Protozoa Models

Protista. Preparation laboratory NHM. 2007.

Protozoa are generally so small that they can hardly be displayed in the original. The lifelike plastic models with glass spines were made at the NHM in 2007.

LIFE IN THE EXTREME
Protista are usually tiny, single-celled living organisms. They have fascinating names like Noctiluca scintillans, heliozoa, euglena, and they are seldom larger than one millimeter. Models made of glass or wood were being made as long ago as the 19th century. Magnified illustrations and microscopic preparations served as the basis for the twelve models created in recent years in the preparation laboratory at the NHM. They are intended to illustrate the aesthetic and ecological diversity of the organisms from which all multicellular organisms have developed in the course of evolution.
Most protozoa live in water, are a significant component of the food chain and occur in amazingly large numbers. When they die, their shells and skeletons made of lime and silicic acid are deposited on the sea or lake bed and can form rock. Not only the chalk cliffs of Dover, but also the pyramids of Giza consist largely of the shells of protozoa.
Many protista are extremely motile. Some swim with the help of cilia or flagella. Other, such as amoeba, glide fluidly forwards by stretching out their pseudopods and constantly changing their shape. Reproduction is usually asexual via cell fission.
Protozoa can exist under the most incredible conditions. Some live in the ice of the polar and glacier regions, others in thermal waters at temperatures of more than 50° C. Several ciliates withstand even the extreme aridity of desert soil. After a rain, they slip out of their resting cyst, eat quickly and reproduce before the next drought period.