There are many small organisms that play a vital role in many ecosystems, and that also need protection and conservation to sure that natural ecosystems function fully.
Populations of organisms are usually restricted in their size by limiting factors, such as the availability of food or light. these factors maintain the size of a population at a fairly constant level. if the limiting factors are removed, the population is able to grow very rapidly. this is clearly demonstrated if a small number of bacterial cells are inoculated into a nutrient broth, and the number of cells is monitored for several hours.