What theory suggests that life evolved from a common ancestor through gradual modifications?

The theory that suggests life evolved from a common ancestor through gradual modifications is Darwinism, which is based on the ideas proposed by Charles Darwin in the 19th century. Darwinism emphasizes natural selection as the primary mechanism driving evolution. According to this theory, species adapt to their environments over time through variations that enhance survival and reproduction. These adaptations accumulate over generations, leading to the diversification of life and the emergence of new species from common ancestors. This concept fundamentally altered our understanding of biological change and provided a scientific framework for explaining the complexity and diversity of life on Earth.

In contrast, other theories like Creationist Theory, Spontaneous Generation, and Intelligent Design do not support the gradual evolutionary process proposed by Darwinism. Creationist Theory focuses on the belief in a divine creation of life, Spontaneous Generation refers to the outdated idea that life can arise spontaneously from non-living matter, and Intelligent Design argues for an intelligent cause behind life’s complexity, rather than a gradual evolutionary process.