Can I switch the sim card from a blackjack 2 and Iphone?

I currently have a Blackjack 2 but I want a Iphone. I was wondering if i switch the sims card from my blackjack 2 into my Iphone would i still be on my Blackjack 2 plan with my family (The plan is not a "Blackjack 2 plan" just a normal family plan)? and would the Iphone work in perfect order with the Blackjack 2 sim card in it?