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Author | Topic: What is the origin of instictive behavior to care for our kin? | |||||||||||||||||||||||||||
Ragged Member (Idle past 3582 days) Posts: 47 From: Purgatory Joined: |
It is common knowledge that there is an instinct which drives parents to care for their young. From evolutionary standpoint it is explained by the fact that parents are trying to make sure that their genes survive in their offspring. This same reasoning can be used to explain why people care about their brothers and sisters and the rest of their kin.
Of course, if we were to ask a parent why they care for their child they would not say "because I am protecting my genes", rather they would say something along the lines of "What do you mean "why"? Its my baby and I love it!" So in this case, we are not motivated to behave in a certain way by evolutionary implications of our behavior, rather we are governed by an immediate instinct. From what I know that such a behavior would have to be genetic in nature, as opposed to being learned, much like eating when hungry. After all, a mother doesn't need to learn that caring for her child is the thing to do, she simply acts according to her instinct. My question is how did this instinct come to be? Was there a time in evolution, when organisms didn't have this instinct? Would an organism X number of years ago not have an instinct to protect its offspring? Was it that at one point a mutation occurred which made organisms care for their offspring and this behavior made the organism so overwhelmingly more successful at making sure its genes survive that it quickly muscled out all other organisms that didn't have this instinct? Or was this instinct present from the very beginning. Did the very first cell ever to reproduce have an instinct to protect its offspring?
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Admin Director Posts: 13044 From: EvC Forum Joined: Member Rating: 2.3 |
Thread copied here from the What is the origin of instictive behavior to care for our kin? thread in the Proposed New Topics forum.
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Dr Jack Member Posts: 3514 From: Immigrant in the land of Deutsch Joined: Member Rating: 8.3 |
Single celled organisms do not, in general, care for their offspring. Neither, in fact, do most multicellular organisms (seen a tree looking after a sapling recently?) or most animals (fish? tapeworms? coral? most turtles?). In fact, looking after your offspring is a strategy isolated to a relatively small proportion of living things. Those livings take a varying degree of care for their offspring: we support our offspring for getting on for two decades in many societies, whereas a seahorse male merely incubates the eggs until release.
Offspring carers evolved from non-offspring carers, first through by providing short term, mild care and later by more and more complex caring behaviour. Each change providing an incremental benefit to their fitness. Edited by Mr Jack, : No reason given.
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RAZD Member (Idle past 1435 days) Posts: 20714 From: the other end of the sidewalk Joined: |
Hi Mr Jack, Nice post.
Offspring carers evolved from non-offspring carers, first through by providing short term, mild care and later by more and more complex caring behaviour. Each change providing an incremental benefit to their fitness. I would think that it allows young to be born earlier, thus reducing the impact on the mother (ability to avoid predators etc), and reducing the impact of death of the mother on the continued living young (with others around to care for it), and finally that it would allow earlier sharing of responsibility of feeding young from just the mother to other individuals. Each of these would provide a small, but evolutionarily significant, increase in the ability of the mother and offspring to survive. Enjoy. by our ability to understand Rebel American Zen Deist ... to learn ... to think ... to live ... to laugh ... to share. • • • Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click) • • •
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Ragged Member (Idle past 3582 days) Posts: 47 From: Purgatory Joined: |
I would think that it allows young to be born earlier How is that?
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InGodITrust Member (Idle past 1699 days) Posts: 53 From: Reno, Nevada, USA Joined: |
I hope one of the scientists here will correct me if I'm wrong, but I believe it is not well understood by science how instincts are encoded in DNA. But some genetic mutation probably started this instinct.
It seems to me that the parental instincts would have had to evolved a number of seperate times, as opposed to just once in a distant common ancestor, like the instinct to flee in the face of danger might have. There are fish and insects that just dump eggs, and then there is a spider that carries its little ones on its back, and the fish that shelters its young in its mouth. Of course mammals suckle their young, and most birds feed their young. I guess I should note that I'm trying to understand evolution, but my true belief is that God gave this instinct. Edited by InGodITrust, : No reason given. Edited by InGodITrust, : No reason given. Edited by InGodITrust, : No reason given. Edited by InGodITrust, : No reason given. Edited by InGodITrust, : No reason given.
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RAZD Member (Idle past 1435 days) Posts: 20714 From: the other end of the sidewalk Joined: |
Hi Ragged, long time no see.
How is that? Precociality and altriciality - Wikipedia
quote: Without care these young would die, because they are not developed enough to be precocial, this level of development occurs after birth while under care of parents\group. Taking an extreme example, in humans this allows the birth of the child while the brain is still small enough to fit through the birth canal. http://www.springerlink.com/content/g183503303307587/
quote: Note that the skull bones are nearly fully developed but deform during birth to pass the canal and the sutures that bind the pieces in place form after birth: http://www.landofskulls.com/site/1534698/page/893371
quote: The brain then grows to fill out the skull. Notice how this ties in to the source that says a human child is able to take care of itself at 8 to 11 years of age. http://www.genefaith.org/...bases/resources/humdevchart.html
quote: Enjoy. by our ability to understand Rebel American Zen Deist ... to learn ... to think ... to live ... to laugh ... to share. • • • Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click) • • •
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Modulous Member Posts: 7801 From: Manchester, UK Joined: |
I hope one of the scientists here will correct me if I'm wrong, but I believe it is not well understood by science how instincts are encoded in DNA. But some genetic mutation probably started this instinct. Well, you are nearly right. The brain is the centre of instincts and brain development is encoded for in DNA. It could be understood better, of course, which is why scientists are still trying to research ethology/genetics.
