Evolution

[JonathanS2]

Inherent life in the fabric of reality sounds like just another way of trying to get God (or some similar metaphysical supreme being) into the equation? It's a bit of a circular argument - of course our reality supports life coming into existence, as if it didn't, we wouldn't be here to be talking about it. Maybe there are countless other universes in existence, in some way we can only conceive of in the most abstract sense, and maybe life is prevalent in all of them or maybe ours is the only one, but frankly that sort of thinking, though interesting in a hypothetical sense, is fruitless as there will never even be any evidence to support any theories let alone any proof.

As for humans continuing to evolve, I don't see much opportunity for the mechanisms of natural selection, that being what is required to turn natural variation/mutation into evolution, to act on humanity. In fact surely we're devolving, as more and more 'bad' genetic traits (bad eyesight for example) become prevalent as we have learnt how to deal with them and prevent them from stopping us from breeding and so passing them on.

And that ends my pseudo-scientific pretentious waffle for today. Oh, and hello, I'm new.

 

[MarkMark]

Oh, and hello, I'm new.

Hello!

 

[gurrier]

Inherent life in the fabric of reality sounds like just another way of trying to get God (or some similar metaphysical supreme being) into the equation? It's a bit of a circular argument - of course our reality supports life coming into existence, as if it didn't, we wouldn't be here to be talking about it. Maybe there are countless other universes in existence, in some way we can only conceive of in the most abstract sense, and maybe life is prevalent in all of them or maybe ours is the only one, but frankly that sort of thinking, though interesting in a hypothetical sense, is fruitless as there will never even be any evidence to support any theories let alone any proof.

As for humans continuing to evolve, I don't see much opportunity for the mechanisms of natural selection, that being what is required to turn natural variation/mutation into evolution, to act on humanity. In fact surely we're devolving, as more and more 'bad' genetic traits (bad eyesight for example) become prevalent as we have learnt how to deal with them and prevent them from stopping us from breeding and so passing them on.

And that ends my pseudo-scientific pretentious waffle for today. Oh, and hello, I'm new.

Welcome aboard!

About the devolving/evolving bit. Current understandings of natural selection suggest that evolution of a species only really occurs in certain circumstances. One of them is where you have a consistent selection pressure across the entire species (eg in evolutionary arms races between predator and prey - there can be a selection pressure to be faster which applies to all members of the species). Another is when a relatively small grouping of the species becomes isolated from the rest. You get what's called the 'founder effect' and you can get an intense localised selection pressure, for example if a particular type of food is disproportionately important in the environment of the isolated group. This is generally seen as the most plausible cause of speciation. Studies of the cichlid populations of the african great lakes seem to show that the optimal conditions for speciation are when there are isolated populations with rare cases of inter-population movement to provide new genetic material. In the right circumstances, you can get enormous numbers of species evolving in a few thousand years.

However, the current human population seems to be subject to too many different selection pressures and to have too much genetic intermingling for any net evolution to take place.

At least that's my understanding of it.

 

[TeeJay]

...that the process of evolution as not one of random, odd-defying fluke, but one of ineherent natural process.

I'm not sure that these things are mutually exclusive: don't atomic events (eg atomic decay) happened 'randomly' but are predictable overall/in aggregate (eg the halflife of an element)?

"Defying the odds" is slightly problematic since we only have one universe to look at, so we can't re-run the experiment again and again to see how many times something occurs.

I agree however that it is worth looking at pre-biotic processes and seeing if there "deeper processes" going on. It might be that scientists can recreate certain things in the lab or it might be that we find "life" on other planets or comets that has started out in a very different way to that on earth (eg non-carbon and non-water based for example).

I think that sometimes we project our own anxieties into science - needing to answer the question "are we unique and special" for example. It seems that whole popular science books are based 50% on angst and 50% on science. Actual research however typically seeks to measure, describe and model leaving the more metaphysical philosophy to one side (this is not to say that science is 'value free' or isn't based on its own 'philosophy').

 

[_pH_]

"When it comes, the apocalypse will be part of that process of evolution. Only now we're not going to sprout extra limbs and wings and things. By the very definition of apocalypse mankind will cease to exist, at least in a material form. But he'll evolve - into something that transcends matter: into a species of pure thought. Are you with me?"

Guess the film!

