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Can you think of an evolutionary reason for this?

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Can you think of an evolutionary reason for this?

Postby immunogoblin » Sun Aug 26, 2012 4:43 pm

I'm reading an article on the growing rate of early puberty amongst girls, here's an excerpt:

"Girls who from an early age grow up in homes without their biological fathers are twice as likely to go into puberty younger as girls who grow up with both parents.Some studies show that the presence of a stepfather in the house also correlates with early puberty. Evidence links maternal depression with developing early. "
http://www.nytimes.com/2012/04/01/magaz ... ted=4&_r=4

Any thoughts on what the evolutionary advantage of this situation would be???

for the first one: the presence of a biological father would prevent early fertility simply because it might not actually lead to greater fitness (complications of young pregnancies). On the other hand that pressure has to balanced out with "letting the daughter out of the prepubescent nest" ...

how would this adaptation develop and how would it work...

puts a new spin on parent offspring conflict : P
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Postby possibilitymagazine » Fri Sep 14, 2012 11:54 am

Brilliant connection there bro!
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Postby vk4vfx » Fri Sep 28, 2012 11:35 am

I tried to click the link but took me to a log in page so couldn't really read what it is all about but sort of get the gist, it's a really interesting question and I think there is definitely some sort of link as I have noticed it but have absolutely no idea and can only guess.

As you probably know already to trigger sexual development hormones are released that are received by the pituitary gland this in turn triggers the rest, yes this is a hard one to answer I love these sort of questions as it gets you thinking and hopefully someone can answer it as I would like to know also.

All that I can think of is it would definitely be something to do with pheromones, really it was not that long ago scientists discovered VNO which are very tiny receptors in our noses, you have heard the term "the chemistry was right" between a couple it is the VNO that is responsible for that I cannot remember what it stands for now the O stands for "organ" veranonasal or something similar just google it, actually I am pretty sure I responded to a post on this forum that involved VNO or was that another biology forum? :)

Anyway without the presence of a male in the house the preteen would not be receiving male pheromones and that would have something to do with it for sure, it sort of reminds me in a way of women that are completely developed and they all live in the same house eventually they will all go into sync with ovulation and also their periods all at the same time, anyway that's another story.

Hope you find an answer immunogoblin as it is an interesting occurrence.
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Re: Can you think of an evolutionary reason for this?

Postby Cat » Fri Sep 28, 2012 3:12 pm

immunogoblin wrote:I'm reading an article on the growing rate of early puberty amongst girls, here's an excerpt:

"Girls who from an early age grow up in homes without their biological fathers are twice as likely to go into puberty younger as girls who grow up with both parents.Some studies show that the presence of a stepfather in the house also correlates with early puberty. Evidence links maternal depression with developing early. "
http://www.nytimes.com/2012/04/01/magaz ... ted=4&_r=4

Any thoughts on what the evolutionary advantage of this situation would be???

for the first one: the presence of a biological father would prevent early fertility simply because it might not actually lead to greater fitness (complications of young pregnancies). On the other hand that pressure has to balanced out with "letting the daughter out of the prepubescent nest" ...

how would this adaptation develop and how would it work...

puts a new spin on parent offspring conflict : P



This whole thing is nonsense. Study is correlation NOT cause and effect. I hate correlation studies done on humans as they are rarely done correctly and people reading them usually dismiss part of the information for greater effect. In the study mentioned, STRESS in the childhood correlates with early puberty. "Biological fathers” and "stepfathers" etc. are irrelevant.

From the same article (http://www.nytimes.com/2012/04/01/magaz ... ed=4&_r=5&):

"Bruce Ellis, a professor of Family Studies and Human Development at the University of Arizona, discovered along with his colleagues a pattern of early puberty in girls whose parents divorced when those girls were between 3 and 8 years old and whose fathers were considered socially deviant (meaning they abused drugs or alcohol, were violent, attempted suicide or did prison time)."


With this information you can correlate biological fathers' "socially deviant" behavior with early puberty which would be nonsense as well...
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Postby Rap » Fri Sep 28, 2012 9:08 pm

Even then, the correlation between stress and early puberty does not imply causation. A twin test might help. If you had two twins separated at birth, one raised in a low stress environment, the other in a high stress environment, and the high stress twin reached puberty significantly earlier, then you would begin to reasonably expect causation. If both twins reached puberty early , and then both went on to raise their children in high-stress environments, you would start to think maybe the situation was genetic rather than environmental.
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Postby Cat » Fri Sep 28, 2012 10:11 pm

Exactly, Rap. Not the kind of experiments you can actually perform due to ethical repercussions.
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Postby vk4vfx » Mon Oct 01, 2012 12:22 am

Yes it is only really a hypothesis but it is interesting, by the looks of it researchers are saying it is pheromone related, took me a while to find but I knew there would have to be something out there on the subject http://www.sciencedaily.com/releases/19 ... 064822.htm to me it all adds up and the pieces fall into place.
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Postby Rap » Mon Oct 01, 2012 2:44 pm

Yes, and its when all the pieces fall into place that you have to be careful, especially if it is a result that supports your value system, i.e makes you feel good, or puts money in your pocket.

If you are going to be truly scientific, you not only have to verify that the facts fit your theory, but that they falsify other theories. This is hard, because it might not make you feel good or might cost you money, and scientists are human. Einstein made that mistake when he introduced the cosmological constant into his cosmology. He "valued" a stationary universe which required the constant. When Hubble experimentally discovered "Hubbles law" - the increase of redshift of celestial objects with distance, Einstein abandoned it.

You have to "falsify" the genetic theory before accepting the environmental theory. Well, its not that cut and dried, but you have to show the relative influences of genetic and environmental factors before accepting the "its almost entirely environmental" theory. From what I can see, the scientists in the article you refer to have not done that.

Also, a good way to evaluate a theory is to see who the scientists who support it are being funded by. I have worked in the climatology field, and there is a process that occurs that is counter-scientific. If a scientist delivers results that indicate "no problem", their funders say "thank you very much, bye", but if the scientist delivers results that indicate "big problem" the funders throw money at them, saying "go for it". Its like going to the doctor, if the doctor says you are healthy as a horse, you go home and relax, if not, you ask for a second opinion. It's not a right-left problem, its a human nature problem.

The scientists who wrote the article you refer to were funded by the Eunice Kennedy Shriver National Institute of Child Health and Human Development. Look at their web page and ask yourself what would have happened if the researchers had come up with any other result? If the researchers had been funded by, oh, I don't know, the Institute for the Elimination of Genetic Defects, how long would their funding last after publishing this article?

Good science ain't easy, especially if you have an axe to grind or want to be rich and famous. Or even consistent.
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Re: Can you think of an evolutionary reason for this?

Postby vk4vfx » Mon Oct 01, 2012 9:42 pm

Gday Rap

Completely understand and very well explained/ written, yes correct it does not take much to apply for a research grant and be accepted. I have seen some absolutely ridiculous amounts paid out for the most ridiculous research and to top it of it was mostly pseudoscience anyway, but it did not stop the money pouring in.

Anyway, the whole topic is extremely interesting as there is definitely some link whether it be environmental or genetic, I am hanging my money on the pheromones theory as to me that is what adds up, it just amazes me at how many of these little hidden biological triggers are actually hardwired into us and as you say you hate correlation studies I agree they are not an accurate answer but they are a stepping stone in the right direction after all that is what science is, all about asking questions, getting results that usually lead to more questions.

This is not a question any scientist is going to have an answer for overnight but it is going to be interesting what results they come up with as I am not funding it they can take as long as they like and I am sure they will :) I say this bearing in mind your last paragraph :)

Regards
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