That's true. There is little variety among organisms found in pools, pounds and lakes. Despite that fact that many ponds are seasonal, lasting just a couple of month (for exemple sessile pools) while lakes can exist for more than hundred years. Lakes and ponds have limited species diversity because they are often limited from each other and from other water sources like rivers, seas and oceans.
It is called the Milky Way because it appears as a milky band of light in the sky when you see it in a really dark area. Just as the Earth goes around the Sun, the Sun goes around the center of the Milky Way.