 

[ska invita]

I just had an interesting thought, let me see if i can make it clear:

- if the perfection we find in the living world is a process of evoluitionary adaptability (animals/life forms fitting in to their environment through the millions of years processes described by evolutionary theory), then what of the perfection we find in the supposedly "non-living" world?

What got me thinking was this:
"Imagine if the values of one or two of nature's fundamental constants were slightly different, say the strengths of forces that hold atoms together. One consequence might be that the Earth's oceans would regularly freeze. Water - essential for life - is unique in being lighter as a solid than as a liquid. So ice sheets float and form an insulating layer that stops the deeper waters freezing. If water was more conventional then the primordial oceans would never have stayed liquid for long enough for life to evolve. But then of course we would not be here to ponder our good fortune.
[...]
There are lots of other fine tunings. Carbon, also essential for life, is made in stars by the fusion of three helium atoms. It is only due to an extraordinary "coincidence" in the resonant energies of helium, beryllium and carbon that stars make lots of carbon. Change the resonant energy by just 0.0001% and no carbon."
http://www.guardian.co.uk/comment/story/0,3604,1568491,00.html

The article hints at God and other possibilities for resolving the coincidences.

-As a general speculative point, perhaps processes that at first glance seem random or the product of incredible coincidence occuring over time are "simply" hard-wired in someway into the very programming of the fabric of reality. Again, as with pre-biotic investigations, the value-tweaking excercise above maybe puts pressure on the evolutionary process as something occuring through excercises in probability. One point where this could be localised is in the "random" replications of genes.

As far as I am aware (when I asked on these boards before at least!) there is little known about the actual process of gene replication - other than it is thought to be random (Im sure they know a bit more than that!). Perhaps there is more order behind the replication of genes than meets the eye. Speculation...

 

[JonathanS2]

Coincidences happen. I once spent a month in New York. During that month I walked around exploring quite a lot, in the process of which I twice randomly bumped into people I knew. I know about 10 people in New York. Of course, most of the time, coincidences don't happen (or rather, noteworthy coincidences don't happen), but we don't notice when they don't happen.

So yes, we notice when the universe exists in such a way that coincidental aspects of its nature mean life can happen, because if they weren't we wouldn't be here to notice them, so who knows how many other universes there may be or have been where it would be impossible for life to happen, because noone would ever have been around to notice it. I see no reason to turn to divine beings to resolve coincidence ...

 

[Crispy]

What got me thinking was this:
"Imagine if the values of one or two of nature's fundamental constants were slightly different, say the strengths of forces that hold atoms together. One consequence might be that the Earth's oceans would regularly freeze. Water - essential for life - is unique in being lighter as a solid than as a liquid. So ice sheets float and form an insulating layer that stops the deeper waters freezing. If water was more conventional then the primordial oceans would never have stayed liquid for long enough for life to evolve. But then of course we would not be here to ponder our good fortune.

This is the Anthropic Principle. The universe appears to be tailor made for us and our brand of life. Of course, the reality is that only this sort of universe can have our sort of life in it to contemplate it. It's easy to imagine countless other universes out there that don't even manage stars, but just seethe away as a soup of incoherent matter and energy.

 

[parallelepipete]

Bollocks, too slow.

^^^^ What Crispy says, innit. ^^^^

 

[TremulousTetra]

Our brains are still evolving, scientists say:
The organ that has been most important in human
evolution is still evolving, and possibly getting
bigger, findings show.
http://www.world-science.net/othernews/050908_brainevolvefrm.htm

 

[nuffsaid]

I was under the impression that evolution only happens when you have certain external factors that will cause some individuals to survive better than others (purely becuase of slight mutations that happen by chance) so the less able individuals pass on their genes less and less until superceded by more successful ones and so can be deemed to have 'evolved'.

In current day society our genes are so similar and we have mastered the external world so completely that I don't think that any particular advantage can be gained by certain individuals, (and with freedom of travel we are levelling any possible advantage/disadvantage gained by living in a particular part of the world). If/when we start to meddle with our genes to have certain types of babies that's when evolution could really kick off again. This technology will be available firstly to the rich and they will have children who are better able to be more successful and eventually, if this carried on, we could end up like H.G.Wells' Time Machine future society where we become 2 distinct species. Pretty horrible really.

 

[TeeJay]

In current day society our genes are so similar and we have mastered the external world so completely that I don't think that any particular advantage can be gained by certain individuals, (and with freedom of travel we are levelling any possible advantage/disadvantage gained by living in a particular part of the world).

