Published on October 25, 2007
Land Ho—The Isthmus Forms!: Land Ho—The Isthmus Forms! Focus Questions ● How did the Isthmus of Panama form and what were the local, regional, and global effects? ● How did the formation of the isthmus affect animals? ● What effect did the formation of the isthmus have on ocean currents? The Geologic History of the Isthmus of Panama(Master A-page 26): The Geologic History of the Isthmus of Panama (Master A-page 26) Introduction to Earth Plate Movement The theory of plate tectonics explains that mountain building, earthquakes, and volcanoes result from the movement of plates. http://www.enchantedlearning.com/subjects/astronomy/planets/earth/Continents.shtml Formation of the Isthmus of Panama ● Volcanic Eruptions-Panama is part of the Pacific Ocean’s “Ring of Fire.” These volcanoes are formed when plates are thrust downward. ● Uplift- Tectonic plate movement caused the ocean floor to be pushed upward. Islands were formed as part of the ocean floor rose above sea level. ● Sedimentation-Over millions of years sediment (sand, fine soil, and mud) was deposited into the ocean. Sediment filled the gaps between existing land masses. The Isthmus of Panama(Master B-Map Activity-page 27): The Isthmus of Panama (Master B-Map Activity-page 27) What the isthmus looked like…………. 15million years ago (Color A brown. Color B,C and water blue.) 7 million years ago (Color A and B brown. Color C and water blue.) 3 million years ago (Color A, B, and C brown. Color water blue.) Draw arrows to show how you think the ocean’s currents flowed during you time period. Slide5: The Great American Interchange (Master C-page 28) Was the Isthmus of Panama formed all at once? Could the marine animals in the Atlantic and Pacific Oceans interact 15 million years ago? 7million years ago? 3 million years ago? Why or why not? Which terrestrial animals (if any) could have traveled between North America and South America during these different time periods? How did the isthmus affect ocean currents?