Darwinsbulldog

Maybe so, but one would risk oxygen narcosis.

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.

Unfortunatly I don't have access to that Pennisi paper.

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:-

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.

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.

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".

http://speaklolcat.com/

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.

Very good to know!

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.

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.

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.

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].

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.

Science is not about belief, or lack of belief, it is about testing various ideas to destruction and seeing what the evidence leaves you with. Credulity or incredulity has nothing to do with it. Nevertheless, there has been something of a "credibility gap" with coding mutations [ie. changes in proteins] being able to supply enough variation to supply the diversity observed. But since the 1980's advances in non-coding DNA elements, such as Hox genes and clusters have explained why it is possible for a single mutation in Hox expression to have huge morphological and phenotype effects, and thus be visible to selection. In other words, the concept of the "hopeful monster" as Gould and others have called it, has regained respectability. Knockout experiments and "rescue" experiments have not only elucidated many of the mechanisms of development, but shown how these genes are both highly conserved, and yet able to produce huge changes to morphology. Hox genes have been around since at least the times of the Cambrian "explosion", over half a billion years ago, and the first "proto-Hox" genes seem to predate the bilateria. [Animals that show bilateral symmmetry, like us: two eyes, two legs..a mirror image on each side]. Plants have their own Genetic Regulatory Networks [GRN's] called MADS genes. The interaction of sex determining genes and the Hox family of genes explains how sexual dimorphism works too. Some animal sex determination pathways can be activated by temperature [eg Crocodiles], and of course hormones and other [internal and external] environmental inputs. A good book for the layperson is by Sean B. Carroll [note the "B" as there is a creationist called Sean Carroll also!] Carroll, S. B. (2005). Endless Forms Most Beautiful:The New Science Of Evo-Devo and the Making Of The Animal Kingdom. London, Phoenix. If you want to go into more technical detail:- Carroll, S. B. (2005). "FROM DNA TO DIVERSITY: Molecular Genetics and The Evolution Of Animal Design". Oxford, Blackwell. Carrol is not the only good source on this stuff, [there are plenty of other good sources] but I am more familiar with the material in these books because I own them. [And they are getting pretty dog-eared!] Another interesting source on evo-devo and macroevolution for the layperson is:- Shubin, N. (2009). "YOUR INNER FISH: The Amazing Discovery Of Our 375-million-year-old Ancestor". London, Penguin. A very technical book on evo-devo is:- Minelli, A. a. F., Giuseppe, Ed. (2008). Evolving Pathways Key Themes in Evolutionary Developmental Biology. Cambridge, Cambridge University Press. A very dated, but prescient book by S.J. Gould:- GOULD, S. J. (1977). "ONTOGENY and PHYLOGENY". Cambridge, Mass & London, UK., Belknap, Harvard University Press. [Heavy-going, but worth it. ] Of course, now that I have given you some key-words, you can find some sources on google scholar. Enjoy, and if you have any further questions, please ask.

Wrong. Somatic evolution. eg Cancer is a prime example of this. We can work out the probability that an oncogene has been fixed in time (t) with:- P(t) = 1- e -Nupt (Nowak, 2006: 220) Where N is the number of cells in a compartment, u is mutation rate per gene per cell, p is the Moran process [1-1/r /1-1/r N], t=time Although all cells share the same genome, cells are compartmentalised and specialised, and face different environmental challenges, and have different genes expressed. REF:- Nowak, M. A. (2006). EVOLUTIONARY DYNAMICS: Exploring The equations of Life. London, Harvard University Press.

Advanced metazoans are highly "disciplined" communities of cells. Natural selection has ensured that growth and repair is under strict control. The worst and most aggressive and untreatable cancers seem to involve the knock-out mutation of the TP-53 gene and several others. Once the expression of the P-53 protein is knocked out, the body is less able to detect cancer cells, and switch on other anti-cancer genes. That is vastly over-simplifying things. Cancer is an example of somatic evolution, whereby the more simple and less differentiated cancer cells outgrow [[replicate faster than] the normal cells in tissues. The gene regulatory Networks have broken down. So cancer cells look primordial.

If the gene is close enough, then you can use a gene from species X to "rescue" the "same" gene in species Y, even though there may be great genetic distance between the two species. Experiment shave knocked out a fruit fly gene, and rescued it with the equivalent human gene. So presumably, becuase the rescue of function works, then the human gene is being expressed in the fly. That surely implies that the info from the human gene gets put into the 'fly" mRNA, and goes to the fly ribosome, and the human protein pops out at the other end of the assembly line.Genes are just software. So long as the organism is "IBM-compatible" , the program will run.

