Modern human migrations, the first 200,000 years

Floyd A. Reed, Ph.D.
Max Planck Institute for Evolutionary Biology

We can infer the presence of ancestral human populations, and how these populations are related to each other, from genetic studies. With new data and methods, more details are rapidly being added to the evolving picture of modern human (pre/)history. This history is incredibly complex, occasionally strong isolation of local populations can lead to new distinctive genetic compositions, which can then undergo admixture with other regional populations. On a larger scale, the serial expansion of modern humans from Africa around the globe has led to long range clines in genetic variation, which give us clues to more ancient human history. Migration, both into new geographic regions and back into old ones appears to be a natural component of modern human behavior. From the point of view of biology, ongoing migration and admixture can have evolutionary advantages, both in the flow of cultural ideas and in the spread of adaptive genetic variation.


Migration and the Origin of Species

Claus Rüffler, Ph.D
Institute of Mathematics

The earth is inhabited by a breathtaking amount of species. The question of how new species arise from existing ones puzzles evolutionary biologists ever since Darwin. Particularly hotly debated is the question of how much migration between two sub-populations is admissible for each of them to evolve into a separate species. If no migration takes place, for example because of a geographical barrier, speciation is considered being easy (allopatric speciation). If migration is strong and the populations can be considered as freely mixing, speciation has long been dismissed as impossible (sympatric speciation). These two cases are the extremes of a continuum of possibilities and speciation in the face of intermediate rates of migration seems to depend on a subtle balance of  forces (parapatric speciation). In my lecture I will introduce the different modes of speciation in more detail and sketch new empirical and theoretical findings supporting the possibility of speciation in the presence of migration.