Chapter 8, Problem 1RQ

To determine

The list of evidence which supports the idea that continents have moved over Earth’s surface.

Answer to Problem 1RQ

The coast on the two sides of Atlantic Ocean fit together just like two separated parts of jigsaw puzzle, the similarity between the fauna of two lands, and the presence of similar fossil flora on widely separated landmasses are some evidence which supports the idea that continents have moved over Earth’s surface.

Explanation of Solution

The evidence which supports the idea that continents have moved over Earth’s surface are as follows:

(i) Best-fit positioning of continents that are currently present on the two opposite side of Atlantic Ocean.

(ii) The similarity between the fauna of two lands (such as Madagascar and India) that are separated from each other by ocean (Indian land separated from Madagascar by nearly 4000 kilometers of ocean).

(iii) Discovery of fossils on the two opposite sides of ocean. For example, 27 species of fossil land plants found in Antarctica, 20 species of the same fossil plants have been found in India also.

(iv) During 19^th century, late Paleozoic coal deposits of India, Australia, South America, and South America were found to contain group of fossil plants that were collectively called the glossopteris flora. The presence of this fossil flora on widely separated landmasses was also led to the idea that land bridges had once connected all of these continents.

(v) Scientists have also hypothesized that the immense submarine mountain chain called the Mid – Atlantic ridge that is one of the several ridges of present-day seafloor, marks the lining along which one such ancient landmasses ruptured to form the Atlantic Ocean.