Search results
Results From The WOW.Com Content Network
A protist (/ ˈ p r oʊ t ɪ s t /) is any eukaryotic organism (one with cells containing a nucleus) that is not an animal, plant, or fungus.The protists do not form a natural group, or clade, since they exclude certain eukaryotes with whom they share a common ancestor; [a] but, like algae or invertebrates, the grouping is used for convenience.
The 16-cell Gonium colony shown in the diagram on the right is organized into two concentric squares of respectively 4 and 12 cells, each biflagellated, held together by an extracellular matrix. [51] All flagella point out on the same side: It exhibits a much lower symmetry than Volvox, lacking anterior-posterior symmetry.
Systematists today do not treat Protista as a formal taxon, but the term "protist" is still commonly used for convenience in two ways. [22] The most popular contemporary definition is a phylogenetic one, that identifies a paraphyletic group: [23] a protist is any eukaryote that is not an animal, (land) plant, or (true) fungus; this definition [24] excludes many unicellular groups, like the ...
In 1866, the 'father of protistology', German scientist Ernst Haeckel, addressed the problem of classifying all these organisms as a mixture of animal and vegetable characters, and proposed Protistenreich [190] (Kingdom Protista) as the third kingdom of life, comprising primitive forms that were "neither animals nor plants".
Protistology is a scientific discipline devoted to the study of protists, a highly diverse group of eukaryotic organisms. All eukaryotes apart from animals, plants and fungi are considered protists. [1]
The phylum Sarcomastigophora belongs to the Protista or protoctista kingdom and it includes many unicellular or colonial, autotrophic, or heterotrophic organisms. It is characterized by flagella, pseudopodia, or both.
Kingdom Protista (or Protoctista) is included in the traditional five- or six-kingdom model, where it can be defined as containing all eukaryotes that are not plants, animals, or fungi. [ 16 ] : 120 Protista is a paraphyletic taxon, [ 47 ] which is less acceptable to present-day biologists than in the past.
In some older systems of classification, Zoomastigophora is a phylum (more commonly known as zooflagellates) within the kingdom Protista.Organisms within this group have a spherical, elongated body with a single central nucleus.