The Last 5 Mass Extinctions

[jillery]

Somewhat related to another current topic, the following is a link to
a 1 hour and 15 minute video which provides a reasonably comprehensive
and accurate narrative of the five mass extinctions life on Earth has
endured and survived, along with speculation about a likely 6th mass
extinction happening right now:

<https://www.youtube.com/watch?v=ZkOPahZM3qI>

My impression there are some inaccurate details. For example, it
makes no mention of the mass extinction resulting from the Great
Oxygenation Event:

<https://en.wikipedia.org/wiki/Great_Oxidation_Event>

but its broad strokes are substantially correct.

--
You're entitled to your own opinions.
You're not entitled to your own facts.

[erik simpson]

At one time, oxygen would have been described as a poisonous gas, had there been creatures
capable of descriptions. But oxygen is painless, It brought us many changes.

See the Wiki entry on the Francevillian biota, an enigmatic and short-lived phenomenon that
may have been eukaryotic or even multi-cellular. https://en.wikipedia.org/wiki/Francevillian_biota

[Bob Casanova]

On Wed, 15 Mar 2023 08:31:42 -0700 (PDT), the following
appeared in talk.origins, posted by erik simpson
<eastsi...@gmail.com>:

>On Wednesday, March 15, 2023 at 1:40:28?AM UTC-7, jillery wrote:
>> Somewhat related to another current topic, the following is a link to
>> a 1 hour and 15 minute video which provides a reasonably comprehensive
>> and accurate narrative of the five mass extinctions life on Earth has
>> endured and survived, along with speculation about a likely 6th mass
>> extinction happening right now:
>>
>> <https://www.youtube.com/watch?v=ZkOPahZM3qI>
>>
>> My impression there are some inaccurate details. For example, it
>> makes no mention of the mass extinction resulting from the Great
>> Oxygenation Event:
>>
>> <https://en.wikipedia.org/wiki/Great_Oxidation_Event>
>>
>> but its broad strokes are substantially correct.
>>
>>

>At one time, oxygen would have been described as a poisonous gas, had there been creatures
>capable of descriptions. But oxygen is painless, It brought us many changes.
>

Ah, another MASH fan... :-)

>
>See the Wiki entry on the Francevillian biota, an enigmatic and short-lived phenomenon that
>may have been eukaryotic or even multi-cellular. https://en.wikipedia.org/wiki/Francevillian_biota
>

Interesting; thanks. That's the first time I'd heard of
these, and I'd think that at 12cm diameter it probably *was*
multicellular, assuming that they were structured in a
similar fashion to what we know. The most interesting point
to me is that they are proposed as early (2.1 Bya) aerobic
biota, and died out when the oxygen level dropped. I assume
that the oxygen level increase and decrease were the result
of purely non-biological processes or it would have
continued, since the later one, which *did* continue, was
(IIRC) biological.

So I assume this would qualify as another "Great Extinction"
if such weren't, as jillery notes, apparently restricted to
"our sort of life".
>
--

Bob C.

"The most exciting phrase to hear in science,
the one that heralds new discoveries, is not
'Eureka!' but 'That's funny...'"

- Isaac Asimov

[Athel Cornish-Bowden]

On 2023-03-15 15:31:42 +0000, erik simpson said:

> On Wednesday, March 15, 2023 at 1:40:28 AM UTC-7, jillery wrote:
>> Somewhat related to another current topic, the following is a link to>
>> a 1 hour and 15 minute video which provides a reasonably comprehensive>
>> and accurate narrative of the five mass extinctions life on Earth has>
>> endured and survived, along with speculation about a likely 6th mass>
>> extinction happening right now:>>
>> <https://www.youtube.com/watch?v=ZkOPahZM3qI>>> My impression there are
>> some inaccurate details. For example, it> makes no mention of the mass
>> extinction resulting from the Great> Oxygenation Event:>>
>> <https://en.wikipedia.org/wiki/Great_Oxidation_Event>>> but its broad
>> strokes are substantially correct.>> --> You're entitled to your own
>> opinions.> You're not entitled to your own facts.
>
> At one time, oxygen would have been described as a poisonous gas,

It still is, for compulsory anaerobes.

> had there been creatures
> capable of descriptions. But oxygen is painless,

Not if you're a Clostridium it isn't. Actually the metabolism of
organisms like ourselves goes to great lengths to avoid oxygen
toxicity. Look up the Wikiparticle on "Oxygen toxicity."

