E

19 yrs old she/they, loves speculative biology and might or might not be working on a project.

[eleven-screams]

@tribbetherium what the hell why is this on wikipedia lol

[a-dinosaur-a-day]

ftr I am forever going to be bitter that the post I wanted to be "let's talk about extinct ecosystems and how cool they are!" got derailed into yet another post just talking about a single taxon like the millions of other posts on palaeoblr

[parttimepunner]

Please tell me more about these extinct ecosystems. Why did they go extinct? Could an ecosystem like that return?

[a-dinosaur-a-day]

When I say "extinct ecosystem", I mean those ecosystems that have existed in the past, with extinct animals and plants etc. inhabiting them

by their very definition, they are gone forever

there are ones that were truly unique, like Polar Tropical Forests and Fern Prairies, that we just could not have today

but there were ones that have equivalents to today, as well, like the first savannahs and steppes of the Miocene - they just have earlier versions of the plants and animals

there were so many because there are so many today, and each one had its own flora and fauna and was glorious

There's the wetlands and forests of Hell Creek in the Latest Cretaceous

the bizarre Volcanic Lake Forests of the Jehol Biota

whatever the hell the Ediacaran Reefs were

the Scale Tree Swamp Forests of the Carboniferous

"Mesozoic 2" aka pre-human Aotearoa

the Western Interior Seaway dominated by Mosasaurs

and so many other things, I couldn't possibly list them all. Every time period had its own biosphere and biomes, and they were all unique.

[a-dinosaur-a-day]

#i wanna see the Aurora Borealis over a tropical forest#BC Canada has a Boreal Rainforest so you can definitely get that

that isn't what I mean by "Polar Tropical Forest"

I mean a tropical forest

at the poles

ie, the ecosystems present during the Paleocene-Eocene Thermal Maximum

we have fossils of plants that showcase how different tropical plant lifestyles had to be up at the poles because of the light weirdness

the important part is "tropical", not "wet/rainforest". those are two different things

Temperate and Boreal Rainforests are wonderful and some of my favorite living biomes, but they aren't what I was talking about

[adeptarcanist]

May I ask about the fern prairies? That sounds really cool!

[a-dinosaur-a-day]

Grass is a relatively recent thing

it first evolved in the latest Cretaceous, but it didn't actually take over everywhere until the Miocene, when grasses that process light differently (look up C3 vs C4 photosynthesis) evolved and just took the fuck over the planet

before then, other plants formed the low ground cover over the earth, and in many places those plants were ferns - spread all over the ground and covering it, much like grass, but significantly less dense. Dirt would have been much more common everywhere.

This is why I am begging every single game developer to remember that grass is not a neutral ground cover

[im-flashtoo]

My favorite extinct ecosystem, if it counts while being as physically tiny as it was, is the floating logs that existed in the ocean between the first appearance of woody trees and the first appearance of organisms that could break down wood - floating reefs of a sort, trailing enormous filter-feeding crinoids below them. The baleen whales of their time

[a-dinosaur-a-day]

yeah that counts! And how bizarre those must have been!!!

[i-draws-dinosaurs]

Speaking of reefs, we're so used to rocky or coral reefs in the moderns world but there have been so many different reefs throughout prehistory that were made of things that straight up don't exist any more!

Like the reefs of the late Devonian, which were made of stromatoporoids, which may have resembled corals but were actually a highly diverse extinct group of sponges!

This is one of my own reconstructions of a stromatoporoid reef off the coast of Devonian Australia (plus anachronistic underwater baited camera):

The Cretaceous also had some wild extinct reefs which are known as carbonate reefs and were dominated by a group of bivalve molluscs called rudists!

[ferncube]

Scale tree swamps are the only one of these I know anything about and they were SO WEIRD. There's definitely some controversy about how they functioned cause these things are hard to work out from fossils, but the current thinking is that these trees shot up to around 100 feet tall in 10-15 years, grew more tightly packed together than basically any modern forest, produced spores one time and then promptly keeled over and died. Forests just do not work like this anymore! It's not just different types of trees, it's a whole *different type of forest* that has gone extinct! Different nutrient cycling, different natural rhythms, different everything!

Even today there are all kinds of niche hyperlocal ecosystems that function in their own distinct ways - shale barrens, waxcap grasslands, cataract bogs. What else have we just never seen??

[a-dinosaur-a-day]

Anxiety over all the prehistoric organisms we’ll never know, meet your big sibling: anxiety over all the prehistoric ECOSYSTEMS we’ll never know

[eleven-screams]

What about the weird cousin: Anxiety over the organisms and ecosystems of the Future that we'll never know?

I should stop reading speculative evolution projects.

[mindblowingscience]

Mammals may be driven to extinction by volcanic new supercontinent Pangaea Ultima

The next supercontinent, Pangea Ultima, is likely to get so hot so quickly that mammals cannot adapt, a new supercomputer simulation has for

Mammals will most likely be wiped from the face of the Earth by our planet's next supercontinent, a new study has revealed.  By modeling the heat tolerance of mammals alongside Earth's climatic conditions 250 million years into the future, scientists have discovered that the formation of the most probable next supercontinent — called Pangaea Ultima — will bring about the likely extinction of our animal order. The researchers made the prediction using a climate model that factored in the changes to land surface temperature of a new supercontinent; alongside increases to the intensity of the sun's radiation and carbon dioxide in the atmosphere. The study was published Sept. 25 in the journal Nature Geoscience. "A supercontinent seemingly creates conditions that more easily lead to mass extinction," first-author Alexander Farnsworth, a climatologist at the University of Bristol in the U.K. told Live Science. "[Supercontinent formation] has coincided with four of the last five mass extinctions in the geologic past." 

