Evolution of life on Espa

This page is a documentation of the **Evolution of Espan life forms**. This page will not include every single one of the evolutionary creatures, for the obvious reason that ecosystems over time are insanely diverse.

The stronger gravity combined with the high oxygen levels on Espa requires life to have twice the muscle strength of earth life. Odjor has a luminosity 0.69 times that of our sun on earth, therefor leaves on Espa are found blue in order to capture the right amount of sunlight.

Due to the stronger gravity and dense atmosphere on Espa creatures are vastly different from Earth life, big animals can easily get airborne in the dense atmosphere.

## The building blocks

This section documents the earliest history of the planet and its lifeforms.

### Formation

The planet Espa is approximately 4.139 billion years old, formed by method of accretion the planet was able to gather a great mass, it is unclear when but at some point the planet was able to capture the planet Yattu in her gravity turning it into her first moon, at some point after this it had a disastrous encounter with another planet which let to the creation of a ring around the planet which in turn would accrete into it's second moon Archentes.

### The Story begins

Around 250 million years after its initial formation Espa was able to form the first fragments of a solid crust, due to the planets size this took significantly longer than the earth did to cool off. While it was cooling these fragments gradually transformed into the first tectonic planets of Espa.

With heavier elements such as Iron gradually sinking to the planets core a very weak magnetic field became active around 3.85 billion years ago.
Water arrived on meteors during the Late Heavy bombardment of the Odjoran system which lasted until ~3.7 billion years ago. Early oceans on Espa where highly acidic but life arose not long after through abiogenesis somewhere around 3.9 billion years ago with a biosignature boundary at 3.81 billion years ago. This period marked the end of the Plutonian Eon and the start of the Katagogian Eon (named after the Greek word for origin).

The Espan LUCA lived at around 3.4 BYA.

### The first lifeforms

Life on Espa started out being anaerobic. Because of the thick atmosphere it did not develop much photosynthesis in these early stages, instead starting out as heterotrophic, incapable of producing their own food so instead the searched for food in their environment.

However at some point very soon after life first appeared some organisms evolved to use inorganic molecules to power chemical progresses from which they derive their energy, thus becoming autotrophic, able to produce their own food.

Early autotropic bacteria diversified into phototrophes (photosynthethic) and chemotrophes (chemosynthethic), whereas photosynthethic organisms use sunlight to power themselves, the chemotrophes use H2S to power themselves.

sunlight photosynthesis of phototrophes:
6**CO**2 + 6**H**2**O** → **C**6**H**12**O**6 + 6**O**2
hydrogen sulfide chemosynthesis of chemotrophes:
12**H**2**S** + 6**CO**2 → **C**6**H**12**O**6 + 6**H**2**O** + 12**S**
Additionally H2S dissolves in water making the oceans acidic meaning these early lifeforms had some means to tolerate the acid.

## The March of Life

As these early bacteria proliferated they started changing the composition of the atmosphere, with the phototrophes releasing **O2** into the atmosphere and the chemotrophes releasing **S2** into the oceans.

As the ocean began to accumulate Oxygen and Sulphur rusting becomes possible leaving vast iron deposits at the ocean floor as well as further acidifying the oceans.

By around 2.9 BYA the oceans have completely saturated with oxygen which means its now being released into the atmosphere. By 2.7 BYA the oxygen levels reached 0.3% by volume passing the Pasteur point above which facultative aerobic microorganisms and facultative anaerobes adapt from fermentation to aerobic respiration.

### Oxygen Catastrophe

This sudden appearance led directly to extreme benefit aerobic organisms now had over anaerobic microorganisms, oxygen was a poison to anaerobic life leading all the non-chemosynthetic anaerobic life to die out in the first mass extinction during which 99% of lifeforms died out. This event marked the end of the Katagogian Eon and the start of the Synéchisian Eon (named after the Greek word for continuation).

Additionally to the oxygenation the higher oxygen levels drop the methane levels - The oxygen combined with the methane to form carbon dioxide and water, which do not retain heat as well as methane does - sending Espa deep into a vast ice age called the Pagonian Ice Age. For the planets climate to adapt to the new atmosphere 500 ma had to pass, and only by 2.2 BYA the ice began to retreat.

### More Complex Cells

In the new oxygen atmosphere aerobic lifeforms soon developed into complex colonial and eventually multi-cellular lifeforms, drastically speeding up evolution.

While this was happening somewhere around 1.9 BYA the first bacterial viruses appear. Followed at around 1.6 BYA by the evolution of sexual reproduction. At about 1.84 BYA the first bacteria with a nuclei form separating the line of prokaryotic and Xenokaryotic Cells on Espa.

At around 1.76 BYA an aerobic protist enters the system of a larger protist and avoids digestion, becoming a source of energy instead. Eventually it becomes just another organelle inside the larger protist causing mitochondrial symbiosis. These symbiosis's happen again for phototrophes at 1.56 BYA, where a Photosynthetic Autotrophes became integrated into a larger Xenokaryota making the basis for all plants and algae. Followed by Chemotrophic symbiosis at 1.41 BYA.

## Multi cellulars

Up to this moment living cells that had been produced by cell division simply drifted away from each other. But now with the aid of increased oxygen levels some cells stuck together, some of these clumps of cells would eventually evolve into the first animals.

There were many advantages to being multicelled, colonies of cells could collect more food, control their internal environment and act efficiently by working as a team.

### The first Multi-cellulars

Espa is entering a period of increased dynamics called the Omádian Period, the multi cellular clumps were evolving, the first clumps of cells evolved to be sponge like creatures in various shapes.

These early multi cellulars still faced a critical handicap, they were sessile meaning they couldn't move around.

On of the first creatures to be identified was Fteró Archaía. Since it was a sessile life form, it needed to have a surface as a means of capturing food particles, according to the Square–cube law this favours a tall feather like structure. These creatures showed alot of diversity mainly centered around the feathershaped designs and are commonly grouped as Fteromorphs.

An evolutionary breakthrough was reached when the first motile animals evolved, these creatures were still primitive
The first motile animals were very slow, they crept along the seafloor moving from one feeding spot to the next absorbing the organic matter beneath it and then moving on to the next place.

Motile animals had an tremendous advantage over sessile animals, they could move away from danger, move towards a more richer food source and they could leave a spot overcrowded by their neighbours.

With movement unlocked the first species were able to unlock predation and change the game forever. With the apperance of the first predators creatures had to develop new means of defense and an evolutionary arms race would ensure between predator and prey and be the driving force behind the evolutionary progress of Espa.