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About Darwinsbulldog

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  • College Major/Degree
    B.A. (West Aust) Env Science, (Murdoch)
  • Favorite Area of Science
    Evolutionary theory
  1. Maybe so, but one would risk oxygen narcosis.
  2. Whatever rocks your boat. Believe or not believe. And yet you are making claims about nature....that natural beauty and order etc are not due to natural processes, but supernatural ones. Also, absolute proof or disproof in science is probably impossible. [To make an absolute claim, you would have to have absolute knowledge. ] But i think you are pulling my leg! And the beauty thing? yes there is beauty, but also ugliness in nature. If there are god, they are probably cunts. A "benevolent god" certainly dreamed up this monster:- http://www.suite101.com/content/isopod-parasite-eats-fish-tongue-a148659 Then again, it is only doing it's thing...natural selection and all that.
  3. Unfortunatly I don't have access to that Pennisi paper.
  4. Some parts of the human [and of course other organism] genomes possess endogenous endoviruses...genes sequences very similar to retroviruses in the wild. It might help to check out a paper like this one:-
  5. Words in science have specific meanings which may bear little or no relation to the vernacular. An obvious example of this is pre-adaptation. [s.J.Gould suggested exaptation instead]. Obviously, pre-adaptation has a specific meaning within evolutionary theory, meaning that a gene, trait, organ that evolved for one purpose gets co-opted for a new one. An example is bird feathers. Bird feathers could have originally been used for thermo-regulation or display [and both used today for those roles too], but are also used for flying. Physical DNA is not important, it is the information content which is replicated. This is what is mean by the "survival" or immortality of genes. But genes do die out, or mutate. "Selfishness" is another metaphor. It means that genes replicate. But the key thought here is replication, not survival. Obviously, if the vehicle of those genes dies before reproduction, then the genes are not passed into future generations. "Survival" is therefore a necessary, but not a sufficient condition for gene replication. It depends on the organism and it's style or mode of reproduction. [sexual, asexual, etc]. Organisms are in some sense, gene vehicles that provide and arena for the cooperation and conflict of genes. Genes mainly work together and cooperate, but as others have pointed out, cancer is an example where they don't. Cancer cells are much simpler than normal somatic cells and so they can reproduce faster. In evolution, "selfish genes" such as segregation distorters can screw up sex ratios, and even cause extinction and pseudoextinction. [speciation] Phadnis, N. and H. A. Orr (2009). "A Single Gene Causes Both Male Sterility and Segregation Distortion in Drosophila Hybrids." Science 323(5912): 376-379. Jaenike, J. (2001). "SEX CHROMOSOME MEIOTIC DRIVE." Annual Review of Ecology and Systematics 32(1): 25-49.
  6. Yes and no. I have seen wiki articles range from the bloody excellent to the pathetic. It is good for a quick reference to get you started, think up keywords for literature searches, and glance at the references listed by the article. But there is no substitute to going to the primary sources and doing your own research.
  7. IMHO, science confines itself to to asking falsifiable questions and determining the answers [which are always tentative] by a differential diagnosis of the evidence for and against an idea. A natural selection of sorts, where the "fittest idea" has the most evidence to back it up, and little or ideally no evidence which contradicts it. [if such contrary evidence does come to light, the theory is thrown out or modified according to the severity of the anomaly. As others have said, to some extent science is natural philosophy, but only in the limited sense I have outlined above. Philosophy explores ideas which are not constrained by reality, only by logic. Because philosophy can ignore evidence, it can sometimes build magnificent logical structures that may bear little or no relation to reality [whatever reality is]. Philosophy, or at least the philosophy of science is of great value to science by pointing out possible problems in induction, evidence, falsification and so on. Some very good cautionary tales have come from philosophy and good scientists take these to heart. However, some philosophers can become irrationally overcritical about scientific "truths". That science is limited and can have it's problems does not detract from the fact that it is about the best methodology around for discovering "truth" about nature. other systems, especially religious attempts to explain nature have consistently and abjectly failed, and yet the religious are those that do claim to absolute truth and yet have the least basis for asserting those 'truths".
