Amoebae as organisms Amoeba

1 amoebae organisms

1.1 history , origins of sarcodina
1.2 dismantling of sarcodina
1.3 classification

amoebae organisms
early history , origins of sarcodina

the first illustration of amoeboid, roesel von rosenhof s insecten-belustigung (1755).

the earliest record of amoeboid organism produced in 1755 august johann rösel von rosenhof, named discovery der kleine proteus ( little proteus ). rösel s illustrations show unidentifiable freshwater amoeba, similar in appearance common species known amoeba proteus. term proteus animalcule remained in use throughout 18th , 19th centuries, informal name large, free-living amoeboid.

in 1822, genus amiba (from greek amoibè, meaning change ) erected french naturalist bory de saint-vincent. bory s contemporary, c. g. ehrenberg, adopted genus in own classification of microscopic creatures, changed spelling amoeba.

in 1841, félix dujardin coined term sarcode (from greek sarx, flesh, , eidos, form) thick, glutinous, homogenous substance fills protozoan cell bodies. although term referred protoplasm of protozoan, came used in restricted sense designate gelatinous contents of amoeboid cells. thirty years later, austrian zoologist ludwig karl schmarda used sarcode conceptual basis division sarcodea, phylum-level group made of unstable, changeable organisms bodies largely composed of sarcode. later workers, including influential taxonomist otto bütschli, emended group create class sarcodina, taxon remained in wide use throughout of 20th century.

within traditional sarcodina, amoebae divided morphological categories, on basis of form , structure of pseudopods. amoebae pseudopods supported regular arrays of microtubules (such freshwater heliozoa , marine radiolaria) classified actinopods; whereas unsupported pseudopods classified rhizopods. rhizopods further subdivided lobose, filose, , reticulose amoebae, according morphology of pseudopods.

dismantling of sarcodina

in final decade of 20th century, series of molecular phylogenetic analyses confirmed sarcodina not monophyletic group. in view of these findings, old scheme abandoned , amoebae of sarcodina dispersed among many other high-level taxonomic groups. today, majority of traditional sarcodines placed in 2 eukaryote supergroups: amoebozoa , rhizaria. rest have been distributed among excavates, opisthokonts, , stramenopiles. some, centrohelida, have yet placed in supergroup.

classification

recent classification places various amoeboid genera in following groups:

it should noted of amoeboid groups cited (e.g., part of chrysophytes, part of xanthophytes, chlorarachniophytes) not traditionally included in sarcodina, being classified algae or flagellated protozoa.