Kingdom Protoctista

Kingdom Protoctista is defined by exclusion: its members ar neither animals (which develop from a blastula), make ups (which develop from an embryo), fungus kingdom (which deprivation undulipodia and develop from spores), nor prokaryotes. They comprise the eukaryotic microorganisms and their immediate posterity: in all nucleated algae (including the sea-weeds), undulipodiated (flagellated) water molds, the colly molds and slime nets, and the phylum Protozoa. Protoctist cells shake nuclei and former(a) characteristically eukaryotic properties; most perk up aerobiosis and ventilating system in mitochondria and 9+2 undulipodia at approximately submit of the life cycle. Why protoctist rather than protist? Since the 19th century, the expression protist, whether used informally or formally, has come to connote a single celled organism. In the last two decades, however, the root word for classifying atomic number 53-celled organisms separately from multicellular ones has we akened. It has become evident that multicellularity evolved m each an(prenominal) times from unicellular forms - mevery multicellular organisms ar far more than closely related to certain unicells than they are to any other(a)wise multicellular organisms.

For example, the ciliates, which are unicellular microbes, include at least(prenominal) one species that forms a sorocarp, a multicellular spore-bearing structure; euglenoids, chrysophytes, and diatoms in any case have multicellular derivatives. Protoctists are aquatic: approximately chiefly marine, some primarily freshwater, and some in debile tissues of other organisms. Nearly every animal, fungus and plant - perhaps ev! ery species - has protoctist associates. most protoctist phyla include hundreds of species, all of which are parasitic on other organisms. No one knows how many species of protoctists there real are; thousands have been described in the biological literature. water supply molds and plant parasites have traditionally been dealt with by the mycological literature, parasitic protozoa by the medical literature, algae by the botanical literature,...If you wish to substantiate a full essay, order it on our website: BestEssayCheap.com

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