If I connect an Ethernet cable, will my Mac automatically select the fastest route for local network traffic? Background

I have a fairly robust network setup at home, but am a little unclear on internal Mac networking. My LAN consists of two bridged AirPort Extremes and a cable modem. Everything is connected using Cat 5e inside the walls, and Cat 6 patch elsewhere. Additionally, I have a Netgear Gigabit switch in my office.

I use my MacBook Pro throughout the house on Wifi. When I bring it in the office, I connect an Ethernet cable for 1000BASE-T awesomeness. Elsewhere on the network I have backups and a media server.

Question

When I connect the MBP to Ethernet, will the Mac software determine the fastest route for local network traffic? I can see by the activity lights on the switch that I have a full Gigabit Ethernet connection, but since Wifi is still on, I'm not clear which network mode is being utilized.
You want to make sure that your Mac's ethernet device is before the wifi device in the system's network service order. In System Preferences, Go to Network; under the device listing, click the 'gear' icon and select 'Set Service Order.' Drag 'Ethernet' to the top. Per my understanding, all traffic will attempt to be routed through the top-most device, and will only be routed through devices lower in the chain should the above route(s) be unavailable.