protozoa

Protozoa are a diverse group of unicellular, eukaryotic organisms that lack a cell wall. They are classified based on their movement, such as flagellates, which move using flagella; amoebas, which move using pseudopodia; ciliates, which use cilia; and sporozoans, which are non-motile. Protozoa are heterotrophic, obtaining their nutrition by consuming other organisms. They inhabit a wide range of environments, including freshwater, marine, and terrestrial habitats, as well as functioning as parasites within other organisms. Reproduction in protozoa is typically asexual, occurring through processes like binary fission, budding, or multiple fission in spore-forming species.

Protozoa play significant roles in ecosystems as primary consumers and recyclers of organic matter. Some species are important in the food chain, serving as prey for higher organisms. However, certain protozoa are pathogenic, causing diseases such as malaria (caused by Plasmodium), dysentery (caused by Entamoeba histolytica), and sleeping sickness (caused by Trypanosoma). The study of protozoa, known as protozoology, is important for understanding their ecological roles and impacts on human health.