There's no save/load function in-game, but I found a way to do it by changing the game's appdata files.
You can find the necessary files through the pathway C:\Users\[USERNAME]\AppData\LocalLow\OwenBellGames\Mendel
They're, of course, the XML files titled "IslandSave_[NUMBER]". The game will use whatever files are in this folder, so playing on someone else's world is as simple as replacing your islandsave files with theirs.