Monday, October 19, 2015

Multistage evolutionary process is supported by recent data

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Global environment

Evolution produced highly ordered biological systems, the complexity of the brain, particularly the incredible self-awareness of the human mind that is capable to comprehend and understand the world and itself. The widely accepted evolutionary drive toward increasing complexity is hard to reconcile with our everyday experience and the scientific understanding that disorder is increasing in nature. The book, The Science of Consciousness, introduces a cosmological view of evolution. It suggests that evolution has started right after the Big Bang as a physical process by the formation of the elements of the atomic table, followed by the synthesis of organic molecules, the chemical building blocks of life. Biological evolution transpires as a step-wise process, which can be divided into distinct and separate periods and eras, each characterized by special flora and fauna. Massive environmental changes lead to mass extinctions, which create an evolutionary opening that accelerate the emergence of genetic innovations. In the fast-changing environment genes and proteins acquire new functions and find new uses. At the beginning of the evolutionary period new organisms and new species appear from almost nowhere in seemingly arbitrary evolutionary jumps. This is well supported by paleontology; bizarre morphologies and unexpected features appearing in early evolutionary periods were often noted. But the brisk changes of early evolution always give way to stable ecosystems, in which an interconnected structural complexity exists between the species, which form predator-prey cycles, for example. However, every evolutionary period eventually becomes unstable. In the third stage of evolution the environment cannot support the ecosystem, which inevitable moves toward an irreversible, final stage, and collapse.

The idea of such multistage evolutionary process is well supported. Important pieces of evolutionary innovations appear well ahead of their evolutionary importance. For example, a substantial part of the molecular architecture necessary for the evolution of the nervous or muscle system evolved in advance. Moreover, mutation frequency has been shown to be related to population number! When the mutation frequency as a function of population was examined, in contrast to the common expectation of increasingly deterministic evolution, during periods with low genetic concentration, entropy initially decreases (increasing order of genetic innovations) and subsequently changes in parallel with the increase in population (an arbitrary spreading of genetic material). But the decreasing entropy during the initial stage of evolution is not limited to the laboratory! It is also true for the natural environment and ecosystems. For species ranging from plants to vertebrates, the emergence of new species appears to occur fairly shortly after an environmental or evolutionary upheaval, as reported by Hedges and colleagues.

Other studies that have examined the social aspects of evolutionary change also support the above idea. During the first vibrant, energetic stage of evolution, species from bacteria and fish to humans appear to lean toward generosity, leading to cooperation and altruism. The generosity appears most prevalent when mutations occur at an appreciable rate, which is only true for the first stage of evolution! This idea was highlighted by evolutionary studies that used the so called prisoner’s dilemma, by Stewart and colleagues. The recycling of the nutrients is gradually becomes insufficient, frustrating the population. After a tipping point is reached, generosity disappears. In the third stage of evolution, cheating becomes the only feasible choice. This disorganized, chaotic stage in turn extinguishes. The above findings defy any other explanation, but can arise as the consequence of the three staged evolutionary process, introduced earlier. In a latest computer modeling of evolution overwhelmingly show that niches vacated by mass extinctions are quickly filled by newly emerging species. Their conclusion is that repeated extinctions actually enhance evolutionary fitness of surviving species, therefore accelerate evolutionary change.

The evolutionary process is described here for animal systems, but the same should hold for all eukaryotes. Today, many species of wild animals are perfectly adapted to their living environments. As a result, they have small genetic diversity, which would make survival difficult or impossible during large environmental changes. Thus, their survival is easily challenged by global warming and the degradation of the environment. This understanding underlines our responsibility toward the environment and its inhabitants.

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