A more sensible discussion of Evolution.

[Tomtomkent]

I know this is being posted right beneath another almost identical topic, but I feel a new thread may be in order simply to cast away a lot of the misuse or misunderstood terminology.

So, before anybody whispers the name "Darwin," in this thread Evolution itself is defined as:

Evolution (also known as biological or organic evolution) is the change over time in the proportion of individual organisms differing in one or more inherited traits.

A trait is:
A trait is a particular characteristic—anatomical, biochemical or behavioural—that is the result of gene–environment interactions

And evolution is not to be confused with Abiogenesis:
In natural science, abiogenesis (pronounced /ˌeɪbaɪ.ɵˈdʒɛnɨsɪs/ AY-by-oh-JEN-ə-siss) or biopoesis is the study of how biological life arises from inorganic matter through natural processes, and the method by which life on Earth arose. Most amino acids, often called "the building blocks of life", can form via natural chemical reactions unrelated to life, as demonstrated in the Miller–Urey experiment and similar experiments that involved simulating some of the conditions of the early Earth in a laboratory.[1] In all living things, these amino acids are organized into proteins, and the construction of these proteins is mediated by nucleic acids, that are themselves synthesized through biochemical pathways catalysed by proteins. Which of these organic molecules first arose and how they formed the first life is the focus of abiogenesis

You will no doubt note that Evolution as a testable fact is entirely seperate from the Theory of Evolution which is the revising theory of how and why evolution has happened across millenia, as proposed famously by Darwin. In the "other" thread there was a continued insistence by one party that "Evolution" included abiogenesis, as well as related, but seperate, issues. I intend this discussion to avoid such unnecessery tail chasing by virtue of working to defined terms.

So when it coumes to sources of evidence, the term text book or course book should only refer to those that:
A textbook or coursebook (UK English) is a manual of instruction in any branch of study. Textbooks are produced according to the demands of educational institutions. So, if it is not endorsed by an examing board, even if it is a serious study, it is not a text book. It may be a Pop-Science book, or so forth. These are valid as references as long as they are not falsely represented.

Of more value, as always, are Research papers, Studies, and Peer Review articles. To be considered "Peer Review", the article is simply published in a recognised journal relevant to the field. These give ample oppertunity to other users to read the critiques and rebuttles, as well as any issues that may have been spotted in the methodology of the study, article, or paper.

The term theory, is used in the working sense:
A scientific theory comprises a collection of concepts, including abstractions of observable phenomena expressed as quantifiable properties, together with rules (called scientific laws) that express relationships between observations of such concepts. A scientific theory is constructed to conform to available empirical data about such observations, and is put forth as a principle or body of principles for explaining a class of phenomena.[1]

A scientific theory is a type of inductive theory, in that its content (i.e. empirical data) could be expressed within some formal system of logic whose elementary rules (i.e. scientific laws) are taken as axioms. In a deductive theory, any sentence which is a logical consequence of one or more of the axioms is also a sentence of that theory.
So all the usual expectations apply: It should be revisable to fit new data, be founded upon all available data, should not suffer confirmation bias, and should not be mistaken for the term as used in the common lexicon or fields of humanity. If it is in the stage of Hypothosis, before evidence has been gathered, this should be noted to avoid conclusion.

If these terms are agreeable, or if there are any further definitions that should be clarified before we begin, feel free to highlight them now at the top of the discussion.

[sphenisc]

Originally Posted by Tomtomkent

...Evolution (also known as biological or organic evolution) is the change over time in the proportion of individual organisms differing in one or more inherited traits.
...

By this definition there is no Evolution since the proportion is always 1 (at least since there has been more than one organism).

[Tomtomkent]

But do they differ in more than one inherited trait? (Thus moving the proportion significantly). Taking humanity as the easiest example, we can see traits are subtly different between generations, with slight varioations in features, because we are all slightly different and we recognise each other based on those variences. I do not look like my father of mother. Neither of those look like you. So there is a noticable rate of change.

[sphenisc]

Originally Posted by Tomtomkent

But do they differ in more than one inherited trait? (Thus moving the proportion significantly). Taking humanity as the easiest example, we can see traits are subtly different between generations, with slight varioations in features, because we are all slightly different and we recognise each other based on those variences. I do not look like my father of mother. Neither of those look like you. So there is a noticable rate of change.