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Richard Townsend Member (Idle past 4762 days) Posts: 103 From: London, England Joined: |
quote: Also allows mother to produce fewer offspring as parents give greater protection from predators.
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Dr Jack Member Posts: 3514 From: Immigrant in the land of Deutsch Joined: Member Rating: 8.3 |
I would think that it allows young to be born earlier, thus reducing the impact on the mother (ability to avoid predators etc), and reducing the impact of death of the mother on the continued living young (with others around to care for it), and finally that it would allow earlier sharing of responsibility of feeding young from just the mother to other individuals. I don't think that's true. The many species that scatter their young to the currents generally produce very, very small undeveloped young that are highly disposable. In fact, if anything, the opposite is true: cared for young represent a much larger investment of energy than scattered young. The two approaches are referred to as K- and r- strategies, but I can't remember right now which is which. I shall look it up tomorrow.
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RAZD Member (Idle past 1435 days) Posts: 20714 From: the other end of the sidewalk Joined: |
Hi Mr Jack,
The many species that scatter their young to the currents generally produce very, very small undeveloped young that are highly disposable. Yes, but these young are still capable of living on their own - they are still "precocial" in that regard (if the word can be applied to larvae), and - it seems to me - the grown organisms are generally smaller than those that do care for their young, even minimally. I was thinking more of the contrast between minimal care precocial animals and maximal care altricial animals, rather than in general to all organisms, where the altricial species are generally less developed than the similar precocial species. Precociality and altriciality - Wikipedia
quote: Many precocial birds get minimal care from parents, similar to crocodiles, turtles, snakes and lizards
In fact, if anything, the opposite is true: cared for young represent a much larger investment of energy than scattered young. We also see precocial animals that are large investments of energy, and which receive minimal, if any, care after birth, so it's not a strict linear relationship, more of a scattered one. Perhaps Edited by RAZD, : splink by our ability to understand Rebel American Zen Deist ... to learn ... to think ... to live ... to laugh ... to share. • • • Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click) • • •
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Ragged Member (Idle past 3582 days) Posts: 47 From: Purgatory Joined: |
Hi RAZD,
That makes sense. Its like, the time that organs complete their development after birth decrease the time that has to be spent in the womb, which allows offspring to be born sooner. And its allowed by the fact that parents takes care of their children for some time after birth. Sound about right?
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Ragged Member (Idle past 3582 days) Posts: 47 From: Purgatory Joined: |
It seems that animals that don't have the luxury (or rather the capacity) to lay thousands of eggs over their lifetime and hope for some of the them to survive due to luck, need to make sure that most of their eggs survive to become self supporting organisms. Because larger animals usually don't produce as many fertilized eggs they have to make as many of the count as they can. They have all their eggs in one basket so to speak. Which is why they care for their young.
Not to say that there are no counter-examples to this principle. (which there probably are)
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Dr Jack Member Posts: 3514 From: Immigrant in the land of Deutsch Joined: Member Rating: 8.3 |
Yes, but these young are still capable of living on their own - they are still "precocial" in that regard (if the word can be applied to larvae), and - it seems to me - the grown organisms are generally smaller than those that do care for their young, even minimally. Isn't that a change of position from your first post? I think if you plotted them both graphically, you'd determine that the very largest animals do, indeed, care for their young (see, blue whales) and the very smallest do not. This part of the pattern makes sense, it's much more difficult for a microscopic organism to effectively care for young both in terms of the advantage it can give, and the requisite behavioual repetoire to provide that care. Conversely, if you want to be very, very large it's going to be easier to get part way there, right? But in the middle there would be a huge spread of animals in which no clear pattern occurs. There are certainly plenty of large animals that do not care for their young, and small animals that do. So it seems to me that you've identified the wrong key characteristic here. Organisms which do not care for their young can produce more of them, usually massively more. If the environment allows it these organisms can massively increase their numbers in a very short time (these are r-strategists), meaning they can take advantage of highly variable environments. These environments* select for fast-growing, short lived, small body sized, early breeding, semelparous (i.e. organisms that breed only once) organisms that produce large broods. In contrast we have K-strategists. K-strategists aim to maximise their eventual population size. They cannot increase their populations so quickly, but their young are much more likely to survive and prosper. There are found in stable environments*, which select for slow-growing, large body size, late breeding, iteroparous (i.e. breeding multiple times), long lived organisms. These are also the organisms that will tend to provide maternal care. The chapter on 'Principles of Population Ecology' in Pianka's Evolutionary Ecology covers K- and r- strategists pretty well. * - w.r.t. K- and r- strategists, the environment should not be considered just as the environment in a single area. Many r-strategists also act as early colonists of new areas, whether fresh lava flows, where a tree has fallen in a forest, or whereever.
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caffeine Member (Idle past 1054 days) Posts: 1800 From: Prague, Czech Republic Joined: |
The easy way to remember the difference is alliteration (at least phonetically:
K = qualityr = rate
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