Colossians 1:17 - All things hold together in Christ.

Christ is before all things. Everything is utterly dependent upon Him for its very existence, and everything holds together in Him. Christ did not just create all things, He is actively involved in keeping everything going. Ie God did not just wind up the clock and then let it get on with it. However, this does not mean that God is "tinkering" with creation all the time. We need to be careful how we interpret what this means and what conclusions we draw. I believe that getting this wrong is the cause of much of the disagreement and misunderstanding between "science" and "religion". On the on hand many who believe in creation (and rightly so) either actually believe or give the impression that to explain creation we have to envisage God repeatedly intervening directly (this includes some intelligent designers as well as six-day creationists). On the other hand, many atheist scientists seem to think that because we find a process that explains how something happens or came about then wrongly imagine that this proves that God does not exist. Evolution is the most prominent example of this. 

Both of these views are badly mistaken and this makes for bad science and bad theology. Even if evolution was 100% right (which I don't believe it is, largely on scientific grounds) it would not prove that God did not use evolution as His design process. On the other side, the "interventionists" have a shallow view of what God can do and how He interacts with the world. If you want a philosophical question to ponder that relates to this: How does eternity map on to the temporal world?. There, you don't know do you, and neither do I, nor does anyone else. So lets acknowledge the limits of our understanding.

We need to be careful in distinguishing between what God does and how He does it. We can be certain about lots of things that God does because the Bible states them clearly, we need to exercise much more caution when talking about how He does them.

It is absolutely certain that all things were created by Christ, and that all things are utterly dependent upon Him for every moment of their existence. Exactly how this works out in scientific terms is for us to explore.