Each individual human differs from at least one other individual human in at least one inherited trait. Therefore the proportion of humans which differ in one or more inherited traits is 1. This has been the case for all generations of humans and indeed all the way back to LUCA+1. Thus the proportion has not changed. So by your definition no evolution has occurred.

[Dinwar]

That's why I prefer the definition "a change in allele frequency within a population over time". It gets around that. Alleles, by definition, are different "versions" of a gene--the Mendellian A and a. Over time, the frequency of A and a change, thus causing evolution.

[sphenisc]

Originally Posted by Dinwar

That's why I prefer the definition "a change in allele frequency within a population over time". It gets around that. Alleles, by definition, are different "versions" of a gene--the Mendellian A and a. Over time, the frequency of A and a change, thus causing evolution.

Perhaps "satisfying the definition of" rather than "causing", but otherwise yes.

[Tomtomkent]

Then we use Dinwars definition. Fair enough.

[Tomtomkent]

So I thought we could kick off with a look at humanity. There are two broad theories of where ourgenetics are taking us. I lean towards genetic convergence where the skin colours, hair colours, eye colours and other traits normally associated with varying ethnic groups gradually get spread across andcarried by all of humanity pretty much indiscriminantly.

The polar opposite, which i think I probably discount on moral and ethical grounds because it stinks of a "then and us" attitude is that at some point humanity will split, to form one or moredistinctnew species. Morlocks and Enoi to use a fanciful example.

Which would appear more likely? How would we recognise it happening? What outside events (nuclear war, genetic modification, increased birth rates, what ever you want to discuss) would be needed todrive the process?

Hey, if this doesnt work we can try something else.

[sphenisc]

That depends on the time-scale you're talking about. If you're talking about the next few generations then it's quite likely that rapid long-distance transportation will partially undo the work of the last 50,000 years. n the longer term, however, if at some point the capacity to travel long distances was heavily reduced then diversification would recommence. Alternatively if distances got longer - e.g. through colonisation of other planets, then that might have a similar effect.

For other mammal species very few show anything like a global distribution, and of those most have got there as a result of human transportation. Remove that and speciation is the likely result.

[Dinwar]

I think that at one point humans could have diverged--the Americas were pretty much genetically isolated, as were the native people of most islands in the Pacific (though not as much as we usually think). Asia seems to be morphologically divergent from Europe as well, though I think that's more "circle species" than "genetic isolation". That said, we've pretty much mixed that up pretty well. There are certain groups that are voluntarily genetically isolating themselves, but enough people are breeding between races that I doubt there's sufficient genetic isolation to allow us to become separate species.

Well, those groups that are voluntarily isolate themselves might, if they survive (bottlenecks are rough on species), but the rest of us aren't going to diverge if we continue on this path.

As for recognition....The issue is, as usual, the definition of "species". Morphologically we're an increadibly diverse species, enough so that it's not unreasonable to think that paleontologist cockroaches in a million years or so will probably classify us as different species. And populations mating isn't an option--if they don't mate due to different mating rituals they don't mate, and they're different species. Well, some of those self-isolation groups don't mate outside the group. It's an open question.

[Tomtomkent]

Assuming that humanity is a single species with a limited number of morphological (think that is the rightword) varients I can see the ethnic groups becoming blurred at an increasing rate as increased traveland immigration, as well as the collapse of classical social barriers, allows for different groups to mix. I think we are heading for convergence not divergence in most cases.

[sphenisc]

Originally Posted by Tomtomkent

Assuming that humanity is a single species with a limited number of morphological (think that is the rightword) varients I can see the ethnic groups becoming blurred at an increasing rate as increased traveland immigration, as well as the collapse of classical social barriers, allows for different groups to mix. I think we are heading for convergence not divergence in most cases.

Over what time scale are you talking? That may well be true for the next one or hundred years but that not the timescale speciation's likely to occur on anyway. I don't think there's any reason to think that pattern will continue for the next 50-100 thousand years.

