Alien Biosphere Evolution #3: Contingency Decides Life's Fate

The Cambrian explosion, often called the “Big Bang” of biology, marks the period when the earliest animals diversified into a remarkably wide range of different life forms, leading to the major phyla known today. Famed paleontologist Stephen Jay Gould made the case that the Early Cambrian was exceptional and saw it as a biological lottery. Historical contingency would make it unlikely that anything like human species would arise again. Although somewhat exaggerated, contingency does play an important role as do the developmental constraints that flow from these events. Convergent evolution on the other hand would result in superficially similar results nonetheless. So when speculating about alien biospheres how can we apply the interplay of contingency, constraints and convergence? How can we use actual scientific insights into worldbuilding projects? Let’s find out!
CHAPTERS
0:00 Introduction
1:16 Gould & Cambrian Contingency
2:52 Human Exceptionalism
5:20 The Tetrapod Conquest of Land
6:41 Evolution's Lack of Direction
9:33 Closing Thoughts
LINKS:
‪@JacksonWheat‬ on the Cambrian Explosion Pt. 1:
• The Cambrian Explosion...
SOCIAL MEDIA:
Twitter: / phrenotopian
Reddit: / phrenotopia
REFERENCES:
- "Wonderful Life: The Burgess Shale and the Nature of History" (1989) by Stephen Jay Gould
- "The Cambrian Explosion: The Construction of Animal Biodiversity" (2013) by Douglas Erwin and James Valentine
CREDITS
Images:
- "Cambrian Explosion Illustration" by Mesa Shumacher from the Santa Fe Institute: www.eurekalert.org/multimedia...
- A plethora of images of extinct animals were created by paleo-artist Nobu Tamura and available here: spinops.blogspot.com/ & www.deviantart.com/ntamura
- "Sanctacaris" courtesy of Nix Illustrations: nixillustration.com/science-i...
- "Illustration of Eogyrinus attheyi" by Andreyi Abelov www.deviantart.com/abelov2014...
- "Onychodus" by DiBgd commons.wikimedia.org/wiki/Fi...
- “The Road to Homo Sapiens” from: "Early Man" Time-Life Books (1965)
- "Acanthostega model" by Dr Günter Bechly
- "Acanthostega swimming" by Sylvia Lorrain / sylvia-lorrain
- pixabay.com
- Wikimedia Commons
Footage:
- "Proconvoluta primitiva" by @haplorhini1 | • Proconvoluta primitiva
- "Back to the Future part III" (1990) Universal Pictures
- "Frankenstein" (1931) Universal Pictures
- "The Simpsons" S9 E8: "Lisa the Skeptic" (1997) 20th Century Fox
- "Howard the Duck" (1986) - Universal Pictures
- "X-Men" (2000) - 20th Century Fox
- "The Great British Year" Episode 4 (2013) - BBC One: www.bbc.co.uk/programmes/p01d...
- pixabay.com/videos/
Music:
- "Ambience composition" by Georgke freesound.org/people/Georgke/
- "Cinematic Ambient" licensed from Stereo Nuts audiojungle.net/user/stereonuts
- "Pretty Synth Melody" by LemonCreme freesound.org/people/Lemoncreme/
- "Stalemate" by TechSmith
- "Kick and Progressive Leads" by Frankum J. freesound.org/people/frankum/
COPYRIGHTED MATERIAL
Any unlicensed copyrighted material used in this video is done so for purposes of education, review and/or satire and thus covered by "Fair Use". No ownership is claimed for any such materials other than my own.

[@erisstewart4236]

X-Men fact: the x gene, the gene that causes their abilities, was the result of the celestials meddling with the genes of humans while we were in the stone age

[@Phrenotopia]

Yeah, I came across that, but it's clearly an post hoc explanation/rationalization, like the one in Star Trek for universal humanoids.

