Ray Comfort wrote
Why did hundreds of thousands of animals, fish, reptiles and birds (over millions of years) evolve a female partner (that coincidentally matured at just the right time) with each species?
Alright Ray, here's how it may well have happened.
The cellular organisms we started out as, like many today, would have been asexual but with the capability to exchange genes with others of their species. This is beneficial to survival: being able to exchange genes allows beneficial traits to spread throughout the population much faster.
Many generations later, this trait would have been amplified to the point where the creatures must exchange genes with another before reproduction. The exchange itself would also become a little more controlled so that the creature can 'choose' which creatures to exchange genes with. This isn't immediately beneficial to it's offspring, but is a neutral mutation. Later, when the creature develops behaviours which cause it to seek out strongor fertile members of it's own species, it becomes an extremely beneficial mutation.
At this point, creatures have both 'male' and 'female' reproductive systems. Keep in mind that these are still small gooey organisms, so it's not quite as weird as it sounds. It simply means that all creatures can lay eggs, and all creatures can fertilise others.
Now, this is inefficient. A creature needs not develop the fertilising organs in order to reproduce if it can lay eggs, and a creature need not lay eggs
if it can fertilise another. So the next step is specialisation: some members of the species become better at fertilising, others get better at producing eggs. Eventually, the one type becomes incapable of doing the other types job.
The end result? Sexual reproduction. Easy.
I hope this helps everyone understand the subject matter a little bit better, Ray.
Posted on Ray's blog.
PS: POST 997.