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h. The Human Economy

The Human Economy

When we speak of competition and ecosystems we speak of “competition within ecosystems” rather than “competition between ecosystems”. In this post, I will argue that competition between the human economy and natural ecosystems can be regarded as an example of ecosystem level natural selection. I would like to emphasise, however, that this is purely speculation on my part, based on human history and anthropology.

  • Historically, human society has progressed through the following stages:
  1. Hunter/gatherers: small tribes which gather food and other materials from the natural environment to satisfy their needs. They may migrate permanently as resources become depleted or relocate temporarily to exploit locations of known seasonal abundance. Apart from their hunting and gathering activities, they do not greatly alter their environment. Such people can, therefore, be regarded as a part of the natural ecosystem.
  2. Pastoral communities: small tribes or groups that acquire their food and materials from a particular species of animal, usually flocks or herds of herbivores. Reindeer, for example, provide not only a source of meat but also pelts for clothing and shelter. Pastoral communities usually migrate with the herd and help to defend it from other predators. This stage sees the emergence of the human economy and, to a limited extent, modification the natural ecosystem.
  3. Agricultural communities: larger settled groups who cultivate selected species of plants and domesticate certain animals. In doing so, they significantly modify the natural ecosystem. Examples of modification include land clearance, and the selective breeding of favoured animals and crops. An agricultural community must also defend and protect these animals and crops from natural predators. Such communities have significant effects on the natural ecosystem, e.g., the depletion of soil fertility, overgrazing, etc.
  4. Industrial communities: these have undergone substantial reorganisation to enable them to meet their needs by manufacturing goods from non-living materials. In doing so they have, in part at least, bypassed the natural ecosystems upon which the satisfaction of their needs previously relied. Examples include stone and concrete building materials, the use of technology, and energy from fossil fuels.

This process has taken place over many millennia leaving very few truly natural, as opposed to human dominated, ecosystems. As this development progressed the following features have emerged:

  1. What might be described as “elimination of the natural middleman”. Resources previously supplied by a natural ecosystem are being replaced by those acquired directly from the habitat. For example, the pelts, leaves and timber previously used for shelter are now replaced by industrially manufactured bricks and plastics.
  2. The hunting down and elimination of natural predators such as wolves, etc.
  3. Pollution and over-exploitation leading to a high rate of species extinction.
  4. Larger human group sizes together with increasing specialisation and complexity of organisation.
  5. Increasing population.
  6. Centralisation of the population in ever larger communities. The industrial revolution, for example, caused a significant movement of people from the countryside to the cities. This process is continuing as industrialisation spreads across the world. The UN World Cities Report of 2016 stated that the number of mega-cities, i.e., cities with more than 10 million inhabitants, increased from 14 in 1995 to 29 in 2016.

There are similarities between the present human economic system and a natural ecosystem. This is reflected in the language we use, such as “niches” and “competition”, to describe both. Like natural ecosystems, our economy also has “specialists” acting as producers, consumers and decomposers and there is a complex interdependence between them.

There also exist significant differences. Energy flow in a natural ecosystem is uni-directional but in the human economy it is bi-directional. All groups are composed of human beings whose needs are fulfilled by the economy as a whole. Some organisations provide the energy and materials needed by others but there is also a reverse flow to satisfy the needs of the people who operate them. We also put effort into caring for our animals and crops. In that sense, the human economy is more co-operative and less exploitative than a natural ecosystem.

In natural ecosystems, population growth goes through a lag phase, a growth phase and a stable phase. This is dictated by the availability of resources. The same is true of the human economy. At each stage in our social development there was an initial spurt in population growth followed by a levelling off as constraints on resources came into play. However, a new growth phase has always been initiated by our ability to innovate and improve our access to resources.

Our economic system, although fraught with imperfections, is now essential for the survival of our large population and has priority in our psyche. Some elements of this economy function independently of natural ecosystems but inflict considerable pressure on them. Others comprise modified and subsumed natural ecosystems. The remaining elements are entirely reliant on natural ecosystems, for example, the air we breathe, gut bacteria to digest our food and the ability of natural ecosystems to regulate the climate.

