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alext87

Humans - are we going anywhere.

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Humans cannot be evoluting as there are too many in the population to get a complete change in the gene pool and everybody regardless of the fitness makes it to reproductive age.

 

Therefore, does this mean that we are just waiting until another species catches up or are we now here for ever? without natural disease do you think humans could ever be competiting for food and shelter again?

 

In a million years will we have changed?

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We are not going forwards, i agree to that.

 

However, with all this keeping ill or weak people to reproductive age, are we going backwards? Are we getting weaker?

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Yeah, we could be just keeping the bad genes in the system and therefore moving backwards as they spread further into the gene pool.

 

Surely as beautiful people tend to go for beautiful people and smart people with smart people and tall people for tall people. We will end up will different groups (classes) of people. eg. group of really tall people etc...

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Three things will likely change human evolution: gross genetic manipulation, catastrophic event that dramatically alters earthly conditions, and extraterrestrial colonization.

 

Whether humans are truly "moving backwards" in terms of evolution is based on the evolutionary goal:

 

Are we talking mere propagation? If so, we are doing splendidly...for now.

 

Are we talking fitness? Well, then we must define "fitness"--specifically, fit for which type of environment; are we fit right now to live in wilderness sans technology? Not anymore. Are we fit right now to live a spaceship? Not yet. Are we fit to live in sunny surburbia with all the comforts and security that it brings? Well, probably more so than others.

 

Are we talking technological advancement? If so, our evolutionary achievement will double every 18 months at least according to Moore.

 

Are we talking existing in peace with ourselves and other species, taking a minimalistic approach to comsumption, having unified theories on god, science, politics, and philosophy, living in harmony with mother nature, eradicating hate, fear, and apathy, while holding hands across borderless nations singing kumbaya around the big campfire of enlightenment? Then we are doomed.

 

The point is, whether humans are evolving depends on the arbitrary criteria set by the observer.

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The point is, whether humans are evolving depends on the arbitrary criteria set by the observer.

Everytime the frequency of any certain gene changes in a population that population evolves, reguardless of any observer.

In a million years will we have changed?

The idea that the human population will not change over a million years is flawed. There are still pressures exerted on the species and making it change, its just that these pressures aren't traditional and as symple any more. Maybe more sick people will live and reproduce, but if you don't think about it then it doesn't really matter, becuase this is our environment, and if they live and reproduce in our enviornment even though we are "sick" then they are in fact finely suited for your envionment, because they lived and reproduced.

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Are we talking existing in peace with ourselves and other species, taking a minimalistic approach to comsumption, having unified theories on god, science, politics, and philosophy, living in harmony with mother nature, eradicating hate, fear, and apathy, while holding hands across borderless nations singing kumbaya around the big campfire of enlightenment? Then we are doomed.

 

LOL I like how you put this. Very Hellbender-ish :P

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You can never escape natural selection and therfor evolution. Even if we cannot notice it we are evolving, even if it is evolution to stay as we are as with the ceolocanth.

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Humans cannot be evoluting as there are too many in the population to get a complete change in the gene pool and everybody regardless of the fitness makes it to reproductive age.

 

Um, you do realize that "fitness", in terms of evolution, means number of surviving offspring, right? It has nothing to do with strength, intellect, diseases, lifespand, quality of life or any of that. It's a strictly reproductive term.

 

Fitness, and the fitness conseuquences of traits, are soley determined by environment. Take Sickle-cell. In the USA, it's a genetic disease, but in Africa, it's adaptation to resist malaria. The adaptive value, and the fitness consequences, are determined by the presense of a particular aspect of the environment.

 

Humans are currently dealing with a novel environment. Gene frequencies will change, as a result. For instance, I predict metabolisms will be higher in the future, since those with high metabolisms are less likely to get fat, a condition with drasticly reduces one's mating opportunities and is therefore maladaptive in terms of sexual selection in the current environment. But, should a giant asteroid then hit earth and cause a global famine, those with low metabolisms will then be selected for, since the environment changed. The evolutionary trend will have reversed itself.