[@keithinadhd6693]

Man! I am a bit disappointed that’s it’s a premiere. I mean, not REALLY, but I was excited to watch it now. Waiting 24 hours is gonna kill me! I cant wait for this one.

[@Phrenotopia]

Wait, what? No, thankfully it's premiering today. The date got flipped for some reason. Fixed it and It's on in a few hours! If it wasn't for your comment, I may have overlooked this, so thanks!!!

[@keithinadhd6693]

Phrenotopia Haha! Even better!

[@lexibyday9504]

I try to differ the events of my alien planets' evolutionary histories. I have one where basic life on one particular region of the planet was pressured to move onto land early on. They formed colonies on the beaches that evolved into coral like organisms covering the entire perimeters of some islands. As a result complex terestrial life was never able to form and the planet has been in a cambrian-devonian limbo for millions of years.

[@Phrenotopia]

Maybe I should open up for viewer submissions, because that sounds really cool!

[@lexibyday9504]

that would be cool. Finnish this series first and maybe after you can start a planet review series where, kinda like the Darwin IV documentary, you focus on adding your speculation about the planet as oposed to critecising how scientifically corect it is or is not.

[@grubbybum3614]

@@Phrenotopia I think that would be a great idea

[@weebnonce8327]

maybe an asteroid causes the extinction of that coral

[@dibershai6009]

But wouldn't this limbo end when a complex aquatic creature will evolve to move onto land in order to eat these coral like organism?

[@DTux5249]

4:30 That's less expectation of them evolving that way, and more expectation that you want your characters/beings to be either reliable or understandable If I see a giant blob, I don't know the threat If I see bandits with guns, I know the threat.

[@Phrenotopia]

I recommended you to watch part 1 also where I point out exactly that and more.

[@lava2istrue]

AFAIK didn’t the Cambrian explosion have something to do with predation becoming a thing?

[@Phrenotopia]

That's one hypothesis out there, but I don't buy it. More in my next video in this series.

[@Rhaenarys]

It's the most accepted hypothesis right now. There was a previous explosion, but not to that extent, and once we saw the emergence of jaws, suddenly it seems like arms race to either be top dog, or just not become prey.

[@smergthedargon8974]

2:33 "Butterfly effect" _video of hawk moth_

[@ImpossibleEvan]

I'm sorry if this is a big ask but could you please make a video on how different body plans have all formed because if body plans can't really change from the starting blueprint then how did they all come to be in the first place I would love to see a video on it and if you already made one I'm unable to find it

[@complex314i]

While super powers are quite unlikely, X-Men's claims of "evolution being slow but every so often evolution leaps forward" is a real evolutionary concept called Punctuated Equilibrium.

[@Phrenotopia]

The clincher here is in "forward". There is no "forward" in the theory of Punctuated Equilibria like there is no "forward" in evolution. Besides, who do you think came up with the theory of Punctuated Equilibria? Take a wild guess.

[@petersmythe6462]

Evolution is not goal directed, but it does direct itself. In the same way that water going down a slope may veer left and right but never goes UP.

[@Phrenotopia]

The slope in that metaphor can only correspond to the arrow of time and not any evolutionary process that I'm aware of.

[@vianneyb.8776]

I'd heard that the Cambrian explosion was not "the period when the earliest animals diversified into a [...] wide range of different lifeforms", but that it was the period during which hard bodies developed for the first time and made it much easier for fossilization to happen. So, it's not that, suddenly, many different lifeforms appear, but rather that, suddenly, they are much easier to find. Am I wrong to think that?

[@Phrenotopia]

It's one hypothesis, albeit a dated one. It's true that bilaterian lineages had already diverged before the Cambrian, but they remained diminutive until something kickstarted their evolution. More in the next video(s).

[@vianneyb.8776]

@@Phrenotopia Okay, interesting, thanks for the reply. One of the reasons I said that was because some branches of life had already gone extinct even before this event, like trilaterian animals, which I find a very peculiar path that evolution took. But, now that I am looking for it, I can't find research on it, so maybe this information is outdated too.

