Modern Day Selection Pressures.

[Psycho]

Throughout history many different selection pressures have changed organisms to be better adapted to their current environment, these have lead to different alleles being removed from the gene pool and other becoming far more prevalent within it. In the past many of these selection pressures were created by nature or the predator/prey relationship with the most successful organisms passing on their alleles and others perishing into history, due to the lack of competitiveness compare to other organisms.

 

However, in modern day human society things are far different with the environment being controlled through buildings and electricity and food supply being constant.

Also the idea of leader of the pack being pushed to one side for a more open society where the ideal would be there is a slice for everyone.

 

This will move the selection pressures away from what could be thought to be the classic pressures that are found within the animal kingdom to a more select few.

 

Of course the aspect of genetic embryonic engineering also plays a part but I would rather leave that to one side for this topic as for all intents and purposes we are meddling with a select few parts of a system as we don't really know what the out come will be if we did make more radical changes to try and make "better" offspring.

 

So my question to you is, what in your opinion do you think the strongest selection pressures are within the first world and how significant, if at all do you think selection pressures are in current human society?

 

Is diversity just going to increase due to interracial and continental partnership or are some alleles going to lose out in the long run.

[cameron marical]

i think that the stronger selection pressures for humans right now are probably any qualities that make them more sexually attractive at the time since they have a higher chance of reproduction. {only fit hot people in the future!yay!}

i think that its going to be a bit of both. i think diversity will definetly increase, and also some alleles are going to run out.{like blue eyes}

 

a little of topic

the human race is getting taller, anyone have any ideas why?

[GDG]

Keep in mind that when talking about evolution, "success" refers to how many decendents you manage to leave. Looking at current population trends, the leading alleles are probably those that promote fertility in the face of overcrowing and poverty.

[Psycho]

. Looking at current population trends, the leading alleles are probably those that promote fertility in the face of overcrowing and poverty.

Hence I specifically specified the first world.

[GDG]

Hence I specifically specified the first world.

 

Answer stands. I'm not as familiar with the situation in the UK, but in the US it seems that children are more likely to be born in overcrowded and/or impoverished areas. Birth rates are nearly always highest for poor immigrants.

[MM6]

i think diversity will definetly increase, and also some alleles are going to run out.{like blue eyes}

 

a little of topic

the human race is getting taller, anyone have any ideas why?

 

Why would blue eyes run out?

 

What evidence do you have of the human race getting taller? I'm familiar with increase in height in industrialized nations since their industrial revolution, but that's due to better sanitation and diet, not any difference in allele frequencies (unless you have data to the contrary).

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Consecutive posts merged

Resistance to pandemic infections (increasingly important)

 

Intelligence (IQ scores are increasing. Whether that will plateau, who knows?)

[Psycho]

Why would blue eyes run out?

 

What evidence do you have of the human race getting taller? I'm familiar with increase in height in industrialized nations since their industrial revolution, but that's due to better sanitation and diet, not any difference in allele frequencies (unless you have data to the contrary).

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Merged post follows:

Consecutive posts merged

Resistance to pandemic infections (increasingly important)

 

Intelligence (IQ scores are increasing. Whether that will plateau, who knows?)

The increase in height is due to better nutrition it is nothing to do with genetics it is happening way too fast for one thing.

 

I can't really see why intelligence would be a selection pressure, I wouldn't say having a high IQ means you have more offspring.

 

Resistance to pandemic infection maybe to an extent but it hasn't really occur within recent human history due to the creation of new pharmaceutical and I would think this would be the case if one ever did occur.

 

the leading alleles are probably those that promote fertility in the face of overcrowing and poverty.

Answer stands. I'm not as familiar with the situation in the UK, but in the US it seems that children are more likely to be born in overcrowded and/or impoverished areas. Birth rates are nearly always highest for poor immigrants.

To an extent I see your point but I would say it is far from the case in the UK that the majority of people live in overcrowded areas or in poverty.

 

Even so what alleles would cause fertility in those circumstances?

[lucaspa]

This will move the selection pressures away from what could be thought to be the classic pressures that are found within the animal kingdom to a more select few.

 

So my question to you is, what in your opinion do you think the strongest selection pressures are within the first world and how significant, if at all do you think selection pressures are in current human society?

 

You have the classic misconception that selection pressures apply to the entire population and that the entire large population must evolve. The vast majority of evolution has occurred in small, isolated populations facing a slightly different environment. Of course, modern transportation technology makes it difficult to have an isolated human population.

 

So, instead of looking at global selection pressures that would affect all 6 billion humans over the entire earth, look at small, relatively isolated populations of humans for the next evolutionary change. People have done this and it turns out the both Andean and Himalayan highlanders are showing adaptations to living at high altitude.

1. Hum Biol 2000 Feb;72(1):201-28: Tibetan and Andean patterns of adaptation to high-altitude hypoxia. Beall CM

2. Comp Biochem Physiol A Mol Integr Physiol 1999 Sep;124(1):1-17 Adaptation and conservation of physiological systems in the evolution of human hypoxia tolerance. Hochachka PW, Rupert JL, Monge C

3. Am J Phys Anthropol 1998;Suppl 27:25-64 Human adaptation to high altitude: regional and life-cycle perspectives. Moore LG, Niermeyer S, Zamudio S

 

The !Kung in Africa are showing unique alleles not present in other human populations:

1. Am J Trop Med Hyg 1994 Oct;51(4):460-5 Low prevalence of human T lymphotropic virus type I in !Kung San in Bushmanland, Namibia. Steele AD, Bos P, Joubert JJ, Evans AC, Joseph S, Tucker L, Aspinall S, Lecatsas G

2. Ann Hum Genet 1979 May;42(4):425-33 Red cell adenosine deaminase (ADA) polymorphism in Southern Africa, with special reference to ADA deficiency among the !Kung. Jenkins T, Lane AB, Nurse GT, Hopkinson DA

3. Am J Phys Anthropol 1988 Nov;77(3):303-19 Fitness and fertility among Kalahari !Kung. Pennington R, Harpending H

 

If you've ever seen the movie The Gods Must Be Crazy, you will see the beginnings of reproductive isolation between the !Kung and Europeans.

 

You might also do research on islanders in Melanesia, since they face a hot, tropical climate and have been reproductively isolated from other human populations for about 20,000 years.

[MM6]

Resistance to pandemic infection maybe to an extent but it hasn't really occur within recent human history due to the creation of new pharmaceutical and I would think this would be the case if one ever did occur.

 

Swine flu. HIV. Drug resistant TB.

 

I was thinking along the lines of a more aggressive anti-viral immune system (e.g., more aggressive natural killer cells), not particular to any one infection.

[cameron marical]

Why would blue eyes run out?

 

Ive read that blue eyes are a recessive allele, and are becoming less common as time progresses. Though they wouldnt fully run out due to the combination of recessive alleles can happen, but their supposedly running thin. At least thats what I read, I may be wrong though.

[GDG]

Ive read that blue eyes are a recessive allele, and are becoming less common as time progresses. Though they wouldnt fully run out due to the combination of recessive alleles can happen, but their supposedly running thin. At least thats what I read, I may be wrong though.

 

Although heavily outnumbered by brown eyes, as long as blue eyes are considered attractive to some, they will probably remain in the gene pool After all, attracting a mate is one of the clearest selection pressures.

[CharonY]

Actually recessive alleles generally stay in the pool even if they are selected against, due to the masking of the dominant alleles.