evolution in modern human society

Dak · January 29, 2006

is evolution 'happening' anymore? with the ability of humans to correct disadvantageouse alleles and generally lower the death rate to a level whereby most people, barring random events, get a chance to pass on their genes, is the human race evolving?

ed84c · January 29, 2006

imo, no it isnt. i think with all the hospitilisation we have these days and uncurable dieases such as Cancer occuring after reproductive age, i cant see how we could.

bascule · January 29, 2006

Well, beyond human memetic evolution, which is increasing at an exponential rate, and the recent evidence of an intelligence-improving gene circulating through the population, human skull shape was recently discovered to be changing to support increasing brain size:

http://news.bbc.co.uk/1/hi/sci/tech/4643312.stm

insane_alien · January 29, 2006

The selective pressures have changed dramatically since the introduction of civilisation but evolution is still happening both through genetic drift and selection(although selection is more about the current definition of "beauty" now than about what makes a good mother/father)

herpguy · January 29, 2006

I think we are probably losing our athletic abilility over time, and gaining intelligence. At my middle school, the presidential fitness scores are decreasing, and grades are increasing. this could also be because kids aren't as healthy and there are better ways of teaching. hmm...Maybe we can have about 1,000 middle schoolers take an IQ test now, and then again next year, and so on. The results may tell us what's happening.

abskebabs · January 29, 2006

Hi everybody:D !

There is still an ongoing debate in America between intelligent design and darwinian evolution. I think people supporting intelligent design fail to observe how life does not follow a preset plan[and why should it?] but adapts according to its enviroment. I know there are many other flaws in this theory, such as the fact it cannot be tested. However because it has such a poor opposing theory, I don't think many people are paying enough attention to the flaws in Darwinian evolution. I am referring specifically to the random nature of mutations. I have begun to start doubting this is true. I think I've gone on for too long already but I'd like to quote some sites where I received the information to support my current understanding of this[sorry if it's highly flawed I'm no expert on this].

http://www.surrey.ac.uk/qe/Outline.htm

Introduces the argument and has links to other sites.

http://www.emergentmind.org/gariaevI2.htm

http://www.emergentmind.org/gariaevI3.htm

These are research papers written by Russian scientists investigating the behaviour and purpose of the junk DNA.

You can also find out much more on this by typing "Gariaev" on google.

Dak · January 29, 2006

The selfish gene theory is a valid 'alternative' theory to darwinian evolution.

I didn't read the papers due to their inclusion of words such as 'quantumn phisics' (i dont get phisics), but as for junk dna, it would seem asif they may have some structural/functional purposes, for example introdusing bends into the chromosome, weakening the adhesion of the two strands (poly-pyrimidine repeats), forming hoogstein-bonds and thus allowing for self-anneling and so the formation of complex structures (eg, telomeres), so yeah junk dna seems asif it could be far from 'junk', even tho it doesnt code for protiens (hope that was relevant).

Both darwinian evolution and the selfish gene theroy can explain how the junk dna could evolve.

However, any darwinian evolution requires a limitation of resorses -- food, mates, etc -- and the fact that failure to acquire those resorses results in a decreased ability to reproduce.

Therefore, any inheritable trait -- read 'strech of dna', coding or otherwize -- that increases an organisms ability to get food, mates, etc, will increase the chances of the organism passing on that strech of dna, and so the advantageouse trait will propagate throughought the population at a rate that is proportional to its usefulness (slight over-simplification, but hey-ho).

My question is as follows:

In developed countries, very few people seem to be lacking in any resorse to the point that they cannot reproduce: very few people have so little food/money that it stops them from having childereen, and mates are found, reguardless of the traits of the individuals involved, including some otherwize pretty crippling traits -- i, for example, am extremely short-sighted, and im sure that i wouldnt be able to function and survive to reproduce if it werent for my contacts, the lack of predators, etc (very shortsighted).

With the lack of effective limitation on resorses, i don't see how darwinian evolution can work on humanity as a whole, although i realise that this is only really applicable to developed countries.

In other words, random mutation --(selection)--> evolution; is it possible that selection has been largely negated in modern society, thus turning evolution back into random change?

