What profession was Erlich primarily known for?

Erlich is primarily known for his contributions to the field of medicine and research, particularly related to the dynamics of population growth and its impact on the environment, which he explored through medical and ecological research. His work focused on the negative consequences of overpopulation, leading to significant attention on public health issues, resource depletion, and ecological sustainability. His background as a doctor allows him to intertwine medical research with environmental and population health, making substantial contributions to both fields. This is why the identification of him as a doctor and medical researcher is accurate in reflecting his primary profession.