Rebuild Past Continents Practice Test

Two student groups created different past reconstructions (models) of continents using the same evidence. The evidence includes (1) matching coastline shapes and (2) identical seafloor features (a ridge segment and an offset fracture zone) that line up when plates are moved.

Evidence:

• The west edge of Continent D has a curved bay that matches the east edge of Continent E.
• On the seafloor between them, a mid-ocean ridge segment and a fracture zone form a “zig-zag” pattern that should line up as a continuous feature when the continents are brought together.

Reconstruction A: D and E are rotated so the bay-and-peninsula shapes match, but the ridge/fracture “zig-zag” does not line up. Reconstruction B: D and E are moved so the ridge/fracture “zig-zag” lines up continuously, and the coastline match is close but not perfect.

Which reconstruction is more accurate and why (based on the evidence shown)?

Students are choosing the best past reconstruction model for Continents W, X, and Y using two evidence types: fossils and continental shapes.

Evidence:

• Fossil A (a land animal) appears on W’s east edge and X’s west edge.
• Fossil B (a plant) appears on X’s south edge and Y’s north edge.
• W has a notch that matches a bump on X; X has a curved bay that matches a curved peninsula on Y.

Three reconstructions are proposed:

1. W is matched to X (notch/bump) but X is not connected to Y.
2. X is matched to Y (bay/peninsula) but W is placed far away.
3. W is matched to X and X is matched to Y so both fossil matches occur at touching edges.

Which reconstruction best fits the evidence?