The Deadly Chemistry That Made Life Interesting

↓↓↓ More info and sources below ↓↓↓

Life’s been around on Earth for at least 3.7 billion years. But for most of that time, it was incredibly boring — just simple little cells squirming around in water. It only got interesting in the last few hundred million years. And that might never have happened without the help of a deadly, but also life-giving, element.

-----------

High fives to all our Brain Trust Patrons:

Holly, Brett, and Ashe Bullion
Jaap Westera
Millennial Glacier
Mark Littlehale
Mehdi Damou
Barbora Bei
Burt Humburg
dani bowman
David Johnston
Salih Arslan
Baerbel Winkler
Robert Young
Eric Meer
Dustin
Karen Haskell

Join us on Patreon!

Twitter

Instagram

Merch

Facebook

This episode of Be Smart is licensed exclusively to YouTube.

[besmart]

They say you can't live without love, but personally I think oxygen is more important 🤓

[EduardQualls]

In the 1990's a professor at Rice University was studying the largest kind of amoeba when he noticed that those in 11 of his 12 specimen-dishes were dying. It turned out that they had been infected with a bacterium that killed the amoebas after the amoebas had "eaten" them. But, he found that in that final dish, the same kind of bacteria, which had been "eaten, " were living, and thriving, within the amoebas, and the amoebas themselves were also thriving. When he extracted the bacteria from the cytoplasm of some of the amoebas in that final dish, both amoeba and bacteria died: they could not survive without each other. They had, accidentally and almost spontaneously, replicated the bio-synergistic event that happened when those most ancient anaerobic cells had taken in the aerobic bacteria (the mitochondria) and each had become inseparably dependent on the other.
Sorry I can't find the details of the reference (Google is often not a great help with older info), but the finding was reported in _Science News_ magazine, and _Scientific American, _ too, as I remember.

[johnnyhudson]

This could be a contributing factor to the Fermi Paradox. Its not that life cant spontaneously form on other planets but that generally its hard to jump from a single-celled organism to a multicellurlar equivalent.

[firstcynic]

4:15. Note what he said. Oxygen didn't go to almost 10% of the atmosphere, but to almost 10% of what we have today... under 10% of 21% or... less than 2% of the atmosphere. That was after more than a billion years. Why so slow? For most of that time the oxygen was rusting out all the iron in the water. How much iron? Enough to make the worldwide formation called The Banded Iron formation, about 60% of the planet's accessible iron reserves.

[HeisenbergFam]

You can always rely on chemistry for bombastic effects, a true gift that keeps on giving

[sciencenerd]

The Cambrian explosion didn't just come out of nowhere. There was a lot of interesting fauna in the Ediacarin, such as Charnia, Dickinsonia, Spriggina, Priapulid Worms, Kimberella, etc. The Cambrian Explosion was an adaptive radiation that took millions of years, and we have a good amount of fossils from this time because of certain lineages evolving harder body parts. They were less squishy so more fossils got left behind.

[of_science_and_superstition]

Another important step is the forming of Ozone layer when Oxygen percentage increased, probably complex cells were forming but got destroyed by ultra-violet rays until the ozone layer became effective.

[charlesjmouse]

I don't know why I keep forgetting to look at this channel, it's videos are really good.
While I don't necessarily subscribe to the idea, one of the potential solutions to the Fermi paradox is how rare Phosphorous is in the universe - as far as we can know it's one of the very few absolute requirements for life, complex life needing lots more. That Earth somehow got an unusually huge supply coupled with erosion during snowball events bumping up availability, in turn leading to life and then complex life is a beguiling thought.

Further thoughts to chew on:
-For reasons unknown it seems the gas cloud from which our solar system formed had a relatively very high supply of phosphorous. (still rare)
-It seems 'super' Earths are far more common inner solar system bodies than the smaller rocky bodies 'we' have - the former not so useful for life.
-It also seems the very unusual formation then interaction of Jupiter and Saturn in the places they started caused them to first 'tack' in to the inner solar system so kicking out any 'super' Earths that had formed, then back out again to spray icy bodies about, so seeding the newly forming smaller Earth with water.
-Phosphorous tends to bind with iron, so depleting the crust of a rocky planet of what little may be available. But being hit a glancing blow by 'Theia' will have seeded our crust with enough to allow life to happen at all. That the blow didn't obliterate the Earth, and came in at just the right angle to create our huge Moon is also incredibly unlikely. That moon has stabilised our planet for billions of years while shielding it from many blows, in so doing allowing life and then complex life a place to be.
-Without plate tectonics there can be no (complex) life, another gift we likely only received through being hammered by a 'Theia' of just the right size, at just the right angle, at just the right time.
-If the Earth had formed any closer or further away from the Sun it would almost certainly have been either too cooked or cold for life to get going, certainly for all but the most primitive types.
-If the Sun had been smaller or larger we would have likely ended up too cool or hot to start anything... but more, 'we' needed the precise balance of star size and orbital distance to allow for early 'snowballs' to occur to 'scrape' enough phosphorous out of the rocks for complex life to be possible - the timing of the innovation of aerobic respiration with the evolution of our star being just as important: Too soon and 'snowballs' would have been so severe the planet might have iced over permanently, to late and any life may have been cooked away.
-Which brings us on to the development of stars, which get hotter as they age. If our sun had been smaller it would heat slower, likely leading to far more severe 'snowballs', which would have at best severely stunted life if it got going at all. If larger it would have heated faster, so cooking the planet to death before the Cambrian explosion had a chance to get going - as it is 'we' have about another 500-1000 million years before our warming sun renders the Earth uninhabitable.
-There are so many reasons why an Earth significantly smaller or larger than 'ours' would be no good for (complex) life, so I'll list two: If smaller our core would have 'frozen' long since and Earth would be like Mars. If any larger space travel would be impossible because of the 'tyranny' of the rocket equation, even assuming the many reasons why big is bad for intelligent life didn't get in the way.

This very long comment barely scratched the surface as to why it's mind-bogglingly amazing 'we' are here at all. Until such time that conclusive proof can be shown to the contrary it has to be assumed the universe is functionally devoid of all life but us - I would say that privileged position is a huge responsibility to look after what we have.

[jonathanm]

I think this is the best 15 minute primer on the subject that I have ever seen. Great job and thank you.

[Mazurking]

Wonderful storytelling. Even though I was taught all of this already, I watched to the end.

[aleleeinnaleleeinn]

Our origins are based on a very long series fortunate events. One misstep and the process stopped or everything fell apart. Just finding a planet with the right conditions is a very small first step. Maybe other forms of life had a different history and path, but Earth is one lucky rock.

[brockmckinney]

This is the best video you’ve done on this channel. Thanks.

[simarkarmani]

6:16 As always, 'mitochondrion' is followed by 'THE POWERHOUSE OF THE CELL⚡'

[masterimbecile]

1:03 life didn’t wanna stay boring. It wanted to stay curious.

[RonnyCoalman]

Dude i was just watching "History of the Earth"'s videos about the boring billion stuff and now you drop this video. :D

[Sarappreciates]

LOL, I had a dream in which aliens said they didn't want anything to do with us until we "leave the food chain." As silly as that may sound, it was a disturbing dream that left me feeling almost embarrassed for not photosynthesizing light.

[NewMessage]

So let's all raise a glass to Reginald, and his dinnertime emissions!
🥂

[alien]

Great explanation of the great filters we've passed 👀👀

[stvp]

I really liked the background music in this. Nice work, APM!

[larryo]

Nice video! Interesting how to get complex life forms a series of events need to occur in just the right way.