 

There is no over-arching "progess" behind evolution. It's simply adaptation of populations to the current local environmental conditions. If the environment changes, so do selective pressures, and what was good can become bad.

 

The only traits that are absolutely "bad" are those that are lethal or sterilizing, and those will *always* be selected against, no matter what the state of socieity, since, after all, they're lethal or sterilizing. And even *those* could change with advances in medical science.

 

Mokele

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Fitness, and the fitness conseuquences of traits, are soley determined by environment. Take Sickle-cell. In the USA, it's a genetic disease, but in Africa, it's adaptation to resist malaria. The adaptive value, and the fitness consequences, are determined by the presense of a particular aspect of the environment.

Having one recessive gene gives you the adaptation, and having only one does not give you sickle cell anemia, you have to have both recessive genes. So that’s why the gene stays in the population, because the hybrid (one recessive) is good for you, even though purebred for sickle cell is bad (both recessive).

There is no over-arching "progess" behind evolution. It's simply adaptation of populations to the current local environmental conditions. If the environment changes, so do selective pressures, and what was good can become bad.

Evolution does no only happen to animals in the wild, we have selective pressures too. Just thought I'd lend my support :D

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Having one recessive gene gives you the adaptation, and having only one does not give you sickle cell anemia, you have to have both recessive genes. So that’s why the gene stays in the population, because the hybrid (one recessive) is good for you, even though purebred for sickle cell is bad (both recessive).

 

Yes, but heterozygote advantage only works when there actually is a fitness advantage to heterozygotes. In the modern US, without malaria, there is no such advantage, and a penalty for homozygotes, so the gene frequency will no longer be maintained as it was in Africa.

 

Also, heterozygotes for sickle-cell can and do develop full on sickle-cell (if only temporarily) at high altitudes. Sickle-cell allele beta hemoglobin causes unusual hemoglobin agregations when the blood loses oxygen. In homozygotes this happens just in normal metabolic processes, but in heterozygotes, situations which deplete the oxygen of individual RBCs can cause it too (such as malarial infestation or moving to high-altitude).

 

So, for a heterozygote in Denver, there are actually more fitness penalties than advantages.

 

Mokele

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Humans cannot be evoluting

 

No. Humans, and more specifically their genome is constantly evolving. There is not a progress bar on evolution, therefore you can not tell that evolution is standing still or is no longer at play. Natural selection and mutation are constantly present. For some people who want to think of it as a whole species, they may be inclined that Homo sapiens sapiens are done evolving, just because we as a species have yet to get a new limb or a head, etc. That however is incorrect.

 

as there are too many in the population to get a complete change in the gene pool

 

Are you assuming that if an organism is to evolve, it must undergo a gradual transition from one species into the next? Well, that may happen sometimes, but it does not have to happen. Evolution does not follow a certain - predetermined direction. It can branch into whatever direction that is more fitted for the particular environment. What about all the species that were led into a dead end, and who barely(if any) had any resemblence to their CA's? Taxonomists and others(paleontologists, archaeologists, etc) are always debating about a particular fossil or species and should it either be lumped into an existing species or split into a new species or subspecies. Hence the 2 schools of thought: The Lumpers and the Splitters.

 

and everybody regardless of the fitness makes it to reproductive age.

 

Uhm, no, absolutely not true at all.

 

Therefore, does this mean that we are just waiting until another species catches up or are we now here for ever?

 

This has already been asnwered by myself, and others on this page. Don't think of evolution as a mechanism that follows a certain path.

 

without natural disease do you think humans could ever be competiting for food and shelter again?

 

Once again, I'm not quite sure what you're trying to say here, but it doesn't hold any merrit in it's current school of thought or structure.

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I think i can rephrase. Can our species gradually become more fit as a whole? factoring in the usage of all these gizmos and gadgets to thwart what determines fitness in the first place...survival no longer weeds out the unfit and thus, I think we AREN'T going anywhere...

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As a whole species, perhaps not.

