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Evolution of flagella - Wikipedia, the free encyclopedia The evolution of flagella is of great interest to biologists because the three known varieties of flagella (eukaryotic, bacterial, and archaebacterial) each represent an extremely sophisticated cellular structure that requires the interaction of many different and finely-tuned systems to function correctly. There are two competing groups of models for the evolutionary origin of the eukaryotic flagellum (referred to as a cilium below to distinguish it from its bacterial counterpart). Margulis is, though, still strongly promoting and publishing a revised version of her hypothesis (Margulis' 1998 book Symbiotic planet: a new look at evolution has some frank autobiographical comments about her support of the symbiotic hypothesis for the origin of the cilium). en.wikipedia.org /wiki/Evolution_of_flagella   (1109 words)

Evolution vs. Creationism Evolution by natural selection is a scientific theory, in that it claims that current variation among organisms arose by billions of generations of selection of the "most fit" ancestral organisms that changed in form and function over the eons. Evolution by natural selection makes a suite of predictions about how organisms are related to one another, how certain "selective pressures" (e.g., predators, availability of mates, global warming) will affect body form and function, and how the fossil record should be structured. Again, they are using the theory of evolution as their basis (in a negative sense) and stating "if it hasn't been explained yet by evolution by natural selection, then it never will be and thus must have been created by a supernatural intelligence." This way of thinking is antithetical to the entire enterprise of science. www3.uakron.edu /biology/evolution/html/id_supernatural.htm   (835 words)

Flagellum Summary Flagella are tiny, hair-like appendages on the surface of many cell types that provide either the motile force for movement or that serve as sensory receptors for information about the cell's external world. Because the doublets are firmly anchored to the cell wall by a centriole, sliding of adjacent tubules causes a bend to propagate along the length of the flagellum. Bacterial flagella are thicker than archaeal flagella, and the bacterial filament has a large enough hollow "tube" inside that the flagellin subunits can flow up the inside of the filament and get added at the tip; the archaeal flagellum is too thin to allow this. www.bookrags.com /Flagellum   (1988 words)

The Serial Endosymbiosis Theory of Eukaryotic Evolution The SET states that the evolution of eukaryotes from prokaryotes involved the symbiotic union of several previously independent ancestors. As a result, Darwin’s notion of evolution as the "survival of the fittest," a continual competition among individuals and species, is incomplete. This hypothesis is also referred to as direct filiation, which is the nonsymbiotic view of evolution that emphasizes the role of various kinds of mutations in the evolutionary separation of eukaryotic cells from prokaryotic cells. www.geocities.com /jjmohn/endosymbiosis.htm   (2294 words)

Evolution: Glossary concerted evolution: The tendency of the different genes in a gene family to evolve in concert; that is, each gene locus in the family comes to have the same genetic variant. evolution: Darwin defined this term as "descent with modification." It is the change in a lineage of populations between generations. In general terms, biological evolution is the process of change by which new species develop from preexisting species over time; in genetic terms, evolution can be defined as any change in the frequency of alleles in populations of organisms from generation to generation. www.pbs.org /wgbh/evolution/library/glossary/index.html   (13292 words)

Brainstorms: Evolution in Single and Dynamic Environments Evolution in a dynamic environment is a very different phenomena from evolution in an artificially stable environment. Evolution in a single environment might be described as evolution the photograph and evolution in a dynamic environment might be described as evolution the movie. Eventually, however, evolution in darwinian terms is defined as the outcome of differential reproductive success, and this is by definition an average over the course of the life of the individual (or gene, or group of individuals, or combination thereof, depending on what "school" you subscribe to). www.iscid.org /boards/ubb-get_topic-f-6-t-000086.html   (4421 words)

Irreducible Complexity Demystified The chemistry and probable evolution of this system are explained in much greater detail in Shelly Copley's article "Evolution of a metabolic pathway for degradation of a toxic xenobiotic: the patchwork approach" in Trends in Biochemical Sciences (5). Flagella participate in the cause of quite a few bacterial diseases, including diarrhea (38), ulcers and urinary tract infections (39). Evolution of a metabolic pathway for degradation of a toxic xenobiotic: the patchwork approach. www.talkdesign.org /faqs/icdmyst/ICDmyst.html   (9143 words)

Evolution of Bacterial Flagella Eubacteria and archebacteria have flagella that look almost identical, except that they are composed of completely different, non-homologous proteins (and they are both different from the eukaryote flagellum)(3,12). A possible scenario for the evolution of the eubacterial flagella is as follows: a secretory system arose first, based around the SMC rod pore forming complex, which was the common ancestor of the type III secretory system, and the flagellar system. Thus, if the flagella is a secretory system that has been co-opted for a motile function (while still retaining some of it's secretory function), then the ICness of the system is in the mind of the beholder, and a clear path for it's evolution is opened up. www.health.adelaide.edu.au /Pharm/Musgrave/essays/flagella.htm   (2420 words)

