Shutter speed and aperture relationship?

Shutter speed is the amount of time that the camera's shutter (which lets the light coming in through the lens onto the film/chip inside the camera) is open. Aperture is the size of the opening inside that lets the light in. Both affect the amount of light entering the camera to result in an exposure - the longer the shutter is open and the wider the aperture, the more light that is coming in. Aperture also affects the depth of field of the image, so a wide open aperture such as f/2.8 will let in a lot of light and have a shallow depth of field.