What Are The Four Major Phyla Of Animal Like Protists?
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I. If we consider only living things:|
phylum (or division)
II. If we include the environment it is
Atom – a collection of one or more protons and zero or more neutrons forming a nucleus and surrounded by electrons (leptons), one for each proton, and forming an uncharged material unit.
Molecule – a collection of covalently linked atoms forming a functional unit
Biomolecule – a large complex molecule found only in living things, such as DNA
Organelle - a differentiated structure within a cell, such as a mitochondrion, vacuole, or chloroplast, that performs a specific function.
Cell - the smallest structural unit of an organism that is capable of independent functioning, consisting of one or more nuclei, cytoplasm, and various organelles, all surrounded by a semipermeable cell membrane.
Tissue - an aggregation of morphologically similar cells and associated intercellular matter acting together to perform one or more specific functions in the body. There are four basic types of tissue: muscle, nerve, epidermal, and connective.
Organ – a structure that contains at least two different types of tissue functioning together for a common purpose such as an eye, wing, or leaf, that performs a specific function.
Organ system – Organ systems are composed of two or more different organs that work together to provide a common function. There are 10 major organ systems in the human body: Skeletal System, Muscular System, Circulatory System, Nervous System, Respiratory System, Digestive System, Excretory System, Endocrine System, Reproductive System and the Lymphatic/Immune System.
Organism – an individual form of life, such as a plant, animal, bacterium, protist, or fungus. It has a body made up of organ systems in the case of larger organisms
population - a group of living things within a certain area that are all the same species.
Community - the living things in an area
Ecosystem - An ecological community together with its environment, functioning as a unit.
Biome - A major regional or global biotic community, such as a grassland or desert,
Biosphere - the part of the earth and its atmosphere in which living organisms exist or that is capable of supporting life. The living organisms and their environment comprise the biosphere.
Animal-like Protists (Protozoa) - 4 phyla |
Fungus-like Protists - 2 phyla
Myxomycota (Slime molds)
Oomycota (Water Molds & Mildews)
Cell division in protists, as in plant and animal cells, is not a simple process, although it may superficially appear to be so. The typical mode of reproduction in most of the major protistan taxa is asexual binary fission. The body of an individual protist is simply pinched into two parts or halves; the “parental” body disappears and is replaced by a pair of offspring or daughter nuclei, although the latter may need to mature somewhat to be recognizable as members of the parental species. The length of time for completion of the process of binary fission varies among groups of organisms and with environmental conditions, but it may be said to range from just a few hours in an optimal situation to many days under other circumstances. In some unicellular algal protists, reproduction occurs by fragmentation. Mitotic replications of the nuclear material presumably accompany or precede all divisions of the cytoplasm (cytokinesis) in protists.|
Multiple fission also occurs among protists and is common in some parasitic species. The nucleus divides repeatedly to produce a number of daughter nuclei, which eventually become the nuclei of the progeny after repeated cellular divisions. There are several kinds of multiple fission, often correlated with phases or stages in the full life cycle of a given species. The number of offspring or filial products resulting from a multiple division (or very rapid succession of binary fissions) may vary from four to dozens or even hundreds, generally in a short period of time. Modes of such multiple fission range from budding, in which a daughter nucleus is produced and split from the parent together with some of the surrounding cytoplasm, to sporogony (production of sporozoites by repeated divisions of a zygote) and schizogony (formation of multiple merozoites, as in malarial parasites). The latter two phenomena are characteristic of many sporozoan protists, which are obligate parasites of more advanced eukaryotes. Some multicellular algal protists reproduce via asexual spores, structures that are themselves often produced by a series of rapid fissions.
Even under a light microscope, differences can be seen in the modes of division among diverse groups of protists. The flagellates, for example, exhibit a longitudinal, or mirror-image, type of fission (symmetrogeny). The ciliates, on the other hand, basically divide in a point-by-point correspondence of parts (homothetogeny), often seen as essentially transverse or perkinetal (across the kineties, or ciliary rows). Most amoebas sensu lato exhibit, in effect, no clear-cut body symmetry or polarity, and thus their fission is basically simpler and falls into neither of the categories described above.
Sexual phenomena are known among the protists. The erroneous view that practically all protists reproduce asexually is explained by the fact that certain well-known organisms, such as species belonging to the genera Euglena and Amoeba, do not demonstrate sexuality. Even many of the unicellular species can, under appropriate conditions, form gametes (male and female sex cells, although sometimes multiple sexes are formed, which makes the terms “male” and “female” inappropriate), which fuse and give rise to a new generation. In fact, sexual reproduction—that is, the union of one male and one female gamete (syngamy)—is the most common sexual phenomenon and occurs quite widely among the protists—for example, among various flagellate and sarcodine groups and among many parasitic phyla (e.g., in Plasmodium, a malaria-causing organism).
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