> It brought us many changes.
>
> See the Wiki entry on the Francevillian biota, an enigmatic and
> short-lived phenomenon that
> may have been eukaryotic or even multi-cellular.
> https://en.wikipedia.org/wiki/Francevillian_biota

--
athel cb : Biochemical Evolution, Garland Science, 2016

[Burkhard]

On Wednesday, March 15, 2023 at 6:30:29 PM UTC, Athel Cornish-Bowden wrote:
> On 2023-03-15 15:31:42 +0000, erik simpson said:
>
> > On Wednesday, March 15, 2023 at 1:40:28 AM UTC-7, jillery wrote:
> >> Somewhat related to another current topic, the following is a link to>
> >> a 1 hour and 15 minute video which provides a reasonably comprehensive>
> >> and accurate narrative of the five mass extinctions life on Earth has>
> >> endured and survived, along with speculation about a likely 6th mass>
> >> extinction happening right now:>>
> >> <https://www.youtube.com/watch?v=ZkOPahZM3qI>>> My impression there are
> >> some inaccurate details. For example, it> makes no mention of the mass
> >> extinction resulting from the Great> Oxygenation Event:>>
> >> <https://en.wikipedia.org/wiki/Great_Oxidation_Event>>> but its broad
> >> strokes are substantially correct.>> --> You're entitled to your own
> >> opinions.> You're not entitled to your own facts.
> >
> > At one time, oxygen would have been described as a poisonous gas,
> It still is, for compulsory anaerobes.
> > had there been creatures
> > capable of descriptions. But oxygen is painless,
> Not if you're a Clostridium it isn't. Actually the metabolism of
> organisms like ourselves goes to great lengths to avoid oxygen
> toxicity. Look up the Wikiparticle on "Oxygen toxicity."

I "think" it's a reference to a song in MASH:

Through early morning fog I see
Visions of the things to be
The pains that are withheld for me
I realize and I can see
That suicide is painless
It brings on many changes
And I can take or leave it
If I pleas

[Ernest Major]

Modern day xenophyophores, which are unicellular, but multinucleate, are
comparable in size. Caulerpa can be appreciably bigger.

https://en.wikipedia.org/wiki/Xenophyophorea
https://en.wikipedia.org/wiki/Caulerpa

Apart from coencytic organisms such as the above, there is also the
possible alternative that they are colonial in nature.

>
> So I assume this would qualify as another "Great Extinction"
> if such weren't, as jillery notes, apparently restricted to
> "our sort of life".
>>

--

alias Ernest Major

[Bob Casanova]

On Wed, 15 Mar 2023 19:20:28 +0000, the following appeared
in talk.origins, posted by Ernest Major
<{$to$}@meden.demon.co.uk>:

Thanks for the refs; again, I was unaware of that. I suppose
I may have even seen examples of Caulerpa, since some are
apparently a common food in some areas. Xenophyophorea, not
so much; I can't dive that deep. :-)

>
>Apart from coencytic organisms such as the above, there is also the
>possible alternative that they are colonial in nature.
>>

Yes, that was noted in the Wiki article, and I should have
mentioned it..

>
>> So I assume this would qualify as another "Great Extinction"
>> if such weren't, as jillery notes, apparently restricted to
>> "our sort of life".
>>>
--

[Bob Casanova]

On Wed, 15 Mar 2023 11:49:13 -0700 (PDT), the following
appeared in talk.origins, posted by Burkhard
<b.sc...@ed.ac.uk>:

>On Wednesday, March 15, 2023 at 6:30:29?PM UTC, Athel Cornish-Bowden wrote:
>> On 2023-03-15 15:31:42 +0000, erik simpson said:
>>

