Slime molds :: essays research papers

slant-eye regorgeslime mold or slime fungus,a heterotrophic organism once regarded as a fungus but later classified with the Protista. In a recent formation of classification based on analysis of nucleic acid (genetic material) sequences, slime molds take up been classified in a major group called the eukarya (or eukaryotes), which includes plants and animals. There atomic number 18 two groups of slime molds, the plasmodial slime molds of the phylum (division) Myxomycota and the cellular slime molds of Acrasiomycota. soil molds have complex life cycles that may be divided into an animallike mobile cast, in which growth and feeding occur, and a plantlike, immotile, reproductive phase. The motile phase is commonly found under rotting logs and damp leaves, where cellulose is abundant. It consists in the cellular slime molds of solitary, amebalike cells, and in the Myxomycota of a coenocytic (multinucleate) quite a little of protoplasm called a plasmodium, which creeps about by ameboid movement. Plasmodia often grow to a diameter of several inches and are frequently brightly colored. Both types submit solid food particles using a process called phagocytosis (see endocytosis). They feed on living microorganisms, such as bacteria and yeasts, as well as decaying vegetation. Before entering the reproductive stage, a plasmodium moves to a drier, better-lit place, such as the top of a log. In the amebalike, or cellular, slime molds, up to 125,000 individual cells aggregate and flow together, forming a multicellular mass called a pseudoplasmodium that resembles a slug and crawls about before settling in a location with acceptable warmth and brightness.In the reproductive stage the plasmodium or pseudoplasmodium is transformed into one or more reproductive structures called fruit bodies, each consisting of a stalk topped by a spore-producing enclose that resembles the reproductive structures of many fungi. Eventually the cellulose-walled spores are released an d dispersed they germinate in wet places, releasing naked cells. In a typical plasmodial slime mold the germinated spores go through an ameboid or flagellated swimming stage, followed by sexual fusions and cell divisions. The diploid ameboid cell (i.e., the zygote) grows and its sum divides repeatedly, resulting in the formation of a new plasmodium. Under adverse conditions a plasmodium may be transformed into a hard, dry, inactive mass called a sclerotium. Resistant to desiccation, it becomes a plasmodium again when favorable conditions return.In the case of the cellular slime molds, each spore released becomes a single ameba, which feeds respectively until starving cells release a chemical signal that causes them to aggregate into a new pseudoplasmodium, and the process is repeated.