Our present economy may be a transition between a natural ecosystem and something yet unclear. However, there is a need to place less burden on the natural ecosystems which gave birth to us and for greater co-operation within our economy. Recently, we have begun to speak of the “value” of ecological “goods and services” and it seems that the endpoint may be to subsume natural ecosystems into a highly co-operative economic system managed and controlled by humanity. The questions are, of course, whether the nature of evolution makes this inevitable or whether it is a peculiarity of the human species. Are we confident that we can make such a transition? If not, how can we ensure that sufficient natural ecosystems remain as insurance against failure?

In my next post, I ask the question “Is mankind still evolving?” and provide a summary of multi-level selection theory.

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g. Species and Ecosystem Level Natural Selection Uncategorized

Species and Ecosystem Level Natural Selection

Species Level Natural Selection

Natural selection at species level relies on there being a geographical separation between groups within a species so that they can follow their own independent evolutionary path. Eventually, the genomes of two groups will become so different that they have difficulty interbreeding. For example, a male donkey and a female horse will produce a sterile mule. Ultimately, they will become separate “child” species and incapable of interbreeding. This process is known as speciation.

Population pressure among successful “child” species can cause them to migrate and come into contact with “sibling” species. There can only be one species in each ecological niche. If there are more, then competition for the niche will result in the fittest species, normally the migratory one, prospering and the least fit one becoming extinct. It is theoretically possible for this process to take place but, because millions of years would be required and there is, therefore, relatively little evidence of it, not all evolutionary biologists believe that it does. It may, however, have occurred among hominins.

Hominins are human-like species that evolved after our predecessors and those of the chimpanzees speciated between 12 and 5 million years ago. Since then, there are believed to have been 15 to 20 species of hominins, all of which, apart from our own, have become extinct. The migration of homo sapiens from Africa, where we originated, into Asia may have resulted in the demise of Homo Erectus, and our migration into Europe in the demise of the Neanderthals. Neanderthals were a sub-species, and some are known to have been subsumed by modern humans through interbreeding. This is confirmed by the existence of part of the Neanderthal genome in non-African branches of our species. However, most were probably outcompeted by modern humans. It is unclear whether Homo Erectus was an entirely separate species and became extinct or whether it too was subsumed in a similar way.

Presently, it is difficult to identify any behavioural traits which may have evolved in modern humans as a result of species level selection as this would require a comparison with other, now extinct, hominin species.

Ecosystem Level Natural Selection

The final level in the organisation of life comprises the world’s ecosystems. These are the final, and largest, Russian dolls on which individual organisms depend for their survival and ability to procreate.

A natural ecosystem comprises all the non-living ingredients for life, e.g., a source of energy, water, minerals, atmospheric gases and so on. It also comprises numerous species, each of which has its own niche or role to play, and each of which interacts with other species to form a complex system. Each ecosystem is adapted to its own habitat, and these can be highly variable to include, for example, freshwater, marine, tropical, mountainous, and desert habitats.

The roles played by species are classified using the food chain. Generally, there are only up to 4 or 5 levels, which typically comprise:

  1. Producers: organisms that produce food for all other species in the ecosystem, e.g., green plants which convert inorganic substances into organic material through photosynthesis.
  2. Primary consumers or herbivores: animals that consume plants, e.g., sheep and goats.
  3. Secondary consumers or carnivores: animals that feed on others, e.g., the big cats and sharks.
  4. Tertiary Consumers. These are also carnivores but ones that consume other carnivores, e.g., polar bears and crocodiles.
  5. Decomposers: organisms which feed on dead organic material and help in the recycling of nutrients, e.g., fungi and earthworms.

The flow of energy in a natural ecosystem is largely unidirectional. Plants, which take their energy from sunlight, were the first to evolve and altered the environment, thereby permitting the evolution of herbivores, which take their energy from plants, followed by carnivores, which take their energy from herbivores.

Some species do not fit neatly into these classes. For example, humans are omnivorous, consuming both animals and plants. There are also parasites which feed on a living host. Nevertheless, the above classification is a helpful guide.

All levels of natural selection exist within an ecosystem: individual, kin, group, and species. However, for ecosystem level selection to be possible, there must be more than one ecosystem competing to control the same habitat. This is not apparent in the natural world. Rather, it appears to have been introduced by mankind, as will be discussed in the next post.