Life History Parameter: Sex ratio/Age of First Reproduction
June 6, 2005 at 4:38 pm #1092sole_05Participant
Some interesting issues that needs some input to clarify some of these evolutionary changes in human sex ratio and age of first reproduction. Here we go!
1. There is common concept that males in some human professions (e.g. deep sea divers, footballers) are more likely to father daughters than sons. Just wondering if there is an evolutionary explanation for why particular males may be more likely to have daughters? Can you think of a mechanism explanation of how this might happen?
2. Even for the earliest maturing species of animals and plants there is always a development phase before individuals are fully mature and able to reproduce. But why is it so rare for species to be born with fully reproductive organs ready to go?
3. Back to humans. Another common concept is that the age of maturity in humans has been declining over recent centuries. ie. humans are capable of reproducing at an earlier age now than they could three or four hundreds years ago. Any explanation on this, and what role of evolution in this change?
Would appreciate any thoughtful comments.
June 6, 2005 at 4:58 pm #23902JamesParticipant
Wouldn’t really be benficial to be able to reproduce immediately. The population would surely become overcrowded; the body wouldn’t be prepared to give birth; the likelyhood of survival for offspring is low enough without having to mate and give birth etc etc
Physical evolution over a few hunded years is not the answer, it’s more likely a social and behavioural change.
June 6, 2005 at 6:27 pm #23909
1. This is wrong. The probability is 50-50, the profession of the father has nothing to do with it. Think of it like this: a football player has a boy, he teaches his son footbal, happy family, end of story. He has a daughter, he will complain to everybody that he has a daughter. So, it is more likely that you hear about him having a daughter than a son–> that popular belief
2. This differs for r and k organisms. R organisms usually are closer to that situation than k organisms.
3. Like it was said, it is a matter of behaiviour. In USA, one out of 10 children has sex before the age of 13(i was stunned when i heard this!). Though I, as a 13 year-old, could have sex at this age 300 years ago, i was not permitted to. Since now we live in a more liberal society, girls, watch out! 😉
June 6, 2005 at 6:33 pm #23910
sex is an instinct. You can not stop it… 😉
June 6, 2005 at 6:40 pm #23912
Yeah, but sometimes we need to control our instincts. Fortunately, only sometimes 😀
By the way i am not 13. Am i am 16 and a half 😀
June 6, 2005 at 7:56 pm #23923mithParticipant
1.Football players might get hit in the nuts more than people in other professions. I dunno how that might affect sperm count though 😉
2.Probably requires too much energy. The parent would need to contribute extra energy to support the child and allow it to mature sexually, and the child would expend extra energy to keep the sexual organs functional. I’d think that the first priority is not sex, but survival.
3.Not sure about this. Wasn’t Juliet 13 and Romeo 15?
June 6, 2005 at 8:59 pm #23948
Hello… That wasn’t for real!! Shakespeare imagined it 😀 Anyway, it was simply an opinion
PS: you are probably right on the second one
June 7, 2005 at 6:16 pm #23986
At the age of 13 you can have sexual desire. Especially if u are a girl. And you know, the age of teenage can change.
June 8, 2005 at 8:17 pm #24086
I saw a boy on a talk-show who began his sexual life at the age of 9. That is twisted
June 9, 2005 at 6:05 pm #24132
9? with whom? I don’t think it is normal, Actually, I’m sure that it isn’t normal. 🙂
June 9, 2005 at 9:24 pm #24154
With a 12 year-old girl who had done it before and taught him
June 10, 2005 at 12:39 pm #24177har0bed1813Participant
that’s really sick… Half my friends are stil virgins, and they are mostly 16-20!
and I think it’s not just evolution, but mostly upbringing and culture.
June 10, 2005 at 3:56 pm #24203quote MrMistery:
teaching sex. 😀 sounds strange. I cannot imagine what the girl (actually the girl is youg too.) said to him.maybe she said: “I will give you some lollipops, if you do that.” 😛
And it is also strange that, a child at the age of 9 is sexually active!!! I felt myself very old. Hey guys, maybe it’s too late for us to have sex. 😆 Be careful, we might have an heart attack. 😛quote har0bed1813:
I agree. I know some people who are virgin, and their age is over 20. Being a virgin or not is just a choice. And of course culture plays an important role too.
June 10, 2005 at 9:00 pm #24234
An american pshycologist said that man acts on 3 principles:
1. pleasure principle- you do what you like
2. denying non-pleasure principle- you don’t do what you don’t like
3. heard principle- you do what others do
So if everybody around you is having sex you will also be tempted to do it. But being a virgin at the age of 20 is not a bad thing. If you ask me, waiting until the wedding night is a little romantic, although i do not intend to do it 😆 😆
By the way, Ozge, it’s “have sex”, not “make sex”. I am not obsessed with grammar but that something you should know 😉 General knlowledge 😉
June 10, 2005 at 10:47 pm #24271b_d_41501Participant
Have Sex. Make Love.
June 11, 2005 at 5:17 pm #24351quote MrMistery:
Thank you my grammer teachers. I edited it.. 🙂
June 13, 2005 at 9:30 am #244552810712Participant
for the time being i need to control my disers to make jokes on the background of this thread… 😥 and have to try to answer those qs asked . ❗
💡 If we get ans. of !st one , it will explain or help explain the effect of soma on germa , which may help to establish some more concepts in NEO-LAMARKISM…
So, we need to think guys…
October 13, 2005 at 12:24 pm #30881AntonytheParticipant
The reason that fathers of a certain profession like divers and footballers father more daughters is because of the lowered testoserone level they have.
October 13, 2005 at 6:59 pm #30905mithParticipant
Where are you referencing from?
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