There are two main types of microphone: dynamic and condenser.
Dynamics (The Shure SM57/SM58, Sennheiser MD421 are two you might have in the band) don't need power. The diaphram vibrates a magnet and it produces its own small current. Condensers need a power supply to magnetise the diaphram. Some condensers have a battery to do this, others take their power from the mixer or camcorder. Nowadays nearly all microphones which take their power from the mixer/camcorder, work on a system called 48v phantom. The 48v is obvious (48 volts) but the "phantom" means that the power is delivered to the microphone along the microphone cable. The same cable sends electricity from the mixer to the mic and then gets the signal back from the mic to the mixer.

If you have a condenser microphone it will need power. If there's no battery, this power has to come from somewhere. 3.5mm jack plugs on consumer camcorders can't supply this power. Just something you need to check. It's not a problem though, there are stand-alone units which supply 48v phantom power for this purpose.