The Human Brains Asymmetry Challenges NeoDarwinism


The article "Evolution of Human Brain Left–Right Asymmetry: Old Genes with New Functions" by He et al. (2023) challenges neo-Darwinism in several ways.

First, it shows that the structural asymmetry of the human brain is shaped by evolutionarily ancient genes that have assumed new functions over time. This is in contrast to the neo-Darwinist view that new traits evolve through the accumulation of gradual changes in existing genes.

Second, the article suggests that the evolution of human brain asymmetry may have been driven by changes in gene expression (epigenetics), rather than changes in gene sequence. This is also in contrast to the neo-Darwinist view that evolution is primarily driven by natural selection acting on changes in gene sequence.

Third, the article shows that the evolution of human brain asymmetry is complex and multifaceted, and that it cannot be fully explained by the neo-Darwinist model of evolution.

Neo-Darwinism

Neo-Darwinism was the prevailing theory of evolution but is rapidly losing ground. It is based on the following four principles:

  1. Variation: Individuals in a population vary in their traits.

  2. Inheritance: Traits are passed down from parents to offspring.

  3. Overproduction: Populations tend to produce more offspring than can survive.

  4. Natural selection: Individuals with traits that are better suited to their environment are more likely to survive and reproduce.

Neo-Darwinism has been criticized for its inability to explain many aspects of evolution, such as the evolution of complex traits like the human brain.

Evolution of human brain asymmetry

Human brain asymmetry refers to the fact that the left and right hemispheres of the brain are not identical. The left hemisphere is typically involved in language and processing sequential information, while the right hemisphere is typically involved in spatial reasoning and processing simultaneous information.

The evolution of human brain asymmetry is a complex process that is not fully understood. However, it is thought to have been driven by a variety of factors including NonDarwinian epigenetics.

Evidence from the article

The article by He et al. (2023) provides several lines of evidence that challenge neo-Darwinism.

First, the article shows that the genes that contribute to human brain asymmetry are evolutionarily old. This suggests that the structural asymmetry of the human brain evolved early in the history of vertebrates, and that it is not a recent adaptation of NeoDarwinism.

Second, the article shows that the genes that contribute to human brain asymmetry are expressed in a brain-specific manner. This suggests that these genes have evolved new functions specifically in the brain.

Third, the article shows that the expression of genes that contribute to human brain asymmetry is different in humans and other primates. This suggests that the evolution of human brain asymmetry may have been driven by changes in gene expression, rather than changes in gene sequence. NeoDarwinism held that all primates evolved similarly.

Implications for neo-Darwinism

The findings of the article by He et al. (2023) have several implications for neo-Darwinism.

First, the findings suggest that the evolution of complex traits like the human brain cannot be fully explained by the neo-Darwinist model of evolution. Instead, the evolution of these traits may be driven by a variety of factors, including changes in gene expression and the evolution of new genes from existing genes.

Second, the findings suggest that the neo-Darwinist view of evolution as a gradual process may be incorrect. Instead, evolution may be a more punctuated process, with rapid periods of change followed by longer periods of stability.

Third, the findings suggest that the neo-Darwinist view of natural selection as the primary driving force of evolution may be incomplete. Instead, other factors, such as epigenetics and developmental constraints, may also play important roles in evolution.

Conclusion

The article "Evolution of Human Brain Left–Right Asymmetry: Old Genes with New Functions" by He et al. (2023) is a significant contribution to our understanding of the evolution of the human brain. The findings of the article challenge neo-Darwinism in several ways, and they suggest that we need to develop new models of evolution to explain the evolution of complex traits like the human brain.

Additional thoughts

The article by He et al. (2023) is a timely and important contribution to the scientific literature. It comes at a time when neo-Darwinism is facing increasing challenges from a variety of sources.

The findings of the article are significant for several reasons. First, they provide strong evidence that the evolution of complex traits like the human brain cannot be fully explained by the neo-Darwinist model of evolution

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