some members of Entamoeba) are parasitic and can be found in the digestive tract of human beings and other animals Free-living species feed on bacteria, protozoa, algae, and rotifers, etc Some species are flagellated at a given stage of their life cycle.Pseudopodia vary in appearance (cylindroid, hemispheroid, fan-shaped etc).Some of the species have an ectoplasm/hyaloplasm located beneath the plasma membrane and surrounding the granuloplasm/endoplasm.Naked amoebas have a contractile vacuole.Some of the other characteristics of Sarcodina include: Whereas naked forms are commonly found in freshwater, the majority of those surrounded by mineralized tests are found in marine environments where they either exist as marine benthic or planktonic organisms. The general morphology has also been shown to influence where given organisms are found. in Rhizopods), others exist as naked amoebae (e.g. While some of the species have an outer shell covering the cell body (e.g. For planktonic sarcodinads, these temporary structures (pseudopods) serve to capture and even dismember larger prey (e.g. For this reason, cytoplasmic streaming can be observed during locomotion or when the organism is gathering food (or environmental matter like mineral particles).įor a majority of arenaceous species, cytoplasmic streaming, which results in the formation of pseudopods allows them to select and collect the appropriate particles for shell construction. Also referred to as the amoebas in some books, the sub-phyla Sarcodina consists of over 13,500 species that move and feed by means of pseudopodia.
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