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| Life Without Vertebrates; *OP updated* | |
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| Topic Started: Dec 24 2009, 04:12 PM (2,289 Views) | |
| KayKay | Dec 24 2009, 04:12 PM Post #1 |
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Adult
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This will be an open project, anyone can join in to give their input and ideas. This is a time line where a major extinction event early in Earth's history wipes out all vertebrate life on the planet, and many invertebrates along with them. Life Without Vertebrates is actually going to see the loss of all chordates. This will happen at the transition between the Devonian and the Carboniferous (if anyone thinks another point in history would be better, feel free to speak out). The remaining invertebrates take the place of vertebrates and dominate the sea and land. The mass extinction that causes this will have to be tailored to give vertebrates the hardest time. It must also be very severe, to be able to wipe out every single last chordate, so there would be a loss of many invertebrates too. Which invertebrates die out will depend upon the extinction event. 1. Decide what the extinction event will be, and how it will affect the climate. It must allow a significant number of invertebrates to survive, but wipe out all chordates. 2. Find out all of the known invertebrates that existed during the Late Devonian and Early Carboniferous, preferably as close to just before the extinction event as possible, and preferably species where there is adequate information available. 3. Decide which invertebrate species will survive, and mark out basic food webs for all of the major climate zones of the surviving invertebrates after the aftermath. This will provide a starting point for the project. So... first an extinction event suited for wiping out vertebrates and allowing enough invertebrates to live... Any ideas? If anyone wants to move on to the other steps that's fine, they were just a guideline anyway. EDIT: what we have so far.... A disease spreads that attacks chordates. Chordate species numbers plummet, but some chordates and a minimal number of vertebrates survive. Soon after, a meteorite impact on the main equilateral continent wipes out a large portion of both invertebrates and vertebrates. Many invertebrates make it through, but vertebrates are already dying out so the impact brings them down to critical numbers. After this point, vertebrate species are too low to ever recover, and they are gradually phased out by invertebrates. Extinct All vertebrates Survivors Arachnids Trilobites Centipede relatives (looking for names to be more specific) Onychophora Nautiloids * Ammonoids * Orthocerids * *Could one of them become squid analogues? Archaeopteris (spore-bearing) Considering Marine arachnids (to replace eurypterids) * Marine scorpions (to replace eurypterids) * Eurypterids (should they live or die off?) * *Did eurypterids survive to the carboniferous? Would they survive the impact? Squid, possibly land squid (maybe leave this idea for later on when cephalopods are more evolved) Edited by KayKay, Dec 28 2009, 02:24 PM.
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| Venatosaurus | Dec 24 2009, 04:16 PM Post #2 |
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HAUS OF SPEC
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Possibly some sort of virus similar to Meningitus affects early Vertabrates, this already devastating ailment is followed by either an asteroid impact or severe volcanic eruptions. |
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| Kingpin | Dec 24 2009, 04:18 PM Post #3 |
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Prime Specimen
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Well i don't think a natural disaster is the way to go, if you're thinking meteor or something along those lines. I think an air/water born disease that deteriorates bones at a rapid rate. That way, only vertibrates would be hurt. |
-Last Olympian, Rick Riordan.
-Nick | |
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| ATEK Azul | Dec 24 2009, 04:23 PM Post #4 |
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Transhuman
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A desease along with another mild disaster sounds like the best solution to me. |
| I am dyslexic, please ignore the typo's! | |
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| colddigger | Dec 24 2009, 10:23 PM Post #5 |
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Joke's over! Love, Parasky
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i think that an alien seafood restaurant chain exhausting the native fish populations into extinction shall be the way to go. |
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Oh Fine. Oh hi you! Why don't you go check out the finery that is SGP?? v Don't click v Spoiler: click to toggle | |
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| Canis Lupis | Dec 24 2009, 11:26 PM Post #6 |
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Dinosaurs eat man, woman inherits the Earth.
