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worldgen:planets:lifelevel [2018/01/14 10:44]
sam
worldgen:planets:lifelevel [2018/01/14 11:44] (current)
sam
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 ===== Evolution ==== ===== Evolution ====
  
-The evolutionary path on Earth can be considered to have been something like the following.+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.
  
-[[:​worldgen:​commodity:​organicchemicals]] originally formed, which were simple amino acids. Most worlds with liquid water will form basic organic molecules like this, but few progress any further.+==== Early Life ====
  
-When abiogenesis gives rise to [[:​worldgen:​commodity:​simple organics]], a world is rated as being [[./​LifeLevel/​Archaean]]. These are the first living ​things, mostly single celled ​organisms ​capable ​of asexual reproduction. Within a few hundred million ​years, ​multicelled ​[[:​worldgen:​commodity:​metazoa]] such as bacteria will evolve. At this pointlife can stall until suitable levels ​of oxygen ​can build up in the oceansLife more complex than bacteria will be present in small amounts towards ​the endincluding ​[[:worldgen:commodity:​sponges]] and [[:worldgen:​commodity:algae]].+[[:​worldgen:​commodity:​organicchemicals]] originally formedwhich 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 [[./​LifeLevel/​Organic]] classification. 
 + 
 +[[:​worldgen:​commodity:​protobionts]] are form of non-living matter that is the precursor to living matter, and are a more complex form of //Organic Chemicals//​. 
 + 
 +The marker for [[./​LifeLevel/​Archaean]] ​worlds is the rise of [[:​worldgen:​commodity:​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 [[:​worldgen:​commodity:​cyanobacteria]], which make use of photosynthesis for energy and produce ​oxygen. ​Because they are so much more efficient, they quickly come to dominate ​the biosphereand are probably dominant during the late stages of //​Archaean//​ worlds. 
 + 
 +However, their production of oxygen changes the biosphere, and turns //​Archaean//​ worlds into [[./​LifeLevel/​Aerobic]] worlds. 
 + 
 +[[:pcl:EoGaian]] worlds are pre-Aerobic,​ with a mostly methane atmosphere. Once the life classification changes from //​Archaean//​ to //​Aerobic//,​ then terrestrial worlds is classes as [[:pcl:MesoGaian]]. 
 + 
 +==== Metazoa ====
  
 With the rise of oxygen, so the [[./​LifeLevel/​Aerobic]] stage is reached. [[:​worldgen:​commodity:​plankton]] consumes smaller life forms, forcing the evolution of larger and more complex organisms. Larger varieties of algae becomes [[:​worldgen:​commodity:​seaweed]] and [[:​worldgen:​commodity:​jellyfish]] evolve. Eventually, the arrival of [[:​world:​commodity:​simple marine]] organisms, such as starfish, sea urchins and worms marks the last stages of the Aerobic classification. With the rise of oxygen, so the [[./​LifeLevel/​Aerobic]] stage is reached. [[:​worldgen:​commodity:​plankton]] consumes smaller life forms, forcing the evolution of larger and more complex organisms. Larger varieties of algae becomes [[:​worldgen:​commodity:​seaweed]] and [[:​worldgen:​commodity:​jellyfish]] evolve. Eventually, the arrival of [[:​world:​commodity:​simple marine]] organisms, such as starfish, sea urchins and worms marks the last stages of the Aerobic classification.
worldgen/planets/lifelevel.1515926645.txt.gz · Last modified: 2018/01/14 10:44 by sam