The process that produces a similar appearance among unrelated group's of organisms is

A convergent evolution is a process of independent evolution of similar traits in unrelated species. These traits are called analogous structures which are similar in form or function but were not present in the last common ancestor of those species. For example, both birds and bats have wings. However, wings were not present in the last common ancestor of tetrapod to which they belong. They are only similar in function and develop in response to the similar way of life.

not sure if this is what you'r looking for nnew= nold