"The Real Eve" combines data with new evidence from the field of genetic archaeology, which traces slight mutations in a section of human DNA that is passed only from mother to daughter. Mitochondrial DNA evolves at a constant rate of about one harmless mutation every 20,000 years, leaving markers of each mutation in nearly every human cell. Just as counting the rings in a tree helps to determine its age, researchers believe they can count markers in the cells of living humans to trace our lineage back to our common ancestor, "mitochondrial Eve." Purpose Communicate interpretations of learning material clearly, concisely, and effectively. Demonstrate critical analysis using knowledge of content and be able to contrast objective thought.