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I also think that a disease would be the best way to go. But this disease would not deteriorate bone. Rather, it attacks the very thing that makes us chordates: the notochord. There are modern parasites that digest the brains of their host and, most likely, their notochord (spinal chord). However, it does not seem likely for a parasite to evolve and wipe out ALL chordates. What I'm thinking is a bacterium that has evolved to attack the nutrient-rich nervous systems of chordates and some invertebrates (particularly cephalopods). |
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| Vultur-10 | Dec 25 2009, 03:10 AM Post #7 |
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Plagues that deadly and widespread aren't very likely... there'll always be *some* resistant creatures (especially a group as diverse as Devonian chordates), which will survive to pass down their genes. It might be better to have some more general disaster, that killed off the chordates because they were either too big (most vertebrates in that time frame) or fairly marginal (tunicates). Say it killed every living thing over 10 grams. |
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| KayKay | Dec 25 2009, 04:02 AM Post #8 |
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Maybe a combination of both disease and natural disaster? The disease could weaken the number of chordate species until the chordate extinction levels out. Then, before they get a chance to diversify again, a natural disaster could wipe out the last few. Even if some chordates remain, there is far more invertebrate diversity so it's more likely that there will be invertebrates better suited to whatever niches chordates were pushed out of, and the chordates might find themselves shut out of so many niches that they cannot adapt to future environmental changes and become extinct. |
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| Canis Lupis | Dec 25 2009, 07:48 AM Post #9 |
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Dinosaurs eat man, woman inherits the Earth.
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KayKay brings up an excellent point. Outcompetition. At the time KayKay says she wants chordates extinct, the oxygen levels were considerably higher than they are today. At that time, arthropods basically ruled the world. With some amphibian help of course. After she brought up that point, my theory is that a disease would serve to slice chordate numbers by about 75%. Then, if oxygen levels remain at the 30% mark they were in the Carboniferous, chordate numbers will not be high enough to retake the niches. |
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| ATEK Azul | Dec 25 2009, 02:19 PM Post #10 |
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Transhuman
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That seems very likely that Desease in combinations with other factors like Outcompetition and a minor disaster might be enough to wipe out Chordates. Also are you including Echinoderms on the extinct list? Also since I beleave Oxygen started going down in the permian you need to kill off the Chordates by the end of the Carboniferous, Otherwise Chordates will have an advantage again and will most likely diversify. |
| I am dyslexic, please ignore the typo's! | |
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| Canis Lupis | Dec 25 2009, 05:35 PM Post #11 |
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Dinosaurs eat man, woman inherits the Earth.
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You are correct. Oxygen levels did go down in the Cambrian. And if that were the case, chordates would regain their numbers and retake the world. But, if oxygen levels never depleted until the end of the Permian, chordates would be completely wiped out. As for echinoderms, they would not be wiped out by the disease, depending on which one we go with. If we go with a disease that destroys advanced nerve tissue, then chordates, cephalopods, and a few obscure species would go extinct. However, if we go with a disease that destroys bone tissue, then potentially you could have chordates, crustaceans, maybe some other arthropods, possibly echinoderms (though that is doubtful), and (again) cephalopods (at least the ones that have evolved a pen). From the way deliberation is going on this topic, it seems like we are going to have some sort of disease cutting chordate numbers down by at least 50%. But we'd need a natural disaster to finish the job. So far, the best ideas I've seen are an asteroid impact and an oxygen level that remains at Carboniferous levels until the close of the Permian (and I'm not picking that because it is my idea). Anybody else got any ideas? |
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| ATEK Azul | Dec 25 2009, 05:45 PM Post #12 |
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Transhuman
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At the beginning of your post I got confused since it says Cambrian, but I get what you mean. I actually like the Oxygen idea which would allow Invertebrates to diversify and push out Chordates. Though a part of me wonders if even that is enough or do we need desease, impact and then high oxygen to finish the job? |
| I am dyslexic, please ignore the typo's! | |
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| Canis Lupis | Dec 25 2009, 05:50 PM Post #13 |
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Dinosaurs eat man, woman inherits the Earth.
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Sorry about that. Typos. Gotta love them. Anyway, now that you put it that way, I'm thinking a massive impact, plus a disease, would be the way to go for chordates to go COMPLETELY extinct. Now, if the disease wipes out 75% of the chordates on Earth, the asteroid would have to wipe out the remaining 25%. The chordates that would survive the disease would have to exist somewhere where the disease could not reach. I'm thinking either underwater or on some isolated continent. Which would mean the asteriod would either have to strike the isolated continent or somewhere where a lot of dust would be kicked up. |
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| ATEK Azul | Dec 25 2009, 07:26 PM Post #14 |
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Transhuman
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I think the Isolated continent would be better since most Chordates at that time had a connection to the water, which makes water a transfer system for this desease. So if this happens in the Carboniferous most of the Surviving Chordates will be fresh water or land animals. making them prone to celestial impact. Also if done in the Carboniferous the high Oxygen content can work in the Invertebrate's favor. |
| I am dyslexic, please ignore the typo's! | |
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| sam999 | Dec 25 2009, 08:48 PM Post #15 |
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I kinda thought we already had done this... |
I am not suffering from insanaty. I truely enjoy being mad.![]() ![]() ![]() Comeon, thy dragons need YOU! Visit them here please... | |
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