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Crawling is one form of amoeboid movement which starts when an extension of the moving cell binds tightly to the surface. [9] [10] The main bulk of the cell pulls itself toward the bound patch. By repeating this process the cell can move until the first bound patch is at the very end of the cell, at which point it detaches.
The third prevalent forms of protist cell motility is actin-dependent cell migration. The evolution of flagellar-based swimming has been well studied, and strong evidence suggests a single evolutionary origin for the eukaryotic flagellum occurred before the diversification of modern eukaryotes. On the other hand, actin-dependent crawling uses ...
Amoebozoa is a major taxonomic group containing about 2,400 described species of amoeboid protists, [8] often possessing blunt, fingerlike, lobose pseudopods and tubular mitochondrial cristae. [ 7 ] [ 9 ] In traditional classification schemes, Amoebozoa is usually ranked as a phylum within either the kingdom Protista [ 10 ] or the kingdom ...
An amoeba (/ ə ˈ m iː b ə /; less commonly spelled ameba or amœba; pl.: amoebas (less commonly, amebas) or amoebae (amebae) / ə ˈ m iː b i /), [1] often called an amoeboid, is a type of cell or unicellular organism with the ability to alter its shape, primarily by extending and retracting pseudopods. [2]
Physarum polycephalum, an acellular [1] slime mold or myxomycete popularly known as "the blob", [2] is a protist with diverse cellular forms and broad geographic distribution. The “acellular” moniker derives from the plasmodial stage of the life cycle : the plasmodium is a bright yellow macroscopic multinucleate coenocyte shaped in a ...
In some cases the cell moves by "walking", with relatively permanent pseudopodia serving as limbs. The most important genera are Amoeba and Chaos, which are set apart from the others by longitudinal ridges. The best known of the species in this family is Amoeba proteus, commonly used in classrooms to demonstrate movement by pseudopodia.
Like many other protists, species of Amoeba control osmotic pressures with the help of a membrane-bound organelle called the contractile vacuole. Amoeba proteus has one contractile vacuole which slowly fills with water from the cytoplasm (diastole), then, while fusing with the cell membrane, quickly contracts (systole), releasing water to the ...
These latter are polyphyletic, but molecular trees by Bolivar et al. [2] identified a core monophyletic subgroup. Subsequent studies showed the testate lobose amoebae belong to the same group, which was thus renamed Lobosea sensu stricto [ 3 ] or Tubulinea.