Human Evolution

[SkepticLance]

Interesting relationship between the age at which a harmful gene shows its effect, and the speed at which natural selection removes it from the population.

 

Progeria is a disease that strikes young people (pre-puberty) and is lethal. The progeria mutation disappears within 2 to 3 generations.

 

Haemophilia may strike later, after puberty, and is removed after many more generations, up to 10.

 

Huntingtons usually strikes after the reproductive years are complete; that is ; in middle age. It is still selected against - probably by some version of the grandfather effect. However, it may take 50 to 100 generations to be selected out of the population.

 

There are other harmful genes that may be a major part of the cause of ageing. They have their effect only after the age at which a grandparent is useful to the survival of the grandchild. Such a harmful gene will NEVER be selected out of the population. Thus, these nasty genes accumulate in the population and ensure that no-one will live much over a century.

[Mr Skeptic]

IMO there is no such thing has a bad gene or a good gene they just become bad in a particular environment and when the environment changes the same gene which you called it has bad may not be bad at all.

 

That may be true for some, even most genes, but there are some that are just plain bad (those that cause death before birth, for example). Among those that are not fatal, or that are recessive, it is likely that the vast majority have some kind of advantage under some conditions. But there are definitely some that are bad with no redeeming qualities, but those are quickly weeded out.

 

Now a days I am hearing that some people wants to have a conscious selection so that they can eliminate bad genes and I am afraid that this conscious selection will never be able to design things as efficiently as natural selection and it may lead to extinction.

 

Yes, it is quite likely that humans would choose genes that are the best for the current environment, without accounting for their adaptive value under different circumstances. For example, the delta 32 mutation affects a component of the immune system, which makes carriers resistant or immune to Black Plague and AIDS, but I'd expect it reduces immune function in other circumstances (or it would have become very common). A major proportion of the distribution of genes involves how useful they have been in the past. On the other hand, it is unlikely that humans would completely eliminate a gene; we would keep samples and some people would refuse or be unable to afford such artificial selection.

 

Cultural evolution does'nt block biological evolution it just takes it in a different path and we are still evolving.

 

Definitely true.

 

The problem with humans is that they don't want to change they want the environment to adapt according to them. I think this is the time to change not only mentally but also biologically

 

That's why I'm a big proponent of genetic engineering. Evolution is too slow for my liking.

 

and the best way to get prepared for the changing environment is to have reproductive success so go on and produce as many offsprings as you can and one thing don't take too much burden and I think we need to take chances very seriously in a world were everything works by chance.

 

Um, no. Increasing the population past the point it can support itself will just cause population collapse, probably with a loss of genetic diversity.

[thedarkshade]

So why so concerned about global warming then?

Huh? Devastating consequences, that means loss of lives. The concern is related to the "fight for survival". There is nothing special about this either.

[ParanoiA]

If one person says "I value all human life" and another person replies with "what's so special about human life?" - then I have to examine that question in the context in which it was asked. Why would anyone be so concerned about global warming if our lives aren't special enough to be valued?

 

This is not my opinion. My opinion is that human life is incredibly special. I'm not into this whole self loathing "humans are parasites" kind of pop culture belief system. And I'm fascinated by those who are. I don't know if that's what YDOAPS believes or not, which is why I'm asking.

[ydoaPs]

ParanoiA, species membership is not morally relevant.

[ParanoiA]

So an ant is as valuable as a human?

[iNow]

Define value.

[ydoaPs]

So an ant is as valuable as a human?

 

Which ant? Which human?

[Mr Skeptic]

So an ant is as valuable as a human?

Which ant? Which human?

 

Go to the ant, you sluggard; consider its ways and be wise! It has no commander, no overseer or ruler, yet it stores its provisions in summer and gathers its food at harvest. Proverbs 6:6-8

 

I can definitely think of some humans that are less valuable than ants. They are, after all, an important garbage disposal system.

[SkepticLance]

Ultinately a value system is subjective, and cannot be justified using strict objective criteria. Asking for such is a waste of everyone's time.

 

I am subjectively rather fond of the species Homo sapiens. My value system puts human life right up there, and I make no apology. I do not need to justify it. According to my subjective value system, a human life is worth more than a billion ants.

[ParanoiA]

I can't say it any better than that SkepticLance. I think most who claim otherwise would still choose a human life over an ant if forced to at gun point in some disturbing scene in 'Saw VII'. No matter "which" ant.

