Re: On The Rise of Oxygen...
(Bear in mind, too, that some of the brontotheres of the mid Cainozoic were pretty weight competitive with at least the smaller sauropods. No doubt the brontotheres were something less than wildly active; but this shows that sauropodian mammals - while probably less likely than their dinosaurian counterparts - were not completely impossible) Then why didn't Imperial Mammoth grow 100' tall, especially when in cold climates such as an Ice Age, it would be a benefit? I suppose that steppe grasses will only take you so far... On the other hand, perhaps the combination of high body mass AND internal temperature regulation would lead to overheating? Perhaps the brontothere and titanothere had a danger of heat exhaustion? tells us clearly is that it _wasn't_ a change in environmental conditions which doomed the giant sauropod line: it was competition (in Siberia, China NAmerica) finally the Chicxulub impact (everywhere else) which did 'em in. Gary Larson suggests it was cigarette smoking that did in the dinosaurs. Another good eg of this phenomenom at work is amboreiser, the enormous ( i do mean enormous: some where the size of small bears) rat of greater Anguilla. No unusual atmospheric situation here; just a total lack of competition, so that a few, probably wet highly bedraggled rattus rattusi grew very big very fast. Now THAT, I am interested in reading about... So, you're saying that the fabled R.O.U.S. of 'Princes Bride' fame is alive and well, and hunting for large wheels of cheddar cheese on Anguilla... hmmm -- JHB == You are subscribed to the Europa Icepick mailing list: [EMAIL PROTECTED] Project information and list (un)subscribe info: http://klx.com/europa/
Re: On The Rise of Oxygen...
In a message dated 12/8/2000 4:06:42 AM Alaskan Standard Time, [EMAIL PROTECTED] writes: Come on over to Jason Perry's "Jupiter List" and "ISSDG" discussion groups and you can see Clements and I tearing at each other and questioning each other's ancestry on a regular basis. It's wonderful. Vodka and whiskey, whiskey and vodka... too much of a good thing is a bad thing. 'Tis best not to drink too deeply from the well, as it were. -- JHB == You are subscribed to the Europa Icepick mailing list: [EMAIL PROTECTED] Project information and list (un)subscribe info: http://klx.com/europa/
Re: On The Rise of Oxygen...
Jayme Blaschke wrote: What in the world is a weta? Director Peter Jackson's Wellington-based SFX company. :-) Jayme Lynn Blaschke No great surprise... Jacko's a Kiwi (New Zealander); with a taste for cinema almost as ugly as the weta itself. The weta is a very large arthropod endemic to NZ surrounding islands; as such is most unlikely to win any animal beauty contests (in fact, it looks a little like a mutant cross between a cockroach a crab). As Bruce pointed out - i acknowledge - being a large hard shelled critter puts you at a serious disadvantage in a mature ecosystem; but the NZ - even more than Australia - was ecologically very isolated prior to the arrival of the Melanesians (now Moari) people less than 1000yrs ago... as a result, the normal rules of competition didn't apply here; insects like the weta large, flightless birds like the tuatara, moa, kiwi kakapo survived quite comfortably. To reconcile my position with Bruce's observations: there's no doubt that some bodily systems are more efficient in the contemporary environment than others; but that isn't the same as saying that - in the absence of competition from more efficient living systems - large cockroaches mightn't reappear in contemporary conditions. Indeed: they almost certainly would (following the bigger is better principle); the palaeontonological Lystrosaurus Interlude (immediately following the Permian extinction; where a single therapsid called the Lystrosaurus which survived the extinction dominated the environment for about 10my) would be matched by a new Cockroach Interlude, as these enormous roaches essentially waited for better designs to supplant 'em. This has a strange relevance to Europa, however. If life exists in the Europan ocean, it's likely to be living in a low energy environment where competition is unlikely to be widespread. Unlike most people, therefore, i don't rule out the possibility of really large life forms there; but would still expect them to be expect them to be extremely primitive All the best, Robert Clements [EMAIL PROTECTED] == You are subscribed to the Europa Icepick mailing list: [EMAIL PROTECTED] Project information and list (un)subscribe info: http://klx.com/europa/
Re: On The Rise of Oxygen...
