The Earth’s magnetic field is produced by dynamo action in the liquid iron core, which has profound influence on our habitable planet. One of the most striking manifestations of the geodynamo are complete reversals of the dipole. Numerical simulations indicate that the lower mantle has a manifold impact on the dynamo whereby the absolute value and pattern of the heat flux through the core-mantle boundary affects the field strength, field geometry and reversal rate. However, neither the structure and the long-term evolution of the lower mantle and the core, nor the coupling between the two, are well understood. Moreover, field strength and reversal rate likely influence the survival and evolution of magnetoreceptive organisms, especially magnetotatic bacteria. We invite contributions that aim at understanding the long-term evolution of the geomagnetic field and Earth's core dynamics, deep mantle dynamics and its influence on the geodynamo. This interdisciplinary session aims to bring together paleomagnetists, seismologists, dynamo modellers, mantle dynamicists, mineral physicists, and biologists.