Avatar - Pandoran evolution

[Serafina]

Don't forget that Pandora has lower gravity (tough it can not be too low, i would say not lower than .9g), a different and denser atmosphere and is a moon.
The gas-giant alone should be interesting, with vastly different tides, no really dark nights (unless you are under a thick canopy of trees), and perhaps some other effects, too.

We simply do not see enough large species to conclude that the six-limbed bodyplan is common to all.
We see the Navi (4), the "monkeys" (4), "horses" (6), rideable fliers (6), giant flier (6), small predator (6), large predator (6) and the armored behemoth (6). Out of 8 observed species, two have four limbs and six species six limbs.

Nothing says that they can not follow different paths - perhaps the six-limbed bodyplan stems from something like our reptiles, while the four-limbed one is for "mammals". Six limbs may be advantageous if you use all of them for propulsion, but the four-limbers are bipedal anyway.

[Gil Hamilton]

You mean like how on Earth animals are all quadrupeds - whoops, except for the rattites (ostrich, emu, moa, kiwi, etc.) and the snakes and some lizards and whales and fish and...

First of all, can you count? Ostriches and all other birds very clearly do have four limbs, or did you miss their wings? Or whales for that matter which have two flukes and vestigal legs. Or snakes, which have vestigal limbs, but still evolutionarily follow the basic plan. You know full well you are making an oversimplification to try to make a point, but our megafauna does basically have four limbs and a tail of some sort, be they legs, arms, wings, or flippers. Fish do too, or have you not looked closely at a fish to notice they have two pairs of fins before their tails?

Or like how on Earth all animals have "pinna", the external, fleshy part of the ear - whoops, except for those whales again and snakes and frogs and....

I'm talking about gross features here. Related animals vary, but how does that relate to the fact that the Na'vi don't seem to follow the body plan of every other megafauna creature around at all except for an interface tentacle that looks like braided human hair (which is a feature on no other animal there, isn't that funny that the "alien" features on the Na'vi just so happen to resemble human hair styles).

It would have added yet more to Pandora to see forms that, like the Na'vi, only have four limbs, or have hair, or otherwise provide a "missing link" between them and the other fauna on the planet. That does not mean such forms don't exist, or didn't exist in the past.

James Cameron already shot you in the foot on that argument. He states in the interview he had with Playboy that the Na'vi have all those features because they were designed to look human and no other Pandoran creature has them. We can't take the "designed to look human by James Cameron" as in-universe, but we can take the creators word that no other creature on Pandora biologically resembles them in structure. That leaves you to explain why the Na'vi have four limbs, hair, boobs, et cetera, while no other Pandoran creature follows that body plan.

I dont see how that follows at all. The NaVi could be part of a separate lineage, or they could have lost the second set of forelimbs. As a matter of fact that part is not universal. The flying reptiloids (cant remember their names) are quadrupeds. We also dont know how functional the ocelli (the secondary eyes that seem to have less function) are. They may detect heat for all we know, and we have only seen a handful of species.

As for the NaVi not being placental mammals, that does not preclude the existence of tits. They could lay eggs and have a mammary gland equivalent for all we know. Hell, they could have pod babies.

Your logic is broken.

The flyers do have six limb equivalents. They have four wings and two legs. They have the big front wings, the two back wings, and their legs. The fact is, they don't resemble the local fauna that much except in a superficial manner.

Further, the second eyes may or may not be very functional, but they are still there and every bit of megafauna has them. Did we see any megafauna AT ALL that didn't have six leg equivalents and several sets of eyes EXCEPT the Na'vi, which look way too much like humans to be coincidence? Which creatures BESIDES the Na'vi have less than two pairs of eyes? Even those lemur things Sully nearly shot up had, you guessed it, no hair, two sets of eyes, four arms, and a pair of legs.

Secondly, in the Playboy article I mentioned about, James Cameron out and out states that the breasts on female Na'vi were an executive decision on the part of the movie designers because they wanted the Na'vi to be sexy and no other Pandoran creature has them. Again, we can't take "Act of James Cameron" as a reason in-universe, which leaves you to explain why?

