EARTH'S ROTATION !!

When I was in school, I was taught that earth rotates on an axis of 23.5 deg. I imagined that there has to be a rod through the earth and earth is rotating on that axis. Later on, I learnt that the axis is imaginary and is with reference to another heavenly body. Later, I got a doubt that when earth rotates, how we land up in the same place when we jumped. I got an answer that atmosphere, to a considerable height, also rotates along with the earth.

My latest doubt now, is that we all know that earth rotates itself in 24 hours, and orbits around the sun which takes 365 days. What force makes earth rotate itself ? and also in a synchronised speed ? Where does it get the energy required . My friends say that it could be due to sun's gravitational pull. If it is so, then how earth goes on an eliptical orbit ? Even then, what force makes earth rotate?

Regards

Ramani