Meaning: The quote you provided touches upon the concept of transformational evolution, which was first articulated by Jean-Baptiste Lamarck, a French naturalist, in the early 19th century. This concept suggests that evolution occurs through the gradual transformation of organisms from one state or condition of existence to another. The quote is attributed to Ernst Mayr, a prominent evolutionary biologist and ornithologist, who further developed and popularized the concept of transformational evolution in the 20th century.

Lamarck's theory of transformational evolution, also known as Lamarckism, proposed that acquired characteristics could be inherited by offspring. This means that an organism can change during its lifetime in response to its environment and these changes can be passed on to its offspring. For example, Lamarck suggested that giraffes developed long necks because they continually stretched their necks to reach high leaves, and this acquired trait was passed down to their offspring.

However, Lamarck's theory of transformational evolution was later overshadowed by Charles Darwin's theory of natural selection, which became the predominant explanation for the mechanism of evolution. Darwin's theory, as outlined in his seminal work "On the Origin of Species," proposed that natural selection, acting on heritable variations within a population, is the primary driver of evolutionary change.

Ernst Mayr, in the quote you provided, appears to be acknowledging Lamarck's contribution to the concept of transformational evolution. Mayr was instrumental in shaping the modern synthesis of evolutionary biology, which integrated Darwinian natural selection with Mendelian genetics and population genetics. In doing so, he expanded the understanding of evolution to encompass not only the gradual accumulation of small changes over time, as proposed by Darwin, but also the potential for transformative events that can lead to new species and ecological adaptations.

The concept of transformational evolution, as articulated by Lamarck and further developed by Mayr, continues to be a topic of interest and debate within the field of evolutionary biology. While the mechanisms proposed by Lamarck have largely been discredited, the idea of organisms undergoing transformative changes over time remains relevant in the context of evolutionary developmental biology (evo-devo) and epigenetics.

In evo-devo, researchers study how changes in the developmental processes of organisms can lead to evolutionary change. This field explores how alterations in gene regulation and developmental pathways can result in the acquisition of new traits and the diversification of species over time. Epigenetics, on the other hand, investigates how environmental factors and experiences can influence gene expression and phenotype without altering the underlying DNA sequence, potentially leading to transgenerational effects.

In conclusion, the concept of transformational evolution, as initially proposed by Lamarck and acknowledged by Ernst Mayr, has played a significant role in the historical development of evolutionary thought. While the specific mechanisms proposed by Lamarck have been largely supplanted by the modern understanding of genetics and natural selection, the broader idea of organisms undergoing transformative changes within their lineages continues to inspire research and inquiry in the field of evolutionary biology.