Ah; that explains my latent fear of small dishes filled with warm butter....
At least a year ago, I posted a scenario where a ship of interstellar castaways ends up the "adam & eve" of their world, and their distant descendants (ignorant of their origins) try to figure it all out. As soon as they realize that they are related to nothing on their world, they would conclude either that they were castaways, or that they were magically created in situ. But we don't have that problem. Everywhere we look we see that we are part of a great inter-related web of life on Earth.
Hmm. Just for the sake of debate, it could be argued that any creature, anywhere in the universe, has developed from a DNA infrastructure; that reproductive life in an atmosphere such as earth's can only exist with a DNA genetic structure. Furthermore, with all of the thousands of physical constructs observable, either past or present, on this planet, the most sentient, clever and creative construct is that of the hominid. The best of that group is homo sapiens sapiens.
Therefore, one could argue that no matter where the planet is in the universe, if it has the same elements and atmospere available, life development will be similar genetically.