I have seen a few handfuls of subjects on Stack Exchange--Worldbuilding, Biology, Earth Science, Science Fiction & Fantasy and Astronomy. In relation, my question is this--can we create a Speculative Biology/Evolution Stack Exchange?
You know that you can propose new sites on area51, right? So if you want to have a new site, this is the place where you can really start it.
However, there have been some attempts at "what ifs" sites, which were so far all closed due to a too speculative nature. And biology.SE already exists.
You'll need a concept to explain why biology.SE and worldbuilding.SE aren't sufficient. And to show that you will get good questions and answer. Not only too broad ones (like the other what-ifs).
Luckily you don't have to do all of it alone :) If you want to discuss it in more details, I'd suggest joining the chat.