Plants typically grew in a permanent site, but some could move about in search of better light, nutrients or soils. As plants grew, they went to seed to bear their young, and then slowly decayed to organic matter and fertilized their habitat for subsequent generations. Plant life could also be found underwater, in which case it was often known as alga. Within a given ecosystem, the diversity of plant life could be extremely high—on the planet Alderaan alone, there existed more than 8,000 different species of grass.