[Gil Hamilton]

We simply do not see enough large species to conclude that the six-limbed bodyplan is common to all.
We see the Navi (4), the "monkeys" (4), "horses" (6), rideable fliers (6), giant flier (6), small predator (6), large predator (6) and the armored behemoth (6). Out of 8 observed species, two have four limbs and six species six limbs.

The "lemurs" Sully saw most certainly had four arms and two legs. All the megafuana that appeared on Pandora did EXCEPT the Na'vi. They also had two sets of eyes like all the above critters (except, again the Na'vi, which had expressive golden human-like eyes)

[CaptainChewbacca]

The 'horses' also had 6 limbs, they just have their front 4 limbs overlapping so its difficult to see, but you could tell when they were able to kick out with their front two limbs that they still had four on the ground.

[Silver Jedi]

The large red fliers had six limbs (main wings, secondary wings, and legs) but the ones the Na'vi ride only had four. They didn't have legs separate from their secondary wings, the wings stretched between their legs and tail.

I wonder if it's significant that the Na'vi seem to be the only ones who don't breath through slits at the base of their neck? Also, I wonder if it's because of necessity, convenience, or just convention that they only seem to connect animals' left antenna?

[Rye]

Or whales for that matter which have two flukes and vestigal legs. Or snakes, which have vestigal limbs, but still evolutionarily follow the basic plan.

Who says the Na'vi haven't got vestigial limbs? If we have no-limbed organisms here, a species or two over there that have lost one set of unnecessary limbs over the course of evolution seems to be a better explanation than God cursing the snake to crawl on its belly and eat dust.

I'm talking about gross features here. Related animals vary, but how does that relate to the fact that the Na'vi don't seem to follow the body plan of every other megafauna creature around at all except for an interface tentacle that looks like braided human hair (which is a feature on no other animal there, isn't that funny that the "alien" features on the Na'vi just so happen to resemble human hair styles).

It seems quite sensible given the target audience.

James Cameron already shot you in the foot on that argument. He states in the interview he had with Playboy that the Na'vi have all those features because they were designed to look human and no other Pandoran creature has them. We can't take the "designed to look human by James Cameron" as in-universe, but we can take the creators word that no other creature on Pandora biologically resembles them in structure. That leaves you to explain why the Na'vi have four limbs, hair, boobs, et cetera, while no other Pandoran creature follows that body plan.

This is where we get to inerrancy vs author's intent, personally, I choose the latter as the best means to understand a text.

The flyers do have six limb equivalents. They have four wings and two legs. They have the big front wings, the two back wings, and their legs. The fact is, they don't resemble the local fauna that much except in a superficial manner.

On Earth we have lobsters, humans, snakes and squid.

Secondly, in the Playboy article I mentioned about, James Cameron out and out states that the breasts on female Na'vi were an executive decision on the part of the movie designers because they wanted the Na'vi to be sexy and no other Pandoran creature has them. Again, we can't take "Act of James Cameron" as a reason in-universe, which leaves you to explain why?

One species of pseudo-mammal survives on a planet that had more in the past or that were originally contained in a different area.

[Shroom Man 777]

Who says those six-legged xeno-doggies and those xeno-panthers don't have bitch tits when they're in heat and giving birth to xeno-puppies and xeno-kittens for them to breastfeed with their titties?

[Junghalli]

Yeah, I'm fairly sure the large fat deposits around human mammaries are unique to us, so it's no great shocking mystery that they might appear in the Na'Vi but not other Pandoran animals.

[Zac Naloen]

I figured that the "breasts" of both the males and females were vestigial muscles/structure that formed part of the shoulder for the sixth Limb and eventually became sexual markers.

[Alyrium Denryle]

How does it rate in terms of running speed, ability to support weight, etc.

It might just be as simple as six legs costing more to produce, and since 2/4 works fine, large animals never evolved them.

Large animals never evolved them on earth because the regulatory mechanisms necessary were never there. Duplicating limbs can cause other problems if complex organ systems are in place before the body plan is evolved.

The flyers do have six limb equivalents. They have four wings and two legs.

Look more carefully. The 2nd set of wings is attached to the rear legs

The fact is, they don't resemble the local fauna that much except in a superficial manner.

Which means a different clade. Not design.

