| View of Variation |
Discontinuous variation; traits inherited as
discrete units (genes) |
Continuous variation; small, incremental
changes |
| Mechanism of Inheritance |
Clear, gene-based segregation and dominance
(Mendel’s laws) |
Lacked a precise mechanism; often relied on
blended inheritance or pangenesis |
| Mechanism of Evolutionary Change |
Emphasis on mutations (sometimes large/sudden,
as in de Vries’ saltationism) |
Gradual accumulation of small variations
through natural selection |
| Strengths |
Provided a robust model for inheritance;
explained how traits are transmitted |
Provided a powerful mechanism for adaptation
and the shaping of populations over time |
| Weaknesses |
Lacked an explanation for adaptation in natural
populations |
Lacked a workable theory of heredity |
| Philosophical Orientation |
Mechanistic, gene-centered, often
experimental |
Naturalistic, population-level, often
statistical and observational |
| Main Proponents |
William Bateson, Hugo de Vries, Carl Correns,
Erich von Tschermak |
W. F. R. Weldon, Karl Pearson, traditional
Darwinists |
| Criticism of the Other View |
Saw Darwinism as vague, outdated, and lacking
genetic basis |
Viewed Mendelism as too simplistic, based on
limited lab traits, and disconnected from natural
populations |
