Natural selection past the reproductive age

[John Connellan]

Nah I HAVE learnt some ecology already in my time.

An example would be a mother feeding her offspring milk. There is absolutely no net benefit to the individual here.

 

[paulsamuel]

Try reading Krebs and Davies, An Introduction to Behavioural Ecology, then get back to me.

Specifically, Chapters 11-14 in the second edition."

 

[paulsamuel]

An example would be a mother feeding her offspring milk. There is absolutely no net benefit to the individual here.

I'm not even going to embarass you by responding to that. I suggest you delete it.

 

[John Connellan]

I won't be embarassed please! Im sure u are quite an expert in this field so I want to hear your views!

 

[Buckaroo Banzai]

At least to me, all these altruistic stuff stays clear when you think about the genetic spread, forgetting momentarily individuals as any other thing than a tool for genetic spread....

 

[spuriousmonkey]

An example would be a mother feeding her offspring milk. There is absolutely no net benefit to the individual here.

This reminds me of the thoughts on the evolution of human fetus size.

For a fetus it is better if it is bigger when it is born.

For the mother there are more risks involved (for instance during pregnancy) when the fetus grows larger.

Both are in a 'struggle' to dominate their our interests. This results in a certain fetus size which is not necessarily optimal for the mother or the fetus.

 

[John Connellan]

At least to me, all these altruistic stuff stays clear when you think about the genetic spread, forgetting momentarily individuals as any other thing than a tool for genetic spread....

Exactly. That is all individuals are.

 

[spuriousmonkey]

I've seen grandparents slandering other peoples grandchildren in talent contests and the like. Once upon a time this instinct may have been focussed on more aggressive activities.

I wonder if anyone researched these agressive tendencies. Is this just an observation or is it a significant behavioural pattern?

 

[BigBlueHead]

John: If a mother is 50% related to her child genetically, then the "feed your child" allele would not be expressed as an altruistic trait, would it? Feeding your child would be helping your genetic material (some of it, anyway) to continue to survive.

Hence, altruistic acts in nature are difficult to find. That's why I had to resort to the pitcher plant example, which by the way I still cannot find a reference for.

EDIT: I mean TRUE altruism, that is, with no measurable benefit to the agent.

 

[paulsamuel]

In nature there are four types of altruism which all involve mutal benefits.

1) Inclusive fitness (aka kin selection).
2) mutualism
3) manipulation
4) reciprocity

AFAIK, there are no examples of altruism in the wild that do not fit into these four categories.

 

[Buckaroo Banzai]

John: If a mother is 50% related to her child genetically, then the "feed your child" allele would not be expressed as an altruistic trait, would it? Feeding your child would be helping your genetic material (some of it, anyway) to continue to survive.

Hence, altruistic acts in nature are difficult to find. That's why I had to resort to the pitcher plant example, which by the way I still cannot find a reference for.

EDIT: I mean TRUE altruism, that is, with no measurable benefit to the agent.

I think that there's no behavior that isn't genetically selfish... allways that something looks altruistic is somehow helping genes of relatives to pass (in the gene perspective, he's just helping himself to pass, no matter in which bodies he's in), and when isn't a relative being helped, it's increasing the agent's own fitness in a situation that he's likely to be repaid.

 

[John Connellan]

John: If a mother is 50% related to her child genetically, then the "feed your child" allele would not be expressed as an altruistic trait, would it?

Of course it is. There is no measurable benefit to the individual there.

Hence, altruistic acts in nature are difficult to find. That's why I had to resort to the pitcher plant example, which by the way I still cannot find a reference for.

Im afraid because of the selfishness of genes, altruistic effects are bountiful in nature.

EDIT: I mean TRUE altruism, that is, with no measurable benefit to the agent.

If u want to call an altruistic act which does not benefit the genes "true altruism" then go ahead. The actual definition involves the individual.

 

[John Connellan]

In nature there are four types of altruism which all involve mutal benefits.

1) Inclusive fitness (aka kin selection).
2) mutualism
3) manipulation
4) reciprocity

No. Kin selection does not bestow ANY benefits on an individual unless it includes reciprocity but u have mentioned that already.

 

[spuriousmonkey]

Nobody really went deeper into the matter than just stating 'altruism'.


a bit disappointing.

 

[paulsamuel]

No. Kin selection does not bestow ANY benefits on an individual unless it includes reciprocity but u have mentioned that already.