[ydoaPs]

So, a self-aware ant with emotions and the capacity to suffer is more valuable than a human with no brain who is only alive due to mechanical aid?

[SkepticLance]

To yourdad

 

We all have our own way of defining humanity. To me, it is based on mentality. This is why I have no strong anti-abortion views. The fetus being aborted has very little brain and hence very little humanity. In the same way, a baby which is born suffering from anencephaly is really little more than a lump of meat with no humanity.

 

For those who do not know; anencephaly is a neural tube defect in which the bulk of the brain never develops. The baby is born with limited hind brain - enough to keep the heart beating for a short time, but no part of the brain that leads to intelligence, self-awareness etc.

 

However, any person with a brain, and with consciousness, must be considered by my code of values to be worth saving. As a basic rule of thumb, if a person can communicate and respond to other peoples communications in an intelligent manner, he or she must be considered human and his/her life of great value.

[ydoaPs]

Human!=person.

 

There are people who are not human and there are humans who are not people. As I said before, species membership(whether or not something is a human) is not morally relevant.

[PhDP]

As humans, we all feel that human life is more valuable. Just as we tend to care more about species close to us. However, we have to be lucid, it's purely subjective.

 

BTW, I do think that species membership is morally relevant. As much as I find sexism and racism disgusting, I do embrace speciesm (at least to a certain extant).

[ydoaPs]

So, if an anencephalic human and a healthy chimp were both it mortal trouble, and you could only save one, you'd save the human simply because it's human?

 

When does humanity cease to be human? How many generations back(or forward)?

You stand on the shore of the Indian Ocean in southern Somalia' date=' facing north, and in your left hand you hold the right hand of your mother. In turn she holds the hand of her mother, your grandmother. Your grandmother holds her hand, and so on. The chain wends its way up the beach, into the arid scrubland and westwards on towards the Kenya border.

 

How far do we have to go until we reach our common ancestor with the chimpanzees? It's a surprisingly short way. Allowing one yard per person, we arrive at the ancestor we share with the chimpanzees in under 300 miles. We've hardly started to cross the continent; we're still not half way to the great Rift Valley. The ancestor is standing well to the east of Mount Kenya, and holing her hand an entire chain of her lineal descendants, culminating in your standing on the Somali beach.

 

The daughter that she is holing in her right hand is the one from whom we are descended. Now the arch-ancestress turns eastward to face the coast, and with her left hand grasps the other daughter, the one from whom the chimpanzees are descended (or son, of course, but let's stick with females for convenience). The two sisters are facing one another, and each holding their mother by the hand. Now the second daughter, the chimpanzee ancestress, holds her daughter's hand, and a new chain is formed, proceeding back towards the coast. First cousin faces first cousin, second cousin faces second cousin, and so on. By the time the folded-back chain has reached the coast again, it consists of modern chimpanzees. You are face to face with your chimpanzee cousin, and you are joined to her by an unbroken chain of mothers holding the hands of their daughters. ... Daughters would resemble their mothers as much (or as little) as they always do. Mothers would love their daughters, and feel affinity for them as they always do.[/quote']

[Mr Skeptic]

Human!=person.

 

There are people who are not human and there are humans who are not people. As I said before, species membership(whether or not something is a human) is not morally relevant.

 

While technically true, we're still quite a ways from genetically engineered non-human people or artificially created non-biological people. I'd not consider any animal other than Homo to be a person, though they can definitely be sentient and empathic and somewhat intelligent.

 

On the other hand, humans who wouldn't qualify as a person are much easier to find. All the ones that are missing their brain (literally), for example.

 

Um, for my purposes, I would consider any entity capable of generalized, abstract thought and some degree of empathy, to be a person.

[ydoaPs]

I'm a fan of Peter Singer:

An Unusual Institution

In the Netherlands' date=' a few years ago, an observer reported on the lives of some people confined in a new kind of institution. These people had a special condition that did not handicap them at all physically, but intellectually they were well below the normal human level; they could not speak, although they made noises and gestures. In the institutions in which such people were usually kept, they tended to spend much of their time making repetitive movements, and rocking their bodies to and fro. This institution was an unusual one, in that its policy was to allow the inmates the maximum possible freedom to live their own lives and form their own community. This freedom extended even to sexual relationships, which led to pregnancy, birth and child-rearing. The observer was interested in finding out how people without language would behave under these conditions.

