Lately, I have been wondering whether it is really a good idea to keep the paintings hidden until the publication of the eventual book. If I do not show the paintings, then I should probably keep interest going by writing posts more often. But the kind of posts I write, with literature searches and illustrations made to order, take a lot of time.
Perhaps I should write some shorter posts instead, just short ones, without much depth. Let me known what you think of such an approach.
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| Click to enlarge; copyright Gert van Dijk |
30 comments:
Don't rush. Don't rush any part of it.
we here are already awaiting the Book, and will savor any posts you make about it and other topics. I suspect there is enough material on the webpages (and the blogthread itself) to capture the attention and interest of passersby,
-anthony docimo
Interesting concept! Honestly I've been pondering the concept of odd-numbered legs ever since I first saw the Tribbetheres from the Serina spec evo site. Would three or five limbs really be feasible for locomotion? Or would the unpaired limb just be subjected to "centaurism" to make it a quadruped or biped? What would a triped/pentaped walk and "trot" even look like?
Anthony: Thank you. The book is moving forward; slowly, yes, but moving.
Anonymous: I think that a five-legged gait would be easier than a three-legged one, but both seem possible to me. Dogs and cats that lose a leg can get around suprisingly well, and that is with a setup that was not at all meant for three legs. if the anatomy and gait are fuly adapted to the number of legs, it seems dobale. But of all the planets in the universe, those with 'odd walkers' are probably in the minoruty 9coampared to 'even walkers'). I just left the following link on the previous post as well, but here it is again. It showed what had been done 10 years ago:
https://planetfuraha.blogspot.com/2009/10/odd-walkers.html
On the topic of odd limbs and centaurism, would hind leg centaurism work for a semi aquatic animal? Think a hexapod or a pentapod using their front four limbs for walking while their rearmost limb or limbs are modified into flippers for swimming? I guess it would be able to retain most land mobility, unlike seals whose back limbs no longer work as legs and can only flop around when on land...
Plantypus: I guess you want an animal that is truly amphibious. For a swimming animal, the middle pair of legs of a hexaped could be transformed into flippers: they would be near the centre of gravity or a bit forward, similar to seal and penguin flippers, and the front/hind placement of the other legs offers easy stability on land. If you turn the last pair of legs of a hexapod into a whale-like tail, you end up with this heavy structure behind the hind legs. That would work in water, bur less well on land.
I wonder what a transitional form between a radially symmetric ancestor and a bilaterally-symmetric descendant would be like. What sort of evolutionary pressure would favor a spidrid to develop a distinct front and back?
I wonder if you have any animations of odd-numbered gaits of bilaterally-symmetric creatures? I saw this walk cycle of an insectoid tripod having its unpaired hind leg take half steps to keep up with the other two, wonder if a more mammal-esque tripod would use a similar walk: https://m.youtube.com/watch?v=5xtKra365ls
As always, the artwork is beautiful! Any time you feel like sharing another snapshot of life on Furaha, I'll never complain!
glrh.. etc. Sorry for the delay (and please see the previous post)
glrh... The transitional form is just one in which one leg is a bit larger while the opposite one is a bit better at catching prey. In this case, I see no problems with intermediate shapes at al. As for the reason, well, that is tricky. Many people seem to reason that bilateral symmetry is optimal for animals because so many animals have it. But I wonder how strong the evidence is when you count the number of times it evolved versus other symmetry patterns. Vertebrates and arthropods MIGHT be successful because of bilateral symmetry, but perhaps they are successful for another reason. So I reasoned that radial symmetry would be nice to have. Perhaps the switch in either direction was coincidental... Don’t echinoderms have larvae with bilateral symmetry, and yet the adults have radial symmetry. Is starfish can get away with it, I should be allowed to do so too.
Sweaty..: yes; just find my old post on ‘Odd walkers’!
Evan: thank you! By the way, will you be returning to the speculative evolution forum too?
so since this is like, the main blog for spec evo here's a weird idea i had:
imagine a planet nearly identical to earth in terms of climate and gravity and atmosphere, terraformed by unknown forces to become hospitable for earthly life. the planet is seeded with earth organisms: plankton and algae in the sea, microbes in the soil, various plants, fungi and arthropods on the land.
then when all the biomes and ecosystems are fully established, a single vertebrate species is introduced to the planet: the northern leopard frog (Rana pipiens).
over millions of years, as the humble amphibian colonists take over all the niches of the planet, they evolve into a myriad of bizarre and diverse forms as they spread throughout the globe. on land, many species have become herbivores, such as the herd-dewlling, hopping "frogaroos" and horned, bulky "bufolows", which are hunted by dromaeosaur-like carnivorous frogs called "raptoads".
the seas have been conquered by "tadfish", neotenous frogs that retained their tadpole form into adulthood and occupied the niche of bony fish, which evolved into many different species, such as massive filter-feeding "tadwhales" and predatory "tadsharks".
even the skies have been conquered by the frogs, as four-winged Microraptor-esque "anuravians" soar the skies on membranous wings modified from their webbed feet, and taking on niches reminescent of earth's birds.
the series focuses on the world at intervals of 10 million, 50 million, 100 million and 250 million years after establishment, chronicling the progress of the simple frog, into a myriad of species both familiar and alien as natural selection takes hold...
