Khan Academy Static

As you learned in Unit 5, the biosphere is not static. The biosphere changes as a result of astronomical, geological, and biological influences. The dinosaurs, for example, became extinct as a result of an astronomical event—the effects of an asteroid impact on Earth. Every species impacts the biosphere, though the extent of that impact can vary dramatically. The impact of humans has changed over time. The impact of foragers was not dramatic, but these early humans did have the ability to destroy flora and fauna and cause fires in different parts of the Earth. Agriculture, and later the modern revolution, significantly increased the impact of humans on the biosphere. The acceleration of the last 100 years has seen an acceleration of these human impacts on the biosphere. What are the most significant of these impacts and what should humans be doing about them?

18297_Crash_Course_World_History_Globalization_II_Good_or_Bad_.html

18298_The_Atmosphere_and_Climate.html