Dak · January 29, 2006

The selective pressures have changed dramatically since the introduction of civilisation but evolution is still happening both through genetic drift and selection(although selection is more about the current definition of "beauty" now than about what makes a good mother/father)

If the main selective pressures have been removed, and mate-selection were all that remains, would that result in a segregation of H. sap. sap into different sub-sub-sub species (as far as i can see, current mate-choice seems to be assortive)

PhDP · January 29, 2006

Hi Dak,

The selfish gene theory is a valid 'alternative' theory to darwinian evolution.

The selfish gene theory is not really an alternative theory, it's merely a slight modification on Neo-Darwinism, advocating that genes, not organisms, are the units of selection.

Both darwinian evolution and the selfish gene theroy can explain how the junk dna could evolve.

In fact, both "darwinian evolution" (selectionism) and the "selfish gene theory" are not very good to explain junk DNA. According to the selectionists, junk DNA is there because of its elevated rate of replication, it's a parasite called selfish DNA. The scientific name of that hypothesis intragenomic selectionist hypothesis. The neutralist hypothesis, on the other hand, say that junk DNA is carried passively because it's linked to functional genes, and as long as the cost for the organism to replicate this junk DNA is not too high, it will be passed from generations to generations. Those 2 hypothesis are probably true to some extant, but neither selfish gene theory or darwinian evolution can account for the evolution of junk DNA on their own, in fact, it took some time for traditional neo-Darwinists to accept junk DNA and neutral evolution.

In other words, random mutation --(selection)--> evolution; is it possible that selection has been largely negated in modern society, thus turning evolution back into random change?

Selection is not as strong, but it's still there. Also, in large populations, even weak selection can mean fixation/extinction for a gene.

Bluenoise · January 29, 2006

In fact, both "darwinian evolution" (selectionism) and the "selfish gene theory" are not very good to explain junk DNA. According to the selectionists, junk DNA is there because of its elevated rate of replication, it's a parasite called selfish DNA. The scientific name of that hypothesis intragenomic selectionist hypothesis. The neutralist hypothesis, on the other hand, say that junk DNA is carried passively because it's linked to functional genes, and as long as the cost for the organism to replicate this junk DNA is not too high, it will be passed from generations to generations. Those 2 hypothesis are probably true to some extant, but neither selfish gene theory or darwinian evolution can account for the evolution of junk DNA on their own, in fact, it took some time for traditional neo-Darwinists to accept junk DNA and neutral evolution.

Okay first of all "Junk DNA" is not junk entirley junk. This is a currently outdated term that was used to explain the existence of DNA that we could not assign a fixed function for due to our limited understand of genetics. Recent insights are showing that "junk DNA" has a strong regulatory role. It produces small amounts of small RNA's that are important in Gene regulation as well as it's general structure having an important regulatory aspect. Not to mention providing a way for genes to duplicate as well as a resevoir for new genes to arise from.

While the main force for the proliferation of these sequences may have been parasitic gene elements this does not mean that the sequences don't serve a purpose.

PhDP · January 29, 2006

Well, I didn't say all "Junk DNA" was useless, but at least some part of Junk DNA is indeed devoid of function and can be deleted without any discernable effect on the phenotype.

And if I remember correctly, Junk DNA was indeed a term used to explain useless DNA.

abskebabs · January 29, 2006

:embarass: I don't think I've fully explained to anyone why I think you should all have a look at this russian research I have mentioned. The reasons I was reluctant was that I feel I do not have enough knowledge of this to do it justice, and for fear of criticism. Basically I think they have found how another, completely different aspect of DNA, RNA and protein molecules affects living processes. This is that the DNA as a whole utilises the EM waves of light we are constantly exposed to; in order to communicate with other cells and organs of an organism. This communication is carried out by a method known as quantum teleportation[something to do with quantum entanglement]. This probably asounds like pseudo science, which is why I urge anyone to have a good look at this and tell me what you think much experimental work has also been carried out by them; and they have reached conclusions on the basis of this. To give you my frank opinion I think the implications of this are quite profound, and how much quantum principles apply in biology has long been underestimated. I'll list the websites I previously posted and a few more for anyone interested;) .