Difference in Equity and Assets (checking a/c)

[Hossain]

Hello, I m very new to GnuCash, I need some clarifications.I m confused 
about Equity.
I have 1000$ in checking a/c (parent-Assets). I make a transaction at Income
for 200$ (Assets:Current Assets:Current Account) but
it doesnt increase my-  opening balance(parent-Equity). IT only 
increases checking a/c (parent-Assets)
to 1200$. As far as I knw, Equity is what I have in total, then why is 
this 200$ not added to Equity?