No, the EES is not just a add on to Neo-Darwinism aka the Modern Synthesis

"The summary of the state of affairs on the 150th anniversary of the Origin is somewhat shocking: in the post-genomic era, all major tenets of the Modern Synthesis fthe theory of evolution) are, if not outright overturned replaced by a new and incomparably more complex vision of the key aspects of evolution (EES). So, not to mince words, the Modern Synthesis is gone" -Eugene Koonin, an evolutionary biologist (Cited by over 270,000 evolutionary scientists.)

The Extended Evolutionary Synthesis (EES) represents a significant departure from the traditional neo-Darwinian framework, also known as the Modern Synthesis. While both theories aim to explain evolutionary change, they differ fundamentally in their underlying mechanisms and the roles they assign to various biological processes. A crucial point of divergence lies in the interpretation and application of the term "evolutionary," particularly concerning the incorporation of epigenetic mechanisms.

Neo-Darwinism solely focuses on genetic variation arising from random mutations and the subsequent filtering of these variations through natural selection. This gene-centric view emphasizes that evolutionary change is driven solely by alterations in DNA sequences, with phenotypic changes stemming directly from these genetic modifications. In contrast, the EES replaces this perspective by acknowledging the significant role of epigenetic modifications in driving evolutionary change.

Epigenetics refers to heritable changes in gene expression that occur without alterations to the underlying DNA sequence. 

These modifications, such as DNA methylation, histone modifications, and non-coding RNA regulation, can influence gene activity and, consequently, phenotypic traits. The EES argues that these epigenetic variations can be transmitted across generations, providing a source of heritable phenotypic diversity independent of genetic mutations.

The notion that the "evolutionary" changes described by the EES are fundamentally different from those described by neo-Darwinism stems from the observation that epigenetic changes can produce phenotypic variations that mimic genetic mutations without altering the DNA sequence. This is a critical departure from the neo-Darwinian assumption that all heritable phenotypic changes are solely rooted in genetic mutations.

One of the key distinctions is the notion of heritability. Neo-Darwinism heavily relies on the assumption that heritable changes are caused by changes in the DNA sequence. The EES recognises that heritable changes come from epigenetic modifications. These modifications can be passed down through generations, and although they may be more labile than genetic mutations, their influence on phenotypic expression can be significant.

Furthermore, the EES emphasizes the role of developmental plasticity and niche construction in shaping evolutionary trajectories. 

Developmental plasticity refers to the ability of an organism to alter its phenotype in response to environmental cues. 

Niche construction refers to the active role organisms play in modifying their environment eg Beavers which can subsequently influence selective pressures. 

These processes mediated by epigenetic mechanisms, challenge the neo-Darwinian view of a passive organism subjected to external selective forces.

It is technically inaccurate to equate the EES with neo-Darwinism because the EES integrates epigenetic mechanisms, developmental plasticity, and niche construction, which are not included in the neo-Darwinian framework. The EES does not simply add to neo-Darwinism, it fundamentally shifts the perspective away from an exclusively gene-centric model.

The idea that epigenetic transmitted states can cause similar phenotypes without genetic change is a core concept of the EES. Epigenetics can be triggered by environmental factors, stress, or other stimuli, leading to alterations in gene expression that are then passed down to subsequent generations. This can result in rapid phenotypic adaptation to changing environments, independent of the slower process of genetic mutation and selection.

In essence, the EES's understanding of "evolutionary" encompasses a broader range of mechanisms than neo-Darwinism. By recognizing the role of epigenetic inheritance, developmental plasticity, and niche construction, the EES provides a more comprehensive view of how organisms change, moving beyond the limitations of a purely gene-centric perspective.