipbuilding and navigation - no matter what.