Further, the second eyes may or may not be very functional, but they are still there and every bit of megafauna has them. Did we see any megafauna AT ALL that didn't have six leg equivalents and several sets of eyes EXCEPT the Na'vi, which look way too much like humans to be coincidence? Which creatures BESIDES the Na'vi have less than two pairs of eyes? Even those lemur things Sully nearly shot up had, you guessed it, no hair, two sets of eyes, four arms, and a pair of legs.

Do you have any idea how many times complex camera eyes have evolved, been lost, and been re-evolved?

No design implication.

Secondly, in the Playboy article I mentioned about, James Cameron out and out states that the breasts on female Na'vi were an executive decision on the part of the movie designers because they wanted the Na'vi to be sexy and no other Pandoran creature has them. Again, we can't take "Act of James Cameron" as a reason in-universe, which leaves you to explain why?

Independent evolution. A novel feature. A synapomorphy that diagnoses their clade.

That leaves you to explain why the Na'vi have four limbs, hair, boobs, et cetera, while no other Pandoran creature follows that body plan.

The rest of their lineage no longer exists. Very fucking simple.

I'm talking about gross features here. Related animals vary, but how does that relate to the fact that the Na'vi don't seem to follow the body plan of every other megafauna creature around at all except for an interface tentacle that looks like braided human hair (which is a feature on no other animal there, isn't that funny that the "alien" features on the Na'vi just so happen to resemble human hair styles).

2 or more lineages diverged after the neural interface evolved. One went extinct with the exception of 1 species. There. More parsimonious than "they were put their by god/aliens"

Or whales for that matter which have two flukes and vestigal legs.

You are a fucking idiot. Modern whales have lost everything except a few tiny bones in their pelvic girdle that you have to dissect to find. Also: flukes are the tail. The proper term for the forearms is flipper.

Or whales for that matter which have two flukes and vestigal legs.

Only the boids.

but still evolutionarily follow the basic plan

HAHAHAHAHAHAH. Have you looked at a snake's eye lately? It has the same plan of internal organs of lizards and they have scales... but outside of that if boids were extinct you would not have much clue that they evolved from legged animals unless you found fossils. They have an eye more similar to that of a fish than a reptile because they re-evolved it after a loss. Using your logic, if we found a colubrid today in the absence of DNA evidence we should conclude that they were specially created because they have different eyes and are missing legs.

The "lemurs" Sully saw most certainly had four arms and two legs. All the megafuana that appeared on Pandora did EXCEPT the Na'vi. They also had two sets of eyes like all the above critters (except, again the Na'vi, which had expressive golden human-like eyes)

No dipshit, they had a bifurcated forelimb.

http://images3.wikia.nocookie.net/james ... Monkey.jpg

[Alyrium Denryle]

The large red fliers had six limbs (main wings, secondary wings, and legs) but the ones the Na'vi ride only had four. They didn't have legs separate from their secondary wings, the wings stretched between their legs and tail.

I wonder if it's significant that the Na'vi seem to be the only ones who don't breath through slits at the base of their neck? Also, I wonder if it's because of necessity, convenience, or just convention that they only seem to connect animals' left antenna?

Or they lost it to facilitate verbal communication.

As for the Great Leonopteryx, any number of modifications could produce that. It was not not a true limb though. Even if it was it wouldnt mean much. It just means that the little ones lost a pair of limbs

[Broomstick]

You mean like how on Earth animals are all quadrupeds - whoops, except for the rattites (ostrich, emu, moa, kiwi, etc.) and the snakes and some lizards and whales and fish and...

First of all, can you count? Ostriches and all other birds very clearly do have four limbs, or did you miss their wings?

Some rattite lineages DID entirely lose their wings, including vestigal bones. They are called moas, all ten of which species entirely lacked wings. Completely. Not even nubs attached to their rib cages.

Or whales for that matter which have two flukes and vestigal legs.

The fluke is an outgrowth of the tail, and really should be considered singular. The vestigial legs of a whale? You need to dissect the animal to find them, they are completely invisible from the outside in all existing cetacean species.

Or snakes, which have vestigal limbs, but still evolutionarily follow the basic plan.