Laws are different from theories. Theories are composed of model, prediction, and explanation. Laws are mathematical relationships which do not change.

I think that evolution has "direction" and "purpose" without implying any teleological or metaphysical woo to those words. "Direction" is the sense that fitness, born of natural selection, can avoid extinction. {for a time}. And "purpose" is the sense that species tend to fill niches opportunistically, but of course, gaps occur. NS is both aided by, and in opposition to, drift. It is the ability of evolution [by totally natural means] is able to fill what Daniel Dennett calls 'design space" by using cranes like sex to give the illusion of intent. Further, we know [with hindsight] evolution was able to produce [at least once] beings with mind who can create and innovate from living material that could create and innovate without mind. And that this material arose out of chemical evolution...the presence of a self-replicating object that copied itself sloppily enough to allow mistakes and thus variation, and so move from chemical evolution to the biological. The philosophical impact of this is profound. Life can pull itself up by it's own bootstraps and create mind. Within a mere four billion years. A mind that can then peer back to it's chemical origins. All this without woo. No divine knob-twiddler is required. Merely some local matter-energy gradients. We may never know all the detail of how it all happened. But we do not need to invoke Kenneth B. Miller's "god-of-the-quantum-gaps", nor Ayala's "Knob twiddling, switch-pulling god who kick-started evolution god". Just brute facts and good theory. That is the true "magic" of our existence.

Sorry, I was not implying that popularity of opinion is any reliable measure of efficacy, I was just replying to your query about me using 'economic language" in the context of a biological problem. The answer, of course, rests with the evidence as always. One of the difficulties in this sort of general discussion about trends is the contrary data people can point to as evidence for this or that hypothesis. We are nowhere near doing basic descriptions of all the species, never mind detailed studies on the evolutionary history and other biological aspects of those species. Estimates vary on the number of extant and extinct species, so we don't even know how many species are still to be formally described. If different disciplines like [econs and biology] sometimes have convergent views or ideas, and if those views are based on evidence, I have no problem with a hypothesis that may be borrowed from somewhere else. Yes, I was talking about specialization vs generalisation, and generalisation is a sort of specialisation. Natural Selection, Sexual selection, drift -we can talk of many things and use many criteria to try to judge what species are the "most evolved".

