It's plausible insofar as animals can evolve from land to sea (as penguins have) and that small animals can become larger over long time periods. Killing off marine mammals isn't particularly difficult, because they're already not doing great, although some have started to recover from human predation. Some seabirds are extremely numerous, which is good for diversity. Penguins in particular aren't doing very well against climate change. Other seabirds have been posited as developing into replacement cetaceans, like the gannet whales.
It could happen. I don't see a prevailing trend for or against though.
This video makes a good case for why it's... not implausible, but unlikely. But I don't really know enough underlying theory to confirm ore refute its points, really.
I do agree with one of its ending conclusions though, that speculative evolution projects can fall into a bad habit of just replacing existing creatures with "same thing, but from a different branch of the tree of life". Which can be fun but gets dull when it happens over and over across many projects. Thankfully there's also other projects that do explore more unusual ideas, so you can get that delicious variety.
I should try to collect some of my favorite spec evo worlds into a post on my main blog sometime.
Forex, I really like the alien speculative biology of >Runaway to the Stars, with the extra incredible bonus that it actually has a narrative story to read, that's being posted a webcomic. Definitely one of my favs. Even if, personal taste detail: I love big long tails and two of the major aliens are rumpies. :p
>>I do agree with one of its ending conclusions though, that speculative evolution projects can fall into a bad habit of just replacing existing creatures with "same thing, but from a different branch of the tree of life".<<
That has happened so often in natural history that people make videos about it. The relationship can be sorta distant or completely distant. The technical term is "convergent evolution," which is to say creatures in the same niche and habitat often wind up looking and acting very similar. And niches don't like to stay empty for long.
Now, when I'm building an ecosystem, I know enough about biology and xenobiology to do a pretty good job of it -- and not repeat myself too much.
So for instance, I did several in Torn World. There was one based on lichens and their associated lifeforms, the Lichenwold. There was one based primarily on avians. There was the sea monster one, a favorite because every species had a different reason for conflicting with humans.
Other times, I look at how Earth's ecosystems could be different. Frex, in Daughters of the Apocalypse, I worked out how native North American animals were likely to respond, plus domesticated ones, plus exotics from zoos and whatever. I'm still working on notes for Peculiar Obligations, where it turns out that a lot more of the megafauna survived. I definitely did not plan the bus-sized crocodiles and had a real WTF moment when I spotted the first one.
...ffs I wrote out a whole long reply and pressed the wrong button and it got ate. Ugh. :(
I'm sorry, I don't have the brain to try to recreate it in whole. Here's a quick summary: 1. Yes convergent evolution but not always, also it gets boring when too many spec evolution projects feel like a checklist of "wolf analogue", "turtle analogue", "bird analogue", etc
2. I think I remember you saying the croc thing before? I should read that page later when I'm not about to be completely zonked out.
3. I wanna spec evo but I need to clean up my desk. + The spectre of chemistry haunts me. Tell-tale Heart joke. Need to remember to dig up my tumblr post about my canid-like aliens who need lead in their diet.
I had one set of humans who had developed ways to cope with heavy metals, and what wound up happening was secreting the lead into thin layers of holding cells in the fat, where it served as shielding against radiation. Not complete immunity, but a useful amount, and the lead was sequestered where it wouldn't to any harm.
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timeasmymeasure
Thoughts
Date: 2025-05-04 12:47 am (UTC)It could happen. I don't see a prevailing trend for or against though.
Re: Thoughts
Date: 2025-05-04 01:02 am (UTC)I do agree with one of its ending conclusions though, that speculative evolution projects can fall into a bad habit of just replacing existing creatures with "same thing, but from a different branch of the tree of life". Which can be fun but gets dull when it happens over and over across many projects. Thankfully there's also other projects that do explore more unusual ideas, so you can get that delicious variety.
I should try to collect some of my favorite spec evo worlds into a post on my main blog sometime.
Forex, I really like the alien speculative biology of >Runaway to the Stars, with the extra incredible bonus that it actually has a narrative story to read, that's being posted a webcomic. Definitely one of my favs.
Even if, personal taste detail: I love big long tails and two of the major aliens are rumpies. :p
Re: Thoughts
Date: 2025-05-04 01:31 am (UTC)That has happened so often in natural history that people make videos about it. The relationship can be sorta distant or completely distant. The technical term is "convergent evolution," which is to say creatures in the same niche and habitat often wind up looking and acting very similar. And niches don't like to stay empty for long.
https://www.youtube.com/watch?v=fYVjknOS_XQ
https://www.youtube.com/watch?v=dQASQBbjmmo
https://www.youtube.com/watch?app=desktop&v=uvOq373njO4
Now, when I'm building an ecosystem, I know enough about biology and xenobiology to do a pretty good job of it -- and not repeat myself too much.
So for instance, I did several in Torn World. There was one based on lichens and their associated lifeforms, the Lichenwold. There was one based primarily on avians. There was the sea monster one, a favorite because every species had a different reason for conflicting with humans.
Other times, I look at how Earth's ecosystems could be different. Frex, in Daughters of the Apocalypse, I worked out how native North American animals were likely to respond, plus domesticated ones, plus exotics from zoos and whatever. I'm still working on notes for Peculiar Obligations, where it turns out that a lot more of the megafauna survived. I definitely did not plan the bus-sized crocodiles and had a real WTF moment when I spotted the first one.
Re: Thoughts
Date: 2025-05-04 02:17 am (UTC)I'm sorry, I don't have the brain to try to recreate it in whole. Here's a quick summary:
1. Yes convergent evolution but not always, also it gets boring when too many spec evolution projects feel like a checklist of "wolf analogue", "turtle analogue", "bird analogue", etc
2. I think I remember you saying the croc thing before? I should read that page later when I'm not about to be completely zonked out.
3. I wanna spec evo but I need to clean up my desk. + The spectre of chemistry haunts me. Tell-tale Heart joke. Need to remember to dig up my tumblr post about my canid-like aliens who need lead in their diet.
Re: Thoughts
Date: 2025-05-04 02:37 am (UTC)Re: Thoughts
Date: 2025-05-04 02:58 am (UTC)https://dreadlord-mr-son.tumblr.com/post/143894951749/rereading-an-sg-1-crossover-fanfic-i-like-i-once
Re: Thoughts
Date: 2025-05-04 07:44 am (UTC)I had one set of humans who had developed ways to cope with heavy metals, and what wound up happening was secreting the lead into thin layers of holding cells in the fat, where it served as shielding against radiation. Not complete immunity, but a useful amount, and the lead was sequestered where it wouldn't to any harm.