Radiolaria

Radiolaria are mostly planktonic marine protists, many of which build intricate mineral skeletons, commonly from silica. They are single-celled organisms whose skeletons contribute to marine sediments.

Protist: A eukaryotic organism that is not classified as an animal, plant, or fungus. Radiolarians are single-celled eukaryotes traditionally grouped among protists.
Axopodium: A stiff, microtubule-supported radiating pseudopodium found in radiolarians and some other protists. Radiolarians use these projections to capture prey and interact with their surroundings.
Polycystine: A major group of radiolarians characterized by intricate siliceous skeletons. Polycystines exemplify the elaborate silica skeletons commonly associated with radiolarians.
Radiolarian ooze: Deep-sea sediment containing abundant radiolarian skeletons. Accumulated skeletons can form silica-rich deposits on the ocean floor.
Ernst Haeckel: A German biologist who studied and illustrated microscopic organisms and proposed the kingdom Protista. His detailed radiolarian illustrations made their skeletal diversity widely known.
Eukaryote: An organism whose cells contain a nucleus and other membrane-bound compartments. Radiolarians have nuclei and the cellular organization characteristic of eukaryotes.
Phagocytosis: A cellular process in which a cell engulfs particles into membrane-bound compartments. Radiolarians obtain food by engulfing prey and other particles.
Acantharea: Radiolarians that typically form skeletons from strontium sulfate rather than silica. Acanthareans show that radiolarian skeletons are not always made of silica.
Radiolarian biostratigraphy: The use of radiolarian fossils to date and correlate sedimentary rock layers. Radiolarian species change through time, allowing their fossils to identify geological intervals.
Kunstformen der Natur: Ernst Haeckel’s illustrated book, published in installments from 1899 to 1904. Its plates of radiolarians became celebrated examples of their geometric forms.

Linked from 6 pages