Not really. The nature of the question is very general in any case...we were talking about general trends. I take your point about my lack of specific examples, but in biology, the exception proves the rule. Carnivores are in the higher trophic levels, and while meat [protein] is energy rich, it's supply is often uncertain. Herbivores, although the supply of food is more certain, contains less calories. Omnivores may be able to access either meat or veg, but they will, in general, be less efficent than carnivores or herbivores. To get better at either, they would have to have their feeding structures etc, modified to be able to better exploit the resource. "Economics" in biology is very relevant. It seems to me tha you have not studied much ecology. Life histories of organisms are very important. Take for example Pacific Salmon. Many species are semelparous. [Have only one reproductive attempt before death] But Atlantic salmon are iteroparous. [More than one reproductive attempt.] Why? You have to look to their environments and their energy budgets. Salmon go back to their birthplace to spawn. In Pacific salmon, the effort of going upstream, jumping up watefalls, against strong currents, etc takes a lot of energy. An animal has only so much energy, some of which has to go to body maintainence, predator avoidence, immunological defence, feeding, reproduction, etc, etc. So a compromise has to be reached. By neglecting maintainece, and putting all it;s effort into one reproductive event because of the effort to get to it's spawning place, the salmon is unlikely to survive after spawning. There is an "opportunity cost" or "trade-offs" to everything. The Atlantic salmon in contrast, faces less of a physical challenge to get to it's spawning grounds, and so can afford to spend a little more on body maintainence so that it can survive several spawning events in it's lifetime. Neither strategy is better than the other in absolute terms, just more relevant to a particular environmental challenge. Over-fishing has caused evolution in commercial fish stocks, driving smaller sizes. Because smaller fish escape though the holes in nets, they survive, so selection pressure will tend to drive them to reproduce when small. So actually, you have it the wrong way round. Economists learn their theory from biologists. And biologists learn it from nature. A few google searches may help you here. eg:- Crespi, B. J. and R. Teo (2002). "Comparative phylogenetic analysis of the evolution of semelparity and life history in salmonid fishes." Evolution 56(5): 1008-1020. The selective pressures involved in the evolution of semelparity and its associated life-history traits are largely unknown. We used species-level analyses, independent contrasts, and reconstruction of ancestral states to study the evolution of body length, fecundity, egg weight, gonadosomatic index, and parity (semelparity vs. degree of iteroparity) in females of 12 species of salmonid fishes. According to both species-level analysis and independent contrasts analysis, body length was positively correlated with fecundity, egg weight, and gonaosomatic index, and semelparous species exhibited a significantly steeper slope for the regression of egg weight on body length than did iteroparous species. Percent repeat breeding (degree of iteroparity) was negatively correlated with gonadosomatic index using independent contrasts analysis. Semelparous species had significantly larger eggs by species-level analysis, and the egg weight contrast for the branch on which semelparity was inferred to have originated was significantly larger than the other egg weight contrasts, corresponding to a remarkable increase in egg weight, Reconstruction of ancestral states showed that egg weight and body length apparently increased with the origin of semelparity, but fecundity and gonadosomatic index remained more or less constant or decreased. Thus, the strong evolutionary linkages between body size, fecundity, and gonadosomatic index were broken during the transition from iteroparity to semelparity. These findings suggest that long-distance migrations, which increase adult mortality between breeding episodes, may have been necessary for the origin of semelparity in Pacific salmon, but that increased egg weight, leading to increased juvenile survivorship. was crucial in driving the transition. Our analyses support the life-history hypotheses that a lower degree of repeat breeding is linked to higher reproductive investment per breeding episode, and that semelparity evolves under a combination of relatively high juvenile survivorship and relatively low adult survivorship. Unwin, M. J., M. T. Kinnison, et al. (1999). "Exceptions to semelparity: postmaturation survival, morphology, and energetics of male chinook salmon (Oncorhynchus tshawytscha)." Canadian Journal of Fisheries and Aquatic Sciences 56(7): 1172-1181. Between 2.1 and 6.8% of fall-run male chinook salmon (Oncorhynchus tshawytscha) reared in two New Zealand hatcheries matured as yearling, parr, of similar size to immature siblings. The incidence of mature parr in 58 half-sib families ranged from 0 to 69% of the available males. Although chinook salmon rue normally semelparous, about 80% of mature parr survived to mature again at age 2, and all fish held for another year matured again at age 3. All three ages produced milt that successfully fertilized eggs. Morphological development in mature parr and repeat-maturing males was consistent with that of older, first time maturing males. The gonadosomatic index for mature age-2 males was 11.7, 7.2, and 5.4% for repeat-maturing males, freshwater-reared males, and sea-run males, respectively. Muscle energy density for repeat-maturing males (4.45 kJ/g) was lower than for normal males (5.20-5.45 kJ/g) and negatively correlated with the gonadosomatic index. Although we think it unlikely that repeat maturation occurs regularly in the wild, our results indicate that under favorable conditions, chinook salmon can exhibit some iteroparous traits. We hypothesize an evolutionary continuum between semelparity and iteroparity in salmonids, primarily characterized by modifications in a few key energetic and physiological thresholds. Narum, S. R., D. Hatch, et al. (2008). "Iteroparity in complex mating systems of steelhead Oncorhynchus mykiss (Walbaum)." Journal of Fish Biology 72(1): 45-60. This study investigated diverse reproductive types in complex mating systems of steelhead Oncorhynchus mykiss. Postspawned steelhead (kelts) were sampled during attempted downstream migration over Lower Granite Dam on the Snake River, U.S.A. Multilocus microsatellite genotypes (14 loci) were used to assign unknown origin, kelt individuals to upstream populations of origin. Results indicated that iteroparity is a life-history trait that remains in several tributaries of the Snake River basin despite strong selection against downstream adult passage because of hydroelectric dams. The largest populations of steelhead in the Snake River, however, were only weakly represented (Clearwater River = 7.5% and Salmon River = 9.4%, respectively) in the kelt steelhead mixture relative to the Grande Ronde River (18.2%), Imnaha River (17.4%), Pahsimeroi Hatchery (25.2%) and Asotin Creek (22.2%). A lack of correlation between population escapement size and kelt proportions (P > 0.05) suggests that iteroparity was not uniformly expressed across populations, but was significantly negatively correlated with body size (P < 0.05). Iteroparity may be a valuable source of genetic variability and a conservation priority, especially in years with poor recruitment or in recently bottlenecked populations. © 2008 The Authors Journal compilation © 2008 The Fisheries Society of the British Isles. Unwin, M. J., M. T. Kinnison, et al. (1999). "Exceptions to semelparity: postmaturation survival, morphology, and energetics of male chinook salmon (Oncorhynchus tshawytscha)." Canadian Journal of Fisheries and Aquatic Sciences 56(7): 1172-1181. Between 2.1 and 6.8% of fall-run male chinook salmon (Oncorhynchus tshawytscha) reared in two New Zealand hatcheries matured as yearling, parr, of similar size to immature siblings. The incidence of mature parr in 58 half-sib families ranged from 0 to 69% of the available males. Although chinook salmon rue normally semelparous, about 80% of mature parr survived to mature again at age 2, and all fish held for another year matured again at age 3. All three ages produced milt that successfully fertilized eggs. Morphological development in mature parr and repeat-maturing males was consistent with that of older, first time maturing males. The gonadosomatic index for mature age-2 males was 11.7, 7.2, and 5.4% for repeat-maturing males, freshwater-reared males, and sea-run males, respectively. Muscle energy density for repeat-maturing males (4.45 kJ/g) was lower than for normal males (5.20-5.45 kJ/g) and negatively correlated with the gonadosomatic index. Although we think it unlikely that repeat maturation occurs regularly in the wild, our results indicate that under favorable conditions, chinook salmon can exhibit some iteroparous traits. We hypothesize an evolutionary continuum between semelparity and iteroparity in salmonids, primarily characterized by modifications in a few key energetic and physiological thresholds. read some of these papers, and if you take out the species names etc, they do sometimes read like papers in economics. But i have digressed a little, mainly to address your claim that I was thinking as an economist rather than as a biologist. The terms like "predator", "herbivore" and omnivore are too generalist in some ways. Some organisms that are carnivores will sometimes be able to eat plants, and some herbivores can eat meat. Some omnivores tend to eat more meat and less herbivory, and so on. However, an obligate carnivore [herbivore etc] is specialized. I am not denying that bears, which are part of the carnivore family, often eat a lot of plant material. hence the difficulty with examples. Nevertheless, these concepts can be tested. And have been tested. Palaeontologists and biologists have done work on species extinction rates for different groups like carnivores, Herbie, and omnis. By comparing background extinction rates with extinctions in mass extinction periods, we can see clear trends in survivorship in these ecological groups. See studies Stanley and Raup, Simpson, and many others. Generally, "generalist" /omnivores/small species tend to survive mass extinction events, while specialists to be when the environment is more stable. The marine environment is generally more stable than land environments, which is why you see more "living fossils" in sea environments than land. eg coelacanths and Ginkgos on land. There are 'exceptions" of course.

