Avatar - Pandoran evolution

[Serafina]

How can we explain the massive bio-network between the plants on Pandora, and how can we explain that most or all larger (nad potentially all) animals have those plug-in connections?

Well, my possible explanation:
-A single species of trees starts to exchange nutritiens between several individual trees
-After some time, basic information is exchanged, too. Presence of dangerous animals, weather conditions etc.
-Over time, that networks grows denser, exchaning more and more information.
-Other plant-species start to tie into that network at some point. Eventually, this might grow into a symbiotic relationship.

That should cover the connection between the plants. It seems like a good advantage, all it would take is a stable enviorment for a long time. Pandora should be a pretty old planet, with no great climate changes and no mass-extinctions for many billions of years.

Now, the animals are a bit more complicated.
-At some point, a species of animal ties into that network, too. Propably a small, land-based animal that lives close to the roots of the trees. It is quite imaginable how they could profit from that information.
The first connections would have to be pretty basic - reading something like "danger close" or "storm approaching", but not much more.
-Over time, the animal could learn to interpretate more and more information.
-The plants can gain an advantage, too, since an animal might be tricked to attack herbivores, or similar things. Grows into a symbiotic relationship later on.
-The connection prooves to be a significant advantage, and it prospers, eventually producing more and more species.
-Even for species that do not use the network anymore (such as the fliers), it might proove advantageous for connections with other of it's species. Since they are all already tuned to the same frequency, there would be little to no advantage in changing the connection itself. Hence, inter-species communication is still possible.
-For domesticated (by the Navi) species, it actually is an advantage.

Now, the biggest step is the first connection between animal and plant, since those should be pretty damn different.
Either it was possible with a huge margin of error and got better, or some kind of plant (say, a fungi) got mobility long ago and then evolved into animals.
Alternatively, the connection could be a symbiont. A plant integrates into an animals body. It provides the animal with information, and the animal it with mobility. That still requires the inital connection (with all its problems), but it grants an advantge for both sides and thus greater evolutionary pressure.

What would you add/change about that explanation?

[Valk]

I was thinking more along the lines of design by the Na'Vi.

If the Na'Vi for some reason never started to develop technology but were intelligent they could achieve such fantastic results using selective breeding over a period of millions of years. They could for example artificially favor the evolution of their 'USB-plug'.

Once these features become useable, at the time of the movie, it might be that all the non-domesticated animals we saw with 'USB-technology' are descendants of formerly domesticated animals that were bred to have this but escaped. For the 'USB-plants' to spread beyond the borders of the Na'Vi they only needed to be better than the original non-USB plants.

[Nephtys]

Ugh. This entire 'Na'vi designed everything' set of ideas people are cooking up are pretty absurd. I'm sorry, it's just so... convoluted that it's not something I'd want to see. It's that kind of continuity that destroys universes

[Serafina]

I was thinking more along the lines of design by the Na'Vi.

If the Na'Vi for some reason never started to develop technology but were intelligent they could achieve such fantastic results using selective breeding over a period of millions of years. They could for example artificially favor the evolution of their 'USB-plug'.

Once these features become useable, at the time of the movie, it might be that all the non-domesticated animals we saw with 'USB-technology' are descendants of formerly domesticated animals that were bred to have this but escaped. For the 'USB-plants' to spread beyond the borders of the Na'Vi they only needed to be better than the original non-USB plants.

You know, while it is a terrible strawman regarind evolution, as far as selective breeding goes, it is true:
You can not produce new features by it.

At least not such radical ones. They would have to start out with some kind of connection.

It is, of course, possible that the inter-species compatability is due to selective breeding (say, the "horses" are compatible because of it), but you still need the inital animan/plant connection.

[Zor]

I still like to think of it as being More like the Relationship that Remoras have with sharks taken to another level with the neural links. The Na'vi provide Dire Horses with an extra pair of eyes and defense against predators with their bows and the the Dire Horses provide speed. Both the Dire Horse and Na'vi (and Banshees and posibly other Pandoran Critters that they use elsewere) evolved to work together rather than one domesticating the other. I am pretty sure that you would find other creatures with fairly similar relations (say a flying critter which serves as an airborne scout to things such as a relitive to the Thanator and so forth).

Zor

[Valk]

You know, while it is a terrible strawman regarind evolution, as far as selective breeding goes, it is true:
You can not produce new features by it.

At least not such radical ones. They would have to start out with some kind of connection.

It is, of course, possible that the inter-species compatability is due to selective breeding (say, the "horses" are compatible because of it), but you still need the inital animan/plant connection.

