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In the first the cell extends small pseudopods which then move down the sides of the cell, acting like paddles. [9] [10] [12] In the second the cell generates an internal flow cycle, with the cytoplasm flowing backward along the membrane edge and forward through the middle, generating a force on the membrane which moves the cell forward. [10] [12]
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]
The amoeboflagellate cell type has been acquired numerous independent times across the evolution of protists (i.e. primarily unicellular eukaryotes that are not plants, fungi or animals). [3] Some examples of protist phyla with amoeboflagellate body types are:
Syssomonas multiformis is a species of unicellular protists with naked cells (lacking any shell or scales) that presents with a variety of life forms during their complex life cycle. These forms include: round flagellate cells (7–14 μm in diameter) with one posterior flagellum , amoeboflagellate (i.e. with both flagella and pseudopodia ...
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.
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.