Talk:Protist
From Academic Kids
Brief comment: it seems to me that an article like this could benefit greatly, for the benefit of people who don't actually know what protista are and therefore need this article, to begin with examples of protists. Whenever defining any term in any field, it always helps to begin with concrete examples (if possible). Generally speaking, unless you're just trying sum up the knowledge of biologists, without good examples generously interspersed, and other jargon explained, these articles aren't going to be as helpful as they might otherwise be. --LMS
Ok. What protists are people familiar with that reference can be made to? The only ones I can think of that are truly well-known are Amoeba - maybe Paramecium and Euglena, but I'd be surprised if anyone has heard of those and didn't know they were protozoa. Multicellular forms people would know, but they're already mentioned on the page. Maybe it would help to say the rest comprise all single-celled forms, instead of are just single-celled? --JG
You'd know the answer to your questions better than I would, I'm sure. When I write an article or lecture about a philosophical subject to nonphilosophers, I try to ease my way into the subject, if I can. That's all. --LMS
The term seaweed covers a large array of lifeforms, some of which are in the plantate (plant) kingdom, and some of which are in other kingdoms, specifically protista. Are all commonly eaten seaweeds in the plante kingdom? Are there any protista seaweeds (or any protista anything) which are eaten? RK
The Sea Palm is a brown alga, and it is eaten. I believe kombu, one of the most commonly eaten algae, may also be from a brown (Laminiaria?). Brown algae are chromalveolates, definitely not plants. Safay 07:06, 19 Apr 2005 (UTC)
Perhaps we can add some sort of breakdown of the Protista "kingdom" like this?
There are many Eukaryote Kingdoms, including Plantae, Fungi and Animalia. The rest of the many eukarote kingdoms are, for the sake of convenience, lumped together into a super-kingdom known as "protista". However, DNA and RNA analysis of these lifeforms shows that the protista actually consist of many kingdoms, each as distinct from each other as plantae is from fungi or animalis. The precise terminology and method dividing these kingdoms is still undergoing many changes, and the terms below are not accepted by all authorities.
Diplomonads - Only a very small number of organisms are in this category.
Microsporida - These all live as parasites inside the cells of their hosts. They reproduce by sudden bursts of division to generate an instan swarm.
Parabasalids - Only a small number of organisms are in this category.
Myxomycota - True slime molds. They form patches of wet slime on fallen, rotting logs.
Euglenozoa - Single-cellular organisms that can move by waving a flagellum. Some have chloroplasts and engage in photosynthesis, while others do not.
Naegleria - They live as amoebas in dirty water, feeding on bacteria. They can develop flagella and swim.
Entamoeba - A kingdom with many kinds of parasitic amoebae. Some species in this kingdom live in the human colon.
Acrasiomycota - Cellular slime molds. They live in fresh water, on damp soil, or on rotting logs and vegetation.
Rhodophyta - Red seaweeds; these are not in the plant kingdom! About 400 species are known.
Alveoles - Contains three taxa (large categories): ciliates, dinoflagellates and apicomplexans.
- Ciliates - These have cilia all over their surface, and most have more than one nucleus. They live in both fresh and sea-water, and feed on bacteria.
- Dinoflagellates - Marine plankton that mainly live in salt-water. They are propelled by a single flagellum. Most live as single cells, while some species will form colonies. A few species have chlorophyll and undergo photosynthesis.
- Apicomplexa - These are all parasites of animals that can reproduce in bursts by producing a host of spores.
Stramenophiles - A group of six related protist kingdoms:
- Labyrinthulids - better known as marine slime nets. They form transparent colonies that live on seaweed. They secrete mucus and actin-like proteins, creating a trail that they then travel along.
- Oomycota - While not a true fungus- these are fungus-like protists. Some species in this kingdom include water moulds, white rusts and down mildews. They digest their food by secreting enzymes and absorbing he dissolved nutrients. They live off of dead, decaying material, or as parasites. The most infamous member of this kingdom is potato blight, which caused the Irish famine during the 1840s.
- Xanthophyta - Yellow green cells that can form colonies in fresh water. Only a hundred species in this kingdom are known.
- Chrysophyta - Golden algae, that live in fresh or salt water. Some are single-celled, some form colonies. The ones in salt water form beautiful silicon shells.
- Phaeophyta - Brown seaweeds; these are not in the plant kingdom! About 1500 species are known. All live in salt water. The most famous form is giant kelp, which can grow up to 100 meters (about 300 feet) long.
- Diatoms - A kingdom with about 10,000 species of marine plankton. They are surrounded by hard shells. They can live as single cells or form colonies. Most can photosynthesize.
Source: “The Variety of Life: A survey and a celebration of all the creatures that have ever lived” Colin Tudge, Oxford University Press, 2000
This looks good to me, but Josh Grosse is our Protista guy around here - I'm just a generalist who happens to have a lot of bacteria-focused micro training. --mav
Ha, I'm a mathematician by training, and this is just a subject I've done a great deal of reading in. Don't worry about stepping on my toes.
