8th plate tectonic theory

Alfred Wegener's hypothesis of continental drift was not widely accepted because --

• he could not provide evidence to support his claim
• the puzzle fit was his only evidence and scientists thought it was a coincidence
• he could not explain what mechanism caused the plates to move
• he claimed continents drifted on the oceans

Scientists have compiled fossil records over several continents.

Which statement best explains the pattern in the diagram?

• The animals migrated over time looking for food.

• The organisms shown on the map lived after Pangaea.

• These species were found on each continent because they were native to all continents.

• The organisms lived when the continents were connected.

What is the name of the supercontinent Alfred Wegener used to discuss his hypothesis of continental drift?

• Laurasia
• Gondwanaland
• Euramerica
• Pangaea

Which statement is NOT evidence of the plate tectonic theory?

• Fossils of the same animals are found on different continents.
• The continents fit together like pieces of a puzzle.
• Similar weather patterns exist on different continents.
• Mountain chains line up along the edges of continents.

One of the key pieces of evidence that supports the theory of plate tectonics is the puzzle fit of the continents.  The theory was weakened by areas which lacked an exact fit.  Later, scientists realized that the continental shelf should be included in the theory.  Which statement explains why the continental shelf should be included?

• Coastlines of continents have not changed over time.
• Coastlines have been eroded over time, but the continental shelf is less affected by erosion and thus allows a better fit.
• Coastlines changed as the continents broke apart and the continental shelf remained unchanged.
• The continental shelf has grown over time and fills in the gaps, allowing for a better puzzle fit.

Which change is least likely to result from future plate movement?

• Mt. Everest will increase in height.
• Parts of California will separate from North America.
• The Grand Canyon will become larger.
• Asia and Australia will become connected.

How does the diagram provide evidence of plate tectonics?

• The diagram shows two plates pushing together, proving that mountains are formed.
• The diagram shows the formation of volcanoes, proving the existence of underwater volcanoes.
• The diagram shows symmetrical magnetic stripes, proving the seafloor is spreading.
• The diagram shows an underground pool of magma, proving the mantle is hot.

Scientist purposed the theory of Continental Drift

• Harry Hess

• Dan McKenzie

• Alfred Wegener

• Bill Nye

cyclical (circular) motion that causes the plates to moves

• Subduction
• Convection Currents
• conventional currents
• gravity

occurs because of density...
warmer, less dense, lower regions of the mantle rise...
then, denser, cooler regions sink

• subduction
• tranformation
• sublication
• Convection