The northern dispersal of early modern humans in eastern Eurasia

Wegener and the Continental Drift HypothesisIn the early 1900s, Alfred Wegener, a German scientist, proposed the Continental Drift Hypothesis, the idea that Earth’s continents were once joined together in a supercontinent called Pangaea and slowly drifted apart over millions of years. Although his ideas were not widely accepted then, later discoveries provided evidence supporting continental movement, leading to the modern theory of plate tectonics. Understanding Wegener’s hypothesis helps...

Speciation is the evolutionary process resulting in the formation of new, distinct species—groups of reproductively isolated populations.

Magnetic Polarity Evidence for Continental DriftOne of the most substantial pieces of evidence supporting continental drift and plate tectonics comes from Earth’s magnetic field. Over millions of years, Earth’s magnetic polarity has reversed many times, meaning the north and south magnetic poles have switched places. When molten rock cools and solidifies at mid-ocean ridges, the magnetic minerals inside align with Earth's magnetic field at that time. This creates striped patterns on the...

Gene flow is the transfer of genes among populations, resulting from either the dispersal of gametes or from the migration of individuals.

Overview

Hybrid zones are narrow regions where two closely related species interact, mate, and produce hybrids. Relative to either parent species, hybrids may possess distinct phenotypic or genetic differences that impact their survival and reproductive success. The genetic variances introduced by hybridization influence species diversity and speciation processes within the hybrid zone.