word looked up : home / archive

 Protist 

The Kingdom Protista or Protoctista is one of the commonly recognized biological kingdoms, including all the eukaryotes except for the plants, fungi, animals, and sometimes other groups which are treated in separate kingdoms. A few forms are multicellular, for instance the brown and red algae. The vast majority, though, comprise the single-celled organisms, and are typically only 0.01-0.5 mm in size, too small to be seen without a microscope. Protists are ubiquitous throughout aqueous environments and the soil, commonly surviving dry periods in the form of cysts; a few are important parasites.

Traditionally protists have been divided into:

In early classifications the Protozoa were considered a phylum of animals, and the algae and slime molds were placed among several divisions of plants. Many forms were classified under both kingdoms and researched by zoologists and botanists alike. Eventually the kingdom Protista was created to house these forms, with the classes of protozoa (corresponding roughly to the above) being promoted to phyla. Except for the ciliates and Oomycota, however, all the above groups are polyphyletic[?] and frequently overlapping. Further, the protists themselves are understood to be paraphyletic to the other eukaryotic kingdoms.

More recently attempts have been made to divide protists into more genuine groups on the basis of ultrastructural, chemical, and genetic features. In newer systems these are often treated as separate kingdoms. However, there are still many different lines of protists whose relationships are not understood. Many workers now consider the various protist clades as direct subgroups of the eukaryotes, with the admission that we do not yet know enough about them to properly arrange them into a hierarchy. These various clades are listed on our evolutionary tree and under the linked pages above.

from time to time he puts on his coat and goes up to her. "Has no one come?" he asks timidly. "No, Monsieur, no one." In the beautiful red drawing.html">drawing-room--for they have a drawing-room in red centre of the light.html">light-flowered carpet--Sidonie has established herself in shapes around her. Here and there are books, reviews, a little work- in a glass vase, and green plants in the jardinieres. Everything is the taste, that invisible line which separates the distinguished from the pretty genre picture. The hostess's attire, even, is too new; she looks Risler's eyes everything is superb, beyond reproach; he is preparing to glance, he checks himself in terror. "You see, it's four o'clock.html">clock," she says, pointing to the clock with an Claire not to come up. She is at home--I am sure of it--I can hear her." Indeed, ever since noon, Sidonie has listened intently to the slightest Risler attempts to go down again in order to avoid a renewal of the very least he can do is to stay with her when everybody else abandons like those people who dare not move during a storm for fear of attracting salon, changing the position of a chair, putting it back again, looking to ask Pere Achille if no one has inquired for her. That Pere Achille is that she was out. But no, the concierge has not seen any one. Silence and consternation. Sidonie is standing at the window on the garden, where the darkness is gathering, and the black smoke which the first to show a light on the ground floor; the cashier trims his lamp flame and bends double behind the grating. Sidonie's wrath is diverted a .

 On wordlookup.net  

All is still licensed under the GNU FDL.
It uses material from the wikipedia.



logo

navig stuff

home
archive