Life on Miavegr
Life appeared on the planet Miavegr around 4 billions years before present.
Origin
First unicellulars (4 Gy BP)
The first organisms appeared on the surface of Miavegr after a period of strong activities of the Semor (the star). The planet had cooled down enough to have a global ocean but its magnetic field had still not stabilized. The high levels of gamma rays and UV permitted the splitting of water in hydrogen and oxygen; the strong solar wind carried out the light hydrogen while the oxygen enriched the atmosphere. The first simple organisms emerged on the first landmasses in water pools. These first organisms where made of a lipid bi-layer containing a set of auto-replicating proteins. However after the first 500 million years the Cobalt Porphyrin-Peptide Mesh (CPPM) evolved in the first oxygen-photosynthesizing organism. These polymers first evolved as part of the photosynthesis metabolism, but quickly became an effective way of encoding protein information. This gave rise to a rapid diversification of these unicellulars.
Complex cells (2 Gy BP)
Two billions years ago, Semor stabilized and Miavegr became a much more stable planet with a strong internal magnetic field. The oxygen levels continued to rise thanks to photosynthesizing lifeforms. Some of these simple cells, the Eudiktya, evolved phagocytosis and a more complex internal structure with a nucleus and organelles. Their nucleus was made of a pigment-protein capsule which blocked unwanted light to hit the CPPM. Their CPPM lost most of its enzymatic and metabolic properties, but evolved a better replication system. 200 millions years later, a drop in sunlight, due to a change in Miavegr orbit, provoked a 100 million years of global ice age. To this event only a small part of the great diversity of unicellulars survived, the Anthrachroma, Kalkapria, Subpauperia. The Anthrachroma adapted to live under the thick ice sheet and derived their energy form photosynthesis. They evolved to use what little of the light that came under the ice, absorbing even most infrared. The Kalkapria formed dense biofilm and calcareous structures near thermal seeps. The Subpauperia adapted to live in anoxic sediments in the deep ocean, they evolved a large diversity of metabolisms and some retained photosynthetic capabilities. The Eudiktya present during these times mostly fed on Anthrachroma biofilms under the ice sheet.
After the ice age, around 1.5 GY BP, a gourp of Kalkapria formed an endosymbiosis with a group Subpauperia. The smaller Subpauperia living inside the Kalkapria. During millions of years this symbiosis stabilized giving rise to a photosynthesizing organelle inside the Kalkapria. This group of Kalkapria, called Lithochromia, made extensive surface reefs in the following years. Around the same time a group of Eudiktya that possessed silica spines, absorbed a Anthrachroma cell as an endosymbiont. Called Vitrophyta, they acquired this way the capability to do photosynthesis and in the following hundred millions of years evolved to form multicellular colonies.
Multicellular life (1 Gy BP)
Another important endosymbiosis event occured around 1 Gy BP. When the Episcleria a group of Eudiktya absorbed a Litochromia cell. Most importantly this endosymbiosis gave them the ability to fixate calcium carbonate minerals. These organisms quickly diversified and multicellularity appeared in multiple clades. 300 millions years later the Strigophyta, a group of Vitrophyta), made a symbiosis with a group of Episcleria, the Phlebata, which helped them conquer land for the first time. The Phlebata were saprophagic organisms, that made filaments (like fungi). In the symbiosis it rooted the holo-organism and transported nutrients and water to the Strigophyta. This second organism, fed the Phlebata with sugars made from photosynthesis. These organisms expanded and diversified over all land forming large colonies.
Complex life (0.5 Gy BP)
Three clades of Episcleria (Nectozoa, Diplozoa, Plicozoa) evolved cellular differentiation and tissues nearly at the same time, around 500 millions years ago. These organisms could be compared to earth's animals and quickly became more complex and diverse.
Phylogeny
The last common ancestor of all life (present today on Miavegr), lived around 3,5 Billions years ago. This ancestral organism gave rise to the 5 domains of life on Miavegr.
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One view of the great kingdoms and their stem groups.[1][2][3][4] The Metamonada are hard to place, being sister possibly to Discoba or to Malawimonada[4] or being a paraphyletic group external to all other eukaryotes.<ref name="Al Jewari Baldauf 20232">Template:Cite journal
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Chemical composition
Like terrestrial life, living organisms on Miavegr, are composed mainly of organic molecules (containing Carbon, Hydrogen and Oxygen). The other macronutrients are Nitrogen , Sulfur and Phosphorous. A notable distinction in Miavegr biology is the central role of cobalt, however in both cases Iron, Sodium and Calcium are important for different metabolic processes.
Molecular biology
Like on earth, catalytic functions are mostly performed by proteins. These long amino acids polymers can also have a structural role. Like on most Earth organisms cells membranes are made of a phospholipid bi-layer. While, carbohydrates polymers are the main molecule used in energy storage and structure, however small specialized polymers also have a central role in intracellular and extracellular communication, called Information Bearing Poly-Saccharides (IBPS).
Genetic information is encoded in the Cobalt Porphyrin-Peptide Mesh (CPPM), these extremely large bi-dimensional molecules can be translated in protein or carbohydrates sequences. It is composed of porphyrin cores cross linked in four directions by 5 amino acids long peptide sequences. 25 diffent amino acids are present in Miavegr organisms, but not all of them in all organisms. The asymmetry of the Porphyrin cores give a directionality to the mesh. This cores are most often complexed with Cobalt atoms, however other metals replace it sometimes, Copper represents the starting position for translation. This molecule is most of the time highly folded to reduce the occupied volume, thanks to Zirconium complexed with two far away porphyrins. Two types of proteins interpret the CPPM, Amino-Translators (ATs) that synthesize proteins and Carbohydrate Translators (CTs) that synthesize IBPS. Each organism has in most cases at least four versions of ATs and two of CTs, capable of reading in different directions of the mesh. The ATs most common function is to replicate the amino acid sequence, following a direction on the mesh, however some types of AT can modify the protein in correspondence of some type of porphyrin complexes. The CTs translates most often shorter sequences of at most 30 monosaccharides, each 5 amino acid sequence gives information on the next monosaccharide identity and bond position. A CT and AT can work together to synthesize complex glycoproteins, to give precise transportation directions. These Glycoproteins can also be replicated by some ATs types, this gives cells the ability to produce quickly large quantities of proteins. Replication of the CPPM is mediated by Zirconium Bonding Replicators (ZrBR), these proteins bond porphyrin-Zr complexes, fully unraveling the CPPM. They then recruit ATs and prophyrin chelators enzymes, to assemble an exact copy of the CPPM. They then recruit other proteins to assure the correct folding of the meshes and avoid cross linking between them. However mutations are still possible.
