Move to the EES

The modern synthesis of evolutionary biology, which emerged in the mid-20th century, has long served as the framework for understanding how life evolves. It integrated Darwinian natural selection with Mendelian genetics, positing that evolution is a gradual process driven by changes in gene frequencies within populations.  Central to this view are the concepts of random mutation as the sole source of new genetic variation and the inheritance of traits being solely through DNA. However, in recent decades, a growing body of evidence has challenged the sufficiency of this framework, leading to the proposal of an "extended evolutionary synthesis" (EES). This new paradigm incorporates a broader range of causal factors, and at the heart of this debate lies the increasing recognition of the role of epigenetics. The inclusion of epigenetics in the evolutionary narrative is not merely an addition; it represents a fundamental shift that challenges the core tenets of the mod...

The Modern Synthesis, or Neo-Darwinism, forged in the mid-20th century, provided a framework for understanding evolution by integrating Darwin's theory of natural selection with Mendelian genetics and population genetics. Its core tenets emphasized the primacy of genes as the units of inheritance, random genetic mutation as the sole source of novel variation, and natural selection acting on populations as the primary engine of evolutionary change.  For decades, this gene-centric view dominated evolutionary biology. However, emerging fields, particularly Evolutionary Developmental Biology (Evo-Devo), have brought forth phenomena that challenge the sufficiency of the Neo-Darwinian framework, necessitating a broader perspective often termed the Extended Evolutionary Synthesis (EES). Evo-Devo's focus on the interplay between development and evolution, significantly bolstered by insights into epigenetic mechanisms, offers crucial contributions to ...

This blog covers the core concepts and arguments typically involved. Integrating Development and Inheritance: The Epigenetic System, Evo-Devo, and the Case for an Extended Evolutionary Synthesis The theory of evolution, as solidified in the 20th century's Modern Synthesis (MS), provided a framework centered on genes as the primary unit of inheritance and variation. Natural selection, genetic drift, mutation, and gene flow acting on randomly generated genetic variation were seen as the principal engines of evolutionary change. However, accumulating evidence from diverse fields, particularly developmental biology and epigenetics, has prompted a call by researchers for an 'Extended Evolutionary Synthesis' (EES). This proposed extension seeks to integrate phenomena inadequately addressed or conceptualized by the MS, arguing that factors like developmental processes and non-genetic inheritance play crucial causal roles in evolution. The interc...

For decades, the neo-Darwinian synthesis has provided the dominant framework for understanding evolution. It posits that evolution occurs through the gradual accumulation of random genetic mutations within a population, with natural selection acting upon the resulting phenotypic variations. Inheritance, in this view, is almost exclusively mediated by the DNA sequence passed from parents to offspring. This process operates on long timescales, with significant evolutionary change typically unfolding over many generations. However, the burgeoning field of epigenetics is introducing a profound challenge this picture, revealing inheritance mechanisms that operate on potentially much shorter timescales and challenging some core assumptions of the traditional model. The Long Timescale: Genetic InheritanceGenetic inheritance is the bedrock of classical evolutionary theory. It involves the transmission of genes – specific sequences of DNA – from one generatio...