 

However, individual and especially geographically isolated human societies can and will.

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I think i can rephrase. Can our species gradually become more fit as a whole? factoring in the usage of all these gizmos and gadgets to thwart what determines fitness in the first place...survival no longer weeds out the unfit and thus, I think we AREN'T going anywhere...

We still change!! Read mine and moleke's posts dangit.

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We still change!! Read mine and moleke's posts dangit.

 

I think some of us are speaking of macroevolution, while others such as yourself and Mokele are speaking about evolution--period.

 

I for one was speaking in terms of becoming a whole another species, one that would be no longer "interbreedable" with the current species. Just an assumption I made, I suppose I should have been clearer.

 

If we were debating about simple evolution, I would agree that we are indeed constantly changing.

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Thanks for clarifying. I agree then, individual humans are changing all the time, but there is no way a distinct species can branch off, impossible. Except maybe in the event of nuclear holocaust, but if that day comes, YOU guys go debate on the new evidence while I go steal food.

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yes, yes, and colonization of an isolated habitat.

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In order to encourage "speciation" you would need to seperate humans from the general breeding population. But if their diet, lifestyle, and other such factors remain similar the seperate humans would follow a generaly similar path of evolution and possibly remain basically the same as the general population outside of the quote "isolated habitat."

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Humans cannot be evoluting as there are too many in the population to get a complete change in the gene pool and everybody regardless of the fitness makes it to reproductive age.

 

Therefore' date=' does this mean that we are just waiting until another species catches up or are we now here for ever? without natural disease do you think humans could ever be competiting for food and shelter again?

 

In a million years will we have changed?[/quote']

 

well, its true that speciation usually occurs due to geographic (or another type) of isolation. However, it's possible that we are evolving on a very large scale, on a vastly long time period, so that we wouldn't notice it.

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In order to encourage "speciation" you would need to seperate humans from the general breeding population. But if their diet, lifestyle, and other such factors remain similar the seperate humans would follow a generaly similar path of evolution and possibly remain basically the same as the general population outside of the quote "isolated habitat."

 

necromancer.jpg

 

Necormancer has a supernatural ability to bring long-dead forum discussion threads back to life. After having been flogged to death the thread may have been deceased for many years, and bringing it back may have scant relevance to the current topic, yet Necromancer will unexpectedly exhume the thread’s rotting corpse, and strike horror in the forum as its grotesque form lurches into the discussion. The monster, instantly recognized by all who knew it in life, seems at first to breathe and have a pulse, but, alas, it is beyond Necromancer’s skill to fully restore the thread’s original vitality. The hideous apparition may frighten away some of the weaker Warriors or Warriors badly wounded in former battles, but the thread is only a shadow of its former self and very quickly expires.

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Especially with the increasing frequency of people being able to travel across the world, geographic location will have little to do with evolving humans differently, so as long as we all stay on Earth, I doubt any new human species will evolve seperatly from everyone else...

 

However, seeing as Extraterrestrial colonization is most likely in our future, a colony on another planet would very well evolve differently, because there will be on big difference, even if they get a nice cozy earth atmosphere to breath; the gravity would be different then Earths.

 

And different gravity's have an effect on most human functions and/or organs...

 

anyways, thats my input :)

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Evolution never stops. Just changes direction and speed.

 

Humans are probably not changing very quickly at present due to the fact that selection pressure has dropped. However, some changes are inevitable.

 

My favourite is the response to the fact that women now have control over their fertility. In many countries, replacement rates are now as low as 1.3 per couple. Many women are opting for no kids at all. However, there are some women who love kids and are opting for larger numbers. If the desire to have children is at all genetically based, the descendents of those women who want more kids will increase in number generation by generation, till eventually (in 1000 years??) the whole world will be descended from women who love lots of kids. What a population explosion we will see then!

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I often wonder how much technology may alter modern evolution.

In "The War of the Worlds" by H.G. Wells the Martians are described as having an ultra-simplified anatomy as they have evolved to have massive brains and are physically dependant on a variety of machines.

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