Are Kryptonians and humans the same species?

Or, on a large scale, are humans and incredibly human species the same species on different planets? Or is it convergent evolution?

I have heard some speculation that there was one species put on multiple planets. So, they evolved in different ways but originate from the same source.

If not, what are the biological differences between Kryptonians and humans? They share most of the same traits and can interbreed. The only difference is how their body reacts to different light sources. On Krypton, a Kryptonian is as normal as a human is on Earth. They break bones, can get hurt, can't fly, etc.