Evolution and Penis Size

[Padawan787 Moderator ReservePEGym Hero Find all posts View Profile Close Padawan787]

Some people even did an experiment that involved putting pretend semen in a pretend vagina and then fucking it with various pretend penises attached to a crankshaft (hur hur, I said 'shaft!') - the penises were all the same size but had various differently shaped heads. The one that was shaped like a read penis successfully scooped out most of the 'semen', while the one that had a plain round knob on the end was pretty useless and left most of the 'semen' where it was.

So there you go. Pretty interesting, I thought.

That must have been a fun day at work

[Ivor Senior Member Find all posts View Profile Close Ivor]

I would love to have read their grant proposal...

[Dr. Jay92 Junior Member Find all posts View Profile Close Dr. Jay92]

Well for starters evolution is 4.6 billion years in the making. We represent the current state of it.

Ur theory's are very good.

Someone probably answered this already but, apes could've been given super strength thru natrual selection ect.. Because they climb trees all day and don't have to use their brains as much as humans.

Apes/humans although they do have surprisingly similar genetic code.

Although one crazy theory could be humans could've possibly been a result of a huge mutation in the brain in the ape gene pool that "human" just so happen to thrive more so than the Apes themselves.

Humans being smarter made it unnecessary for them to be expert tree climbers therefore apes kept there super strength and humans kept their super brains.

[Dr. Jay92 Junior Member Find all posts View Profile Close Dr. Jay92]

I think there COULD be more subtle dynamics going on. In fact the genetics could be effected as follows: stretching necks may create damage in some specimens perhaps leading to paralysis. Genes that protect against such injury, or preclude damage by providing a pre-made longer neck could dominate over generations.

Exactly just like big muscles and smarts are passed down thru genes.

Ex. If ur dad was born a skinny POS then worked out and gained a substantial amount of muscle. A part of ur dads brain is adjusting his genetic code, because his heart mmmo telling him that he needs that muscle for better chances of survival and therefore the passing on of his genes.

[Wolfemother Senior Member Find all posts View Profile Close Wolfemother]

Sounds like a cool job to me too....

That must have been a fun day at work

[Wolfemother Senior Member Find all posts View Profile Close Wolfemother]

Are penises getting bigger?

[Pegasus AdministratorPE Gym EditorPEGym Hero ☺ Admin of the Month Mar 2015 Find all posts View Profile Close Pegasus]

Are penises getting bigger?

Yes, pegym is here to make it happen.

[Ivor Senior Member Find all posts View Profile Close Ivor]

Exactly just like big muscles and smarts are passed down thru genes.

Ex. If ur dad was born a skinny POS then worked out and gained a substantial amount of muscle. A part of ur dads brain is adjusting his genetic code, because his heart mmmo telling him that he needs that muscle for better chances of survival and therefore the passing on of his genes.

Hahaha, um, no - that's not how evolution works at all. Genetic code does not get 'adjusted' during an individuals lifetime, it's fixed at the moment of conception and remains the same until we die. The genetic make-up of a *population* changes over time as some genes are preferentially selected and some are weeded out.

You're not *really* a doctor, are you?

Also, exactly how many babies are born massively ripped? No-one has lots of muscle mass without eating protein and exercising. It's just that some people have more of a genetic predisposition towards putting on muscle than others.

[Jm123 Senior Member Find all posts View Profile Close Jm123]

Genetic code does not get 'adjusted' during an individuals lifetime, it's fixed at the moment of conception and remains the same until we die. The genetic make-up of a *population* changes over time as some genes are preferentially selected and some are weeded out.

Not trying to argue, I am just using this as an opportunity to educate. Biology like many fields is continuously expanding and what was once thought of as a law is no longer that way.

Humans and chimpanzees are 99.9% similar in DNA code. However, the differences lie in the expression of the genome. Human's only actively use about 2% of our genome. The rest of our DNA use to be regarded as junk DNA or heterochromatin. A recent study has shown that while only 2% of our DNA is active, 80% maybe biochemically active; which means that the junk is not really junk. Again this is what I was eluding to when I was talking about epigenetics.

So your point is both valid and invalid. First, yes a persons DNA is the same throughout their lifetime unless a mutation occurs. However, a persons genetic code does get adjusted via methylation and heterochromatin adjustments throughout their lifetime. In addition theses adjustments may be passed down to the next generation. These adjustments affect the expression of genes, which in-turn affects the production of mRNA, which in-turn affects protein production, which finally affects the phenotype expression of a person's DNA.

Lastly, if your are interested embryology might shed some light on this. There is a term Ontogeny recapitulates phylogeny, and basically this means that we go through stages of looking like our evolutionary ancestors in utero.

[Ivor Senior Member Find all posts View Profile Close Ivor]

How does anything you've said make my point "invalid"? Yes, some genes are only expressed under certain circumstances or environmental influences, fine. But that doesn't alter the fact that an individual's DNA can't change over the course of a lifetime, which was my central point. The genes you were born with are the genes you'll pass on to any offspring you have, and that's that.

Also I'm pretty sure the recapitulation idea has been discarded for a long time now.

[Jm123 Senior Member Find all posts View Profile Close Jm123]

How does anything you've said make my point "invalid"? Yes, some genes are only expressed under certain circumstances or environmental influences, fine. But that doesn't alter the fact that an individual's DNA can't change over the course of a lifetime, which was my central point. The genes you were born with are the genes you'll pass on to any offspring you have, and that's that.