[@Phrenotopia]

@@vianneyb.8776 - I recommend the video by @Jackson Wheat that I link to.

[@SirEnd3r]

Looking forward to this video man.

[@thekingofnipples9806]

I really enjoy this series one of my favorite on youtube keep em' coming

[@kushim8559]

only 45 minutes left ... CAN'T WAIT

[@drsharkboy6568]

What if radial symmetry bodies started evolving partial bilateral symmetry? It’s an interesting concept, because you could feasibly get bilateral animals with faces that split open like the demogorgon or multiple limbs that radiate outwards like the sea dragon from Subnautica.

[@MisterSketch4]

The sea pig already does exactly this

[@ASlickNamedPimpback]

Thanks for uploading high quality videos

[@keithinadhd6693]

Well done! I enjoyed this a lot.

[@v4l3nt1nn]

do a video about the Fermi Paradox!

[@Phrenotopia]

Other KZbinrs have already done that much better than I can at the moment.

[@JacksonWheat]

Fantastic video and animations!

[@Nemo_Anom]

You make a good point about contingency. And I'm glad to hear that you think Gould exaggerated; I've long held that opinion. I think that convergence gets less attention than it deserves. What is natural selection acting on? The relative fitness of a population to a niche. Thus the niche dictates phenotypes. Given an earth-like planet, and assuming we want an intelligent species capable to complex civilization and tech, then I do think it has to be broadly humanoid. I don't think it has to be mammalian, but humanoid, yes.

[@gunjfur8633]

Oooh, cant wait

[@v4l3nt1nn]

that guy with the mustache looks badass 😎

[@petersmythe6462]

Aw. But entering a new niche under certain circumstances can cause a rapid meta shift that creates biogenic rapid evolution (and significant extinction events). I.E. the development of the first pterosaurs probably forced many creatures to adapt or die as a flying vertebrate predator was just a complete black swan.

[@Fumango]

I CAN'T WAIT

[@fuckYTIDontWantToUseMyRealName]

I'm not going to be learning anything through the rest of this video because I'm going to be thinking back to that mustache.

[@madyluvsanime1248]

So... different things could have happened... LIKE WHAT?

[@Angelmou]

The goal directed ideas were influenced by the aristotelic philosophy of categorization forms of existence from minerals over plants towards angels and god at the other end. So got it a revival in hegelianism. The term is actually: en.wikipedia.org/wiki/Orthogenesis Orthogenesis or progressionism in directed Evolution ideas not only by Lamarck, but names which are long forgotten as historical footnote like Haacke and Eimer.

[@Phrenotopia]

Certainly, as is the related Christian concept of the "Great Chain of Being", but there is no reason to do a exhaustive recapitulation of the entire epistemology of a subject in a shortened overview targeted at a general audience.

[@deathbyseatoast8854]

Nice, a new video.

[@amberkelliher6555]

I was surprised to find out that Wiwaxia is related to cephalopods. I would never have guessed that.

[@Phrenotopia]

According to the latest insights, Wiwaxia and related forms are believed to be basal molluscs.

[@cameoshadowness7757]

I made a stupid "evolution tree" where it is really a trait tree... It is so freaking weird and you just reminded me I did that.

[@Phrenotopia]

Sounds like a phenogram. That's not stupid per se! :-) It can be taken as a way to illustrate similarity. A cladogram on the other hand is based on an evolutionary algorithm and intends to illustrate relationship.

[@Phrenotopia]

I can recommend you look up the difference between phenetics and cladistics.... Or wait until I make a video on that topic. :-)

[@cameoshadowness7757]

@@Phrenotopia thanks!

[@cameoshadowness7757]

@@Phrenotopia question: can I show my tree?

[@Phrenotopia]

On discord you can in the right channel.

[@texrex4926]

Yes it’s here!