I was thinking about an evolutionary process like the eye. This is also possible for natural evolution, rather than selective breeding, but taking selective breeding:

Na'Vi communicate through physical contact on a specific part of the body preferably well-connected to the brain. Through selective breeding you favor a high sensitivity to this contact. Then you might, through selective breeding, favor a parallel bus over a serial bus leading to a bunch of small contacts, which you favor into becoming tentacles.

Now you added a feature.
Admittingly, design is very cheap because a change doesn't need to be naturally beneficial, only a step towards the designers goal so that the designer makes it beneficial.

[Patrick Ogaard]

An important point to keep in mind is that an alien ecology will not have actual plants and animals, instead having organisms that may occupy similar ecological niches to those occupied by plants and animals in our own ecosystem.

One possible conjecture would be an ecosystem dominated by one category of organism that constitutes a sort of metaspecies. That is, what if the natives, the flying critters, the herbivorous critters, the carnivorous critters and the herbivorous ones, as well as the major sessile critters, are derived from something like a communal reef-dwelling superorganism? The interface capabilities of the organisms would thus be a survival of a neural networking scheme developed by their ancestors. Even after extensive speciation, communications between different species would remain possible as long as the organic networking standard is highly stable.

Another conjecture would be that the primary interface is actually a symbiotic organism, maybe derived from the tree-like organisms, that long ago insinuated itself into other local organisms. Those other organisms would derive the potential benefit of improved communications and maybe some other bennies provided by the interface critters, and the interface critters and their parent organisms would benefit from favorable treatment by the "infested" critters.

[Fire Fly]

Another possibility that is simpler:

An early Pandoran plant precursor, something similar to algae, evolved a network of some sort to communicate over relatively long distances. You then have a massive extinction event which kills off 99% of life, leaving behind very little resources and biodiversity. This results in very strong selective pressure on any remaining life. The algae-like organism is heavily predated on by creature A and it eventually evolves a symbiosis with an organism, creature Z, which can tap into this neural network and prey on creature A. Eventually, creature A evolves a mean to tap into this neural network to use it to escape predation. All subsequent organisms evolved from this very small surviving pool, all which evolved a means to tap into this neural network, which remains highly conserved.

[Alyrium Denryle]

I was thinking something more along the lines of a fungal matte. Fungus in forests form a complex network that symbiotically interacts with plants. Plants also communicate with eachother chemically. WIth the plants at least it is not difficult at all to imagine that the communication system evolved on Pandora between plants evolved initially for communication between plants. Probably as an anti-predator mechanism.

If all of the animals and plants are from the same lineage (IE they did not evolve multicellularity separately, and the old predators went extinct) then the communication system may have been conserved.

Alternatively, the animals may have evolved to tap into the same communication network in the same way that they often evolve to intercept signals between prey species.

[Valk]

Another conjecture would be that the primary interface is actually a symbiotic organism, maybe derived from the tree-like organisms, that long ago insinuated itself into other local organisms. Those other organisms would derive the potential benefit of improved communications and maybe some other bennies provided by the interface critters, and the interface critters and their parent organisms would benefit from favorable treatment by the "infested" critters.

A bit like mitochondria?

[Gil Hamilton]

The Na'vi were obviously designed by someone to resemble the native megafauna superficially, but not actually be descended from it. All the megafauna on the planet seems to follow the plan of four forelimbs, two back limbs, two sets of non-binocular eyes, hairless, exposed tentacle, distinctly non-mammalian, sharp pointy teeth.

Meanwhile, the Na'vi have a singe set of binocular eyes, mammalian features like breasts even though James Cameron stated in an interview that they weren't placental mammals, two arms, two legs, hair, et cetera. It seems reasonably clear that some unknown alien race engineered the Na'vi to superficially resemble the native megafauna and be able to interface with it, even though they weren't evolved creatures.

Its quite possible the unknown aliens also engineered the rest of the environment too.

[Alyrium Denryle]

The Na'vi were obviously designed by someone to resemble the native megafauna superficially, but not actually be descended from it. All the megafauna on the planet seems to follow the plan of four forelimbs, two back limbs, two sets of non-binocular eyes, hairless, exposed tentacle, distinctly non-mammalian, sharp pointy teeth.

Meanwhile, the Na'vi have a singe set of binocular eyes, mammalian features like breasts even though James Cameron stated in an interview that they weren't placental mammals, two arms, two legs, hair, et cetera. It seems reasonably clear that some unknown alien race engineered the Na'vi to superficially resemble the native megafauna and be able to interface with it, even though they weren't evolved creatures.

Its quite possible the unknown aliens also engineered the rest of the environment too.

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.