There are many species of snakes which have NO vestigial limbs, not even to the degree whales do. A total loss of limbs. Even those which do retain a much reduced pelvic girdle and "legs" have entirely lost their forelimbs and shoulder girdles.

You know full well you are making an oversimplification to try to make a point, but our megafauna does basically have four limbs and a tail of some sort, be they legs, arms, wings, or flippers.

Except for those lineages that have reduced or even eliminated two or all limbs, right, you keep missing that. Limb reduction have evolved more than once on Earth, why do you discount even the possibility of that occuring elsewhere?

I can imagine Pandorans discussing how improbable humans are - every other land animal on seems to Earth has a tail, why not Humans? They must be engineered!

Fish do too, or have you not looked closely at a fish to notice they have two pairs of fins before their tails?

Actually, quite a few fish have pectoral, caudal, AND anal fins.... hmmm, that's more than four. And other fish, like eels, have less than four.

The group of fish currently believed to be the forerunner of tetrapods (land based vertebrate animals) did, indeed, have four "limbs". If they had had six we might have had hexapods running around.

Secondly, in the Playboy article I mentioned about, James Cameron out and out states that the breasts on female Na'vi were an executive decision on the part of the movie designers because they wanted the Na'vi to be sexy and no other Pandoran creature has them. Again, we can't take "Act of James Cameron" as a reason in-universe, which leaves you to explain why?

James Cameron figuring out that his Na'vi would need to look somewhat human so the average mouth-breathing human in the audience could relate to them is actually one of the more intelligent parts of the movie. While geeks such as myself might have been happy with a more alien group of aliens we have to deal with the fact that, despite form limitations having been defeated by CGI, we still have to cope with audience limitations.

It's rather like how in the 1960's all space shows had to have noise to mark the passage of a spaceship, whereas these days the average person is sufficiently savvy to either cope with the silence of vacuum or actually demand it.

[Coyote]

There are all kinds of one-off whackaloon critters in the world. Not only are there the crabs, lobsters, and platypi, but compare bats and birds, and then throw in flying squirrels (yes, they're more accurately "gliding" squirrels). EDIT: don't forget the octopus, which has tool-using ability, squid, bio-luminescent critters like the angler fish and the electric eel.

And then all the different forms of hooves. Solid hooves, like the horse, which actually evolved from claws (go figure) and then bifurcated hooves like pigs, goats, and cows. And then you have foxes, which look like a dog and have dog musculature, but slit pupils like a cat. And go look at the freaky pupils of a goat. They look like hourglasses.

The Na'vi don't have extra limbs, they don't have extra eyes. They make up for it be having bigger brains. They don't need huge fangs and runfast limbs, they build tree structures and have bows and arrows.

As for the ability to plug into the surrounding environment, it can benefit the plants as much as the critters, since the plants can guide critters, with pollen stuck to their fur/feet/hands, to the plants that need pollenation. Like bees, except more purposefully.

[Sarevok]

By the way has anyone noticed Beta Centauri in the background ? I did for sure on my second viewing. Night time on Pandora should be very interesting depending on time of year. The fact that there is a gas giant in the sky and several moons means that there is always some lightning available. Instead of nights like Earth Pandora probably gets twilight phases.

[Rye]

I think a lot about Na'vi physiology could, if you so wanted, be explained by their (apparently) unique dominant nerve clusters. It's clear that the biosphere as a whole evolved from the plant, perhaps even the cellular level with the ability to synaptically interact with other, related species. It's possible that Na'vi scientists, if the situation were reversed, would be amazed that life could evolve without nerve cluster interfaces.

Even if they had initially come from a species that had 6 limbs and 4 eyes, perhaps the resources involved in mammalian milk production (if they have that), supporting bigger brains and the dominant nerve cluster trait led to the loss of the extra bits. Or maybe like I said, they originally came from an area of the planet where a different body plan was the norm, or they are the only surviving species with that body plan.

[Shroom Man 777]

To reinforce Broomsticks point, the only snakes with "vestigial legs" are pythons and boas. It's seen on the spurs of boas and pythons. The rest of the snakes don't have any vestigial limb remains even if you anatomize them. So it's not "many" snakes that have no vestigial limbs, but the vast majority of them.

