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Fermi Paradox explained by Prof Brian Cox

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funeralxempire
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06 Apr 2024, 2:43 pm

ToughDiamond wrote:
Similarly I don't quite embrace the idea that spiders aren't insects, though I probably should.


But they're not even closely related. Insects are crustaceans, spiders are chelicerates. They're both within Arthropoda but quite distant.


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ToughDiamond
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06 Apr 2024, 3:14 pm

funeralxempire wrote:
ToughDiamond wrote:
Similarly I don't quite embrace the idea that spiders aren't insects, though I probably should.


But they're not even closely related. Insects are crustaceans, spiders are chelicerates. They're both within Arthropoda but quite distant.

Yes that's why I probably should embrace the official view of the matter. But they just look like insects to me. Pluto is also still a planet in my book.



naturalplastic
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06 Apr 2024, 3:15 pm

ToughDiamond wrote:
cyberdad wrote:
An interesting conundrum is a virus. When you seperate the viral coat from DNA you get two components that are not alive, But when you re-insert DNA into the protein coat then by some miracle it becomes a living virus.

It seems most biologists don't consider viruses to be living organisms. Viruses lack most of the characteristics required to meet the usual definitions of life, though they have one or two of those characteristics. So it's not really a conundrum or a miracle, just an interesting fact.

https://www.khanacademy.org/test-prep/m ... d-or-alive

I was surprised when I was told that in school, and still don't quite embrace the idea. Similarly I don't quite embrace the idea that spiders aren't insects, though I probably should.


Yes. I was about point that out. That even when you assemble its parts (put the battery into the flash light) so you have a functioning virus - it's still not "living". Viruses are in twilght zone between non living and living. They rely on the living cells of other organisms for metabolism and reproduction and everything else that living things do.



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06 Apr 2024, 3:28 pm

naturalplastic wrote:
ToughDiamond wrote:
cyberdad wrote:
An interesting conundrum is a virus. When you seperate the viral coat from DNA you get two components that are not alive, But when you re-insert DNA into the protein coat then by some miracle it becomes a living virus.

It seems most biologists don't consider viruses to be living organisms. Viruses lack most of the characteristics required to meet the usual definitions of life, though they have one or two of those characteristics. So it's not really a conundrum or a miracle, just an interesting fact.

https://www.khanacademy.org/test-prep/m ... d-or-alive

I was surprised when I was told that in school, and still don't quite embrace the idea. Similarly I don't quite embrace the idea that spiders aren't insects, though I probably should.


Yes. I was about point that out. That even when you assemble its parts (put the battery into the flash light) so you have a functioning virus - it's still not "living". Viruses are in twilght zone between non living and living. They rely on the living cells of other organisms for metabolism and reproduction and everything else that living things do.

Then we have prions - mere misfolded proteins that are even simpler and less alive than viruses, yet they infect and replicate, if causing misfolding of normal variants of the same protein can rightly be called replication, which I suppose logically it can.



funeralxempire
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06 Apr 2024, 3:45 pm

ToughDiamond wrote:
funeralxempire wrote:
ToughDiamond wrote:
Similarly I don't quite embrace the idea that spiders aren't insects, though I probably should.


But they're not even closely related. Insects are crustaceans, spiders are chelicerates. They're both within Arthropoda but quite distant.

Yes that's why I probably should embrace the official view of the matter. But they just look like insects to me. Pluto is also still a planet in my book.


I think they both look like arthropods, but arachnids only have two body segments while insects have three (distinct head and thorax, meanwhile arachnids have a fused head and thorax). There's also the question of how many legs (8 vs. 6) and where they're attached to (first segment vs. second segment).

Since those are readily visually identifiable diagnostic traits I'd argue spiders don't look like insects or vice-versa even if both share typical arthropod identifiers like a segmented body.


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06 Apr 2024, 3:47 pm

Oh, and strands of DNA will reproduce themselves in a test tube if you treat them right. We used to do that at work using a technique called PCR (polymerase chain reaction). It needed hot-cold temperature cycles to unzip and rezip the double-strands of DNA, plus an enzyme (DNA polymerase, I think) that was taken from bacteria that grow in hot springs and have enzymes that are stable at the high temperatures necessary to do PCR. Self-reproduction seems miraculous but it's actually a "simple" chemical thing in principle.



