From: sbharris@ix.netcom.com(Steven B. Harris) Newsgroups: sci.physics,misc.consumers,sci.med,sci.life-extension Subject: Re: Where There's Smoke (was Re: Microwave oven - big fight over process) Date: 6 Oct 1999 02:44:52 GMT In <939156920.10395.0.nnrp-11.9e98d142@news.demon.co.uk> Ian Stirling <root@mauve.demon.co.uk> writes: > >Carey Gregory <cgregory@gw-tech.com> wrote: >>standebj@slu.edu wrote: > >>>Which of the following animals has the largest brain mass-to-body mass >>>mass ratio: >>> >>>a) a parakeet b) a human or c) a bat > >>Hmmm... I'll go with (c) on the assumption that it's echo-location abilities >>demand a lot of brain matter. > >Me too, for that reason, and that masses of flying creatures tend to be >optimised downwards, so if you have a fixed brain size, due to echo location, >then the relative size will be high. > >I suspect that fruit bats will have smaller brain ratios, than insect eating >bats. It's a difficult question, since for birds, bats, and mammals, (and for that matter, for reptiles) the brain mass scales average as the 2/3 power of body mass, so the smaller the critter you have, the better the absolute ratio is. For any given size, there's a spread, and humans have about 8 times more massive brains than average for a mammal our size. But there's the same spread among birds and bats that there is for land mammals of the same size as birds and bats, and you really can't tell the difference between groups as a whole, on a graph. Cold blooded animals (reptiles, fish, amphibians) all scale the same 2/3rds power law, but with brains 1/10th as large at every size class. Dinosaurs have just the same brain size you'd calculate from being big reptiles. Their small brain/body ratio comes from size and reptile-hood, not from being ancient. From: sbharris@ix.netcom.com(Steven B. Harris) Newsgroups: sci.physics,misc.consumers,sci.med,sci.life-extension Subject: Re: Where There's Smoke (was Re: Microwave oven - big fight over process) Date: 6 Oct 1999 03:43:53 GMT In <7tb8l5$nnh$1@nnrp1.deja.com> standebj@slu.edu writes: >In article <7t1cj9$s2b@dfw-ixnews19.ix.netcom.com>, > sbharris@ix.netcom.com(Steven B. Harris) wrote: >> Sure, if you were a parakeet or bat you'd have a glucose of 2 >> or 3 times what you do, and metabolically live several times >> longer, true enough. But that's because Ma Nature invests a lot >> less repair energy in critters with brains than critters with >> something really useful, like wings. Though brains get us some >> metabolic time, to be sure. You win some, you lose some. > > >Speaking of which, here's a little quiz for everyone: > >Which of the following animals has the largest brain mass-to-body mass >mass ratio: > >a) a parakeet b) a human or c) a bat > >(Someone else will have to post the answer, I fear...) Parakeets and bats, of course, but only because they are smaller, and brain masses scale as surface area (2/3 exponent). A 20 gram warm blooded animal (bat, parakeet) has a brain which is (1/3,000)^2/3 =~ 1/200th the size of a 60,000 g animal (eg, humans), which means that its brain/body ratio is 3000/200 = 15 times better. Since humans are only about 7 or 8 times larger brained than other mammals of our general size, that gives birds and bats a 15:1 brain/body ratio over "standard" 60 kg mammals, and a 2:1 brain/body ratio advantage over humans, just from metabolism considerations. But they still get even more metabolic time for their size than even their brain size would suggest (at least 3 times what humans do, not 2 times). That difference, I presume, is due to wings. From: sbharris@ix.netcom.com(Steven B. Harris) Newsgroups: sci.skeptic,sci.physics,alt.atheism,alt.folklore.urban, alt.folklore.science,rec.org.mensa Subject: Re: Ancient Einstein UL(s) Date: 5 Jan 2000 05:37:34 GMT In <3872c6a6.52661040@news.prodigy.net> kayemmdee@hotmail.com (K. D.) writes: >On Tue, 04 Jan 2000 21:54:48 -0500, j <nospam@null.net> wrote: > >> Well, you know what they say ... it's not how MUCH you have ... > >Yes, this is definitely one of those situations when size may not >matter. I think that was the main thrust (so to speak) of The >Mismeasure of Man -- that cranial volume is NOT directly proportional >to intelligence. Nobody said it was, so that's kind of a straw man (nobody worries about arguing that Neanderthals were as smart as humans, given their large brains, but it seems to work always that Liberals go of there way to deny that one batch of people might have intelligence cuts due to *smaller* brains. Which is the inescapable mirror side to this argument. The problem with Gould is one of honesty: Gould says that brain size flatly has *nothing to do* with intelligence in humans, when he surely must know (since he references one of them) that the best studies finds a minor positive correlation, even adjusted for body mass. From: sbharris@ix.netcom.com(Steven B. Harris) Newsgroups: sci.skeptic,sci.physics,alt.atheism,alt.folklore.urban, alt.folklore.science,rec.org.mensa Subject: Re: Ancient Einstein UL(s) Date: 6 Jan 2000 10:33:40 GMT In <38735039.1483098@news.prodigy.net> kayemmdee@hotmail.com (K. D.) writes: >On 5 Jan 2000 05:37:34 GMT, sbharris@ix.netcom.com(Steven B. Harris) >wrote: > >>argument. The problem with Gould is one of honesty: Gould says that >>brain size flatly has *nothing to do* with intelligence in humans, when >>he surely must know (since he references one of them) that the best >>studies finds a minor positive correlation, even adjusted for body >>mass. > >Well, Gould definitely has *his own* agenda, or multiple agendas. >Brain side does have *some* correlation to intelligence. Not perfect, >of course. But, *that* was not the only point of the book. You must >admit, at first glance, claims such as Einstein having a >smaller-than-average cranial capacity (and, therefore, brain) would >hold a lot of weight with many people in "proving" other claims. > >I think the best lesson illustrated to me in that particular book is >that researchers do, uh, how do I put this, sometimes LIE. Manipulate >the data. Mislead. I'm not pointing directly to Gould, here, but to >the earlier researchers in the measurement of human cranial capacity. Einstein had brain of average weight for a man his age. One rat in any case does not experiment make. Your uncle who smoked for 75 years before being shot by a jealous husband at 95, does not destroy the case that tobacco shortens life and causes cancer. It only shows that it doesn't invariably do so. |