- Which Organisms Evolved Photosynthesis First? The EvidenceBiology
- What Was the First Life on Earth & How Did It Begin?Biology
- When Did the First Flowers on Earth Appear?Botany
- When Did the First Photosynthesis Emerge on Earth?Earth & Space
- Who Was the First Person to Be on Earth?Earth & Space
- The Quaternary Period: Ice Ages, Megafauna, and HumansEarth & Space
- What Survived the Permian Extinction and Why?Environment
- What Came First, Plants or Animals?Biology
- Pleistocene North America: Its Giants, Climate, and PeopleEarth & Space
- The Genetic History of Europe: 3 Ancestral TribesGenetics
- Are Trees Older Than Sharks? An Evolutionary HistoryBotany
- Neolithic Man and the Agricultural RevolutionHealthcare
- What Was the Common Ancestor of All Mammals?Zoology
- Who Was the First Person to Be Alive on Earth?Biology
- How Were We Created? The Science of Human OriginsBiology
- How Long Do We Have Before Humans Go Extinct?Environment
- When Did Prokaryotes Evolve? The First Life on EarthBiology
- What Factors Caused the Cambrian Explosion?Earth & Space
- Who Invented Grass? The Evolution and Human HistoryBotany
- Which Were the Earliest Oxygen-Producing Life-Forms?Biology
- What Did the First Animal Actually Look Like?Zoology
- How Plate Tectonics Drove the Evolution of WhalesEarth & Space
- Where Did Animals Come From? The Origins of Animal LifeZoology
- What Life Was Found During the Archean Time?Earth & Space
- Who Was the First Person to Ever Live?Biology
- What Did Humans Look Like 2000 Years Ago?Biology
- Why Did Animals Shrink Over Time?Zoology
- What Was the Most Important Gas Contributed by Stromatolites?Biology
- How Continental Drift and Climate Change Shaped LifeEnvironment
- How Will Sea Turtles Change Over Time?Aquatic