Welcome Guest [Log In] [Register]
Speculative biology is simultaneously a science and form of art in which one speculates on the possibilities of life and evolution. What could the world look like if dinosaurs had never gone extinct? What could alien lifeforms look like? What kinds of plants and animals might exist in the far future? These questions and more are tackled by speculative biologists, and the Speculative Evolution welcomes all relevant ideas, inquiries, and world-building projects alike. With a member base comprising users from across the world, our community is the largest and longest-running place of gathering for speculative biologists on the web.

While unregistered users are able to browse the forum on a basic level, registering an account provides additional forum access not visible to guests as well as the ability to join in discussions and contribute yourself! Registration is free and instantaneous.

Join our community today!

Username:   Password:
Add Reply
Life Without Vertebrates; *OP updated*
Topic Started: Dec 24 2009, 04:12 PM (2,290 Views)
KayKay
Adult
 *  *  *  *  *  *
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.
Offline Profile Quote Post Goto Top
 
Replies:
ATEK Azul
Member Avatar
Transhuman
 *  *  *  *  *  *  *  *
I agree with Arachnids and Trillobites my self.

Also with that type of thinking your right the Virus would get into fresh water quickly.

So are we killing chordates or Vertebrates?
I am dyslexic, please ignore the typo's!
Offline Profile Quote Post Goto Top
 
KayKay
Adult
 *  *  *  *  *  *
We're going to let some chordates live, all vertebrates go.

How about archaeopteris? Very successful spore-bearing trees found in many climate zones (one reason why I think there's a high chance some might survive), but they disappeared quickly after the start of the Carboniferous. Is it worth letting them live, perhaps the extinction might allow them to last longer?
Offline Profile Quote Post Goto Top
 
Canis Lupis
Member Avatar
Dinosaurs eat man, woman inherits the Earth.

Yep. That seems likely to be among the survivors.

As for terrestrial squids, I say let them in. But just the swampus/aeroteuthid/sloth-squid variety.
Offline Profile Quote Post Goto Top
 
ATEK Azul
Member Avatar
Transhuman
 *  *  *  *  *  *  *  *
Okay looking good. Though I must say I dislike Sloth Squid personally.

Also I think Dragonfly's will survive along with any remaining Eurypterids if they survived to that time. A group I'm not sure about are the Gastropods, how would they survive?

Also we might see some changes in Reef builders, but what type of differences? Could they possibly use the ash from forest fires to help build their skeletons or as extra nutrients? And if so what would that equate to in modern times?

Oh and 1 more thing is if Eurypterids are gone then will Arachnids move back under water and replace them? I can see Spider silk being a part of reef building and kelp forests in this world. I can also see these Spiders using new types of webs for support and strength against the tides and for hunting.
I am dyslexic, please ignore the typo's!
Offline Profile Quote Post Goto Top
 
Venatosaurus
Member Avatar
HAUS OF SPEC
 *  *  *  *  *  *  *  *  *
Ooh, I quite like that marine arachnid idea ATEK. Kay you could also allow centipedes and their relatives (like velvet worms as well) to persist.



Offline Profile Quote Post Goto Top
 
ATEK Azul
Member Avatar
Transhuman
 *  *  *  *  *  *  *  *
Thanks I am glad you like it though it is not limated to Spiders if my post implied that.

Also Centipedes and relatives probably could survive though not the giant 1.

I think if Scorpians evolve back into a water species they would find a way to use thier stinger. Maybe they could adapt a body posture simular to Sea Horses or Shrimp?
I am dyslexic, please ignore the typo's!
Offline Profile Quote Post Goto Top
 
Venatosaurus
Member Avatar
HAUS OF SPEC
 *  *  *  *  *  *  *  *  *
Maybe the new sea scorpions could split, the bottom dwelling/coastal forms we are accustomed to, and the then more pelagic forms that use their tail to locomote in a fashion similar to our Earth's cetaceans, their stingers would streamline, and be found and the very tip of their tail , they would retain either one or two the limbs as is, while one pair turns into something akin to a fin, by the time to fully refine themselves to such an existance they have a stingray-like body as well.



Offline Profile Quote Post Goto Top
 
ATEK Azul
Member Avatar
Transhuman
 *  *  *  *  *  *  *  *
That's possible and would be quite wierd, though that sounds simular to the Eurypterids in some ways. Also I think they would keep their pincers. Although I wonder if the Stinger will be very effective if turned into a fluke at the back of the animal?
I am dyslexic, please ignore the typo's!
Offline Profile Quote Post Goto Top
 
Canis Lupis
Member Avatar
Dinosaurs eat man, woman inherits the Earth.