Yeah, but you still have the problem of the total energy budget for the organism. As a generalist , you can survive in a wider range of conditions, but differential reproduction from more specialized types will squeeze you out of the market. All organisms are selected on the basis of whether or not their "life strategies" work. How much to invest in reproduction, how much to invest in cell repair, immunology, etc, etc. Although there appear to be many "solutions" or to put it another way "life history strategies" , some are more equal than others. Very few large organisms hit on the "perfect strategy" for all seasons. So in a slowly changing environment, the generalist will tend to go extinct before his "u-beaut" "I can survive a catastophy generalist" genes can some into play. Some do, of course. Procaryotes are best at this, without question. Amounst the Metazoa, small is best. Rat-shrew-like things in mammals, most, if not all stem metazoans adaptively radiate after a big extinction event.

I think it depends. Suppose I present a hypothesis like: "All vertebrates require haemoglobin". It sounds good, I can test it on many vertebrates, and it would ring true. But as with all theories, it is tentative. As we expand our knowledge, theories can become false, as in this case:- http://www.eurekalert.org/multimedia/pub/3289.php [Antarctic Ice Fish] But was the theory really a false one? It depends on what assumptions I made. At STP, the theory definitely works in all cases. Vertebrates are too large in all three dimensions to work around the surface area to volume ratio. [small worms and flatworms do it by not getting so large that the cells most distal to the oxygen supply are still only a few cells away from the surface-but in any case, they are not vertebrates]. Vertebrates compensate for their small surface area to volume ratio by having gills and/or lungs. This increases their surface area because although lungs and gills are "inside" topologically they are still on the surface of the organism. They also have a circulatory system which further reduces oxygen gradients, thus preventing anoxia in the deep tissues. So perhaps my new hypothesis should read: "All vertebrates require haemoglobin in STP conditions. [sTP=Standard Temperature and Pressure]. Obviously, one can't put everything into a model, or it would be as complex as the system it is trying to emulate. So, almost by definition, every theory has to be "wrong" in that they are approximations. Of course, well thought out models have the least mistakes. Well tested models that are true under a wide range of conditions are more parsimonious than models that only work in more restricted conditions. In Newton's day, they could only be accurate to one part in a thousand, so it is doubtful that he could have ever formulated Einsteinian relativity. Today, physics and sciences genrally have better measurement techniques and instrumentation that is accurate in some cases, to dozens of decimal places. this surely affects the quality of the models we can produce.