Pelvic spurs are the snake vestigial limbs, and they merely appear as tiny barely-noticeable pointy claw spurs near the blowholes of pythons and boas. So, those are the vestigial limbs.

Would it make the "rargh two four six eight legs!" crowd happy if the Na'vi also had tiny barely-noticeable pointy claw spurs on them? Perhaps they can be seen on the nipples of the Na'vi, the nipples on those breasts which upset people so much that they want to make those breasts bleed blood from the milkbags because alien whores (Pandora's most beautiful creations) shouldn't have sexy titties?

Or maybe like snakes, those vestigial limbs can be featured around the Na'vi's organs. The reproductive organs. Like the penis.

Or vagina.

[Sarevok]

Maybe like General Grievous the Navi quad limbs eventually fused into two. I imagine two strong arms are better than four weak ones for a tool user species. Especially if that species depends on using powerful bows and spears against much larger super predators. The extra arms would just get in the way of making an accurate and powerful long range shot.

[Shroom Man 777]

He's right! REVERSE General Grievous! Maybe those monkeys, the ones with sorta Grievousy-limbs, were progenitors and aside from ape ancestors gradually learning to walk upright we could see the Na'vi's ancestor "Na'vinids" fore limbs gradually fuse. If you're standing upright, and learning to do complicated tasks with your hands, what will those extra limbs be for? For complicated tasks, the extra limbs might even be a downside because complex tasks require coordination and shit and working with four arms might be too bothersome for the brains!

[Sarevok]

Yeah the extra complexity required in the brain could be a reason as well. In humans few people can use both arms ambidextrously. Using four arms with human like dexterity would be a tremendous mental challenge. Manipulating four different arms is a burden if just two arms were enough to make and use tools necessary for survival.

[Companion Cube]

Pandorapedia seems to have been updated recently (there're lots of empty entries at present, and they've recently been alphabetised), and the entry on the Na'vi is particularly long (and full of spelling errors; perhaps they've got an intern transcribing it).

The evolutionary lineage of the Na'vi among the lifeforms found on Pandora is something of an open question. The work of reconstructing Pandora's evolutionary past is hampered by the fact much of the world is covered in lush rain-forests with acidic soil, which is a poor medium for fossilization to take place. Therefore classification must be done largely through the techniques of gene sequencing and comparison, as well as application of evodevo principles.

The Na'vi possess a single pair of eyes, where most animals have two pair, with the smaller pair specialized for infrared sight. The Na'vi are also one of only a very few vertebrate terapods (four limbs) among a bestiary filled with hexapods (six limbs). The other notable exception is the Ikran (banshee), which also appears to be unique among Pandora's flying vertebrates for having only one pair of primary wings. The Ikran's secondary wings are extensions of their rear legs. All other flying genus identified so far, (such as the Great Leonopteryx) possess two pair of wings and dedicated hind legs. But this is suspected to be an example of parallel evolution, with the Ikran simply losing a pair of wings. It is unlikely that a direct line between the Na'vi and Ikran will be drawn without going extremely far back in time.

The most likely candidate for a close relative of the Na'vi is a creature called a prolemuris. It is a medium-sized, arboreal animal that possesses a unique kind of hybrid body form. While it has six limbs, its two sets of lower arms branch off from a single pair of upper arms and shoulders, which could identify it as a transitional form between the hexapod plan of most of the rest of Pandora's vertebrates and the terapod form of the Na'vi. Further, the prolemuris sees with only a single pair of forward facing eyes, exactly like the Na'vi. At this point, it is unknown how far back in their shared lineage a common ancestor was, if it existed at all.

EDIT: ahahaha

Perhaps the most distinct characteristic of Na'vi anatomy, indeed that of nearly all Pandoran vertebrates, is their neural interface. This is a roughly meter long appendage that protrudes like a slender, flexible tail from the base of the skull. It is informally known as a Lekku, in reference to the head tails of the Twi'lek species from the Star Wars films.

In the Avatar universe, the Star Wars films retain a fan-base well into the 22nd century.

[Sarevok]

In the Avatar universe, the Star Wars films retain a fan-base well into the 22nd century.

Battle of Endor was required viewing for all RDA mercenaries.