Mosses-07-web

Mosses-07-web - Mosses 1 The Protists (continued): The...

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Mosses The Protists (continued): The Kingdom Protista The Kingdom Protista contains both multi-cellular and unicellular eukaryotes. It is an incredibly diverse Kingdom that contains some of the earliest-branching eukaryotes. However, it is not a ‘natural’ or monophyletic kingdom, and, as a result, the taxonomy of this kingdom is in a state of flux. This kingdom contains far too many organisms to cover in comprehensively, so I’ll mention only a few prominent taxa before I turn in more detail to a one particular taxon. The Foraminifera: are single-celled organisms with calcium carbonate shells. Most of the estimated 4,000 living species of forams live in the world's oceans. Of these, only about 40 species are planktonic, that is they float in the water. The remaining species live on the bottom of the ocean, on shells, rock and seaweeds or in the sand and mud of the bottom. In places, foraminifera are so abundant that the sediment on the bottom is mostly made up of their shells. The are particularly interesting because of their extensive fossil record. Paleontologists are able to use foram fossils to decipher changes in the earth’s climate. Euglenids: I’ll only mention two. The first, Trypanosoma cruzi, causes Chagas’ disease. It infects people through an inset. The second is a neat little protist call Trichonyma that lives in termite guts and helps termites digest wood. Apicomplexans: Apicomplexans are parasitic protozoa. From a human standpoint, the most important apicomplexan is Plasmodium falcipurum . Plasmodium is a parasite that causes malaria, which, after years on the decline, is once again one of the major causes of disease, particularly in the third world. The current global picture: from World Health Organization Malaria is a public health problem today in more than 90 countries, inhabited by a total of some 2 400 million people -- 40% of the world's population. Worldwide prevalence of the disease is estimated to be in the order of 300-500 million clinical cases each year. More than 90% of all malaria cases are in sub-Saharan Africa. Mortality due to malaria is estimated to be over 1 million death each year. The vast majority of deaths occur among young children in Africa, especially in remote rural areas with poor access to health services. 1
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Mosses An interesting tangent is that the entire Plasmodium genome has been sequenced. It is hoped that the DNA sequence of Plasmodium will help lead to treatment strategies. Please note that the life-cycle of the malaria parasite is quite complex. The life-cycle includes proliferation of Plasmodium in specialized regions of the human body (the liver and red blood cells); part of the life cycle features separate male and female parasites; the male and female parasites are taken up by mosquitoes, where fertilization occurs; the fertilized zygote becomes spores (or sporozites) that are released by mosquitoes into the human body. Eukaryotic Algae
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This note was uploaded on 03/14/2009 for the course BIOL 94 taught by Professor Gaut/summers during the Winter '08 term at UC Irvine.

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Mosses-07-web - Mosses 1 The Protists (continued): The...

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