-Original Message- From: Robert Clements [EMAIL PROTECTED] To: [EMAIL PROTECTED] [EMAIL PROTECTED] Cc: [EMAIL PROTECTED] [EMAIL PROTECTED] Date: Friday, December 08, 2000 6:11 PM Subject: Re: On The Rise of Oxygen... This has a strange relevance to Europa, however. If life exists in the Europan ocean, it's likely to be living in a low energy environment where competition is unlikely to be widespread. Unlike most people, therefore, i don't rule out the possibility of really large life forms there; but would still expect them to be expect them to be extremely primitive It should be pointed out, however, that multicellular organisms never evolved on Earth at all until the evolution of photosynthesis provided them with a much more efficient energy supply -- so it still seems overwhelmingly likely that all Europan life will be single-celled unless large amounts of photosynthesis are possible in water pockets or cracks very close to the surface (and that is an extremely big "if"). (And, by the way, there's a surprising amount on the weta available on the Web -- it turns out to be a huge cricket. Apparently its maximum length is 90 mm, though -- which, I think, is still somewhat smaller than the African Goliath beetle and maybe one or two other huge insect species as well.) Bruce Moomaw == You are subscribed to the Europa Icepick mailing list: [EMAIL PROTECTED] Project information and list (un)subscribe info: http://klx.com/europa/
Re: On The Rise of Oxygen...
Bruce Moomaw wrote: It should be pointed out, however, that multicellular organisms never evolved on Earth at all until the evolution of photosynthesis provided them with a much more efficient energy supply -- so it still seems overwhelmingly likely that all Europan life will be single-celled unless large amounts of photosynthesis are possible in water pockets or cracks very close to the surface (and that is an extremely big "if"). Only if you think in terrestrial terms. One possibility which springs to mind would be a large colonies, perhaps even of subcellular creatures, assembled on long strands of nonliving matter: horizontal stromatolites, if you like. In the absence of competition with the primary need to collect as much nutrient from the Europan ocean as possible, these could grow extremely long while still being organically incredibly simple. All the best, Robert Clements [EMAIL PROTECTED] == You are subscribed to the Europa Icepick mailing list: [EMAIL PROTECTED] Project information and list (un)subscribe info: http://klx.com/europa/
Re: On The Rise of Oxygen...
In a message dated 12/8/2000 5:28:26 PM Alaskan Standard Time, [EMAIL PROTECTED] writes: This has a strange relevance to Europa, however. If life exists in the Europan ocean, it's likely to be living in a low energy environment where competition is unlikely to be widespread. Unlike most people, therefore, i don't rule out the possibility of really large life forms there; but would still expect them to be expect them to be extremely primitive It should be pointed out, however, that multicellular organisms never evolved on Earth at all until the evolution of photosynthesis provided them with a much more efficient energy supply -- so it still seems overwhelmingly likely that all Europan life will be single-celled unless large amounts of photosynthesis are possible in water pockets or cracks very close to the surface (and that is an extremely big "if"). A giant Europan jellyfish might be the prototype, then. Something large enough to be able to absorb energy across a broad area (say, 1 km across). Freezing or ice shifts might only kill off a section of it, quickly regenerated. All speculative of course. Probably lousy eating. (And, by the way, there's a surprising amount on the weta available on the Web -- it turns out to be a huge cricket. Apparently its maximum length is 90 mm, though -- which, I think, is still somewhat smaller than the African Goliath beetle and maybe one or two other huge insect species as well.) There's a similar cricket in Mexico. When I lived in Northern Mexico (the Sonoran desert) I often saw immense 4" crickets creeping across the roads. Very brightly colored, they were so slow I often wondered how they could survive cars and predators. I still say that in order to be competitive, they'd need O2 supercharging. Same goes for dragonflies. I'd think they would simply need thicker air to supply loft to those inefficient wings. Could the pterosaurs have been their end? I dunno... because in the transition interim from developing from hoppers to flyers, wouldn't they still be easy meat for those 2' dragonflies? Dragonflies are, after all, voracious predators, with jaws that can chew up insects far larger than they are. -- JHB == You are subscribed to the Europa Icepick mailing list: [EMAIL PROTECTED] Project information and list (un)subscribe info: http://klx.com/europa/
