I myself believe that there is a chance of 2 or more completely distinctive organisms (although,live in different places),through the changes in genetics due to adaptation,can become a same specie and share many similarities. Different families that behave in a same way would eventually develop into a new one without merging or encountering another whatsoever (since their locations are different).
For example, fish and cat are located differently ( since cats, in general, are incapable of swimming and fishes, on the other hand, cannot inhaling oxygen directly when out of water). However, through some changes in nature and ,of course, mutation, they undergo different processes of developing. Can they,despite the differences in the processes, "accidentally" develop many same characteristics and behave in a same way to encounter their own environments? ----Lets say fishes finally can walk and cats finally can dive.Although cats and fishes have never met, fishes now look somewhat like cats, and cats look somewhat like fishes:Fishes have fur while cats have scales. Still located in different places, but their appearances are strikingly similar ,so are their behaviours. Would that case ever happen?
I am only sure about 80%. I am looking for more ideas and evidences.
