Does the theory of evolution explain why penguins found along the equator as opposed to a population found in the Arctic?

I don't believe that's strictly evolutionary theory. The penguins in the Galapagos are there because of a confluence of oceanic currents.

The Peru current brings cold water life such as penguins, albatross and fur seals.

The warm Panama current encourages animals such as turtles, iguanas and dolphins.

Finally, the deep Cromwell current surges up with rich marine algae from the ocean floor to feed everyone.

So, the penguins are there because they will have followed the Humbolt and Peru currents up from Antarctica (no penguins in the Arctic) and come to a rest in the Galapagos where there is and was plentiful food.

They have subsequently evolved into a distinct species but I don't believe they were mentioned in Darwin's Origin of Species. I don't think he even mentions the giant tortoises so not surprising that he didn't get around to figuring out the penguins.