The word “evolution” now reaches across a vast and changing landscape of “meaning”.
This document attempts to explore this changing geography in a collaborative & expansive way to provide signposts to places of interest.
Please add your questions, wisdom, images, examples…as the document progresses
Evolution as Adaptation
The original term, as used by Darwin, was very precise.
Evolution (also known as biological, genetic or organic evolution) is the change in the inherited traits of a population of organisms through successive generations.
This change results from interactions between processes which introduce variation into a population, and other processes which remove it.
Two main processes cause variants to become more common or rare in a population.
- One is natural selection, through which traits that aid survival and reproduction become more common, while traits that hinder survival and reproduction become more rare. These adjustments are called adaptations.
- Another cause of evolution is genetic drift, which leads to random changes in how common traits are in a population.
A change in the environment can be viewed as an opportunity for adaptive change to occur. Depending on your temporal perspective, evolution is a very rapid or a very gradual process. From a geological time frame it is almost instantaneous. A couple of examples may help.
Millions of years ago, oxygen producing plants developed in the oceans. The oxygen allowed the development of CO2 producing animals in the ocean. Oxygen then diffused into the atmosphere and a blanket of CO2 provided warmth and a shield from hazardous radiation. As soon as it was safe to move out of the ocean, creatures flooded over the surface of the earth. Note that it was a consequence of life in the ocean that life on land had become possible. (This relationship between the earth, atmosphere and life is described by the Gaia hypothesis)
Thousands of years ago, gatherers in the Middle East selectively grew the occasional ears of wheat they found with with multiple seeds. Consequently farming became productive. Of course humans had to become gluten tolerant. Wikepedia again:
Wheat was a key factor enabling the emergence of city-based societies at the start of civilization because it was one of the first crops that could be easily cultivated on a large scale, and had the additional advantage of yielding a harvest that provides long-term storage of food.
Once again, it was the elements within a system, that expanded conditions to create a “space” for new adaptations, in this case, societies.
Evolution as contrasted against Revolution
A dualist perspective can cast evolution as an alternative to revolution. Where evolution is characterised as a gradual transformation from one state of organisation to another, while revolution is a sudden state change with no intermediary, transitional, states.
At its heart, even adaptive evolution appears to be “digital”. There is an identifiable change in the genetic sequence (genotype) with an observable alteration in the organisms appearance or behaviour (phenotype). Revolution may just be a larger “phenotypic” expression than usually encountered for a single “genotypic” alteration. Alternatively it may be that a number of “genotypic” alterations have been occuring until, finaly, one alteration enables the full expression of the accumulated changes.
What is the “purpose” of evolution
From one perspective this question is its own answer. To be able to ask this question demonstrates an ability of reflection that is a consequence of evolution. To be unable to see the answer is testament to the fact that evolution continues.
“Fit for purpose” may be an interesting starting point to unravel the question. Particularly when becoming “fit for one purpose” creates a landscape on another dimensional plane with many more “purposes”. What characterises an individual human is the lack of physical adaptation for any particular physical environment. We are characterised by behavioural adaptability that has been encouraged by sequential environmental and social challenges. Arguably the most recent being population growth. Perhaps the factor for “civilzation extinction” in the Drake equation.