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Mapcraft - Fantasy map designer

WorldGen - SciFi universe generator

Mapcraft Web - Web based fantasy map designer

All code for the project is released under the GPL, and is copyright Samuel Penn.

The text on this wiki is dual licensed CC-BY-SA and GPL.

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Life Level

The life level of a world defines (in very broad terms) how advanced native life is on the world. It ranges from no life at all, through simple single celled organisms, to land animals and extensive (Earth-life) conditions.


Organic and Archaean are quite common on worlds that could potentially support life, but life becomes significantly rarer as you move up through the classifications.


The evolutionary path on worlds can be very different in the details, but the initial steps are broadly similar at the high level. Diversity really comes in beyond the Aerobic stage.

Early Life

Organic Chemicals originally formed, which were simple amino acids. Most worlds with liquid water will form basic organic molecules like this, but few progress any further. Such worlds have an Organic classification.

Protobionts are a form of non-living matter that is the precursor to living matter, and are a more complex form of Organic Chemicals.

The marker for Archaean worlds is the rise of Prokaryotes, which are the first living organisms. They are very basic cellular life. Once they arise, they quickly come to dominate the ecosystem. They may be found in trace amounts on Organic worlds, but an Archaean world will be dominated by Prokaryotes or more complicated forms of life.

Within a few tens of millions of years, these give rise to some form of Cyanobacteria, which make use of photosynthesis for energy and produce oxygen. Because they are so much more efficient, they quickly come to dominate the biosphere, and are probably dominant during the late stages of Archaean worlds.

However, their production of oxygen changes the biosphere, and turns Archaean worlds into Aerobic worlds.


With the rise of oxygen, so the Aerobic stage is reached. Plankton consumes smaller life forms, forcing the evolution of larger and more complex organisms. Larger varieties of algae becomes Seaweed and jellyfish evolve. Eventually, the arrival of simple marine organisms, such as starfish, sea urchins and worms marks the last stages of the Aerobic classification.

The Complex Ocean period is heralded by the arrival of crustaceans, fish and other free swimming vertebrates.

Alien Evolution

The above assumes that things progress in much the same way as they did on Earth. This is unlikely, but easy. The above categories probably fit most evolutionary paths, however the details of each are unlikely to be the same on all worlds - e.g. when grasses first evolve and so on.

worldgen/planets/lifelevel.1515927765.txt.gz · Last modified: 2018/01/14 11:02 by sam