Animals Might Be Much Older Than We Thought

What are animal-like fossils doing in rocks a billion years old, and what does that mean for our understanding of their evolution and geologic time itself? Turns out, there might've been a long, slow-burning fuse that ultimately ignited the Cambrian Explosion.

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Eons is a production of Complexly for PBS Digital Studios.

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References:

[z.zomb.z]

Something about this just made me smile. The complexity of animal life today and the little blobs of cells that came before us, both experienced a pond. Idk, life is magical and sometimes the past doesn’t feel so far away.

[BnTjr]

As a developmental biologist, molecular clock studies have long suggested that animals split from choanoflagellates >800 million years ago. There's evidence of something like 10 whole genome duplications, and many of the important signaling proteins involved in animal multi cellularity during that time, these genes would not have been selected for if these organisms were living as single celled organisms. It makes a lot of sense to me that the systems that pattern embryos would have taken at least a couple hundred million years to reach the level of sophistication seen in all modern animals, including sponges. If all of this happened in little multicellular ball like organisms that look vaguely like blastulas - which is the stage when these pathways are particularly active, that makes a lot of sense.

Molecular clock studies often put the dates for these major milestones way earlier than fossil evidence. Paleontologists often respond by saying that molecular clock studies must be flawed (they are not perfect), but the fossil record is also incredibly biased towards large bodied animals with hard bones and shells, it's a little niave in my opinion that we will find fossil representatives of every major evolutionary transition at the earliest time point.

[fatmalcontent]

This is the kind of news that makes one wish it was actually possible to talk to the dead. I can just imagine how excited Darwin would be to get periodic updates on just how freaking right he was.

[GeorgeHalas]

This stuff gets me hyped for no reason. Well there is a reason; NATURE IS AWESOME

[LaceMyChucks]

People living on the other side of the world love this presenter/host. She speaks clearly and her enunciation is superb. Me and my children can understand her even without subtitles 😊

[andrewweisbrod]

The frequency of the phrase "the Scottish fossils" puts me in mind of a euphemism for one of Shakespeare's plays.

[elijahisconfused]

ive got no clue how people dont find this interesting, i love learning about how we managed to get here :)

[Yesirr]

Biology is like that chill dude on the science major group

[maautrap]

I find mind blowing how you could theorically go back generation to generation long enough where you would find yourself being a single celled organism.

[deano]

Makes sense that cells started clumping and starting to work together for a long time before making the big jump to becoming a single organism... which seems to have required quite a difficult set of circumstances to perfect before it all worked, but lead to massive flexibility and hence the Cambrian explosion.

[kamilaleksander]

Since I became a teenager, I haven't considered paleontology interesting, but videos of Eons are so well made that I have already watched lots of them. Thank you for your work.

[DaveTexas]

Scotland is quite the place for finding "earliest" stuff. The earliest evidence for houses there is fascinating, and these fossils are even more interesting. Having gone to college in the 1980s, I’m continually amazed by everything that has changed and emerged in our understanding of biological over the past 40 years.

Jeez, 40 years? How can I be that old? 1984 was just a few years ago! Seeing Footloose in the theater and going immediately to buy the soundtrack LP. Buying my first CD player and the soundtrack to Purple Rain on CD, then playing it LOUDLY over and over and over…along with Madonna’s Like a Virgin CD and Tina Turner’s Private Dancer…man, that was a great year.

[sirsplintfastthepungent]

Ragged Scottish Microfossils was my favorite punk band, back in the day.

[EdinMike]

A new species of Pterosaur was found in the north west of Scotland recently too, seems it’s just teaming with hidden life up there !

[randomdummy]

smol anecdote, the thing at 2:25 is an animal but is also a single cell, but it is multi-cellular in the same sense that snake are tetrapod, as it actually evolved from simple jellyfish which turned to a parasitic lifestyle, becoming simpler and simpler as it had no need to make any effort anymore, until at some point it turned back to a unicellular organism

[DWargs]

I'm both completely astounded about the fact that life, especially animals, was able to survive and thrive so long ago already in freshwater.
At the same time, it makes complete sense considering the extreme environments life has been found today.

[gerarddearie-zdgb]

As someone from the NW coast of Scotland, I can guarantee you there is lots of animal life EVERYWHERE.

[Kualinar]

As I understand it, the Cambrian explosion is not the the appearance of animals, but the emergence of hard structures in animals, like shells, exoskeletons and skeletons. It's a certitude that soft body animals existed long before, even during the early Precambrian.

[grizzlywizzly]

The vibe of lil guys just chillin in the sun on the beaches of Scotland is calming to me

No thoughts, just livin’ cell bois

[DrBunnyMedicinal]

It's amazing how far palaeontology has grown as a field over such a short time, from such humble beginnings.