Theoretical biology is a branch of biology that uses mathematical models and abstract concepts to understand biological systems and processes. It aims to explain complex phenomena in living organisms, such as evolution, development, and ecology, by creating simplified representations that can be analyzed and tested. Researchers in theoretical biology often collaborate with experimental biologists to validate their models and predictions. This interdisciplinary approach can lead to new insights in areas like population dynamics, genetics, and ecosystem modeling, ultimately enhancing our understanding of life and its underlying principles.