Introduction

Protozoa are unicellular, eukaryotic microorganisms. The amoebae move by means of pseudopodia. Many of them obtain their food by holozoic nutrition characterized by direct feeding on microbial cells such as bacteria.  "It has been estimated that one species of amoeba requires 40,000 bacteria per cell division. consequently bacteria must reproduce at a rapid rate to keep pace with their predators."(Alexander,1967.p.108)  This information suggests that the protozoan population is important in limiting the bacterial population by maintaining a balance in this habitat.

Ameoba are usually found near the surface of the soil in the upper 6 inches. Warm, moist, and organically rich soil encourage a high bacterial population.  Ameoba tolerate a range of pH, with a preference for acidity and are capable of encysting when conditions are unfavorable.

In this lab we enriched for soil amoeba using Enterobacter aerogenes because these bacteria are a known food source for amoeba.  In addition to isolating amoebae, other organisms were found in the soil. Extensions of this lab lead to more inquiries of  soil ecosystems.