Age of Frogs: So you've let frogs loose on a world otherwise populated by arthropods only, as far as animals are concerned. The arthropods wouldn't stay still. You might have giant dragonflies again (they could exist at normal -'our'- levels of oxygen). I can also imagine that crabs would ievolve some interesting shapes in this world, and theymight pose a serioous theread to fromgs here and there.
But regardless, this seems like the kind of idea that would be at home on the speculative evolution website: https://specevo.jcink.net/
yeah that was kind of my idea too, that along the way the arthropods get big and joust with the frogs over niches, among them are cricket-like omnivores the size of rabbits, and a large predatory fly that hunts smaller anuravians, though the frogs are still the most widespread in the "bigger animal" niches.
and idk, perhaps beyond 250 million years the climate changes to favor the arthropods, leaving them to the bigger niches while the frogs are pushed aside, essentially becoming to the bugs as mammals were during the dinosaur age? doubt that arthropods would get any bigger than the largest living crabs tho.
Just curious...but if most creatures on a particular planet lack eyes how would that affect the evolution of color patters given the uselessness of visual signaling or camouflage? I was reading "Expedition" and some creatures there were brightly colored or bioluminescent, even though none of the large dominant animals have eyes and instead navigate with echolocation...
???: I wrote a whole post on that subject once, and here it is: https://planetfuraha.blogspot.com/2012/01/eyes-have-it.html
perhaps the glowing parts are seen as warmer than the rest of the body, or however the sonar/radar reads such things.
Anonymous: that's what i thought at first... but please see the 2012 post for a discusiion of that possibility.
Going off "Age of Frog" suggesting that arthropods eventually take over, would it be feasible for them to get much bigger with enough adaptations and start filling mammal-esque niches?
Basically now they can't get big because of their exoskeleton supporting weight and the less efficient oxygen intake, but perhaps some burrowing/aquatic species could evolve internal air-storing sacs, and internalized extensions of their exoskeleton, and when a mass extinction takes out the frog competition the bugs take over, modifying their air sacs into lung-like organs for more efficient respiration and turning their internal support structure into an endoskeleton-analogue of sorts? Then they can get significantly bigger, at least to the size of goats and sheep for the herbivorous ones..
Kevin: with the set of adaptations you describe, they would basically no longer be arthropods... This is a subject often discussed on places like the speculative biology forum. One of the problems is that becoming larger and developing a better respiration probably depend on one another, so they may be stuck at their present 'optimum'.
could mammals re evolve oviparity somehow and start laying eggs again
Anonymous: if you can fill in the 'somehow'... But seriously, the reverse makes sense: it can be advantageous to keep the phase short between laying the egg and it hatching. The shortest period is that the egge immediately opens on birth: ovovivipary. Once that is achieved, the egg shell largely loses its mechanical functions so it can be lost. But the opposite? I can see purpose nor mechanism.
The prigoon is kind of cute. If there are humans settling in Furaha I bet they'd be fairly popular and might even be kept as pets (which depending on exotic species laws may be illegal...)
Anonymous: attitudes towards dealing with animals varied over Furahan history, but generally keeping animals for their owner's amusement only was frowned upon in most times, and was considered slightly disturbed at others. Of course, there have been times in which vivaria were a status symbol...
I would imagine that some circumstances - captive breeding of endangered Furahan biota & studying the harder-to-locate species - might be used to justify some captive populations. Or maybe not. *shrugs*
-Anthony.
I wonder if the prigoon has a radially-symmetrical larval form, similar to how many advanced arthropods have larval forms resembling the ancestral wormlike proto-arthropod?
I'd love to see the transitional forms between the typical radially-symmetric spidrids to the bilaterally symmetric prigoon, wonder what those missing links would have looked like and how many eyes and mouthparts they had?
Anthony: actually, yes: at some times animals were captured for study, i.e. mostly dissection, while at other times such tendencies in researchers of citizens would be dealt with by 'thought insertion'. (!)
Gallon and Nonny: are the persons using these silly names in fact one and the same person? At any rate, please stop doing so, as I find it annoying.
- about the radial larvae: I like that idea! I had not considered their larval forms yet, but this sounds logical.
- nonny: well, I doubt I will paint any more spidrids, and am currently working on plants. But if I feel I need another spidrid painting, this would make a nice supplementary figure.
Thoughts on a pentapod evolving from a mudskipper like ancestor? Mudskippers have their pectoral and pelvic fins both close to the front while their tail fin helps push them forward, so perhaps they could end up with a vaguely-tetrapod-like body plan but with four front legs and one hind leg?
Whizzle: I can see the tail keeping a locomotor function, but I wonder how the four limbs bundled together would evolve. The alternative would be that the locomotor functions are taken over by the limbs, freeing the tails for specific tails tasks (of which there sem to be so few that I often wonder why did not disappear).
How big is the prigoon anyway? Will there be a page on the furaha site detailing more stuff about this critter?
The prigoon is about 1,5 to 2 cm in size. I don't reaaly know at present how much I should update the main site. I do intend to blog a bot more often though.
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