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06 Apr 2024, 3:51 pm

funeralxempire wrote:
ToughDiamond wrote:
funeralxempire wrote:
ToughDiamond wrote:
Similarly I don't quite embrace the idea that spiders aren't insects, though I probably should.


But they're not even closely related. Insects are crustaceans, spiders are chelicerates. They're both within Arthropoda but quite distant.

Yes that's why I probably should embrace the official view of the matter. But they just look like insects to me. Pluto is also still a planet in my book.


I think they both look like arthropods, but arachnids only have two body segments while insects have three (distinct head and thorax, meanwhile arachnids have a fused head and thorax). There's also the question of how many legs (8 vs. 6) and where they're attached to (first segment vs. second segment).

Since those are readily visually identifiable diagnostic traits I'd argue spiders don't look like insects or vice-versa even if both share typical arthropod identifiers like a segmented body.

You're correct. Clearly I'm not completely scientific.



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06 Apr 2024, 3:56 pm

ToughDiamond wrote:
funeralxempire wrote:
ToughDiamond wrote:
funeralxempire wrote:
ToughDiamond wrote:
Similarly I don't quite embrace the idea that spiders aren't insects, though I probably should.


But they're not even closely related. Insects are crustaceans, spiders are chelicerates. They're both within Arthropoda but quite distant.

Yes that's why I probably should embrace the official view of the matter. But they just look like insects to me. Pluto is also still a planet in my book.


I think they both look like arthropods, but arachnids only have two body segments while insects have three (distinct head and thorax, meanwhile arachnids have a fused head and thorax). There's also the question of how many legs (8 vs. 6) and where they're attached to (first segment vs. second segment).

Since those are readily visually identifiable diagnostic traits I'd argue spiders don't look like insects or vice-versa even if both share typical arthropod identifiers like a segmented body.

You're correct. Clearly I'm not completely scientific.


Or just less prone to nitpicking. :nerdy:


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06 Apr 2024, 5:10 pm

As an ex-microbiologist we were told viruses aren't "classically life" in that they do not self-replicate like bacterial cells and dont fit into prokaryote or eukaryote groups. But they do directly exchange genetic information with living organisms—that is, within the web of life itself. Viruses contribute to DNA of humans (1/10 of our DNA contains snippets of ancient viral infections passed on to subsequent generations which protect us from infections).

They are certainly something in-between.



funeralxempire
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06 Apr 2024, 5:23 pm

cyberdad wrote:
As an ex-microbiologist we were told viruses aren't "classically life" in that they do not self-replicate like bacterial cells and dont fit into prokaryote or eukaryote groups. But they do directly exchange genetic information with living organisms—that is, within the web of life itself. Viruses contribute to DNA of humans (1/10 of our DNA contains snippets of ancient viral infections passed on to subsequent generations which protect us from infections).

They are certainly something in-between.


We like to imagine there's a strict boundary between life and not-life but like many other things in nature it seems to have a fuzzy, indistinct boundary.


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06 Apr 2024, 5:29 pm

^^^ Fair to say viruses (whether RNA or DNA) could not have evolved without life. And ironically humans may not have survived without protection from said viruses.



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06 Apr 2024, 5:54 pm

funeralxempire wrote:
ToughDiamond wrote:
funeralxempire wrote:
You're correct. Clearly I'm not completely scientific.

Or just less prone to nitpicking. :nerdy:

I'm a highly selective nitpicker.



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06 Apr 2024, 6:36 pm

cyberdad wrote:
^^^ Fair to say viruses (whether RNA or DNA) could not have evolved without life. And ironically humans may not have survived without protection from said viruses.

