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| Rewriting Earth; a new wave of spec evo projects | |
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| Topic Started: Nov 21 2009, 11:38 PM (7,631 Views) | |
| ATEK Azul | Nov 22 2009, 07:20 PM Post #31 |
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Transhuman
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My thoughts are that Cephalopods being top predators in the Cambrian would actually not have much(predator versus prey) compitition with Anomalocarids. Infact as their brains grow and their color changing developes they will actually out compete the Anomalocarids(forcing them on to land?). Another thing is that I highly doubt the pen structure of cartillage is any where near as adaptable and supportive as chordates. Plus as octopie show they eventually dissapear(if life reduces stuff it does not normally last long). So the best bet for land Cephalopods is them developing an exoskeleton and becoming bugs on land. |
| I am dyslexic, please ignore the typo's! | |
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| Canis Lupis | Nov 22 2009, 07:42 PM Post #32 |
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Dinosaurs eat man, woman inherits the Earth.
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Or it is possible that the cartilage pen could calcify. I just finished watching this video ( http://video.google.com/videosearch?q=Cambrian+life&emb=0&aq=f#q=%22Walking+with+Monsters%22+anomalocaris&view=2&emb=0&qvid=%22Walking+with+Monsters%22+anomalocaris&vid=491024006184453454 ) explaining the evolution of chordates. According to the video, haikouicthys (spell check) had a cartilage backbone. And of course ours calcified. Could the same thing not happen to cephalopods? Or maybe cephalopods, when and if they calcify the pen, could evolve into their own phylum and push THEMSELVES onto land. In a way, that's what fish did. Placoderms evolved and pushed primitive amphibians onto land. |
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| ATEK Azul | Nov 22 2009, 07:49 PM Post #33 |
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Transhuman
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Except that Cephalopod evolution has clearly shown that the reverse is happening they are loosing the shells and turning them into cartilage. |
| I am dyslexic, please ignore the typo's! | |
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| Canis Lupis | Nov 22 2009, 08:03 PM Post #34 |
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Dinosaurs eat man, woman inherits the Earth.
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Who knows? Maybe if evolutionary pressures are different, the opposite will happen and their shells will calcify. The way competition went in the Cambrian was robust and strong, with good vision. That eventually changed to mobility, which is why fish evolved to become more muscular, arthropod skeletons less rigid, cephalopod shells lost, and anomalocarids extinct. I'm sure that, in a universe where chordates never evolved, cephalopods would diverge into three clades: a shelled group (like nautiloids and ammonites), a squishy group (like modern cephalopods), and a "vertebrate" group. The shelled group would offer some protection from anomalocarids and would prevail for a time. But, as anomalocarids will undoubtedly become sleeker, faster, and more manueverable, their prey will as well. So cephalopods will evolve away their shells to become faster in attempts to swim away from their anomalocarid predators. Eventually, like in the early Silurian, I'd imagine that the squishy cephalopods would become considerably larger to combat their anomalocarid predators. In this way, cephalopods would become the main predators of the sea and outcompete anomalocarids. The main prey for these new cephalopods would be the swimming trilobites and other cephalopods. The main defense of the swimming trilobites would most likely be their exoskeleton and a high reproductive rate. Same with the other cephalopods, minus the exoskeleton part. I'd imagine that speed would eventually be their main defense. To coordinate this change in swimming, an advanced nervous system would have to evolve. Thus, a notochord would evolve to help send electrical signals throughout the body. And, to protect the notochord, I'd imagine the pen would further calcify to protect the notochord. The vertebrate cephalopods would then have a major advantage: an advanced nervous system, advanced muscular system, speed, and structure, giving them a major advantage in the primordial oceans. So, as you may know by now (and if you don't, where have you been?), my vote for dominant land life is cephalopods. Any other votes? I think I heard Atek say something about land anomalocarids. |
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| ATEK Azul | Nov 22 2009, 08:21 PM Post #35 |
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Transhuman
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Okay I get the point I was just going by known evolutionary traits that seemed to happen since I want this to be acurate and interesting. And as for land life Trillobites and Eurypterids are my ideas. If Cephalopods are the new radially symetrical vertebrates then what possible diversity in form can there be? Or does all life look like Megasquids? Another land group could be walking Snails and Serpentine Slugs. |
| I am dyslexic, please ignore the typo's! | |
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| Canis Lupis | Nov 22 2009, 08:34 PM Post #36 |
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Dinosaurs eat man, woman inherits the Earth.