Your language is a bit imprecise.

Biological science contends that kin selection is a means by which apparent altruistic traits can evolve and be maintained in a population.

If you wish to take a position on kin selection and altruism in opposition to biological science, then you should probably state your opposition a bit more clearly and include examples from biological experiments.

Otherwise you sound a bit puerile.

If you wish to know why biological science contends this, then you should probably read the reference which I have provided.

 

[paulsamuel]

Nobody really went deeper into the matter than just stating 'altruism'.


a bit disappointing.

Well there is evidence that cetaceans will help individuals in their group who are beyond reproductive age. These older individuals have been observed aiding the rearing of young. The theory is that inclusive fitness allows these apparent altruistic traits to evolve.

There is also evidence that non-reproductive males in red-winged blackbird populations are tolerated in breeding males' territories for the same reason.

Is that better?

 

[John Connellan]

The theory is that inclusive fitness allows these apparent altruistic traits to evolve.

Why isn't it right to say that inclusive fitness allows these altruistic traits to evolve, rather than "apparent altruistic"? I've always been taught that Kin selection explained altruism

 

[BigBlueHead]

rather than "apparent altruistic"

Why are they apparently altruistic when you know about the selfish gene theory? Do you refer to a speeding Buick as "soft" because it has leather seats? I agree with spurious that we've got a failure of definition here.

We can pretty confidently assert that propagation of your genetic material is of benefit to you. Since inclusive fitness theorizes that helping your offspring and their offspring and so on, we can consider the propagation of your offspring's genetic material to be of benefit to you, and hence aiding this is not altruistic. Much as Dr. Lou says, it is not even apparently altruistic because everyone else knows exactly what you're doing.

A truly altruistic action would then be one that
1) Did not improve your personal fitness
2) Did not preferentially aid the transmission of your genetic material

In the sense of (2), an allele that coded for a truly altruistic would never become fixed in a population.

Examples of truly altruistic behaviour:
A) Suicide - since the increase in individual fitness for all of your conspecifics will be about equal, a suicidal gene that does not have some other inherent act (such as defending the hive) could be considered truly altruistic since it does not specifically aid your relatives.
B) Pathological behaviour caused by parasites - some parasites, such as everyone's favourite Leucochloridium snail parasite, can change the behaviour of their host. In the case of the aforementioned snail fluke, they make the snail seek out sunny places so that they can be eaten by birds. Now, this is a case where the parasite has evolved to take advantage of a weakness in the snail's physiology, but the snail's behaviour can still be considered altruistic by the criteria of (1) and (2).

 

[John Connellan]

Why are they apparently altruistic when you know about the selfish gene theory?

They aren't. They ARE altruistic. I think u mixed your sentence up!

Do you refer to a speeding Buick as "soft" because it has leather seats? I agree with spurious that we've got a failure of definition here.

I think its more a disagreement of definition

We can pretty confidently assert that propagation of your genetic material is of benefit to you.

I disagree.

Since inclusive fitness theorizes that helping your offspring and their offspring and so on, we can consider the propagation of your offspring's genetic material to be of benefit to you, and hence aiding this is not altruistic.

I disagree.

Much as Dr. Lou says, it is not even apparently altruistic because everyone else knows exactly what you're doing.

I'm sure only the human species knows about it

A truly altruistic action would then be one that
1) Did not improve your personal fitness

YES. And there are a lot of things in the wild which do not improve personal fitness and in fact lower it (altruism).

2) Did not preferentially aid the transmission of your genetic material

No, I'm afraid I don't believe this should be considered in the definition of altruism scientifically.

In the sense of (2), an allele that coded for a truly altruistic would never become fixed in a population.

Exactly so that definition of altruism should not exist.

 

[John Connellan]

Biological science contends that kin selection is a means by which apparent altruistic traits can evolve and be maintained in a population.

I disagree. I was taught that is a means by which ALTRUISTIC traits can evolve. The reason I am arguing it so much is because I feel it is a better definition.

If you wish to take a position on kin selection and altruism in opposition to biological science, then you should probably state your opposition a bit more clearly and include examples from biological experiments.

I have no idea what u are thinking here. Experiments? I am not opposing biological science as such (I think!)

Otherwise you sound a bit puerile.

What did I say that sounded puerile?

If you wish to know why biological science contends this, then you should probably read the reference which I have provided.

I'll have to get round to reading some text alright to find out what altruism really is nowadays!