  8. Mayden (1997) lists about 22 concepts & definitions of species, as I recall: The biological species concept, the ecological species concept, the cladistic, the phylogenetic, the evolutionary, the morphological and so on. Mome of this invalidates the reality of species. With lots of modes of reproduction [asexual, sexual, budding, fission, LGT, etc] and inheritance, it is not surprising the life does not fit perfectly well into little boxes. Generally, the BSC is fine for most things except obligate asexuals. Mayden, R. L. (1997). A hierarchy of species concepts: The denouement in the saga of the species problem. Systematics Association Special Volume Series; Species: The units of biodiversity: 381-424. As to the gradualism vs PE thing. Darwin never said that things have to evolve at the same rate. We now know that great morphological changes can occur though very small modifications of Hox gene expressions with gene regulatory networks. So variable environments can lead to more evolutionary change than stable ones...no surprise there. See these two papers by Emlen on Dung beetle horns:- EMLEN, D. J. (2000). "Integrating Development with Evolution:A Case Study with Beetle Horns." BioScience 50(5): 403-418. Emlen, D. J., L. Corley Lavine, et al. (2007). "On the origin and evolutionary diversification of beetle horns." Proceedings of the National Academy of Sciences 104(Suppl 1): 8661-8668. Hox and related gene clusters are highly conserved in evolution. They go back at least 500+million years to before the Cambrian Burgess Shale fauna. And yet they are flexible enough for great change and innovation to occur, via gene duplication, function gain, function loss, and subfunctionalization. For a detailed view, read:- Carroll, S. B. (2005). "FROM DNA TO DIVERSITY: Molecular Genetics and The Evolution Of Animal Design". Oxford, Blackwell. for a less technical account read:- Carroll, S. B. (2005). Endless Forms Most Beautiful:The New Science Of Evo-Devo and the Making Of The Animal Kingdom. London, Phoenix. Sex determining pathways [either genetic or environmental -such as temperature] can feed into the gene regulatory networks to express sexual dimorphic traits, as we saw in the Emlen papers above. The mammal male sex determining gene on the Y chromosome is called SRY, and you can see how it interacts with the Hox network to produce sexual dimorphic features here:- DiNapoli, L. and B. Capel (2008). "SRY and the Standoff in Sex Determination." Mol Endocrinol 22(1): 1-9. and here:- Foster, J. W., F. E. Brennan, et al. (1992). "Evolution of sex determination and the Y chromosome: SRY-related sequences in marsupials." Nature 359(6395): 531-533. And Lance discusses sex determination in reptiles here:- LANCE, V. A. (1997). "Sex Determination in Reptiles: An Update." American Zoologist 37(6): 504-513. I hope that helps. PS. There is also a very interesting paper by Airoldi, who has found that a single amino acid change can alter the ability to specify male or female organ identity! Airoldi, C. A., S. Bergonzi, et al. "Single amino acid change alters the ability to specify male or female organ identity." Proceedings of the National Academy of Sciences. Happy reading.
  9. True, chemists and engineers are the worst. Mathematicians that I know of also. And the odd physicist. Even one creationist cretin is one too many if they have been awarded a PhD in any science. I am going on anecdotal and personal information, and on encounters on forums like RDF and Rational Skeptics.
  10. I agree. Except I was not just talking about human life, but all life. More physicists and mathematicians seem to subscribe to creationism. Biologists seldom do, at least not the good ones. There is Michael Behe, of course, but I don't rate him highly.
  11. Males and females have different "interests" [or at least their genes do]. But they are obliged to cooperate because they share a common genetic destiny. That is, they have to cooperate to reproduce. But nevertheless things can go haywire. Like segregation distortion. [Meiotic drive]. So basically, an mutation can act to reduce the fitness of the other sex. If it goes too far, then the species can go extinct. But you were talking about sexual dimorphism. That is usualy caused by male-male competition. [eg Irish Elk or seals] or female choice [peacock's tails]. Interestingly, in mammals the male SRY gene is able to produce modular changes via interacting with gene regulatory networks, especially Hox. This interaction between sex determination pathways and developmental pathways can also work in insects, or any bilateral metazoa really. This is why male dung beetles can have huge horns, and females small ones.
  12. I have two eeePC 's, one is solid state harddrive [flash mem] and the other has a conventional laptop harddrive. I have Linux on both, which I have tuned and turned off demons I don't need. They are fast. I use the solid state one for overseas travel, and I have dual-booted the other with Linux + XP [in case I need it, which is rare].
  13. I don't know about mad, but physicists and mathematicians are the most deluded. They think that life can be reduced to a formula. Biologists are the sanest, even though they use some maths, they are not obsessed with it.
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