[@Angelmou]

It is highly debatable IF the cambrian explosion as over 12+ mio. year lasting time period is really such an "explosive" radiation. Reasons for doubts are that the larvae forms of the majority of famous critters like trilobites had already big similarities of some precambrian small shellies and fossil remains usually overseen, because of the tiny milimeter size of them and general lack of shells. We tend to look at animals when we don't need a microscope and at the adult imagos. For example: en.wikipedia.org/wiki/Spriggina and en.wikipedia.org/wiki/Parvancorina & www.livescience.com/worlds-oldest-animal-track-fossil.html - also that the Anomalocaris were already relatively gigantic for cambrian circumstances (like around ~30cm) and complicated with eyes and grabbing appendages at the early cambrian. To be fully honest: I would not be surprised when they would find arthropodlike critters and more primitive larval forms sooner or later.

[@Phrenotopia]

It's actually not up to debate anymore: The Cambrian "Explosion" was just a regular diversification event, as I explicitly state in this very video. In the next video of this series where I will discuss the possible causes and preamble of this adaptive radiation.

[@itzmedb8290]

ok boomer joke had me there ngl

[@condorboss3339]

I laughed, too. But remember that the tyrannosaurs and the plesiosaurs both went extinct in the end.

[@deadmeme8973]

The way I see it, with our technology and the age of life on earth we should've found intelligent aliens already, or they should've found us. We haven't. They would've become at least briefly detectable if they have. Major countries are nuts about space, they're always watching. Essentially, we're obviously very unusual and awesome as lifeforms, or the first sapient lifeform in the general area. Earth must be quite unique too. The mistake was with a linear view of evolution, not with recognizing the uniqueness of us and our world

[@EdT.-xt6yv]

TY! 3:30 march of the inevitable,,, 💭 4:30

[@LeDingueDeJeuxVideos]

Live without bugs? That's getting rid of the vast majority of pollinaters

[@JanetStarChild]

As well as a massive part of the food chain.

[@complex314i]

Film & TV sci-fi must use human actors. That is all we have. While I do get excited when I see non humanoid aliens: Founders, Hurts, Pyrians, etc, I can forgive TV and movies for having humanoid aliens.

[@v4l3nt1nn]

upload more often & do a video about the Kalabi Yau manifold!

[@Phrenotopia]

pay my bills

[@maavet2351]

It's weird people would say Dinosaurs were inferior to mammals, when no mammal in history Maybe accept the blue whale reached the sizes of gigapods like Argentinosaurus, and reaching those sizes on land no less, obviously dinosaurs didn't have some more advanced features, like their ears or accute smell, but they did most likely saw better then like 90% of mammals.

[@captainstroon1555]

If humanity starts using genetic engineering, the anthropocenic explosion would make the cambrian one look like a firecracker compared to a supernova.

[@v4l3nt1nn]

do a video about the dangers of AI

[@Phrenotopia]

Actually working on it! Or rather: The non-dangers of AI.

[@Dragrath1]

