Originally posted by andy1033
What you just wrote is a good example to me why evolution did not happen to bring man from bacteria.
For creationists we were made by a creator. Can you imagine all the things that would have to go right for a male and female mammel to reproduce if it was left to evolution. There had to be a creator.
[edit on 7/20/2007 by andy1033]

Originally posted by djohnsto77
I've been perplexed by examples like this of complimentary parts in different stages of life or different sexes that work together great, but hard to imagine being evolved in tandem.

Other examples are the placenta and uterus in placental mammals, pouch in marsupials ready for barely developed babies, and many others.

Originally posted by Thousand
Two points I'd like to make:

1) Sexual reproduction has been around far longer than mammals, and is not a unique trait to us, and

2) There are organisms on the planet who have both sets of reproductive organs, as well as others who have the ability to change genders to meet reproductive "demand".

Originally posted by Chorlton

Originally posted by andy1033
What you just wrote is a good example to me why evolution did not happen to bring man from bacteria.
For creationists we were made by a creator. Can you imagine all the things that would have to go right for a male and female mammel to reproduce if it was left to evolution. There had to be a creator.
[edit on 7/20/2007 by andy1033]

Really? so you think someone sat down and designed humans, and butterflies and trees and ants rather than evolution and natural selection?

Sorry but no one is that good.

2) There are organisms on the planet who have both sets of reproductive organs, as well as others who have the ability to change genders to meet reproductive "demand".

2) There are organisms on the planet who have both sets of reproductive organs, as well as others who have the ability to change genders to meet reproductive "demand".

That in it self is not proof. We know there are different ways to reproduce, for me eventually man will go back to having one gender, through technology and evolution.

Ask yourself how can the reproductive process be so perfect(i know there sometimes are things wrong), and how males and females came into being. I suppose its the chicken and the egg.

Originally posted by Heronumber0
This may be the clue that I was looking for. However, we are still talking about Natural Selection here. There would have to be a selective advantage at each step of a mutation - even in a controller/regulator gene otherwise the idea flops. If there is no selective advantage to a penis developing if the female reproductive organ is not fully developed then the feature will be selected out!

Originally posted by andy1033
Ask yourself how can the reproductive process be so perfect(i know there sometimes are things wrong), and how males and females came into being. I suppose its the chicken and the egg.

Originally posted by Heronumber0
Firstly, how did the sperm evolve a protective mechanism (prostatic fluids etc..) against a place (the vagina) that it has never seen before- and develop an acrosome that helps to cut through the egg?

Originally posted by Heronumber0
Secondly, how did the penis and vagina evolve after the requisite millions of years of evolution and selection? How did the organs develop a gradual mechanism that would give a quarter vagina a selective advantage?

For example why would a half penis be more selectively advantageous than a quarter penis?

I suppose I am looking for possible mechanisms because it is a complete puzzle to me.

Interesting conversation to be sure. Allow me to interject again, by saying that there are species where only one gender possesses external reproductive organs, such as squid, and there are yet more species where the reproductive organs serve more than one purpose, such as certain types of spider.

Something else to think about.

Originally posted by TheCosmicSerpent

This seems easily understandable to me... before this evolution occurred, sperm had a much harder time making it to the inside of the egg, and therefore the conception/birth rate was much lower.

Then somewhere along the line, certain mutations occurred by chance which gave at least one individual organism's sperm the necessary prostatic fluids or acrosomes to stand a much better chance of fertilizing the egg. Because this organism was able to pass on these mutations to its offspring, the fertilization rates of all its descendants shot through the roof and eventually the rest of the population without the mutation became a minority and died out. I don't know if you're willing to accept the existence of these chance mutations, but thats what the whole concept of evolution is based on.

Well, if the scenario that madnessinmysoul suggested with the penis fencing is true, then that would explain the evolution of the vagina, and therefore two separate sexes. Organisms with some kind of mutation for a "receptor organ" aka vagina would have had a huge advantage in reproduction.

Originally posted by ingeniouslycorrupt
All the questions you have in your initial post about how these traits evolved are quite simple, just that at some point a mammal had a mutation or gene shuffling created something a little different, and that new trait was able to reproduce more and have a better chance of living. Seeing as we use our brains now to survive, our sexual organs haven't exactly evolved for many millenia.