Plate Tectonics: Earth's Moving Evidence

Grade 8 Earth Science Exploring how continents move and shape our planet

What evidence shows that continents have moved?

Look at the shapes of continents Think about fossils found in different places Consider mountain ranges that seem to connect across oceans

The Puzzle of Fossil Distribution

Same fossils found on different continents Mesosaurus: found in both South America and Africa These reptiles couldn't swim across oceans Evidence that continents were once connected

Continental Drift Timeline

Mapping the Evidence

Work in pairs to analyze fossil maps Circle matching fossils on different continents Record patterns you observe Discuss: Why are the same fossils separated by oceans?

How Plates Move and Create Features

Earth's crust is broken into large plates Plates move due to convection currents in the mantle Convergent boundaries: plates collide → mountains, volcanoes Divergent boundaries: plates separate → ocean ridges Transform boundaries: plates slide past each other → faults

Geological Features Created by Plate Movement

{"left":"Mountains form when plates collide and push upward\nVolcanoes occur where plates meet and magma rises\nOcean trenches form where one plate slides under another","right":"Fault lines appear where plates slide past each other\nMid-ocean ridges form where plates separate\nEarthquakes happen when plates suddenly move"}

Putting It All Together

The same fossils on different continents, matching mountain ranges across oceans, and the puzzle-like fit of continental shapes all provide evidence that Earth's plates have moved over millions of years, constantly reshaping our planet.