Following the Planetary Biology engine. Image created by Tom Morris / PlanetaryBiology.com
You can download a readable *.pdf version of this model here.
I want to escort you on a short tour of the core of the Planetary Biology model. Lately, I have started to refer to this assemblage of recirculating components as the “Planetary Biology Engine.”
Please refer to the above image. This is a closeup of the circular region at the right side of the whole diagram. Notice that there are two colored sets of numbers and two colored sets of lines overlain onto the diagram.
I’m going to start with the reddish numbers and lines. At reddish position 1. We start with the “Planetary Surface Environment” zone of the diagram. This zone represents all the physical and biological factors that contribute to the qualitative state of the planet’s surface environment. We see that this zone influences “Diverse and Dynamic Environmental Circumstances” that living things are obliged to experience, tolerate, and exploit. This is the environmental setting. Depending on the environmental conditions, it can influence operations in living things.
This leads us to reddish position 2. Environmental circumstances can increase “Environmental Stress” experienced by living things. For example, it’s too hot, or too cold, or too dry, or too wet. The environment could be under water, or on a high mountaintop. Environmental stresses can impact and/or trigger operations in living things.
At reddish position 3. We see that environmental stress leads to an increase in dispersal (reddish position 4.) One of the very interesting qualities about life on Earth is that there are so many ways to disperse. Wind can carry fungal spores, or pollen particles, or seeds, or tiny spiders. Animals can walk, run, swim, or fly to new and different territories. Dispersal is a key feature that contributes to life becoming more abundant (reddish position 5.) It he environmental stress is high, then that could benefit dispersal AWAY from the environment. If the environmental stress is low, then that could benefit dispersal TOWARD that environment.
Moving from reddish position 5. To reddish position 6. as life becomes more abundant, the consequences of its presence have a greater impact. This impact results in a transformation of the planetary surface environment (reddish position 7. To reddish position 8.).
Which leads us back to reddish position 1. And the cycle repeats. Life interacts with the planetary surface environment, thereby transforming it – which presents life with a new mix of environmental circumstances, and here we go again.
Now, let’s study the green lines and numbers. These represent a deeper dive into the biological components of this system. We pick up the trail at reddish position 5 (Life’s Abundance). There, the green line branches off from the reddish line and travels to “Biosynthesis.” Increases in Life’s Abundance increase biosynthesis operations across the planet. Biosynthesis includes biochemical operations like photosynthesis and cellular respiration, or nitrogen fixation and denitrification (among many others). These operations churn the planet by exchanging materials with it. The more life, the more churning.
Moving from green 6. To green 7 (innovation). This is a crucial zone because evolution is a consequence of variety interacting with the environment. On our world, that variety is the result of genetic innovations – such as mutations, or other genetic reconfigurations during sex cell formation.
Increases in innovation contribute to increases in Evolution (green position 8.) Sometimes evolution results in new traits that turn out to be very useful – to the extent that this trait significantly increases the reproductive output of the individuals who possess it. In such a case, this new trait would be an Adaptation (green position 9.)
As the future is unpredictable, sometimes an existing and unremarkable trait suddenly becomes useful should the environment change, or should the living individual disperse to new and different environments. In such a situation, the pre-existing trait falls into the category of being a Preadaptation (green position 10.)
From green position 10. We follow the path that leads to increased Dispersal, increased Life’s Abundance, to increased Biosynthesis, and the cycle repeats.
These two pathways represent a basic introduction to the Planetary Biology engine. Look closer and you should see additional detours that form additional feedback pathways.