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May 22, 2020 18 tweets 7 min read Read on X
It's #WorldBiodiversityDay today! The complexity of life is amazing, but also begs one question: what did the first life form on Earth actually look like?

Let's find out... #FridayMotivation Image
Now there's no universally agreed definition of life: even Erwin Schrödinger was uncertain what it was. But an ability to resist entropy, to reproduce, to mutate, to have a metabolism and to self-organise feature in most definitions.
And whatever life is we reliably assume it's all interlinked in some way. We still use the medieval idea of a 'tree of life' to map the connections and currently scientists believe this tree has either two or three fundamental branches. Image
Bacteria and archaea form two of these fundamental branches: both are simple single-cell organisms that usually lack organelles, but their ribosomal RNA is very different. They also form the bulk of the biomass on the planet.
Eukaryotes are different: they have membrane-bound organelles such as mitochondria and form multicellular organisms such as you and I. So fid they evolve from archaea, or are they a third fundamental branch of the tree of life? Image
Views vary on this, and it's due to horizontal gene transfer. You don't just inherit your genes from your parents, you can also swap them with your neighbors! That's how bacteria share antibiotic resistance, and viruses can help it happen. Image
But it also complicates the tree of life, making it hard to tease out who was related to whom in our prehistory based on gene sequencing. Maybe it's best to talk about a mosaic of life instead of a tree. Image
This hasn't stopped biologists trying to discover LUCA: the last comon universal ancestor of all living things. Gene analysis of multiple bacteria and archaea suggest there are 355 common protein clusters across all life, which give us a clue as to what LUCA may have looked like.
LUCA was possibly an anaerobic organism that lived in ocean hydrothermal vents, places rich in H2, CO2 and iron. The energy gradient between the warm vent and surrounding colder water allowed LUCA to make adenosine triphosphate - the molecule that allows energy transfer in cells.
This means LUCA, like a virus, was an organism on the edge of life. It possibly had no cell membrane and relied on iron to form its boundaries. LUCA was a fizzing undersea rock using its unique environment to create energy. Possibly.
The ability for organisms to generate their own energy gradients evolved later on, allowing life to break away from the vents on at least two occasions – one giving rise to the first archaea, the other to bacteria.

But the story has one big flaw...
It's based on working backwards from organisms that currently exist. What about the extinct ones? Plus LUCA is still a complicated organism. How did this complexity come about? What was before LUCA? Image
Well in 1992, in a water tower in Bradford being tested for Legionnaires disease, scientists found an amoeba which contained a starting secret...

It was infected with a giant virus!
Viruses are normally small, but Mimivirus - as it came to be known - was a monster. It was big enough to be seen under a normal microscope and its genome was far bigger than it needed to be for a virus, with almost a thousand protein-coding genes. Image
Since 1992 a number of other scary sounding giant viruses - Pandoravirus, Megavirus etc - have been found. Stranger still these can themselves become infected by other, simpler viruses. So what's going on? Image
Well there are two theories about giant viruses. One is they grew from simpler viruses by capturing DNA from host organisms. They may be huge but that's just accidental; their big genome doesn't really mean anything.
The other theory is they evolved from complicated organisms which lost their ability to reproduce themselves. What's fascinating is that these initial organisms may not have been bacteria or archaea - instead they may have been earlier types of life which are now extinct.
The good news is that giant viruses only attack amoebas. But are they evidence of a lost fourth domain of life? Many are skeptical, but the more examples we find the more we learn about the earliest life on Earth and how it may have developed.

Happy #BiodiversityDay everyone!

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More from @PulpLibrarian

Oct 31
Time once again for my occasional series "Women with great hair fleeing gothic houses!"

I assume everyone's doing it this #Halloween ? Image
The Legend Of Crownpoint, by Monica Heath. Signet Books, 1974.

A lot of moss on that heath... Image
The Legend Of Holderly Hall, by Kate Cameron. Leisure Books, 1974.

This is number one in a series of four novels, proving that nobody really reads Trip Advisor hotel reviews... Image
Read 11 tweets
Oct 28
In January 1919 a new magazine heralded the dawn of the Weimar era. Its aesthetic was a kind of demented Jugendstil, and its stories were dark gothic fantasies.

This is the story of Der Orchideengarten... Image
Der Orchideengarten: Phantastische Blätter (The orchid garden: fantastic pages) is probably the first ever fantasy magazine. Published in Munich by Dreiländerverlag, a trial issue appeared in 1918 before the first full 24 page edition was published in January 1919. Image
"The orchid garden is full of beautiful - now terribly gruesome, now satirically pleasing - graphic jewelery" announced the advanced publicity. It was certainly a huge departure from the Art Nouveau of Jugend magazine, which German readers were already familiar with. Image
Read 12 tweets
Oct 22
Time for a pulp countdown now, and today I'm looking at my top 10 animals in pulp horror! Image
At no 10: cats! Pretty evil, but can be easily defeated with a laser pointer. Image
At no 9: bees! They only attack if you annoy them, or if you're standing near a jam sandwich. Best to take care in either situation. Image
Read 12 tweets
Oct 15
If stock photography has taught us one thing it's how to recognise a hacker! But how much do we really know about these shady characters, with their ill-fitting balaclavas and their Windows 7 laptops?

Here's my essential stock photography guide to cybersecurity... Image
First things first, hacking has come on leaps and bounds in the last few years. Backing up your sensitive data on C60 cassette and labelling it "Flock of Seagulls Megamix' is no longer enough to keep your information safe! Image
And hackers are actually very hard to spot. That's because they dress head-to-toe in black (or very very very dark grey) since they live on the Dark Web and want to blend into the background. Image
Read 12 tweets
Oct 5
Time once again for our occasional series "Women with great hair fleeing gothic houses!"

And today I count down my Top 10 of most gothic goths a' fleeing... Image
At No 10: The Unlamented, by Dorothy Daniels. Pocket Books, 1975. That's a great goth coat! Image
At No 9: The Haunting of Drumroe, by Claudette Nicole. Fawcett Gold Medal, 1971. Who says a gothic lady can't rock a white nightie in the snow? Image
Read 12 tweets
Sep 1
Today in pulp, one of the most influential and outrageous illustrators of the Italian Italian fumetti scene: Emanuele Taglietti!

This will be interesting... Image
Emanuele Taglietti was born in Ferrara in 1943. His father worked as a set designer for director Michaelangelo Antonioni, often taking Emanuele with him on set. Image
In the 1960s Taglietti moved to Rome, where he studied stage design. He began a successful career as an assistant art director, working for Federico Fellini and Marco Ferreri. Image
Read 17 tweets

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