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I wasn't trying to put you down Atek (why is it that when I read people's posts that I feel I've offended them? ).And I thank you for that Atek. Those thing you pointed out actually helped me to get around the problems associated with land cephalopods. And Atek, you have just brought up one of my favorite creatures! An image of a saltokochlid has just rushed through my head. Thank you so much for that image! For those who don't know, the saltokochlid was a fixture in my TFIB project. But I was having a little trouble fitting it into a future world where squamates still exist. The saltokochlids had evolved a skeleton in response to land living and had evolved two legs from their ribs. You know, I actually think that the saltokochlids fit better in NE than they do in HE's future. Again Atek, thank you! If everyone is okay with it, we will still have a cephalopod radiation. But no land cephalopods. Land gastropods will work just fine. Again Atek, thanks! Now, my question is, what could push the saltokochlids onto land in the first place? What about their early forms, their ancestors? What variations in body plan could exist? |
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| ATEK Azul | Nov 22 2009, 08:55 PM Post #37 |
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Transhuman
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I was not trying to sound offended and I am glad to help with all of that stuff. If it makes you feel better when ever people are discussing stuff I feel like their yelling(though I ignore that most of the time). As for how to push them onto land, maybe they would specialize on feeding from the Lichen since they would be easier to digest. I would also think that They would develope some abillity to hop/walk before they go to land(most likely as an escape mechanism). |
| I am dyslexic, please ignore the typo's! | |
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| Canis Lupis | Nov 22 2009, 09:42 PM Post #38 |
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I know you weren't trying to sound offended. I just read that in everyone's posts. It's like you thinking everyone is yelling. It's just our upbringing I guess. Yes, that lichen thing makes sense. As does the hopping thing in the water. In fact, that's how TFIW thinks snails will evolve into desert hoppers. But it does make sense for a walking snail to evolve a cone snail-like hopping mechanism. And on land, the skeleton would definantly begin to evolve as trilobites move onto land. For added protection when they lose their shells (if snails are to become a major land contender, losing their shells would be a must. It would be an immediate speed booster), I could see them evolving an endoskeleton. A primitive notochord would then extend from the brain to aid in muscular control. Eventually, to further aid in speed, ribs would form six primitive "scutes", or legs that help the saltokochlids to scoot along the ground. This would most likely occur in the Carboniferous. After the Carboniferous, I'd imagine these scutes would evolve into six fully functioning legs. Then, after P-Tr, these hexokochlids have numbers that are greatly rediced. As you all know, Hox genes control the segmentation of the body and the limbs that the creature possesses. So, due to some Hox gene mutations in the Triassic, two new groups of saltokochlids form: the tetrakochlids and the dikochlids. Now, in the Mesozoic, oxygen levels are considerably higher than today. Therefore, plants are more widespread. Thus, it would seem logical that a creature that could take advantage of these numerous plants would rule the world. That is why tetrakochlids take over the Mesozoic because their legs and the number of their legs can carry a massive bulk, so they can eat a large number of plants because the ensuing bulk is supported by a strong skeleton and four limbs. Predator species of tetrakochlids also evolve, and are just as vicious as their dinosaur counterparts from HE. Waiting in in the wings (and near the rivers) are the dikochlids. They have evolved into fish eaters in NE's Mesozoic. But, at the end of the Cretaceous, this all changes. An asteroid strike spells doom for the vast majority of the tetrakochlids, some of the larger dikochlids, some teuthidipterans, all the aerokochlids (flying descendents of the hexapod scutes), and the largest swimming trilobites and squids. A few obscure groups are also wiped out, bet those I just mentioned are the main casualties. After K-T, dikochlids take over. With the decline of forest and with the spred of lichen-grass, speed and sleekness is favored over bulk. This is why the dikochlids take over the world after K-T instead of the remaining tetrakochlids. This two legged body structure is just what the doctor ordered in this new, more open, and colder, environment. Any critiques of that evolutionary history of the saltokochlids of NE? Seriously, are there any flaws in that? I'm not trying to discourage critique; I'm trying to encourage it. Are there any flaws in my reasoning? |
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| ATEK Azul | Nov 22 2009, 09:56 PM Post #39 |
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What are the teuthidipterans and aerokochlids? Also if the Snails have a launching limb simular to marine Snails how do the ribs in the chest move into the launching limb inorder to form the scutes? Or do they form on the sides of the torso and eventually replace the launching limb? Also what flying group evolves after the K-T extinction? And what group are they from? Also what was the fate of the six limbed group? I would also like to know a little about the flora of the forests and the mentioned Lichen Grass(great idea!)? |
| I am dyslexic, please ignore the typo's! | |
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| Canis Lupis | Nov 22 2009, 10:37 PM Post #40 |
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Dinosaurs eat man, woman inherits the Earth.