[Tomtomkent]

What time scale can be given? It is a reliant trend. As long as travel is becoming cheap and migration continues the rate at which ethnic groups become intertwined will accelerate. When one slows the other will slow.

[Dinwar]

Speciation tends to take about 10,000 generations. For a human, we can call a generation 20 years. That means that it would take about 200,000 years (or since hte mid/late Pleistocene) for a speciation event. It's not surprising we didn't fully diverge, and it would be very surprising to see any major divergences. My point with the self-isolating groups was simply to point out the unpredictable nature of evolution--you frequently get very, very weird events which more or less defy prediction. Or, to be more precise: Evolution is a chaotic process, which is HIGHLY sensitive to initial conditions and contingency (for a full argument see Gould's "Wonderful Life").

[Tomtomkent]

We can however see trends that our suggesting certain traits are becoming more common across the board, though that may be more to do with being able to recognise them these days. Specifically I have seen (admittedly dubious) reports claiming allergies are more common, or puberty is kicking in earlier and so forth.

[Dinwar]

I've seen a lot indicating that puberty is hitting earlier; however, I question whether this is evolution or something else. Specifically, we're eating better now than ever before, which may be triggering puberty earlier (we may have evolved to put off reproduction until times of relative plenty, within certain limits). That would not, by our definitions, be evolution, just aclimation.

What would interest me most is women giving birth later. That would, over time, increase human longevity (though in the short term we'd run all kinds of risks of genetic defects, which may increase our rate of evolution by itself).

[Tomtomkent]

The way of testing it would to do some kind of study and see if there was a correlation between background and puberty onset. If poor hungry people develope later than those with enough wealth to grant a more consistent diet, there may be something in it.

Or it could be that puberty setting on earlier, means more reproduction, means more kids with an early onset gene. (See interesting things happen in science).

[Tomtomkent]

So over in Skeptoid the Religion as a moral centre discussion rollson and Gregory from Alabama has made an interesting point with evolutionary ramifications. He has briefly discussed the biological reasons for what we would consider to be ethics and morals.

Although not I am not entirely convinced by his views, taking an evolutionary view there are some intersting connections that can be made. Assuming that emotions are just. Chemical reactions in our brain tissue, it would make sense for certain patterns to have evolved. If you see your kid being hurt it is putting your genetic heritage at risk, so you react accordingly. If your spouse is sharing his or her genetic material with somebody else you react accordingly to ensure it is your brood that prosepers and benefits over the usurper. What we try to hammer into a complex ethical framework may well have its roots in a series of reactions honed by evolution.

This may explain unusual reactions outside of ethics. Take for example the way a child will convince themselves that there is a monster under the bed or in the shadows. This could be a throwback to an evolutionary device that helped us survive in the wilds. If there are shadows and strange noises that might be a predator, you will survive longer if you assume it is a predator and react accordingly. Those who think "it is nothing" will roll over, go to sleep and fing themselves being nibbled by something with sabre teeth.

Is this worth a chat about here?

[Dinwar]

Probably, as I still have to convince you I'm right.

I've heard evolution used as an explination for why children are afraid of the dark before. In the Pleistocene a child who wasn't afraid of the dark (remember, a large number of predators are nocturnal, while humans are generally not) stood a good chance of being eaten. Of course, there was a ballance--if all the adults were afraid of the dark the tribe would get eaten (you need guards and the like).

Similarly, a lot of our views on what's cute are thanks to evolution. Large eyes, large head, pudgy arms, and the like, be they on dogs, cats, or babies, tend to trigger the "That's cute, I need to protect it" response in mammals (and not just humans). It's the reason "puppydog eyes" work so well.

The real question is, how far does this go?

[Tomtomkent]

It may not be the whole of the cause of modern ethics, or even psychology in general, but I thinkitmay strongly influence the most basic instincts; protect your family, close ranks against outsiders who may be a potential threat, etc. But it would also mean we have evolved our sentience and self awareness for a reason too, which allows us to contradict these instincts on ethical grounds.

I can see it being argued that our continuing trend towards tolerence is our genetics allowing for better mixing of geneticgroups to avoid stagnation of the gene pool, but that would be stretching the point to fantasy.

