Unit 3 Flashcard 1 - Early Earth and Plate Tectonics

Front

What was the condition of Early Earth?

Back

Violent and chaotic with constant meteor and asteroid bombardment; toxic and noxious atmosphere; no life.

Front

What process do producers use to make food and oxygen?

Back

Photosynthesis: Producers use light and carbon dioxide to make food and oxygen; most of the oxygen in the atmosphere is formed from this process.

Front

What is a convection current?

Back

A current caused by the rising of heated fluid and sinking of cooled fluid; a giant wheel of magma that moves the crust.

Front

What happens at a divergent boundary?

Back

Two plates move away from each other, forming new crust, mid-ocean ridges, and rift valleys.

Front

What occurs at a convergent boundary?

Back

Two plates collide, forming mountains, trenches, volcanic mountains, islands, subduction zones, and earthquakes.

Front

What is seafloor spreading?

Back

The process by which new oceanic crust is formed at mid-ocean ridges as tectonic plates pull apart.

Front

What is the significance of cyanobacteria in Earth's history?

Back

Cyanobacteria are important because they were among the first organisms to perform photosynthesis, producing oxygen and changing the atmosphere.

Front

Define tectonic plates.

Back

Large sections of the Earth's lithosphere that move and interact at their boundaries, causing geological activity.

Front

What is a transform boundary?

Back

A boundary where two tectonic plates slide past each other, causing earthquakes.

Front

What is the role of magma in plate tectonics?

Back

Magma rises and cools to form new crust at divergent boundaries and can cause volcanic activity at convergent boundaries.