[Patrick Ogaard]

Another conjecture would be that the primary interface is actually a symbiotic organism, maybe derived from the tree-like organisms, that long ago insinuated itself into other local organisms. Those other organisms would derive the potential benefit of improved communications and maybe some other bennies provided by the interface critters, and the interface critters and their parent organisms would benefit from favorable treatment by the "infested" critters.

A bit like mitochondria?

A lot like mitochondria.

Ultimately, the fact that assorted Pandoran life can link their nervous systems doesn't really seem like that impossible a development of natural evolution, so long as it provides or provided some evolutionary advantage over those competing creatures that could not do so.

[Broomstick]

The Na'vi were obviously designed by someone to resemble the native megafauna superficially, but not actually be descended from it. All the megafauna on the planet seems to follow the plan of four forelimbs, two back limbs, two sets of non-binocular eyes, hairless, exposed tentacle, distinctly non-mammalian, sharp pointy teeth.

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...

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....

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.

[Companion Cube]

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.

Sigourney Weaver points out one such species during their initial safari, actually. Blue monkey-like things with two arms. The arms bifurcate, so each animal has four forearms and four hands.

[LadyTevar]

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.

I point out that there are two related egg-laying mammalian species on Earth, the Platypus and the Echidna. Both have primitive mammary glands without nipples -- the milk seeps out through slits on their skin, and the little puggles lap it up.

Now, from my lay-man's view, it would seem that nipples evolved because they were easier for mammalian babies to grab and suckle. On Earth, the Marsupial babies finish their crawl up to the maternal pouch and latch onto a nipple, and it swells slightly to help the baby hold fast, up until the joey is large enough not to be easily dislodged. One can imagine how useful this is for survival of the joeys. One huge climb to find safety and food when you're the size of a large bee is enough; being dislodged from the tit while the mother is fleeing predators would be deadly.

Thus, if the tit is a bonus to survival, and non-placental animals can have mammary glands, why is it so surprising that the Na'vi have them?

[Guardsman Bass]

The Na'vi were obviously designed by someone to resemble the native megafauna superficially, but not actually be descended from it. All the megafauna on the planet seems to follow the plan of four forelimbs, two back limbs, two sets of non-binocular eyes, hairless, exposed tentacle, distinctly non-mammalian, sharp pointy teeth.

Meanwhile, the Na'vi have a singe set of binocular eyes, mammalian features like breasts even though James Cameron stated in an interview that they weren't placental mammals, two arms, two legs, hair, et cetera. It seems reasonably clear that some unknown alien race engineered the Na'vi to superficially resemble the native megafauna and be able to interface with it, even though they weren't evolved creatures.

Its quite possible the unknown aliens also engineered the rest of the environment too.

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.

That's a good point. We ended up with the "4-limbs" body plan here on Earth, but there's no reason why there couldn't be multiple ones with different limb arrangements on Pandora. For all we know, the Na'vi (among others) descended from "four-limbed" creatures, while most of the other megafauna came from the "six-limbed" lineage.

[Junghalli]

We don't even have all terrestrial animals having the same basic body plan here on Earth. Insects have six legs and arachnids have eight. They just tend to not pop into our minds as comparable because they're much smaller than the quadrupeds so we tend to naturally think of them as not really counting.

[adam_grif]

It's possible that there's a reason why there aren't any/many 6 or 8 limbed creatures at large scales. Perhaps the body plan isn't any good for scaling up, in the same way a human body plan isn't good for scaling up to 50 feet high?

That's just speculation, of course. It may well be just coincidence that there aren't any.

[Shroom Man 777]

It's because insects and arthopods can't live in such large sizes. They don't have lungs and they don't have bones, if they got too big they die.

[adam_grif]

I don't mean the entire insect body plan, I just mean the 6 or 8 legged nature of it. Perhaps it's just very inefficient at larger scales?

Not a clue really. Just speculating.

[Junghalli]

I don't see any reasons 6-8 legs wouldn't work about as well as 4. I think the limitations on insect size is mainly their breathing apparatus and maybe also the weight of the exoskeleton at large sizes.

[Shroom Man 777]

Well, it just so happened that the ones who chose six/eight legs were the invertebrates while the vertebrates chose four legs when they decided to crawl around and start walking. If the vertebrates had six/eight legs while the invertebrates had four legs, the current situation might be different.

[Alyrium Denryle]

I don't mean the entire insect body plan, I just mean the 6 or 8 legged nature of it. Perhaps it's just very inefficient at larger scales?

Not a clue really. Just speculating.

It scales just fine. Insects, and arthripods in general can get a lot bigger if oxygen levels are higher. Back prior to the existence of amphibians there were semi-marine scorpions several meters long that could crawl around on land, dragonflies with several meter wingspans etc.

[adam_grif]

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.