Aggressiveness in one years olds?

Eli has emerged as quite an aggressive little man lately and it really makes me nervous. He seems to get frustrated very easily and when he does - he shows it in the form of aggressiveness usually towards Nate. If Nate is playing with something Eli wants - Eli will just crawl over and yank it out of his hands. If Nate is riding one of their toys and Eli decides it's his turn...he will crawl over, stand by it for a short while, and if Nate doesn't get off - he will reach out, grab him by the collar and pull him to the ground. If he doesn't feel like Nate has gotten the picture he will kind of lean into him hard and kind of yell/grunt. His new thing is biting. As soon as he gets aggravated w/ Nate he will lean over and bite him - sometimes on the arms - but usually on the face.

All this is very concerning for me. I've looked up "aggressiveness in one year olds" on the internet and it seems to be a fairly common problem - but that doesn't change the fact that it's bothersome when it's happening with your own child.

How are we dealing with it? Well, as of right now, it's really difficult because they have no reasoning skills. So, what I do when I witness Eli doing something aggressive is go over and intervene immediately. Tell him "NO" and "we will not " and "we will be sweet to brother" then put him in a "pack and play" in the spare bed room. I only keep him in there for about a minute or so. Then I go and get him out and explain (as well as you can explain to a 14 mo old boy) what he did wrong.

I'm hoping I'm handling this the correct way.

I try to rationalize this with humor. I think with his double vision - he's like "holy crap there are two of him and they NEVER go away!!!". I think that's really why he's so ticked off. I mean, I would be.