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Swaping Places
Topic Started: Jan 9 2010, 11:19 PM (1,408 Views)
TheCoon
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Happy merry Jesusmas inhabitants of the Spec Forums!
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Here's a good one: What if arthropods and vertebrates swaped places?

What if the vertebrates were the tiny critters that polinize flowers while arthropods were gigantic grazers and feroceous carnivores?
Greetings young life form! Procyon Lotor at your service.

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ATEK Azul
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Transhuman
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I'm not sure that's possible, but it would be a very interesting world.

Does anybody know why Vertebrates(besides competition) can't seem to get as small as Arthropods?
I am dyslexic, please ignore the typo's!
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Canis Lupis
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Dinosaurs eat man, woman inherits the Earth.

It probably has something to do with their skeletal system. Vertebrate's have a skeletal system that naturally forces them to be larger than most arthropods.

In short, vertebrate skeletons are expansive in nature whereas arthropod skeletons keep inpansive in nature (I know inpansive is not a word, but hopefully you catch my drift).

If you don't understand that statement (with the made up word), then basically vertebrate skeletons put a minimum on the size whereas arthropod skeletons put a maximum on the size.

If the respiratory systems of vertebrates were placed in arthropods and vice versa, the largest an arthropod could get would be about the size of a house cat, maybe larger (but that's stretching it). The smallest vertebrate would still be only about the size of a wrasse.

The only way for this world to actually come about is for arthropods to evolve an endoskeleton and for vertebrates to never ossify a skeleton.

The smallest chordate ever was probably haikouicthys, which was about the size of an average man's thumbnail. To the best of my understanding, haikouicthys did not have an ossified skeleton like almost all vertebrates possess. This was most likely one of the reasons vertebrates are restricted to larger sizes.

Though tunicates and cephalochordates, to the best of my knowledge, remain small and they possess no ossified skeleton. So, in theory, if vertebrates never evolved an ossified skeleton, then they could remain small. And thus the niches could be reversed (but only if arthropods evolve an endoskeleton. If they do, then perhaps arthropods will also evolve an efficient respiratory system).
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Ddraig Goch
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Ar hyd y nos

But, in the oceans at least, arthropods can get reasonably large (Eurypterus, Brontoscorpio, and even Anomalocaris were all at least a metre in length)
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ATEK Azul
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Yes And in the Carboniferous we had huge Arthropods like that Centipede one(was it named Arthropluera?)

also are you saying Vertebrates can only replace Arthropods if they have Cartillige Skeletons?

Also Every thing can get bigger in water it appears.
I am dyslexic, please ignore the typo's!
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Ddraig Goch
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Ar hyd y nos

Yes, it was Arthropleura. And there was Meganeura.
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ATEK Azul
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Okay thanks.

I know Sharks have Cartillige Skeletons but could that type of skeleton support a Vertebrate at Arthropod size?
I am dyslexic, please ignore the typo's!
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Holben
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Rumbo a la Victoria

Meganeura wasn't actually a dragonfly, it was a primitive species which doesn't exist anymore. Just for clarification.

Arthropods, as Canis said, face massive problems to circumvent in growing in size. Why did you think the largest reach 30cm long and are as thick as sticks? The heaviest weigh 100g.

And also, given any opputunity, vertebrates would outcompete arthropods.

Arthropods are limited by their exoskeleton- they can't have much growth time since the larval stage, and the larvae would have to be massive for even a cat-sized arthropod.

The smallest mammal possible is about shrew-sized, the smallest reptile about 2/3rds of that, and the smallest bird would be a kind of hummingbird size, which already act as pollinators.

Bird-eating spiders are already ferocious predators and quite large anyway.
Time flows like a river. Which is to say, downhill. We can tell this because everything is going downhill rapidly. It would seem prudent to be somewhere else when we reach the sea.

"It is the old wound my king. It has never healed."
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Ddraig Goch
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Ar hyd y nos

To be fair, Holbenilord, I never said that Meganeura was a dragonfly. And I agree - the only way that the roles would be reversed would be if some mad scientist shrunk all the vertebrates, and blew up the invertebrates. And even then, that wouldn't work either.
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Holben
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Rumbo a la Victoria

No- i know you didn't. I didn't mean it to make you look wrong or anything, sorry. I just wanted to clarify.

The vertebrates have very active lifestyles, and need lots of food- less available when you're small.

The invies wouldn't be able to sustain their lifestyles, and many would collapse under their own weight.
Time flows like a river. Which is to say, downhill. We can tell this because everything is going downhill rapidly. It would seem prudent to be somewhere else when we reach the sea.

"It is the old wound my king. It has never healed."
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Ddraig Goch
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Ar hyd y nos

So "Attack of the Eight Legged Freaks" could never happen? :lol:
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Holben
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Rumbo a la Victoria

:) . Surprisingly, arachnids would find it easiest to cope. They spread their weight more and have highly advanced 'book' lungs.
Time flows like a river. Which is to say, downhill. We can tell this because everything is going downhill rapidly. It would seem prudent to be somewhere else when we reach the sea.

"It is the old wound my king. It has never healed."
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Ddraig Goch
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Ar hyd y nos

But still, the scene where the massive tarantula topples that caravan is probably taking it a bit too far.
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Holben
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Just a bit. ;)

Maybe we could have cat-sized beetles, if we stretch it.
Time flows like a river. Which is to say, downhill. We can tell this because everything is going downhill rapidly. It would seem prudent to be somewhere else when we reach the sea.

"It is the old wound my king. It has never healed."
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Ddraig Goch
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Ar hyd y nos

Or perhaps something like the giant cockroaches from "The Future of the Kinds"? Although that would require elavated oxygen levels.
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