From the Modern Synthesis to the Other (Extended, Super, Postmodern…) Syntheses - review

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Article: From the Modern Synthesis to the Other (Extended, Super, Postmodern…) Syntheses

Biology has always been in search of “syntheses.” Darwin's On the Origin of Species (1859) gave maybe the most famous of such syntheses, bringing together the previously disparate fields of anatomy, geology, paleontology, and systematics under the unifying theory of natural selection. This synthesis, known as the Modern Synthesis, dominated evolutionary biology for the latter half of the 20th century.

However, in recent years, there has been a growing recognition that the Modern Synthesis is not adequate to explain all of the phenomena of evolution. This has led to the development of a number of alternative or “extended” syntheses, such as the Extended Synthesis (ES) and the Super Synthesis (SS). These syntheses incorporate additional concepts from fields such as development, genetics, and epigenetics, in an attempt to provide a more comprehensive understanding of evolution.

The ES is particularly notable for its emphasis on the role of development in evolution. Development is the process by which an organism grows and changes from an embryo to an adult. The ES argues that development is not simply a passive process of following a pre-programmed set of instructions, but is instead an active process that is influenced by the environment. This means that environmental factors can play a role in shaping the evolution of organisms, not just natural selection.

The SS goes even further than the ES, arguing that there are multiple levels of selection operating in evolution, not just natural selection. These levels of selection include intragenomic selection (selection between alleles within a gene), developmental selection (selection between different developmental trajectories), and group selection (selection between different groups of organisms). The SS argues that these multiple levels of selection can interact with each other in complex ways, leading to a more nuanced understanding of evolution.

Some have also argued for the development of a “postmodern” synthesis of evolution. Postmodernism is a philosophical and intellectual movement that emphasizes the fluidity and uncertainty of knowledge. It rejects the idea of a single, objective truth, and instead argues for multiple perspectives on the world. A postmodern synthesis of evolution would incorporate this emphasis on multiple perspectives, arguing that there is no single “correct” way to understand evolution as with neo-Darwinism.

The development of these extended, super, and postmodern syntheses is a sign of the ongoing vibrancy and creativity of evolutionary biology. These syntheses  provide a more comprehensive and nuanced understanding of evolution.

Conclusion

The Modern Synthesis was a landmark achievement in evolutionary biology, but it is now clear that it is not adequate to explain all of the phenomena of evolution. The development of extended, super, and postmodern syntheses is an attempt to address the shortcomings of the Modern Synthesis and provide a more comprehensive understanding of evolution. 

The Modern Synthesis, which emerged in the 1920s and 1930s, is the prevailing paradigm in evolutionary biology. However, in recent years, there has been a growing body of criticism of the Modern Synthesis, and some have argued that it is no longer adequate to explain the full range of evolutionary phenomena. These critics have proposed a variety of alternative theories, which they have called "extended syntheses," "super syntheses," and "postmodern syntheses."

One of the main challenges to neo darwinism is the question of how to explain the rapid evolution of complex traits. Neo Darwinism posits that complex traits are the result of gradual accumulation of small, beneficial mutations. However, some biologists have argued that this mechanism is too slow to account for the rapid evolution of complex traits that we see in the natural world. They have proposed alternative mechanisms, such as genetic assimilation and punctuated equilibrium, which can explain the evolution of complex traits more quickly.

Another challenge to neo darwinism is the question of how to explain the role of non-genetic factors in evolution. Neo Darwinism is primarily a theory of genetic evolution, but it is now clear that non-genetic factors, such as epigenetics and symbiosis, can also play an important role in evolution. These factors are not currently well-integrated into the Modern Synthesis, and some biologists have argued that a new synthesis is needed that can account for their role.

The rise of extended syntheses, super syntheses, and postmodern syntheses is a sign that the Modern Synthesis is no longer adequate to explain all of the phenomena of evolution. These new theories are still under development, but they offer promising new ways of understanding the evolution of life.

Here are some specific examples of how the Modern Synthesis is challenged by these new theories:

  • Extended syntheses argue that the Modern Synthesis is too narrowly focused on genetics and that other factors, such as development and behavior, also play important roles in evolution.

  • Super syntheses argue that the Modern Synthesis is too focused on populations and that individuals and lineages also play important roles in evolution.

  • Postmodern syntheses argue that the Modern Synthesis is too focused on adaptation and that other processes, such as drift and self-organization, also play important roles in evolution.

Only time will tell what the future holds for evolutionary biology, but it is clear that the Modern Synthesis is no longer the only game in town.

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