This is a work in progress... please bear with me, come back and watch it grow? Send constructive suggestions?
What you see below might be seen as an outline for what will eventually be spread across multiple pages.
Some readers may be disappointed upon coming to this page to learn that sex is a very small part of the story of reproduction.
Many, many, many organisms reproduce in a remarkably simple manner. They are remarkably simple organisms... tiny "blobs" of life, too small to see without a microscope. They grow. When they get big, the split in two, and where you had one individual, you now have two. Simples! (That link will open a new tab or window with CompareTheMeerkat.com, a merely fun destination. Their tag line is "simples".)
Many macroscopic (big enough to see without a micro-scope) organisms also reproduce without sex. I have some stick insects which have been laying viable eggs (eggs which have hatched) for over 30 years... again, without sex. The fancy term is "parthenogenetically").
Even more common is reproduction, particularly in plants, by shoots, runners, cuttings, etc. People think plants are dull. Imagine (don't try this at home) chopping off your little finger, and hoping that it will grow into a new human. Not much chance. Chop a bit off many plants, pop it in water for a while, and you will soon have a new plant.
So... while sex isn't always involved, that doesn't mean that it is never involved.
But what is sex?
When an apple tree produces seeds, and those seeds grow into new apple trees, did you realize that is an example of reproduction by sex? It is!
Sadly, to keep this site from being banned by some schools, I'm not going to go into the question of human reproduction. Sorry, folks.
Anyway... reproduction in humans is quite boring, compared to the reproduction schemes of some organisms.
Consider butterflies. They come, as I suspect you know, from caterpillars. Now a young human is a bit different from an adult human, but not like a young butterfly is different from an adult butterfly. How cool is that?
Returning to sex for a moment. Again, humans are so dull. You're born a boy, you become a man; born a girl, you become a woman. In some fish, you can be born male (or female) but turn into an adult of the other sex. Luckily, we think their minds are too simple to find this confusing.
Have you ever asked yourself "Why does reproduction occur?"
And once you've asked that, you should ask why does it take many years in some species, but only hours in others.
There is an alternative, in theory. Suppose a new organism came along in which each individual lived forever!
There'd be no need for reproduction! If you could solve the "lives forever" bit.
Under "reproduction", to keep the Great Challenges list down to seven challenges, we are including growth and repair... two topics with fascinating aspects, which you should try to think of for yourself until I can find time to write about them....
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