>> > On Wednesday, March 15, 2023 at 1:40:28?AM UTC-7, jillery wrote:
>> >> Somewhat related to another current topic, the following is a link to>
>> >> a 1 hour and 15 minute video which provides a reasonably comprehensive>
>> >> and accurate narrative of the five mass extinctions life on Earth has>
>> >> endured and survived, along with speculation about a likely 6th mass>
>> >> extinction happening right now:>>
>> >> <https://www.youtube.com/watch?v=ZkOPahZM3qI>>> My impression there are
>> >> some inaccurate details. For example, it> makes no mention of the mass
>> >> extinction resulting from the Great> Oxygenation Event:>>
>> >> <https://en.wikipedia.org/wiki/Great_Oxidation_Event>>> but its broad
>> >> strokes are substantially correct.>> --> You're entitled to your own
>> >> opinions.> You're not entitled to your own facts.
>> >
>> > At one time, oxygen would have been described as a poisonous gas,
>> It still is, for compulsory anaerobes.
>> > had there been creatures
>> > capable of descriptions. But oxygen is painless,
>> Not if you're a Clostridium it isn't. Actually the metabolism of
>> organisms like ourselves goes to great lengths to avoid oxygen
>> toxicity. Look up the Wikiparticle on "Oxygen toxicity."
>
>I "think" it's a reference to a song in MASH:
>

That was my take, too.

>
>Through early morning fog I see
>Visions of the things to be
>The pains that are withheld for me
>I realize and I can see
>That suicide is painless
>It brings on many changes
>And I can take or leave it
>If I pleas
>
>
>> > It brought us many changes.
>> >
>> > See the Wiki entry on the Francevillian biota, an enigmatic and
>> > short-lived phenomenon that
>> > may have been eukaryotic or even multi-cellular.
>> > https://en.wikipedia.org/wiki/Francevillian_biota
>> --
>> athel cb : Biochemical Evolution, Garland Science, 2016

[erik simpson]

Just so. The Francevillian biota is an oddity that has no obvious connection to the
eukaryotic and multi-cellular life that came later. Note that ir precedes the "boring billion" (~1.8 - 0.8 GYA)
where nothing much is preserved to see inthe fossil record.

[Bob Casanova]

On Wed, 15 Mar 2023 13:15:44 -0700 (PDT), the following

appeared in talk.origins, posted by erik simpson
<eastsi...@gmail.com>:

>> Just so. The Francevillian biota is an oddity that has no obvious connection to the
>eukaryotic and multi-cellular life that came later. Note that ir precedes the "boring billion" (~1.8 - 0.8 GYA)
>where nothing much is preserved to see inthe fossil record.
>

Yeah, the combination of "small and soft" and "a *long* time
ago" makes definitive data difficult to come by...

[jillery]

On Wed, 15 Mar 2023 08:31:42 -0700 (PDT), erik simpson
<eastsi...@gmail.com> wrote:

>On Wednesday, March 15, 2023 at 1:40:28?AM UTC-7, jillery wrote:
>> Somewhat related to another current topic, the following is a link to
>> a 1 hour and 15 minute video which provides a reasonably comprehensive
>> and accurate narrative of the five mass extinctions life on Earth has
>> endured and survived, along with speculation about a likely 6th mass
>> extinction happening right now:
>>
>> <https://www.youtube.com/watch?v=ZkOPahZM3qI>
>>
>> My impression there are some inaccurate details. For example, it
>> makes no mention of the mass extinction resulting from the Great
>> Oxygenation Event:
>>
>> <https://en.wikipedia.org/wiki/Great_Oxidation_Event>
>>
>> but its broad strokes are substantially correct.
>>

>At one time, oxygen would have been described as a poisonous gas, had there been creatures
>capable of descriptions. But oxygen is painless, It brought us many changes.
>
>See the Wiki entry on the Francevillian biota, an enigmatic and short-lived phenomenon that
>may have been eukaryotic or even multi-cellular. https://en.wikipedia.org/wiki/Francevillian_biota

Molecular oxygen is a highly energetic free radical and oxidizes
almost all biochemicals, and in that sense is poisonous to all life.
Aerobic life builds many hoops to manage oxygen and capture its
greater chemical potential. Even so, there are conditions where
oxygen breaks those hoops and kills even aerobes:

<https://myhealth.ucsd.edu/RelatedItems/3,90904>

Anybody who has suffered hydrogen peroxide burns is intimately
familiar with that fact.

[jillery]

On Wed, 15 Mar 2023 09:27:58 -0700, Bob Casanova <nos...@buzz.off>
wrote:

jillery noted no such thing. All life on Earth is "our sort of life",
in the sense that all follow a substantially similar nuclear code,
with the arguable exception of viruses being alive. If the Biblical
"in God's image" has any objective meaning, it would be that.

[Bob Casanova]

On Wed, 15 Mar 2023 22:43:06 -0400, the following appeared
in talk.origins, posted by jillery <69jp...@gmail.com>:

I was referring to your comment above, "it makes no mention
of the mass extinction" [of anaerobic life] "resulting from
the Great Oxygenation Event". If you didn't intend this to
imply that only current aerobic life ("our sort of life") is
included in listed mass extinctions my apologies.

