The placenta is the unique organ of therian mammals, key to their evolution and viability. The chorion is the outermost of the extra-embryonic membranes, and in birds and reptiles it is a simple membrane in contact with the shell allowing gas exchange. But in...
Over the past 150,000 years humans have manifestly been migratory, travelling into vastly different climatic regions of the globe. Darwinian evolution can lead to genetic differences in populations living in different climates, but any mechanism that can protect...
