Introduction
In modern science, mass extinctions are a fact, but in the past, scientists did not consider this possibility, so such ideas became fundamental paradigm shifts. Kuhn understood the paradigm shift as significant changes in the foundations of the discipline and scientific assumptions caused by discoveries, which forced a reconsideration of the entire field (Kolbert, 2014). Although researchers such as Cuvier and Darwin proposed influential ideas about extinction, Walter Alvarez’s view was the most significant paradigm shift.
Cuvier’s Perspective
Cuvier, who worked at the turn of the 18th century and the beginning of the 19th century, studied the remains of mastodons. He first proposed the idea of extinction and popularized it among the public (Kolbert, 2014). Later, Cuvier also considered the causes of extinction, suggesting that species went extinct due to multiple catastrophes, which reflects the ideas of catastrophism.
However, Cuvier did not believe that various species could gradually change. The researcher did not consider the influence of humans, which contributed to the extinction of some species. However, this factor can be considered a catastrophe.
Darwin’s Views
Darwin worked in the first half of the 19th century and was of a different opinion. He believed that animal species were dying out gradually and new ones appeared, presenting uniformitarianism (Kolbert, 2014). Moreover, he witnessed how the species became extinct due to human fault, although he did not consider it a significant influencing factor.
Alvarez’s Theory
The theory developed by Walter Alvarez, based on evidence found, was a compromise between the two approaches followed by Cuvier and Darwin. In the Italian city of Gubbio, Alvarez found traces of an asteroid and discovered radioactive iridium after analyzing the clay layer, indicating a significant asteroid impact.
In 1980, Alvarez and his father suggested that such an asteroid could have killed the dinosaurs, leading to their extinction during the Cretaceous period (Kolbert, 2014). Although initially rejected by the scientific world due to the prevailing paradigm of gradual species change, this theory later inspired further research and gained broad acceptance.
Conclusion
Thus, Alvarez’s view represents a paradigm shift, more so than Cuvier and Darwin’s extinction theories, as it established a new hybrid approach. In particular, Alvarez confirmed the possibility of disasters as a cause of extinction and explained the gap in changes in the remains in the Cretaceous period, which was the disadvantage of uniformitarianism. Thanks to Alvarez, the modern understanding of mass extinction now includes the possibility of both gradual changes and catastrophes.
Reference
Kolbert, E. (2014). The sixth extinction: An unnatural history. New York: Henry Holt and Company.