I'd be happy to concede for the sake of argument that the solar system is de facto closed, even though that's not really true. But that's totally irrelevent, because the Earth -- where life evolved -- isn't even remotely closed. You're confusing localized realities with generalized trends. For the Earth to be closed, it would not be able to receive any net radiation, and I'll wager you a large orb of thermonuclear hydrogen that it does.
BTW, I doubt very seriously that you want to make this a question of credentials. I've studied both biology and physics on the post-graduate level, something I seriously doubt you have done.
I was putting Mike's credentials up against your's, and he has graduate degrees in physics as a rocket scientist (engineer). He currently works on Tomahawk missiles.