Figure 3. Resource limitation and escape during progression.
The second law of ecology states that an exponentially growing population will eventually reach some limit to its growth. In neoplastic progression, there appear to be a series of limitations to the growth of neoplastic cell populations. During progression, the neoplastic cell population evolves mechanisms for escaping each limitation, temporarily releasing the neoplastic cell population with a burst of proliferation such that mutant cells with fast life history strategies have a competitive advantage (red background). However, when those populations reach a new resource limitation, selection shifts from fast to slow life history strategies (blue background), such that cells that can best compete, sequester resources, and avoid death, have an advantage.