The northern hemisphere is warmer in the summer than the winter because the northern hemisphere are pointing toward the sun. Because of this the rays hit us more directly making is hotter. So during the winter when the northern hemisphere is not pointing toward us, it makes is colder. It also depends on the tilt of the axis. When it is more direct it makes the temperature hotter.
Most organisms either directly or indirectly use energy from the sun to survive, but not all of them. Plants and some microbes use the energy from the sun to perform photosynthesis.