Flagellum - Wikipedia, the free encyclopedia In some bacterial species the flagella twine together helically outside the cell body to form a bundle, large enough to be visible in the light microscope. Eukaryotic flagella are not the same as flagella of bacteria. Instead, some components of archaeal flagella share sequence and morphological similarity with components of type IV pili, which are assembled through the action of type II secretion systems (the nomenclature of pili and protein secretion systems is not consistent). en.wikipedia.org /wiki/Flagellum   (1661 words)

Evolution -- Abiogenesis -- Origin of Life Evolution, technically, is about what happened after life arose on Earth. And this is a research publication list by the same author, dealing mainly with the evolution of amino acids and biological molecules. Evolution of the Bacterial Flagella : Michael Behe nominates the bacterial flagella as "irreducibly complex" and unable (or unlikley) to be produced via evolution. members.aol.com /darwinpage/abiogenesis.htm   (415 words)

CB200.1: Bacterial flagella and Irreducibly Complexity One plausible path for the evolution of flagella goes through the following basic stages (keep in mind that this is a summary, and that each major co-option event would be followed by long periods of gradual optimization of function): After the evolution of the T3SS pilus, the pilus diversifies for various more specialized tasks by duplication and subfunctionalization of the pilus proteins (pilins). Matzke, N. Evolution in (brownian) space: a model for the origin of the bacterial flagellum. www.talkorigins.org /indexcc/CB/CB200_1.html   (898 words)

Problems in Protein Evolution A problem with the evolution of proteins having new shapes is that proteins are highly constrained, and producing a functional protein from a functional protein having a significantly different shape would typically require many mutations of the gene producing the protein. The typical mechanism proposed to explain the evolution of new proteins is that an existing gene is duplicated, and one of the copies of the gene then begins a series of mutations that eventually results in a gene able to produce a new protein [Ohno 70]. According to the theory of neutral evolution, neutral mutations are eliminated from a population on the average in 2(Ne/N)ln(2N) generations (if I understand the matter correctly), where Ne is the effective population size, N is the population size, and ln is natural logarithm. www.cs.unc.edu /~plaisted/ce/blocked.html   (16250 words)

Brainstorms: Does Darwinism Predict the Absence of Irreducible Complexity? Mutations in the pil gene cluster (responsible for type IV pilus biogenesis and function) were found to be at least partially responsible for the loss of S motility in the majority of evolved lines. Notice that we can discuss the EVOLUTION of this organisms' ability to be motile without understanding anything at all about how the environment around it provides selective pressures that are overcome by whatever processes are being analyzed. If flagella are IC, then twitching motility is also because the twitching system has the same basic components as the archaeal flagellum. www.iscid.org /boards/ubb-get_topic-f-6-t-000165-p-2.html   (6001 words)

Evolution Education and the Law » 2006 » September A review, coauthored by Nick Matzke, of the evidence for the evolution of bacterial flagella appears in Nature Reviews Microbiology, while in Ohio there is renewed concern about the resurgence of attempts to undermine the treatment of evolution in the state science standards. A statement from FASEB in defense of teaching evolution, and a reminder from Geotimes that it isn’t only in the schools that it is in need of defense. Meanwhile, voters in Kansas are encouraged to keep the pressure on politicians who oppose evolution education, and a chapter from Chris Mooney’s The Republican War on Science is now available on-line, with a post-Kitzmiller update. www2.ncseweb.org /wp/?m=20060908   (173 words)

Evolution of the bacterial flagellum Evolution in (Brownian) space: a model for the origin of the bacterial flagellum While “Evolution in (Brownian) Space” was admittedly a first attempt, and I was a dedicated enthusiast rather than a professional, I think the model has stood up rather well over the last two and a half years. I took this position partially to show that even under this assumption the evidence for evolution was strong, and partially because the evidence seemed to lean slightly in that direction. www.talkdesign.org /faqs/flagellum.html   (8497 words)

CA350: Literature on evolution of biochemical systems Professional literature is silent on the subject of the evolution of biochemical systems. David Ussery, for example, found 107 articles on cilia evolution, 125 on flagella evolution, 27 on the evolution of the entire coagulation system, 130 on the evolution of vesicle transport, and 84 on "molecular evolution of the immune system" (Ussery 1999). A biochemist's response to "The biochemical challenge to evolution". www.talkorigins.org /indexcc/CA/CA350.html   (261 words)

Evolution News & Views: Judge Jones and the Shattering of Darwinist Illusions Evolution News and Views: Judge Jones and the Shattering of Darwinist Illusions His grasp of complexities like the evolution of bacteria flagella and blood clotting was impressive. Evolution News & Views presents analysis of that coverage, as well as original reporting that accurately delivers information about the current state of the debate over Darwinian evolution. www.evolutionnews.org /2006/12/judge_jones_and_the_shattering.html   (918 words)

