Movement and phagocytosis in Ammonia beccari, a foraminifer (protist)
This (accelerated) movie shows the gliding movement of Ammonia beccarii and from sediments of the Wadden Sea and the transport of particles along its pseudopodia.
Ammonia is a unicellular organism that belongs to the order of the foraminifer (means hole-bearer, short also called forams), an under group of the Protozoa (the "like animals looking protists"). Forams construct a protective shell of calcium carbonate, silicium oxide or organic debris. The shell of most species is composed of many chambers, called locules. Locules of increasing size are added as the organism grows. The shell usually contains numerous tiny holes from which thread-like extensions of protoplasm can emerge, the so-called pseudopodia. Forams use their pseudopodia to move or to capture and collect particles that they take up as food by phagocytosis. Forams live as benthos (on the floor) or as plankton (free floating) in sea or brackish waters. The oldest unambiguous forams are 550 million years old (source: http://www.paleontology.uni-bonn.de/mitarbeiter/langer/FORAMINI.HTM ). The shells are often found as fossiles in stones. These fossiles are of importance for geological determinations, e.g. for dating sediments or evaluating climatic changes.
Research: Sandra Langezaal, Biogeology (KUN)
Imaging/web text: Department of General Instrumentation (KUN) (E.S. Pierson, B. van der Linden) |