 

The behaviour of the inmates was far more varied than in the more conventional institutional settings. They rarely spent time alone, and they appeared to have no difficulty in understanding each other's gestures and vocalisations. They were physically active, spending a lot of time outside, where they had access to about two acres of relatively natural forest, surrounded by a wall. They co-operated in many activities, including on one occasion-to the consternation of the supervisors-an attempt to escape that involved carrying a large fallen branch to the wall, and propping it up as a kind of ladder that made it possible to climb to the other side.

 

The observer was particularly impressed by what he called the 'politics' of the community. A defined leader soon emerged. His leadership-and it was always a 'he'-depended, however, on the support of other members of the group. The leader had privileges, but also, it seemed, obligations. He had to cultivate the favour of others by sharing food and other treats. Fights would develop from time to time, but they would usually be followed by some conciliatory gestures, so that the loser could be readmitted into the society of the leader. If the leader became isolated, and allowed the others to form a coalition against him, his days at the op were numbered.

 

A simple ethical code could also be detected within the community. Its two basic rules, the observer commented, could be summed up as 'one good turn deserves another', and 'an eye for an eye and a tooth for a tooth'. The breach of the first of these rules apparently led to a sense of being wronged. On one occasion Henk was fighting with Jan, and Gert came to Jan's assistance. Later, Henk attacked Gert, who gestured to Jan for help, but Jan did nothing. After the fight between Gert and Henk was over, Gert furiously attacked Jan.

 

The mothers were with one exception competent at nursing and rearing their children. Then mother-child relationships were close, and lasted many years. The death of a baby led to prolonged grieving. Because sexual relationships were not monogamous, it was not always possible to tell who the father of the child was, and fathers did not play a significant role in the rearing of the children.

 

In view of the very limited mental capacities that these inmates had been credited with, the observer was impressed by instances of behaviour that clearly showed intelligent planning. In one example, two young mothers were having difficulty stopping their small children from fighting. An older mother, a considerable authority figure in the community, as dozing nearby. One of the younger mothers woke her, and pointed to the squabbling children. The older mother made the appropriate noises and gestures, and the children, suitably intimidated, stopped fighting. The older mother then went back to her nap.

 

In order to see just how far ahead these people could think, the observer devised an ingenious test of problem-solving ability. One inmate was presented with two series of five locked boxes made of clear plastic, each of which opened with a different, but readily identifiable, key. The keys were visible in the boxes One series of five boxes led to a food treat, whereas the other series led to an empty box. The key to the first box in each series lay beside it. It was necessary to begin by choosing one of these two initial boxes; and to end up with the treat, one had mentally to work through the five boxes to see which choice would lead to the box with the treat. The inmate was able to succeed in this complex task.

 

The inmates' own awareness of what they were doing was well shown by their extensive practice of deceit. On one occasion, after a fight, it was noticeable that the loser limped badly when in the presence of the victor, but not when alone. Presumably, by pretending to be more seriously hurt than he really was, he hoped for some kind of sympathy, or at least mercy, from his conqueror. But the most elaborate forms of deceit were concerned with-no surprise here for any observer of human behaviour-sexual relationships. Although monogamy was not practised, the leader tried to prevent others having sex with his favourites. To get around this, flirtations leading up to sexual intercourse were conducted with a good deal of discretion, so as not to attract the leader's attention.

 

I have described this community in some detail because I want to raise an ethical question about the way in which people with this condition were regarded by those who looked after them. In the eyes of their supervisors the inmates did not have the same kind of right to life as normal human beings. Though treated with care and consideration for their welfare, they were seen as clearly inferior, and their lives were accorded much less value than the lives of normal human beings. When one of them was killed, in the course of a dispute over who should be leader, the killing was not considered equivalent to the killing of a normal human being. Nor were they eligible for the same kind of medical attention that, throughout the Netherlands, was available for normal human beings. Moreover in the other institutions-not the one I have just described-people with this condition are deliberately infected with diseases such as hepatitis, in order to test the efficacy of experimental drugs or vaccines. In some cases they die as a result of the experiment.

 

How should we regard this situation? Is it moral outrage? Or is it ethically defensible, given the more limited intellectual capacities of these people?