Continue Reading.

[eleven-screams]

oh god the The Future is Wild is real

[a-dinosaur-a-day]

kinda the opposite of your field but how do you feel about The Future is Wild? a lot of the proposed creatures seem like they were designed to seem weird more than to be plausible

that's pretty much my main takeaway. I also thought that their choices in what would live till when were... weaksauce

[chasethemad]

yeah killing off ALL TETRAPODS for the sake of their land squids was a little far fetched

[a-dinosaur-a-day]

Like you’re going to look me in the eye and tell me neither Squamates NOR Neornithes never mind so many other groups make it to the end? Sounds fake

[dragonthunders01]

It always gets me about mammals just stop evolving, previous groups die out and we only have left the Poggle, the equivalent of a tuatara for a mammal living isolated in the north Austra-beringian giant mountains being harvested by Eusocial spiders.

And it all sounds really poorly planned because the format that TFIW present its worldbuilding is very limited and ambiguous, they can only afford to show three or four specific species per ecosystem.

Then the remaining vertebrates die out implied by a mass extinction in 100 m.y. implied in the episode of the great plateau by volcanic activity which got me like "even small reptiles?" for years.

I always wondered if the choice of killing them all was mostly for having a more strange and unique settling where something as alien as a land squid, flying fish and other things could evolve... or maybe because they though that groups could just vanish leaving no descendant, based on something like trilobites, eurypterids or marine reptiles. Maybe would be added in this idea dinosaurs and synapsids, although with them you see the tendency of the majority die out and a handful of survivors being able to thrive and eventually recover, taking again in new forms (Birds as a branch of surviving theropods, mammals as a branch of surviving cynodonts).

This is probably why I feel the idea of "tetrapods die out" seems so implausible at this point, even if you have a mass extinction at the level of the K/Pg or the P/Tr that small handful of survivors will likely recover fast and diversify again before any land squid could take out. The ideal scenarios where TFIW 200 m.y. world would work is a total wipe out of land life that annihilate any competitor that could recover.

[eleven-screams]

me when my fish grows wings while retaining the basic fish shape with scales and a caudal fin then proceed to be the main food source of a whale-sized sea squid that catches you midair

Honestly I feel like an episode/biome that is barely talked about are the Antarctic Forests from 100 m.y. The Spitfire Birds against the gigantic Falconflies and the beetles that mimic flowers were cute but it was already forcing itself way too much on the "invertebrate taking over" scenario. There was so much potential for immense bird diversity in a tropical island-continent but instead we just get weird petrel descendants that are predated upon an insect that should have never gotten the chance to evolve in the first place.

also apparently Swampus and the 200 m.y squids are unrelated and they just convergently evolved to live on land so my whole life as a lie

[keepcalmandcarriefischer]

Did you guys know that the most recent version of sharks have fins that are kinda leg like and they like to walk up onto land?

[bobdylanslesbianlover]

no way i must have missed an update!

[keepcalmandcarriefischer]

The Epaulette shark is only about 9 million years old as a species, making it the most recent branch in the shark family. And it is slowly but surely evolving into a land animal

[froodette]

You know what to do boys

[will-falling-fell]

[evolution-incarnate]

fun fact:  there are other walking sharks alive today and in the fossil record over 300 mya catsharks are another group of modern walking sharks like this coral catshark

and an ancient shark known as onychoselache its from the early carboniferous and has large fin cartilages to help support its weight on the ocean floor while walking its fin anatomy are convergent with modern walking shark fins which share that hole in the fins cartilage

[eleven-screams]

Sorry to ruin the fun but there isn't a such a thing as "surely evolving into land animals". Evolution doesn't have a path and it simply does what it does, what works works, there isn't a path to follow if the evolutionary pressures make it so that they go on land or return to water so be it, the shark adapts the most it can to survive or it goes extinct.

I do agree land sharks would be cool tho. People should read about speculative evolution more I'm pretty sure a lot of people did plausible land sharks in that genre before (see @skyllareich here on Tumblr).

[edgescience]

I can almost guarantee the main posters here know that. The meme is just a meme lol

[eleven-screams]

Fair tbh, but it was just in case because some people genuinely believe it

[keepcalmandcarriefischer]

Did you guys know that the most recent version of sharks have fins that are kinda leg like and they like to walk up onto land?

[bobdylanslesbianlover]

no way i must have missed an update!

[keepcalmandcarriefischer]

The Epaulette shark is only about 9 million years old as a species, making it the most recent branch in the shark family. And it is slowly but surely evolving into a land animal

[froodette]

You know what to do boys

[will-falling-fell]

[evolution-incarnate]

fun fact:  there are other walking sharks alive today and in the fossil record over 300 mya catsharks are another group of modern walking sharks like this coral catshark

and an ancient shark known as onychoselache its from the early carboniferous and has large fin cartilages to help support its weight on the ocean floor while walking its fin anatomy are convergent with modern walking shark fins which share that hole in the fins cartilage

[eleven-screams]

Sorry to ruin the fun but there isn't a such a thing as "surely evolving into land animals". Evolution doesn't have a path and it simply does what it does, what works works, there isn't a path to follow if the evolutionary pressures make it so that they go on land or return to water so be it, the shark adapts the most it can to survive or it goes extinct.

I do agree land sharks would be cool tho. People should read about speculative evolution more I'm pretty sure a lot of people did plausible land sharks in that genre before (see @skyllareich here on Tumblr).

[eleven-screams]

(Art by Gustavo Monroy-Becerril)