Study the coordinated flagellar motion of the motile swarms of Volvox aureus v the immature daughter colonies represented through the dark circles
Motile colonies of Volvox aureus. Volvox swarms move v their setting by the coordinated activities of their cells" flagella. The dark circles on the swarms are immature daughter colonies.

You are watching: Compare the appearance and rate of locomotion in amoeboid flagellated and ciliated organisms

One the the many striking functions of countless protist types is the presence of some form of locomotory organelle, easily visible under a irradiate microscope. A couple of forms deserve to move through gliding or floating, return the vast majority move by method of “whips” or small “hairs” recognized as flagella or cilia, respectively. (Those organelles give their names come informal groups—flagellates and ciliates—of protists.) A lesser variety of protists employ pseudopodia. Those exact same organelles may be supplied in feeding together well.

Cilia and also flagella

Cilia and flagella are similar in structure, though the latter tend to be longer. Castle are likewise fundamentally comparable in function. Cilia and flagella are likewise known amongst plants and also animals, although they space totally lacking from the true fungi. Those eukaryotic organelles room not come be confused with the locomotory structure of prokaryotes, which is a minute organelle written of flagellin, no tubulin, together in eukaryotes. The prokaryotes flagellum is inherently nonmotile (rather, that is moved by the basal part, i beg your pardon is embedded in the cabinet membrane); it is entirely extracellular, and it is no homologous v (i.e., walk not have a typical evolutionary origin) nor genealogical to the eukaryotic bio flagella.


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The distribution of cilia and flagella end the cell varies between the different protists. Countless of the algal protists space characteristically biflagellate, and in numerous instances both flagella originate near or in ~ the anterior pole the the body. The presence, absence, or sample of the mastigonemes (minute scales or hairs spanning the flagellum) may also differ in between two flagella. Part parasitic zooflagellates have actually hundreds of long flagella.

Ciliated protists present an even greater diversity in the number, distribution, and arrangement that cilia over the cell. In part protists, solitary cilia have, in effect, been changed by compound ciliary oribelles (e.g., membranelles and cirri), which might be used successfully in locomotion and in feeding. If both ciliates and flagellates may have actually various rootlet systems associated with their locomotory organelles or with the basal bodies, or both, the oribelles in the ciliates have developed a more complex and intricate subpellicular infrastructure. Called the infraciliature, or kinetidal system, the lies principally in the outer, or cortical, layer of the ciliate’s human body (only the outermost great is dubbed the pellicle) and also serves primarily as a skeletal system for the organism. The mechanism is written of range of single or combine kinetosomes with connected microtubules and microfibrils to add other specialized organelles (such as parasomal sacs, alveoli, contractile vacuole pores, and the cytoproct, or cell anus), which is unique among protists. Variations are of an excellent importance in the evolution and phylogeny that protists.

Typically, flagellates relocate through one aqueous tool by the undulatory activities of the flagella. The waves of movement are created at the base of the flagellum. The direction and also speed the propulsion and other aspects of motion depend on a number of factors, consisting of the viscosity that the medium, the size of the organism, the amplitude and length that the waves, the length and exact position of the flagella, and the kind and also presence or absence of flagellar hairs. Some ciliates have the right to move much an ext rapidly by virtue the having many though shorter, cilia beating in coordination through each other. The synchronized beat follow me the longitudinal ciliary rows to produce a metachronal wave. Distinctions in details attest come the complexity of the all at once process.

Flagella and also cilia are additionally involved in sensory functioning, more than likely by way of their external membranes, i m sorry contain different kinds of receptors. Chemoreceptors, for example, deserve to recognize minute changes in the tool surrounding the organism and also cues indigenous presumed adjustment partners that bring about sexual behaviour.


In contrast to the swim movements developed by flagella and cilia, pseudopodia room responsible because that amoeboid movement, a sliding or crawlinglike form of locomotion. The formation of cytoplasmic projections, or pseudopodia, on the front edge the the cell, pulling the cell along, is characteristics of the microscopic unicellular protozoans recognized as amoebas. Together movement, however, is not exclusive come the amoebas. Some flagellates, some apicomplexans, and also even part other types of eukaryotic bio cells make use of amoeboid movement. Pseudopodia, even more so than flagella and cilia, room widely supplied in phagotrophic feeding as well as in locomotion.


Fingerlike expansions from the amoeba"s solitary cell are dubbed pseudopods, or false feet. Fluid cytoplasm forms and also flows right into these ever-changing lobes, permitting the organism to move.

There are number of different species of pseudopods, including lobopodia, filopodia, reticulopodia, and also axopodia (or actinopodia). The an initial three that those species are basically similar and are fairly widespread amongst amoeboids. The fourth type, axopodia, is distinct, being more facility and characteristics of certain dedicated protists. The types, numbers, shapes, distribution, and also actions that pseudopodia are important morphological considerations.

Lobopodia may be planarization or cylindrical (tubular). Amoeba proteus is most likely the best-known protist possessing lobopodia. Back the an accurate mechanisms that amoeboid motion are unresolved, there is general covenant that contraction of the outer, nongranular layer of cytoplasm (the ectoplasm) reasons the forward circulation of the inner, granular great of cytoplasm (the endoplasm) into the pointer of a pseudopod, thus advancing the whole body of the organism. Actin and myosin microfilaments, adenosine tree phosphate (ATP), calcium ions, and also other factors are involved in assorted stages that this complex process.

Other pseudopodia found amongst amoeboids incorporate the filopodia and the reticulopodia. The filopodia room hyaline, slender, and also often branching frameworks in which convulsion of microfilaments move the organism’s body along the substrate, also if it is bearing a fairly heavy test or shell. Reticulopodia space fine threads that may not just branch but also anastomose to form a dense network, i beg your pardon is specifically useful in entrapping prey. Microtubules are involved in the mechanism of movement, and also the continued migration of whole reticulum carries the cell in the same direction. The testaceous, or shell-bearing, amoebas possess either lobopodia or filopodia, and also the often economically important foraminiferans bear reticulopodia.

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Axopodia are lot more facility than the other types of pseudopods. They are composed that an outer layer of flowing cytoplasm the surrounds a main core comprise a bundle the microtubules, which space cross-linked in particular patterns. The external cytoplasm might bear extrusible organelles supplied in recording prey. Retraction of an axopod is fairly rapid in part forms, although not in others; reextension is generally slow in all protists with axopodia. The modes of activity of the axopodia regularly differ; because that example, the naval pelagic biology Sticholonche has axopodia that move like oars, also rotating in basal sockets storage of oarlocks.