I think the current theory is that "organic" molecules, including RNA, first formed in the atmosphere and fell into the ocean, where the few that happened to replicate were selected by the evolutionary process, i.e. the ones that reproduced quicker proliferated. Eventually they evolved with membranes around them that gave them a further reproductive advantage, and so proto-bacteria came into being, and eventually out popped the human race. Without any knowledge of polynucleotides and their properties, early humans couldn't figure out that explanation for the origin of life, so they thought there had been some kind of magic going on. It wasn't so long ago that it was deemed impossible to create an "organic" molecule from inorganic molecules.



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07 Apr 2024, 1:48 am

ToughDiamond wrote:
cyberdad wrote:
^^^ Fair to say viruses (whether RNA or DNA) could not have evolved without life. And ironically humans may not have survived without protection from said viruses.

I think the current theory is that "organic" molecules, including RNA, first formed in the atmosphere and fell into the ocean, where the few that happened to replicate were selected by the evolutionary process, i.e. the ones that reproduced quicker proliferated. Eventually they evolved with membranes around them that gave them a further reproductive advantage, and so proto-bacteria came into being, and eventually out popped the human race. Without any knowledge of polynucleotides and their properties, early humans couldn't figure out that explanation for the origin of life, so they thought there had been some kind of magic going on. It wasn't so long ago that it was deemed impossible to create an "organic" molecule from inorganic molecules.


The magic "spark" is what's still missing in the warm organic pools of early earth that zapped proteinacious membrane bound bits of nucleotide to become proto-bacteria. There's a series of biochemical coincidences that must happen synchronously which still can't be replicated in a attenuated beaker full of warmly mixed organic soup.



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07 Apr 2024, 5:53 am

funeralxempire wrote:
ToughDiamond wrote:
funeralxempire wrote:
ToughDiamond wrote:
Similarly I don't quite embrace the idea that spiders aren't insects, though I probably should.


But they're not even closely related. Insects are crustaceans, spiders are chelicerates. They're both within Arthropoda but quite distant.

Yes that's why I probably should embrace the official view of the matter. But they just look like insects to me. Pluto is also still a planet in my book.


I think they both look like arthropods, but arachnids only have two body segments while insects have three (distinct head and thorax, meanwhile arachnids have a fused head and thorax). There's also the question of how many legs (8 vs. 6) and where they're attached to (first segment vs. second segment).

Since those are readily visually identifiable diagnostic traits I'd argue spiders don't look like insects or vice-versa even if both share typical arthropod identifiers like a segmented body.


There should be a colloquial terms for ALL creepy crawly tiny arthropods...like "bug"... for every day non learned parlance.

But folks should still be aware that that category includes vastly differing creatures from at least five different classes of arthropods ...insects, arachnids (spiders and scorpions), centipedes, millipedes, and even land dwelling crustaceans (wood lice and pill bugs). Some tropical areas even have big ass crabs that live on land.



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07 Apr 2024, 12:26 pm

cyberdad wrote:
ToughDiamond wrote:
cyberdad wrote:
^^^ Fair to say viruses (whether RNA or DNA) could not have evolved without life. And ironically humans may not have survived without protection from said viruses.

I think the current theory is that "organic" molecules, including RNA, first formed in the atmosphere and fell into the ocean, where the few that happened to replicate were selected by the evolutionary process, i.e. the ones that reproduced quicker proliferated. Eventually they evolved with membranes around them that gave them a further reproductive advantage, and so proto-bacteria came into being, and eventually out popped the human race. Without any knowledge of polynucleotides and their properties, early humans couldn't figure out that explanation for the origin of life, so they thought there had been some kind of magic going on. It wasn't so long ago that it was deemed impossible to create an "organic" molecule from inorganic molecules.


The magic "spark" is what's still missing in the warm organic pools of early earth that zapped proteinacious membrane bound bits of nucleotide to become proto-bacteria. There's a series of biochemical coincidences that must happen synchronously which still can't be replicated in a attenuated beaker full of warmly mixed organic soup.

Not really surprising there are bits of the process that can't be done in a beaker. Evolution has time on its side - a billion years or so. Near-impossible coincidences become much more likely. I'm still awestruck that science has been able to come up with a plausible theory at all, let alone demonstrate most of the steps in a laboratory.