[Dinwar]

Well, my argument at Skeptoid wasn't that evolution programed our ethics into us--I don't believe it does (or, perhaps more accurately, I haven't seen anything I'd consider sufficient evidence to draw any conclusions on whether most ethical behaviors are driven by evolution). My point was that ethics, being the field of philosophy concerned with how one should behave (more or less), should be derived from the nature of the organism in question. In the case of humans, we should behave in a manner consistent with our nature. Humans can do some things and not others, thanks to evolved traits; similarly, humans interact with one another in some ways and not others. There are no biologically derived casts in humanity, for example--all casts are social (and, more importantly, political) constructs, not biological ones. Biologically we're all equal. Similarly, we all need to eat--we cannot photosynthesize, therefore we need to find food. Because we're all equal (biologically) adults cannot expect others to provide them food (children are a special case); therefore "Any who do not work, neither let them eat" is a good ethical guideline. That's the sort of thing I was going for.

This is in sharp contrast to, say, bees. A bee hive has distinct casts, from the workers to the queen to the drones, and the requirements of each cast are different, as are the rolls in a hive. The death of workers is not an issue of ethical importance; the death of a queen is murder. Once drones outlive their usefullness they're killed out-of-hand. The queen doesn't gather food, but is fed. And in a biologically necessitated cast system that's the way things SHOULD work.

[Tomtomkent]

Ah an interesting point I failed to understand. Though I hope my interpretation was at least of some interest or amusement now i realise it was utterly useless. But hey, if I thought I understood everything any conversation would be pointless.

[Dinwar]

I'd hardly say useless--evolutionary psychology is one of the more interesting fields, in that it's at the stage where there's not even really at the point where it has a standard paradigm. There's obvious evolutionary implications to psychology, but the question of untangling anotomical evolution (ie, genes) and psychological evolution (ie, memes) is one of the more difficult questions I've ever heard proposed.

[Tomtomkent]

It is very interesting as a take on nature vs nurture, though I do worry it sailsclose to ill advised ideas that certain groups of people are criminal/lustful/lazy etc because it is "in their blood".

[Dinwar]

There's also the eugenic aspect that's distastefull--if someone has greater odds of being a criminal that means that their offspring will as well, and it'd make society a better place to eliminate criminals...

On the flip side of that equation, it's obvious that certain traits ARE evolutionarily selected within our psychology (again, the cuteness thing is an example), and it's an interesting and important research topic to descern which are and which are not. I mean, the fact that some people find something distasteful shouldn't prevent us from researching in that area, right?

[Tomtomkent]

No, pretty much any science can be used in a distateful way. I think dictators of all kinds have proven that over the centuries. Despite the complaints of Charlie over on the Skeptoid page that human experience is an objective thing that happens to all of us, Genocide keeps cropping up in our history.It would be very nice that somewhere there is a big old notice board in a shared conciousness where humanity somehow decides what is good or evil based on "objective experiences" (no, I don't get how a subjective experience can be objective either) but clearly if it is happening not everybody gets the updates. Right now I want to point out that I don't just mean "there was a man called Hitler", because Genocide did not stop with the Nazis. If you believe it did, you really ought to go read up on Cambodia, DRC, and several Balkan States, then look back in the past at the likes of the Black prince and Pogroms. It seems that no matter how wellintentioned, or innocent seeming some of the data science gathers (often with the best intentions) there will be somebody out there willing to find a way to put it to distastefull use.

Now, the moral line we have to be careful placing is this: If we recognise that different ethnic groups do have differences in their genes, this may have medical implications. Sickle Cell disease, for example, or certain forms of cancer, are more common in some groups than others. By extension it could, possibly, have ramifications that directly effect the emotions and thus the personality of a person: Some groups, or even genders, may have subtle differences in the amounts of hormones they produce, or in neuron clusters, or the brain itself. I am not saying that is a "fact", but it is a possibility. Better understanding these differences could vastly aid medical research. But is it "right" to remind people there are differences knowing the information could be used to repeat some of the atrocities that can, and have, happened in living memory?

That is something of a tangent, that has little to do with evolution itself, but hey, it seems to be an intersting train of thought. If anybody is uncomfortable discussing it i am happy to get back on track any time. If not, go ahead...