That's what one calls convergent evolution. A creature evolving similar traits when it is in a similar ecological situation.

As for sloth-squid, that is completely your personal preference. Given more than 300 million years to evolve, I could see it evolving. Especially without competition from vertebrates.
Offline Profile Quote Post Goto Top
 
ATEK Azul
Member Avatar
Transhuman
 *  *  *  *  *  *  *  *
True that is my prefference. In my book of plausibillity Slug like Cephalopods replace them as very possible.
I am dyslexic, please ignore the typo's!
Offline Profile Quote Post Goto Top
 
KayKay
Adult
 *  *  *  *  *  *
Well, we're not even sure yet if squids will evolve, I don't think it's even known if there were any at the carboniferous. There were some very squid-like animals, but I am sure they all had heavy shells.

I was thinking, if we could do it epoch by epoch, or period by period (maybe do it in epochs as we get closer to present day, since the Carboniferous and the Permian periods can be quite long) we might get more realistic relationships (not just evolutionary relationships, but other more direct relationships such as predator - prey). In fact, that is how I had actually started to do it in the first place a year back before it went on pause, I was hoping we could stick to this? I've found, at least for my other project, it gives the whole thing a lot more clarity and order.

We could still speculate for further future changes (like the terrestrial squid), but keep it in the considering list (see op, I found the edit button) until we reach the age where this occurs? Though, personally, I didn't like the land and tree squids in TFIW, I hope they're nothing like those.

I'm sure eurypterids were still around during that time, I'll have a look for specific species, but I'm not sure how the mass extinction would affect them. If they were quite large, maybe they wouldn't fare so well, leaving niches open for the aquatic arachnid ideas.

I will also try to look for specific species of centipede relatives. So... what about velvet worms? I'd like to see them surviving.

Edit:

Some more ideas: How about nautiloids and ammonoids? I think they were quite diverse. Orthocerids too? Or is that pushing it a bit?

Edited by KayKay, Dec 27 2009, 11:29 AM.
Offline Profile Quote Post Goto Top
 
Venatosaurus
Member Avatar
HAUS OF SPEC
 *  *  *  *  *  *  *  *  *
Actually I don't think the Orthocerid idea is pushing it, and in our own timeline they may have persisted as far as the Cretaceous due to a new possible fossil found in the Early Cretaceous ! I think the centipedes could fare very well, becoming herbivores, deadly carnivores, and even aquatic forms could arise, as for the velvet worms I mentioned that they should survive. I was also thinking about dragonflies and their nymphs !



Offline Profile Quote Post Goto Top
 
KayKay
Adult
 *  *  *  *  *  *
Oh yeah I remember in the first attempt there was fully aquatic dragonflies that bred in their nymph stage. Then some would emerge in the adult form every several generations when conditions in the current habitat. Some terrestrial types did the same thing except they were wood-eating nymphs...

By the way I just updated the OP list and I'd like to ask for opinions on how things should go?

Nautiloids
Ammonoids
Orthocerids

Could one of them become squid analogues?

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?

(I personally think not)
Edited by KayKay, Dec 28 2009, 02:24 PM.
Offline Profile Quote Post Goto Top
 
Canis Lupis
Member Avatar
Dinosaurs eat man, woman inherits the Earth.

I think it would be likely that ammonoids would take the place of cephalopods (even though they technically are cephalopods).

As for eurypterids, this is just a guess, but they probably would not survive the extinction. Eurypterids, from my understanding, depended upon the vertebrates for a majority of their food. When the vertebrates go extinct, so will the eurypterids. So most likely, I'm thinking crustaceans would take eurypterid niches. I know that is somewhat unoriginal, considering the eurypterids were basically scorpion-derived crustaceans, but it seems the most likely.
Offline Profile Quote Post Goto Top
 
KayKay
Adult
 *  *  *  *  *  *
Since a few others have speculated replacements for the eurypterids, should we let them die off? I was also thinking, the meteorite impact that killed off the dinosaurs is thought to have killed off many marine predators too, particularly large ones. Maybe the same case would occur here?
Offline Profile Quote Post Goto Top
 
1 user reading this topic (1 Guest and 0 Anonymous)
Go to Next Page
« Previous Topic · Alternative Evolution · Next Topic »
Add Reply