[jillery]

On Wed, 15 Mar 2023 22:37:40 -0700, Bob Casanova <nos...@buzz.off>

My intent to what you quoted is to show I noted some missing bits in
the narrative, as I noted in the OP, as shown in the quoted text
above. Not sure how you get from that to "our sort of life".

Instead of poorly paraphrasing my comments, how 'bout just letting
what I actually post speak for me? And please don't gaslight me by
claiming this as another "short fuse" thing.

[Bob Casanova]

On Thu, 16 Mar 2023 03:31:03 -0400, the following appeared

Sorry I bothered to explain, and sorry I apologized.

[Lawyer Daggett]

Presumably you meant to write atomic oxygen and not molecular
oxygen as molecular oxygen is not a free radical. Atomic oxygen is.
There are additional nits to pick but at the broadest level the thrust
is correct. Biochemically, oxygen is a dangerous partner. It does,
however, provide pathways for much more efficient extraction of
chemical energy, and for that matter more efficient pathways to
store chemical energy.

I confess to discomfort at your terminology of "hoops" as I can't
seem to map the implied metaphor to the antioxidation pathways
I'm most familiar with. I would rather say that the dangers of
spontaneous oxidation of biomolecules increases with oxygen
concentration and spontaneous oxidation is indeed dangerous.
To guard against spontaneous oxidation that are multiple pathways
that have evolved to keep cells/organisms supplied with molecules
that act to be sacrificial acceptors of over-reactive species, and
pathways to reverse some of the damage that nevertheless occurs.
Such pathways can be, and are at time, overwhelmed by higher
than typical oxygen concentrations, or higher than typical concentrations
of other species with high oxidation potential.

And as a note of relevance to the Panda's Thumb, if you drink booze,
try to keep up your supply of glutathione and don't take acetaminophen
(watch out for meds that include it).

[jillery]

On Thu, 16 Mar 2023 10:08:31 -0700, Bob Casanova <nos...@buzz.off>

Your comment above demonstrates the sincerity of your apologies. Of
course, nobody would accuse you of a "short fuse". I suppose that one
kind of loyalty.

Don't like that I note your habit of poorly paraphrasing my words?
Then stop poorly paraphrasing my words. Think of all the time you
would save not-explaining and not-apologizing.

[jillery]

On Thu, 16 Mar 2023 16:42:25 -0700 (PDT), Lawyer Daggett
<j.nobel...@gmail.com> wrote:

>Presumably you meant to write atomic oxygen and not molecular
>oxygen as molecular oxygen is not a free radical.

Correct.

>Atomic oxygen is.
>There are additional nits to pick but at the broadest level the thrust
>is correct. Biochemically, oxygen is a dangerous partner. It does,
>however, provide pathways for much more efficient extraction of
>chemical energy, and for that matter more efficient pathways to
>store chemical energy.
>
>I confess to discomfort at your terminology of "hoops" as I can't
>seem to map the implied metaphor to the antioxidation pathways
>I'm most familiar with.

I note you don't identify the "implication" you inferred.

>I would rather say that the dangers of
>spontaneous oxidation of biomolecules increases with oxygen
>concentration and spontaneous oxidation is indeed dangerous.
>To guard against spontaneous oxidation that are multiple pathways
>that have evolved to keep cells/organisms supplied with molecules
>that act to be sacrificial acceptors of over-reactive species, and
>pathways to reverse some of the damage that nevertheless occurs.
>Such pathways can be, and are at time, overwhelmed by higher
>than typical oxygen concentrations, or higher than typical concentrations
>of other species with high oxidation potential.
>
>And as a note of relevance to the Panda's Thumb, if you drink booze,
>try to keep up your supply of glutathione and don't take acetaminophen
>(watch out for meds that include it).

[Athel Cornish-Bowden]

No. Molecular oxygen is a diradical. Two unpaired electrons. Naively
one might assume it to be O=O, but actually it has a triplet structure
and is is .O-O.

