Question

review sheet

1. evidence of continental drift

how did scientists use fossils of land animals and freshwater animals to show the continents have moved?

how did scientists use the location of plants to show the continents have moved?

how did scientists use maps to show the continents have moved?

how did scientists use satellites to show the continents have moved?

1. p-waves and s-waves

p-waves	s-waves
do they move through solids/liquids/gases?	do they move through solids/liquids/gases?
what layers of the earth do they move through?	what layers of the earth do they move through?
describe or draw how a p-wave moves rock molecules:	describe or draw how an s-wave moves rock molecules:

Explanation:

Part 1: Evidence of Continental Drift

1. Fossils of land and freshwater animals

Scientists found identical fossils of land (e.g., Mesosaurus) and freshwater animals (e.g., Lystrosaurus) on continents now separated by oceans (like Africa and South America). These animals couldn’t cross vast oceans, so the continents must have been connected (as part of Pangaea) and later drifted apart.

2. Location of plants

Fossils of the same plant species (e.g., Glossopteris) were discovered on widely separated continents (Africa, South America, Australia, India, Antarctica). Glossopteris seeds were too heavy to be dispersed across oceans, so the continents must have been joined when these plants grew, supporting continental drift.

3. Maps (Fit of Continents)

When maps of continents (e.g., Africa and South America) are aligned, their coastlines (especially the continental shelves) fit like puzzle pieces. This suggests they were once part of a single landmass that split and drifted.

4. Satellites (Modern Measurement)

Satellites (e.g., GPS) measure tiny movements (a few centimeters per year) of continents. For example, North America and Europe are moving apart, and Australia is moving north, confirming ongoing continental drift.

Part 2: P - Waves and S - Waves

P - Waves (Primary Waves)

• Speed: Move faster than S - waves.
• Medium: Move through solids, liquids, and gases.
• Earth’s Layers: Travel through the crust, mantle, outer core, and inner core.
• Motion: Compress and expand rock molecules (like a slinky), moving in the direction of the wave (longitudinal motion).

S - Waves (Secondary Waves)

• Speed: Move slower than P - waves.
• Medium: Move only through solids (cannot travel through liquids or gases).
• Earth’s Layers: Travel through the crust and mantle but cannot pass through the liquid outer core.
• Motion: Shake rock molecules side - to - side or up - and - down, perpendicular to the wave’s direction (transverse motion).

Answer:

s

1. Evidence of Continental Drift

• Fossils: Identical fossils on separated continents (no ocean crossing) show continents moved.
• Plants: Same plant fossils on distant continents (seed dispersal impossible) show drift.
• Maps: Continental coastlines fit (once joined).
• Satellites: GPS measures current continental movement.

2. P - Waves and S - Waves

P - Waves	S - Waves
Solids, liquids, gases	Solids only
Crust, mantle, outer core, inner core	Crust, mantle (not outer core)
Longitudinal (compress/expand)	Transverse (side - to - side/up - down)