 

Your answer to this question may vary according to the mental image you formed of the inmates of the community I have described. I referred to them as 'people'. In doing so I was using 'people' as the colloquial plural of 'person' and for that term I had in mind the definition offered by the seventeenth-century English philosopher John Locke: 'A thinking intelligent being that has reason and reflection and can consider itself itself, the same thinking thing, in different times and places'. But because the term 'person', like 'people', is commonly used only of members of the species Homo sapiens, my use of the term may have led you to think the community I was describing was made up of intellectually disabled human beings. My use of Dutch names probably reinforced that assumption. In that case, you probably also thought it very wrong that the lives of these people were accorded less value than those of normal human beings; and the mention of their use as experimental subjects very likely caused shock and a sense of outrage.

 

Perhaps some readers, however, were able to guess that I was not describing human beings at all. The 'special condition' that these people have is their membership of the species Pan troglodytes. They are a community of chimpanzees, living in Arnhem Zoo, not far from Amsterdam. If you guessed this, you may not have been so shocked that the supervisors thought the value of the lives of the inmates was markedly less than that of normal humans; perhaps you were not even disturbed by the use of the inmates in lethal experiments.

 

In all the cases I have discussed so far, the human nature of the life in question has set the whole framework of the ethical discussion. I began this chapter with a subterfuge to make each reader aware of the extent to which his or her attitudes vary according to whether it is a human or nonhuman being who is killed-even when the actual capacities of the being are known, though its species is not. Becoming aware of this is a first step towards a critical examination of another part of the foundations of our ethical attitudes to life and death. I have already noted the curious fact that the term 'pro-life' is used to describe people who oppose killing human fetuses but are quite happy to support the killing of calves, pigs and chickens. This is in itself powerful testimony to the extent to which the killing of any human beings, even fetal human beings, seems to us an overwhelmingly more important issue than the killing of nonhuman animals. But here, too, we shall find that the traditional ethic now looks decidedly shaky.[/quote']

[Mr Skeptic]

I'm a fan of Peter Singer:

 

A very good story, but it is based on deceit. In using the term people, he implies that they would at least potentially have been, or be in the future, capable of certain attributes, which it turns out that they don't have. A similar story could be written about, say, bees (it would have to replace the intelligence/planning portion with something else, such as storage of food in preparation for when there is none). It's definitely food for thought, though, especially for those who are very species biased.

 

---

 

Oh, check out this article about the origin of religion, where Maurice Bloch says that religion is a result of a unique human development of abstract or imaginary people and people groups, such as a god or a clan leader that you've never seen.

[ydoaPs]

Which requisite attributes are they missing?

[Mr Skeptic]

Which requisite attributes are they missing?

 

For religion, the ability to have imaginary friends (or abstract people). The same sort of attributes that allow us to accept and follow a leader that we have never seen. That seems to be what the article says anyhow.

[ydoaPs]

Unless you are suggesting religion is prerequisite for something to be a person, I think you misunderstood. I was replying to: "A very good story, but it is based on deceit. In using the term people, he implies that they would at least potentially have been, or be in the future, capable of certain attributes, which it turns out that they don't have."

 

I apologize for any misunderstanding.

[SkepticLance]

To yourdad

 

In reply to your post 41, I would definitely save the chimp. As I said earlier, an anencephalic is just a lump of meat with blood flowing through it. Not a human. It can only be a baby lump of meat, since anencephalics do not live long.

 

Chimps, as you pointed out, have many human characteristics. However, they are not human, so must be accorded, by my subjective system of values, less priority than a human - if that human has a normal functioning human brain.

 

So if the choice was to save a chimp or a tetraplegic human, then I would save the human.

[ydoaPs]

???

You're saying you choose based on the morally relevant properties(without coming out and saying it) and then you just say you're choosing because of the species. You're confusing me.

[SkepticLance]

To yourdad

 

My choice is based on brain power. A tetraplegic human is more a 'person' than a chimp because he/she has more brain power. A chimp is more a 'person' than an anencephalic for the same reason.

 

Where I would get into real trouble making a choice is deciding whether to save two bottlenose dolphins or one human. I simply do not know which has the most brain power, and hence is more deserving of saving. I would certainly allow a human to die to save a whole pod of those dolphins. You will note that the bottlenose dolphin is just about the only animal in our size range with a similar ratio of brain weight to body weight compared to humans, and is hence very likely to be close in sheer brain power.