NEOLAMARCKISM: BACKGROUND AND CHARACTERISTICS - BIOLOGY - 2025

The neolamarckismo is a theory that emerges as a renewed explanation of the theory transformista Jean Baptiste Lamarck, from the end of the nineteenth century and beginning of the twentieth. The path of biology and its search for an explanation of evolution has been enriched with the appearance of various doctrines that attempt to explain how change occurs in species over the years.

Despite the time that has elapsed, neo-Lamarckism remains a current trend among biologists and acquires renewed relevance in the light of modern genetic studies. But what are the origins of this important doctrine on evolution, its postulates and contributions are questions that will be answered in this article.

Lamarck

Antecedents of Neo-Lamarckism

The transformist theory proposes that species derive from each other and that the changes that occur between one generation and another are due to the action of time. This central idea goes in the opposite direction of the so-called fixist theories, which propose that species are immutable and their appearance is spontaneous.

Although the discussion about the origin of species dates back to the classical Greek philosophers, it was not until the publication of Lamarck's work, Philosophie Zoologique (1809), that the transformist currents began to use the term "evolution" to account for of the process of change that applied to all forms of life.

The central axes of the aforementioned work and which will be the starting point of Lamarckism and Neo-Lamarckism are the following:

-There is no immutability of species. There is what is called evolution, that is, the change between generations due to the physiological capacity of the organism to adapt to the environment.

-Spontaneous generation is denied; on the contrary, organisms are adapting to the environment creating more complex species.

- "The function of creating the organ". If an organism needs to perform an action, its physiology prepares the internal conditions for the creation of a new organ that is passed on to the next generation, which is known as the inheritance of acquired characteristics.

From Lamarckism to Neo-Lamarckism

Lamarck's ideas were taken up by other naturalists and scientists who saw in his work the ideal explanations for the changes that occurred in different forms of life, including man.

Thus begins Lamarckism as a current that considers that the environment is the spark that initiates evolutionary change, and that organisms have an internal tendency to perfect their physiology to survive in their ecosystem.

This tendency can reach the point of modifying biology by creating new structures, modifying organs to respond to a need conditioned by the environment, and most importantly they can be inherited by making the species stronger.

Likewise, one of the most important premises for evolution emerged: organisms derive from simpler forms, therefore, the transformation moves on an ascending scale of complexity.

Lamarckism used Mendel's theory to explain how changes were transmitted from progenitors to descendants, and managed to position itself as a trend with more truthful postulates than Darwin's theory of natural selection, today widely rejected.

However, it also had its criticisms especially from the field of archeology. If "the function creates the organ" the species could always adapt to any environment and never disappear, but the fossils have shown otherwise.

Neo-Lamarckism has been in charge of restructuring the discussion, making the central axis of evolutionary theory lie in genetic inheritance.

The inheritance of characters: postulates of neo-Lamarckism

The inheritance of acquired characters is the basis of evolution. Therefore, it could be said that evolutionary changes are entirely physiological. Living beings adapt to the environment producing modifications that are expressed in the generations of descendants. This is the reason why species that have similar levels of complexity in their structure can develop different changes.

Evolution is perceived as a process where the environment can gradually alter the metabolism of beings, producing increases in the degree of organization, and leading to morphological variations that improve physiology. From this aspect was the Russian horticulturist Ivan Vladimirovich Muchirin, who led the variant of neo-Lamarckism known as Michurinism.

Another variant known as orthogenetics asserts that there is an internal force (consciousness) that drives evolution. This acts as an innate condition in the species that is activated and expanded by the influence of the environment.

How is Neo-Lamarckism explained in nature?

Through the adaptations of the species. For example, the case of the giraffe whose short-necked ancestors had to stretch to reach the highest branches of the trees in dry seasons when food was scarce at ground level. Over the years, the species adapted by modifying its structure to longer necks.

The fossils of the first giraffes showed an evolutionary change to long-necked species to adapt to climatic conditions and get food

The Environment and DNA Transmission: Modern Evidence for Neo-Lamarckism

Genetics and the laws of heredity have served to renew postulates of this current of thought, as well as to discard others. In principle, the premise of the inheritance of characters is accepted, but not at the phenotype level.

Genetics has shown that the only heritable changes are those that occur at the DNA level, so the question remains: can the environment modify the genome?

Science has not been conclusive covering all species, but several studies in bacteria and plants have proven that factors in the environment can modify the adaptation of organisms and that the changes have been inherited. In specific situations living beings could alter their DNA and their offspring take advantage of these evolutionary changes.

In conclusion, it is possible to affirm that genetics is not independent of the environment where it is expressed; Instead, the body registers environmental stimuli and is capable of expressing them as changes in DNA.

Thus, neo-Lamarckism has made it clear that the ecosystem is a tangible influence of how exact the copy of the genome will be that is inherited from the ancestors, even being the response to mutations.

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