Cambrian explosion is so overrated its all about the Avalon explosion now ;) Really though It seems to me that the snowball Earth glaciations were the real flips of the tables needed to make the rise of multicellular life possible fossils and genetics suggest that multicellular life as we know it arose during the Neoprotozoic glaciations and might have even been a prerequisite for the evolutionary shift towards multicellularity to come into play. The most convincing argument for this is the Francevillain biota which appear to be a major radiation of diverse macroscopic organisms which grew in complexity over hundreds of millions of years reaching milestones of complexity including evidence of motility before getting snuffed out as the great oxygenation event came to an end. The discovery of an ancient radiation of definitively complex multicellular life that suddenly vanished as the Earth for some reason slipped back into a largely anoxic state paints the Avalon explosion and later "Cambrian explosion" in a whole new light. We got lucky others came before only to fail for reasons we still do not understand. Extinction level events come and go sometimes doing little lasting damage as life perseveres yet others become mass extinctions when multiple cataclysms coincide simultaneously drive life over the brink. It is generally understood that the dinosaurs reign may have continued unabated were the asteroid to have struck somewhere else far from the hydrocarbon rich continental shelves during an existing climatic turnover associated with ongoing flood basalt volcanism. Earlier this year in September convincing evidence was provided suggesting that the turnover in life that marked the Ordovician to Silurian transition was caused by a collision ijn the asteroid belt destroying a 150+ km asteroid and creating the L chondrite class of meteorites in addition to a large cloud of dust which as it diffused into the inner solar system blocked out a significant percentage of sunlight for millions of years triggering an ice age. tracing fossilized meteorites embedded within Ordovician sedimentary rocks to show a significant increase in meteorites dominated overwhelmingly by L chondrites which as a class can be dated to a major collision 470 Mya advances.sciencemag.org/content/5/9/eaax4184 As new ancient cataclysms that shifted the course of life largely via happenstance come to light as well as the discovery of the sheer extent of traits evolution has "lost" through mutation and genetic drift the notion of a direction to anything or even towards increasing complexity at all has been thoroughly debunked. Perhaps the best example aside from the dynamics of the major mass extinctions such as the Ordovician Biodiversification event, the Devonian extinction events, Mid Permian extinction, The Great Dying/Late Permian extinction, End Triassic extinction, and the K-Pg extinction. Like other radiations so many fascinating organisms appeared and diversified only to get snuffed out by circumstance. The process has even been studied in a laboratory setting abet with E Coli showing that the timing of beneficial or benign mutations is important. myxo.css.msu.edu/ecoli/

[@Phrenotopia]

Again: Slow down, man! I will of course be mentioning the Avalonian Explosion in future video(s). In fact script has been written and audio recorded already, so look forward to that! And yes, there have been many important contingencies in life's history, that I should enumerate at some stage in a video or something. You bring a number of interesting ones, I hadn't heard of!

[@junoguten]

>citing Gould on evolution after 2011

[@Phrenotopia]

>implicitly referring to Lewis et al after 2014

[@ericvulgate]

evolution is all about resources. if the food is in the water, go there. if the food is on land, go there. sloths have an amazing aquatic history.

[@user-jq1zr3uf7r]

2:30 That's a moth

[@Phrenotopia]

Thanks! I'll have to add this one to my #blunders compilation too...

[@marshmallowmonster7731]

04:55 Yeah, it bugs me as well. BTW In new Predator movie they call autism " the next step of evolution" :)

[@vrilnau5396]

Crabs. Crabs are what evolution wants. Everything else is but an accident.

[@Phrenotopia]

Whatever planet you're on, you will always get crabs. 😄

[@downsidebrian]

You talk about more generalist creatures surviving mass extinction events that kill off more specialized species. Where do we humans fall on that spectrum? We're clearly specialized towards using our large brains, but not many specialist species have conquered every continent and biome. Do we break the scale? Or are we somehow specialized for generalism? Or is this an anthropocentric question?

[@Oscar-ek2jx]

Id say we are not specialized. We are omnivores and have had different ways of living throughout our time on the planet (farming, hunting, gathering). Our brains serve to make us even more general and adaptable

[@Daleksaresupreme1]

1:52 you mean descendent not ancestor

[@Phrenotopia]

Actually, I do mean descendant.

[@v4l3nt1nn]

do a video about MGTOW evolution

[@v4l3nt1nn]

are we living in a simulation?

[@Phrenotopia]

nah

[@stonerdog7050]

T-rex: Use your legs Lochnes monster: Ok Boomer. :'DDDDDD

[@orsonzedd]

OK Boomer, hilarious

[@marxtheenigma873]

Why does this one have no alien fantasy creatures? It's just explanations and junk. where are the neat speculative aliens phrenotopia? where are you hiding them?

[@Phrenotopia]

All good things come to those who wait... ...or who check out some of my other videos. :)

[@matthewtheobald1231]

con. tin. gen. cies