> Atomic oxygen is.
> There are additional nits to pick but at the broadest level the thrust
> is correct. Biochemically, oxygen is a dangerous partner. It does,
> however, provide pathways for much more efficient extraction of
> chemical energy, and for that matter more efficient pathways tostore
> chemical energy.
> I confess to discomfort at your terminology of "hoops" as I can'tseem

> to map the implied metaphor to the antioxidation pathwaysI'm most

> familiar with. I would rather say that the dangers ofspontaneous
> oxidation of biomolecules increases with oxygen
> concentration and spontaneous oxidation is indeed dangerous.
> To guard against spontaneous oxidation that are multiple pathways
> that have evolved to keep cells/organisms supplied with molecules
> that act to be sacrificial acceptors of over-reactive species, and
> pathways to reverse some of the damage that nevertheless occurs.
> Such pathways can be, and are at time, overwhelmed by higher
> than typical oxygen concentrations, or higher than typical concentrations
> of other species with high oxidation potential.
> And as a note of relevance to the Panda's Thumb, if you drink booze,
> try to keep up your supply of glutathione and don't take acetaminophen
> (watch out for meds that include it).

[Lawyer Daggett]

I confess that is news to me. I did some quick net searches and
they confirm your answer. I now need to dig a bit to better understand.

[Lawyer Daggett]

That would be because the best I could manage for "hoops" would
be "jump through hoops" yet that is such an odd turn of phrase
for biochemical pathways that I didn't want to assert that as your
meaning. Should you have had something to flesh it out I figured
you would simply expand on your intent.

It's just nitpicking though so didn't seem worth obsessing over.
Instead, I tried to compose something that might be more useful.

[Robert Carnegie]

But inaccurate here (probably) and confusing.
A poorly chosen flourish.

[jillery]

On Fri, 17 Mar 2023 00:36:46 -0700 (PDT), Lawyer Daggett
<j.nobel...@gmail.com> wrote:

Since you mention it, I do imagine electrons jumping through
biochemical hoops as they incrementally parcel out their energy:

<https://en.wikipedia.org/wiki/Citric_acid_cycle>

ISTM odd you think my metaphor odd, but you're entitled to your
metaphorical opinions, as am I.

>It's just nitpicking though so didn't seem worth obsessing over.
>Instead, I tried to compose something that might be more useful.

So are you "discomforted" by your nitpicking? Or by confessing to it?

[Lawyer Daggett]

You ask,

> So are you "discomforted" by your nitpicking? Or by confessing to it?

Neither, as should be obvious. Further, your expansion on your
context of "hoops" does nothing to make it seem more apropos to me.
It just doesn't mesh with my understanding of biochemistry.
As I don't think you value my perspective on biochemistry, that
should end this.

[jillery]

On Sun, 19 Mar 2023 00:32:16 -0700 (PDT), Lawyer Daggett
<j.nobel...@gmail.com> wrote:

Apparently your mileage varies.

>> >It's just nitpicking though so didn't seem worth obsessing over.
>> >Instead, I tried to compose something that might be more useful.
>
>> So are you "discomforted" by your nitpicking? Or by confessing to it?
>
>> >> >I would rather say that the dangers of
>> >> >spontaneous oxidation of biomolecules increases with oxygen
>> >> >concentration and spontaneous oxidation is indeed dangerous.
>> >> >To guard against spontaneous oxidation that are multiple pathways
>> >> >that have evolved to keep cells/organisms supplied with molecules
>> >> >that act to be sacrificial acceptors of over-reactive species, and
>> >> >pathways to reverse some of the damage that nevertheless occurs.
>> >> >Such pathways can be, and are at time, overwhelmed by higher
>> >> >than typical oxygen concentrations, or higher than typical concentrations
>> >> >of other species with high oxidation potential.
>> >> >
>> >> >And as a note of relevance to the Panda's Thumb, if you drink booze,
>> >> >try to keep up your supply of glutathione and don't take acetaminophen
>> >> >(watch out for meds that include it).
>>
>>
>

>You ask,
>> So are you "discomforted" by your nitpicking? Or by confessing to it?
>
>Neither, as should be obvious. Further, your expansion on your
>context of "hoops" does nothing to make it seem more apropos to me.
>It just doesn't mesh with my understanding of biochemistry.
>As I don't think you value my perspective on biochemistry, that
>should end this.

There's that word again. Obviously, what's "obvious" to you isn't
obvious to me. For another example, apparently it's obvious to you I
don't value your perspective on biochemistry, but you provide no basis
expressed or implied why you think that. That makes it obvious to me
"this" should have ended before you lit your own short fuse.