As for the above, it's fine but very incomplete. The full list of groups which currently are considered top-level is on evolutionary tree - as you can see, it's kind of long, which is why I originally broke things down into subpages. But we could have the whole thing here, if we really want. Alternatively we could mention a few notable groups, things like the Euglenozoa, without bothering to list smaller groups like Ebriids.
Removed from article:
- The following information is according to a taxonomic system that is generally considered to be obsolete. Many taxonomists agree that it should be divided into a large number of smaller kingdoms, though there is disagreement as to the precise method of division.
This statement is misleading since even though those that do use this taxon (still the vast majority of biologists) know that Protista is a multiphyletic taxon. The trouble is that there are perhaps dozens of kingdoms in Protista but most of those only have a very small number of known living genera. So most textbooks simply admit that Protista isn't really a kingdom in the classic sense and this is also what most professors still teach. But there is significant movement toward the 6-kingdom classification system in order to make the now standard 5-kingdom system be compatible at the kingdom level with the 3 domain system. I'm not aware of any major movement to split Protista into multi kingdoms and have that be the standard (it may happen eventually but until it does our articles should reflect, not lead, scientific development). --mav
Even systems that create new kingdoms from certain groups of protists still typically have a kingdom Protista for the variety of forms whose affinities are unknown. The only exception I can think of off the top of my head is one by Cavalier-Smith, which has a paraphyletic kingdom Protozoa filling exactly the same function. I've changed the article to try and make the status of the Protista a little more clear, though really I felt the description given was adequate. Anyone who feels they can do a better job, please help out! Why is it, btw, that the only interest anyone shows in this group is how it is divided into kingdoms? -- Josh
When wikipedia was first started, there was no source on the different groups that was both up to date and comprehensive. Most of these protist pages were created with the aim of (perhaps) someday filling that niche, essentially in keeping with the stated aim on WP: Tree of Life of classifying all living things down to genera. Since then various other sources have made considerable improvements in this regard; searching for material on some of the newer groups, I ran into this page (http://microscope.mbl.edu/reflections/scripts/protist.php), which includes a full and recent classification system with considerable detail about (most of) the taxa. They did a really excellent job, and I don't think that we would want to duplicate their efforts, even if their was a hope of us achieving the same level of quality. So the question now is, what do we hope to achieve with our Protista section? I was wondering if anyone had any ideas for what sort of goals we should be setting.
- Although many of the products will function in a similar way their method of producing material is very different than ours and much more importantly their text is not free as in libre. Our goal is to provide a living resource of information that is freed from the normal constraints of copyright law and editorial control. I see no reason why we should curtail what we are doing here just because somebody else is working on similar things. Our projects are sufficiently different that they are not really in competition with each other. But we could, of course, use them as an information (not text) resource. Some cooperation also may be possible esp with the use of images. If all they require is attribution then that would be great. --mav
I'm well aware of the special and occasionally superior nature of wikipedia. My main concern was the information, since faced with few reasonably comprehensive sources on relatively new or poorly known groups, any attempt at utilization seems like it is going to border dangerously on plagiarism. We can avoid this for the big, well known taxa, but it seems like something we would have to deal with eventually. I will look into use policies for things like images later, but at the moment I just wanted to raise the issue, while it was fresh in my mind.
I've added a few major groups to the taxobox, since it seems important to people that we have something there. The selection is meant to include all the most notable protists that we can reasonably treat as phyla - the major groups of algae and alveolates, groups containing the best-known flagellates, and groups corresponding to the traditional rhizopod classes (lobose, filose, reticulose) as closely as possible. On the other hand, the radiolaria and heliozoa are completely omitted because there still isn't any concensus on how monophyletic they are. The green algae, Myxozoa and Microsporidia are skipped because they're now considered in other kingdoms.
It's not meant to be complete, but hopefully this is a satisfying compromise. Josh 06:45, 15 Aug 2004 (UTC)
The Linnean system is not dead, but taxonomic ranks are dying as more phylogenetic information emerges. Whether or not PhyloCode will emerge as the newly accepted taxonomic system in the scientific community is not clear. What is clear is that a rank-based taxonomic system is insufficient and becoming more useless (from a phylogenetic systematics point of view) every time we collect more data.
Protists are the perfect example of why ranks like "Kingdom" are not going to survive, and at the most basic level will not make any sense once the early history of life is more clearly understood.
So, I too think the discussion should move away from an emphasis on what's a kingdom and what's not. It was said that people come here to find out what a protist is. The people who care about resolving the deep roots of the eukaryote tree, the ones who are making the taxonomic decisions with their publications, they don't need Wikipedia. The people who are worried about the tree of life will go to the ToL project website, whose function is to address this very problem. Let's concentrate on showing what protists are and what makes eukaryote diversity so fascinating.
Safay 04:02, 30 Mar 2005 (UTC)
The problem is that protists are essentially a kingdom, not much more. They aren't a clade, and they aren't much of a grade - there aren't many things they have in common besides some sort of simplicity. Pages on protist groups can and do go into more detail, but here there isn't much to say besides what they include and how they are classified. And I don't think it's clear that ranks like kingdom are going to be abandoned, so some variations should be noted. Josh
