Closely related? Yes. The same? No.
I suppose ground and rock could be closely related because one is the ground and one is the rocks on the ground. But, if that makes them the same- then, poison and grass would be the same. Since a great deal of the poison Pokemon are grass. And, in real life, a great deal of plants are poisonus. And, bugs and grass would be the same, too. Since bugs live on grass or on plants.
I think they're completely different. But, like many of the other Pokemon (Grass/Poison, Bug/Grass, etc) they are closely related to one another. Which would be why in the card game they require the same energy. ;)