"Do you know how long the average species lasts for?" the professor asked.
Her students looked at each other, unsure of what to say. Finally, one of them hazarded a guess. "About ten million years?"
The professor nodded. "Not bad," she said. "That is the maximum we know of for any mammal. However, the average for mammals is something like one million years from origination to extinction. And that means that there a lot of species that exist for less than one million years." The professor let that sink in for a minute before continuing with her lecture.
"Now, humans - what we would call humans, anyway - have been on this planet for about a quarter of a million years. And if you count the earlier varieties of homo, then we have been around a lot longer. So, what is the obvious conclusion?" Once again, the professor focussed her attention on the students sat in front of her.
A hand was raised - by the same student that had answered her previous question. "That human beings could potentially go extinct any time in the near future?"
The professor smiled. This student would be worth encouraging. "For values of 'near' in terms of evolutionary time. But, yes."
The students turned to each other, and excited murmurs filled the lecture hall. The professor allowed the noise to rise for a minute or so, then raised her hand for silence. "Of course,' she said, "if humans were to become extinct, the losses would be significant. In the average time it would take another species to arise to replace us - let alone develop intelligence - our culture and any remnants of it would have long since vanished. But, it does not have to be this way.
"Human beings are intelligent. We are no longer subject to the whims of natural selection. Instead, we can design our own successors, and pass on our knowledge to them. In doing so, humanity is no longer a species with biological limitations. Instead, humanity becomes a meme, capable of being passed to whoever we define as human."
Once again, the student raised his hand. "But what if our successors don't want to be human? What if they want to develop their own culture, rather than adopt ours?"
"A very good question, Mister," the professor consulted her class register, "Mister Caine. We could always force them to learn our culture. Or we could make it beneficial, so that our chosen replacement would embrace it willingly."
"And what about us? What happens to our species?"
The professor knew the answer to this. "We will eventually die out and be replaced. Let us just hope that our replacements are kind to us in the meantime."
