Having humans in a world where nothing is the same

[Hananas59]

Is it acceptable to have humans in a world where no animal is identical to our world ?

That's just the big question I have right now. Do I have to create a whole new race, or is it acceptable that I just keep humans yet with different cultures?

 

[Jabrosky]

I would say it depends on how precisely divergent you want your world to be from the real one.

If your world's humans are also the product of evolution by natural selection, you might want to consider that they would probably have relatives running around which represent various offshoots of the same evolutionary trajectory. It would be odd for humans as we know them to evolve in a world without any other primates, mammals, or chordates whatsoever. The primates wouldn't necessarily have to be identical to our chimpanzees, colobus monkeys, or ring-tailed lemurs, but we would expect some form of primates in the planet's past that would represent human ancestors.

Of course, if your humans are alien colonists from another world, or if your world was specially created in its current form by some higher power, our world's evolutionary principles need not apply.

 

[Mythopoet]

If you're writing fantasy, yes. Fantasy is the genre that makes the impossible possible.

If you're writing sci fi, it depends on how seriously you want to be taken. If you're writing hard sci fi, you will want to avoid this. If you're writing space opera, sure why not?

 

[ThinkerX]

Sanderson did this, more or less, with his 'Stormlight Archive.' In that setting, creatures like horses and chickens are scarce. Weird shelled plants cling to canyon walls, draft animals resemble immense insects or ambulatory octopuses.

 

[Terry Greer]

Depends on how humans got there. If they are supposed to have evolved there or if they've been transported/created there by some means.

If they've evolved there - then what has happened to all the other species extinct or not that we share the planet with?
If they've just been transported then sure - they could be the only species from 'old earth'.

This applies equally to fantasy and science fiction.