I wish this was true, but in fact a vast number of people are dying of diseases in Africa and elsewhere, and so any genes that confer better resistance to these diseases (for example malaria, HIV/AIDS, TB) may well be 'selected' over time due to a better chance of survival and/or longer life.

* More than 45 million people worldwide are infected with HIV, 95% of whom live in developing countries. In 2002, approximately five million people were newly infected with the virus. HIV/AIDS has killed more than 20 million people worldwide. 3.1 million people died of AIDS-related causes in 2002. AIDS is the leading cause of death in Africa and the fourth-leading cause of death worldwide.

* Tuberculosis kills about two million people each year, making it one of the world's leading infectious causes of death among young people and adults. One-third of the world's population is infected with TB. Five to 10 percent of people who are infected with TB become sick with TB at some time during their life. Each year, more than 8 million people become sick with TB. Due to a combination of economic decline, the breakdown of health systems, insufficient application of TB control measures, the spread of HIV/AIDS and the emergence of multidrug-resistant TB (MDR-TB), TB is on the rise in many developing and transitional economies. Between 2000 and 2020, it is estimated that nearly one billion people will be newly infected with TB, 200 million people will become sick from TB and that TB will claim at least 35 million lives.

* Malaria, one of the world's most common and serious tropical diseases, is a protozoal infection transmitted to humans by mosquitoes. Each year, malaria causes at least one million deaths and an additional 300 to 500 million clinical cases, the majority of which occur in the world's poorest countries. More than 41% of the world's population is at risk of acquiring malaria, and the proportion increases yearly due to deteriorating health systems, growing drug and insecticide resistance, climate change, and war. High-risk groups include children, pregnant women, travelers, refugees, displaced persons, and labourers entering endemic areas.

http://www.theglobalfund.org/en/

Edit: I also don't think that it is true that 'out genes are so similar'. Do you have any evidence that there is less genetic diversity within humans now than at earlier times?

 

[nuffsaid]

Edit: I also don't think that it is true that 'out genes are so similar'. Do you have any evidence that there is less genetic diversity within humans now than at earlier times?

I remember a documentary expalining the theory about a super volcano that went off hundreds of thousands of years ago that nearly exterminated humankind. The numbers that were left, apparently, were so small it means that genetically we are incredibly similar, to the point that we are very susceptible to epidemics. They likend this to putting human DNA through a filtration system that eradicated a lot of the variation that was present before this natural disaster.

Take your point about HIV and TB though, although surely we'll just discover how to wipe those out eventually. Wasn't there a statement the other day saying 7 years to HIV vaccine? While viral evolutions are on a much shorter time frame than evolution for larger lifeforms they aren't too far off the radar for the speed of human vaccine development I didn't think.

 

[Crispy]

I remember a documentary expalining the theory about a super volcano that went off hundreds of thousands of years ago that nearly exterminated humankind. The numbers that were left, apparently, were so small it means that genetically we are incredibly similar, to the point that we are very susceptible to epidemics. They likend this to putting human DNA through a filtration system that eradicated a lot of the variation that was present before this natural disaster.

I remember something like this. Because mitochondrial DNA is always passed down from mother to daughter, and they know the rough rate of change for mutations in that DNA, they reckon the entire human species can trace themselves back to a dozen or so women in Africa

 

[goldenecitrone]

My cousin was born with the ability to echo locate his pingu set. Does this count as evolution?

 

[spiralx]

I believe we are - look at the evolution of the gene for sickle-cell anaemia, which also conveys resistance to malaria and is prevalent in African people, but is less so amongst African-Americans who have no need for the malaria resistance and thus the gene is purely disadvantageous and is being bred out.

http://en.wikipedia.org/wiki/Sickle-cell_anemia

As I recall there are a couple of other examples of genes that certain populations have picked up over the last 100,000 years or so as well.

 

[Callie]

Take your point about HIV and TB though, although surely we'll just discover how to wipe those out eventually. Wasn't there a statement the other day saying 7 years to HIV vaccine? While viral evolutions are on a much shorter time frame than evolution for larger lifeforms they aren't too far off the radar for the speed of human vaccine development I didn't think.

Vaccines are based on the virus though - if the virus keeps changing and mutating as with HIV (of which there are also many different subtypes) it owuld be difficult to make a vaccine. Just think about how we need new flu vaccines every year because the virus keeps changing.