Also I'm pretty sure the recapitulation idea has been discarded for a long time now.

As I said I was attempting to educate. However, I can see you wish to argue, so be it. However, please reread your original post and subsequent post, and avoid the shifting argument. Look you are interchanging DNA and genes in a way that is utterly nonsensical. DNA and genes are not the same thing. That would be like saying a pile of metal is a Corvette. I have no doubt that you are intelligent, and educated. However, I am unaware of when you went through, biology, genetics, embryology, cellular biology, microbiology, evolutionary analysis, or any of the other biology curriculum that covers this topic. Things have changed, and they will continue to change at a very rapid pace.


What I say has no bearing on the fact that what you said is invalid, it is invalid. You said genetic code does not get adjusted, that is invalid. You said genetic code does not change, that is invalid. You said the genes you pass on to your kids are the genes you are born with, that is invalid.

There is no evolution without genes/DNA changing, and those changes have to occur in an individuals lifetime. If there is no evolution, we are all the same. A person does not evolve, but a person's genes/DNA will change. Here is a link to wiki that explains mutations Mutation - Wikipedia, the free encyclopedia

The recapitulation theory is not considered accurate. However Ontogeny recapitulates phylogeny is a term still frequently used, to mean that as we develop we go through stages that look like our ancestors.

[Ivor Senior Member Find all posts View Profile Close Ivor]

OK, sorry, that last post was a bit out of order. This is clearly your field, not mine. But I was mainly rebutting DrJay's claim, which was that an individual's brain can send out signals that change his DNA in some specific way, which is surely incorrect, right? If it was true, a short guy could become tall - or at least, produce tall children - just by wishing really, really hard that he was tall. It sounds Lamarckian, basically.

I think the exchange that just happened was a bit like a guy saying "the earth is flat", then me saying "no, it's round", and then you saying "no, actually it's an oblate spheroid". Fine, so the earth isn't exactly spherical, but it's more or less spherical, and certainly much closer to being spherical than it is to being flat.

[Jm123 Senior Member Find all posts View Profile Close Jm123]

OK, sorry, that last post was a bit out of order. This is clearly your field, not field. But I was mainly rebutting DrJay's claim, which was that an individual's brain can send out signals that change his DNA in some specific way, which is surely incorrect, right? If it was true, a short guy could become tall - or at least, produce tall children - just by wishing really, really hard that he was tall. It sounds Lamarckian, basically.

I think the exchange that just happened was a bit like a guy saying "the earth is flat", then me saying "no, it's round", and then you saying "no, actually it's an oblate spheroid". Fine, so the earth isn't exactly spherical, but it's more or less spherical, and certainly much closer to being spherical than it is to being flat.

It's all cool. Yes I would agree Drjay's claim was stretching reality. Stressors can change the expression of phenotype/proteins i.e. DNA transcription/translation; I am unaware of any non-abnormal process that affects DNA replication e.g. mutations, cancer, and other undesirable events. In addition (to add to your point), I am also unaware of any research that shows a beneficial application to humans concerning the above mentioned epigenetic exploits. I believe it will eventually come, but right now it is more science fiction than fact.

Lastly, yes that was about the gist of our discourse. However, I would like to point to something in your example. Our improved understanding of the earth's shape is a major factor in our development of the space program. Specifically, everyone launches their rockets as close to the geographical equator as plausible to take advantage of the earth's shape, and rotational speed. In the same vein, the above biological distinctions may enable plausible personal genetic manipulation.

[chris3721 Junior Member Find all posts View Profile Close chris3721]

Might be related;

I figured this could offer an empirical answer to the question, "Do women like big dicks?" Hint; it's due to evolution.

Penis size interacts with body shape and height to influence male attractiveness


Abstract

Compelling evidence from many animal taxa indicates that male genitalia are often under postcopulatory sexual selection for characteristics that increase a male’s relative fertilization success. There could, however, also be direct precopulatory female mate choice based on male genital traits. Before clothing, the nonretractable human penis would have been conspicuous to potential mates. This observation has generated suggestions that human penis size partly evolved because of female choice. Here we show, based upon female assessment of digitally projected life-size, computer-generated images, that penis size interacts with body shape and height to determine male sexual attractiveness. Positive linear selection was detected for penis size, but the marginal increase in attractiveness eventually declined with greater penis size (i.e., quadratic selection). Penis size had a stronger effect on attractiveness in taller men than in shorter men. There was a similar increase in the positive effect of penis size on attractiveness with a more masculine body shape (i.e., greater shoulder-to-hip ratio). Surprisingly, larger penis size and greater height had almost equivalent positive effects on male attractiveness. Our results support the hypothesis that female mate choice could have driven the evolution of larger penises in humans. More broadly, our results show that precopulatory sexual selection can play a role in the evolution of genital traits.

Here are some reports of this study in the media that goes into it in more detail than the abstract.

Rob Brooks: Penis Size May Be Driven By Women (Oh, and It Matters)

and

Penis Size Matters, Study Says - Australian Popular Science | Australian Popular Science

[CUSP82 Administrator Admin of the Month Dec 2014PEGym Hero Find all posts View Profile Close CUSP82]

If evolution preferred big dicks why aren't our dicks attached to our foreheads so that our female mate could choose and therefore all the guys with small dicks would be dead by now. Don't you all think that evolution has changed a bit since Darwin did his thing?