- Allen’s Law – Allen
- Artificial Parthenogenesis – Loeb
- Axial Gradient theory – Child
- Bergman’s Rule – Bergman
- Biogenetic Law – Earnst Haeckel (1868)
- Biological Species Concept – Earnst Mayer
- Biogenesis Theory – Developed by F. Redi
- Chromosomal Theory of Inheritance – Sutton and Boveri
- Theory of natural selection – Charles Darwin
