Xvito said:
]Most of my teachers may have been idiots, however this thread was my own doing and shouldn't really be blamed on them...
It was merely a thought.
Also, what makes you think that there weren't times when spiders didn't differentiate based on sex?
Hang on a tick! So you are saying that spiders at one stage did not have the instinct for reproduction? The most basic of all instincts? When you evolve from an organism that uses mitosis to reproduce (cells) you start making gametes through miosis, now these gametes must meet the oposite sex gametes, a spider will always have known that the ones standing over there are what his gametes must touch. This can be done through feromones, sight or behaviour. This is of course generalising that all creatures on the planet that use a distinct male/female reproduction technique, some still divide themselves and some are in fact both sexes rolled into one - although these are single celled.
Now its been a while since I did A level biology but that is basically how it works.
I've thought of a different way to answer your question; Times when spiders wouldn't have differentiate via sex would have been earlier down their evolutionary pathway and they wouldn't be called spiders as they would be a completely different species.