Evolution   (Site not responding. Last check: 2007-11-03) Heterotrophs with flagella probably evolved from one heterotrophic prot-amoeba organism (as most heterotrophs did) which eventually developed into the flagellate ancestor. The other hypothesis for the development of flagella is that a microtubule growth eventually developed beyond the cell membrane, creating a flagellum. Phylogenetically, the heterotrophic groups of the Protist kingdom may have shared one common ancestor, but had different path of evolution into what organisms they are today. www.personal.psu.edu /users/k/n/knl113/evolution.htm   (278 words)

Evolution Education and the Law » Blog Archive » NCSE News, 2006/09/08 Evidence for the evolution of bacterial flagella includes the existence of vestigial flagella, intermediate forms of flagella, and, importantly, the pattern of similarities among flagella protein sequences. Pallen and Matzke offer a call for continued research on flagellar evolution, citing both the need to debunk “the suspicion among members of the public that maybe there is some mystery here, that maybe the ID proponents do have a point” and the prospect of thereby gaining further understanding of bacterial flagella. There is concern again about the resurgence of attempts to undermine the treatment of evolution in the state science standards in Ohio. www2.ncseweb.org /wp/?p=148   (948 words)

The Newsletter of The North Texas Skeptics The point is this: Evolution makes new machines (e.g., animals) from existing ones by allowing small genetic changes to creep in due to accidents of nature during reproduction. His main points of the chapter are: 1.) the complexity of the flagella, as evidenced by 2.) the large number of proteins involved in the cilia and flagella, (240 of which are required for a functional flagella), and 3.) the absence of scientific literature on the subject. The legislature later voted to put evolution back in after a debate in which a creationist senator brought a stuffed ape to the floor. www.ntskeptics.org /1999/1999november/november1999.htm   (2595 words)

Review of Michael Behe's "Darwin's Black Box"   (Site not responding. Last check: 2007-11-03) Behe claims that explaining evolution was "easy" before modern biochemistry discovered how complex life really is, and now that we have this vast amount of knowledge about how the cell works, we realize that it is simply too complex to have evolved by gradualism. Behe is quite critical of the Journal of Molecular Evolution, because most of the articles (85%, he reckons) deal with analysis of biological sequences, and hence somehow don't REALLY deal with evolution. Darwin's theory of evolution was such an accomplishment because it allowed a simple explanation for how all this diversity and complexity has arisen, and continues to arise. www.cbs.dtu.dk /staff/dave/Behe.html   (15268 words)

ToE-random mutation? Most mutation are deletrious to the organism, but evolution demands that there'd have to have been a slew of them, ALL individually advantageous ALL better than whatever was there before and give an overall new structure that was better than what was there before. To quote you again: "But that would impossible to demonstrate, i.e., prove a negative, unless evolution is a nondisprovable science kind of like astrology." First you say it is impossible to prove a negative, and now you are saying that a universal negative proves evolution wrong. He devoted ONE tiny paragraph to how a model for the evolution of the cascade blood-clotting sysem COULD have happened, but all it talks about is "because of gene duplication" OR proposes unregulatory steps, in a system where there's NO room for error. ibelieve.com /fb.aspx?m=1898485   (3689 words)

The Panda's Thumb Stuck on you, biological Velcro and the evolution of adaptive immunity It seems that the Discovery Institute, while disingenuously libeling a Federal judge for his routine use of findings of fact from a plaintiffs’ brief, has been engaged in plagiarism of its own work in a context where such copying is strictly forbidden. So it comes as no surprise that the staff of this friend of the DI has decided that the Smithsonian violated Sternberg’s rights and that new laws need to be passed to establish affirmative action for anti-evolutionists. www.pandasthumb.org   (3124 words)

Has Darwin's theory broken down? - Page 147 - Sean Hannity Discussion As a household example of irreducible complexity, Behe chooses the mousetrap—a machine that could not function if any of its pieces were missing and whose pieces have no value except as parts of the whole. I also thought the "evolution of the mousetrap" rebuttal against Behe was pretty cute. Miller’s argument is that since a subset of the proteins of the flagellum can have a function of their own, then the flagellum is not [irreducibly complex] and Darwinian evolution could produce it. www.hannity.com /forum/showthread.php?p=673048   (3220 words)

This is where my heterotroph page goes   (Site not responding. Last check: 2007-11-03) Here, we will focus on the most evolutionarily developed and complex protists, Heterotrophs with flagella. Heterotrophs with flagella encompass 2 classes of protists: sarcomastigophora (flagellates) and ciliophora (ciliates) The second class of heterotrophs with flagella, (we will refer to them as the ciliates), is considered the most complex group of protists. www.personal.psu.edu /users/k/n/knl113/whatishet.htm   (556 words)

1 Million Links, Creation Vs. Evolution DNA and Darwin: Research shows that evolution repeats itself in Caribbean lizards EVOLUTION - The basis of all life, or a fairy tale for scientists who reject God? The FACE that Demonstrates the Farce of Evolution www.wonderfulword.com /1millionlinks/Creation_Evolution.html   (1858 words)

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