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Sorry I didn't explain that. The teuthidipterans are a flying group of squids. People on this forum have said they'd be likely fliers if chordates are wiped out in the future, so why not fliers in a world without chordates? Aerokochlids are descendents of the primitive saltokochlids that existed in the Carboniferous. These were the saltokochlids with six "scutes", which evolved into the wings of the aerokochlids. The aerokochlids ruled the skies throughout the Permian and well into the Cretaceous. At the end of the Cretaceous (125mya), teuthidipterans began to evolve and slowly began to outcompete the aerokochlids. After K-T, it was the teuthidipterans who took to the skies. This is what became of the "vertebrate" squids. Outcompeted by the squishy squids, the "vertebrate" squids took to leaping out of the water to escape the squishy squids. Eventually, this evolved into full fledged gliding and, when the bouyancy sac evolved into a "lung", true powered flight. The six limbed group ended up kind of like lizards. Their numbers were greatly reduced and they eventually were outcompeted by first the tetrakochlids and then the dikochlids. So the hexakochlids had to content themselves with small, burrowing niches or insectivorous niches or tiny herbivore niches or fishers. In fact, that last niche (the fisher niche) eventually evolved into something akin to a crocodillian. Well, the basic flora is somewhat the same. You've still got your club mosses dominating land in the Silurian and Devonian, then you've got the club mosses evolving into a higher order of trees (similar to HE trees). In fact, the flora is basically the same (mostly due to my lack of botanical knowledge (if someone of more botanical knowledge has any ideas, I'd be much obliged)). All except for the lichen grass. All through the time periods, lichen has dominated forest floors and has been a staple in small animal diets since its appearance. But, starting in the Cretaceous, this lichen evolved hard outer cuticles to prevent so many animals from feasting on it. Some NE scientists (humans have traveled to NE via wormholes. Similar to how humans exist in Spec) have speculated that the evolution of these cuticles may have played a part in the demise of the tetrakochlids (of course, not all tetrakochlids are extinct. You've still got some relict species, mostly arboreal "monkeys" living in forests). Other factors included a cooling world and the asteroid, but that's beside the point. After K-T it was an evolutionary arms race. Or, should I say, beaks race. saltokochlid groups were evolving new beaks to attempt to tear off pieces of lichen-grass and digest them. For about ten million years, the hexakochlids made a comeback. But, at 55mya, dikochlids became the dominant runners of this race, eventually taking over the cenozoic world. A note: cephalopod tentacles became more highly derived in the Devonian and Carboniferous. Four of their tentacles evolved into fins and the other four evolved into a "head". The remaining two tentacles are the graspers, which remained as graspers. They eventually merged their posterior (the bulbous end opposite the eyes and tentacles with their anterior and eventually, their tentacle-derived fins migrated further down the body. It was with this fin evolution that squids greatly diversified. Squid truly came to rule the seas in the Permian, producing a massive array of squishy squids that took the marine niches trilobites had held so long before. When P-Tr occured, these squishy squid populations were decimated. They didn't go completely extinct, but their numbers were greatly reduced. This produced a genetic bottleneck. And, like genetic bottlenecks tend to do, a massive radiation occured in the squids. Squishy squids still remained and somewhat diversified. But after P-Tr, vertebrate squids became more common. As squids became more intelligent, their pen evolved as more of a notochord casing. And, while squids never got onto land, this adaptation would later help the squids take the air after K-T. |
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| ATEK Azul | Nov 23 2009, 01:37 PM Post #41 |
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Transhuman
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Okay thank you for the explaination. So far what is in this world makes alot of sense now that it was explained. But since this is a group project and not just ours maybe we should get some other opinions? |
| I am dyslexic, please ignore the typo's! | |
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| Holben | Nov 23 2009, 03:01 PM Post #42 |
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Rumbo a la Victoria
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Are we going to have arachnids taking over the land? I'd love to see scorpions 10m long. |
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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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| Canis Lupis | Nov 23 2009, 03:39 PM Post #43 |
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Yes Atek, we really ought to. So: any opinions? Holben: If you look at arachnid evolution, you shall see that most modern arachnids evolved because of a land living existence. Though, I'm not sure about that. The place I'm getting this info from doesn't go into detail on arachnid evolution. If someone has more detailed info, it would be much appreciated. Anyway, if we do have an even more massive trilobite radiation here (and everyone, let me know if that is okay), I'd bet the farm that trilobites would take over the chelicerate niches, pushing the chelicerates out of niches they conquer on HE. That said, this in no way means trilobites can't become spider/scorpian like. We could potentially have a horseshoe crab-like creature with a poison sac at the base of the abdomen, used to sting prey. BTW, while in chemistry class, I thought of something. If we do have a mass trilobite radiation, insects may not be as diverse as they are on Earth. There is a very real possibility that insects would go the way of the chordates: extinct. With trilobites taking their niches. Now, I was thinking: what are some limits on the trilobite's anatomy? And is their any way fliers could potentially evolve, even if the trilobites have to go through neotony to produce the fliers? |
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| Holben | Nov 23 2009, 03:50 PM Post #44 |
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Rumbo a la Victoria
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(Not concentrating in class? Well, well...) I'm hoping we do get trilobitian scorpioformes. |
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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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| Canis Lupis | Nov 23 2009, 04:05 PM Post #45 |
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(yeah. I'm a bad science student, ain't I?) I'm just hoping people will approve of the ideas I posited.
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