The strong evidence for Wegener's "continental drift theory" turned out to be manatees and ostriches?

Before the early 20th century, the most popular explanation for the movement of continents was the "fixation theory" (i.e., it denied the existence of large-scale horizontal movement on the earth's surface, but mainly believed in vertical movement). Speaking of the fixation theory, the corresponding one is the "movement theory". I believe many of you have heard of the story of a scientist who advocated the movement theory: while lying on his sickbed, he looked at the world map and saw that the outlines of the two sides of the Atlantic were very similar, so he proposed the hypothesis that the two sides of the Atlantic were once connected.

Has the west coast of Africa ever been connected to the east coast of South America? | Image source: Internet

He is the great marine geologist of the 20th century.

Alfred Wegener

Alfred Wegener (1880-1930) | Image source: Internet

Of course, Wegener would not be the last person to see the similarities between the two sides of the Atlantic Ocean. After all, after him, there are generations of people like us who pursue scientific truth.

Do you think that the story of Wegener seeing the similarity of the land contours on his sickbed ended there? Of course not. Today I will tell you the story of what happened after he saw the map on his sickbed.

Boldly proposing a hypothesis is only the beginning. How to verify your hypothesis is the biggest challenge facing Wegener. The young Wegener embarked on a journey to verify his "bizarre idea". He began to travel to both sides of the Atlantic Ocean to collect evidence that the two places were once connected.

The coincidence of continents was the source of Wegener's inspiration and is also the easiest for us to observe.

Wegener's hypothesis is also supported by the fact that adjacent continents share the same rock sequence and connected mountain ranges. For example, the Appalachian Mountains in eastern North America match the mountains of the British Isles and Scotland in Europe.

Mountains connecting the two sides of the Atlantic Ocean | Image source: Internet

The fossils of the now extinct large Mesosaur that lived 250 million years ago have only been found in eastern South America and West Africa. If it could swim across the ocean, why didn't it have a wider distribution?

Mesosaur and other ancient fossils are distributed in different continents | amuseum.cdstm.cn

Wegener's theory of continental drift provides a good explanation: in the geological history, the continents were connected, and creatures did not have to be good swimmers or flyers to leave fossils on two distant continents, such as manatees and ostriches that are distributed correspondingly on both sides of the Atlantic Ocean.

Species distributed on both sides of the Atlantic Ocean | Image source: Internet

Another example is the similarities between Australian marsupials (kangaroos and koalas) and the opossums found in America. Examples of biological distribution such as these are evidence for Wegener's theory.

Wegener compiled his findings into a book, "The Origin of the Continent and the Sea", which comprehensively discussed the theory of continental drift.

However, in the era when the theory of continental drift was dominant, the theory of continental drift was not widely accepted. One important reason was that Wegener could not explain the driving mechanism (power source) of continental movement. Wegener also sacrificed his precious life for science in 1930 while conducting scientific research in Greenland amid doubts from the world. People still remember Wegener today because of his scientific spirit of seeking truth, facing facts, and daring to explore throughout his life.

Map of changes in land and sea | Source: Internet

More than 30 years after Wegener's death, his theory was gradually accepted by people because of technological advances and people's increased understanding of the seabed, ocean and the earth, such as the discovery of spreading mid-ocean ridges and the mastery of paleomagnetism (which can reveal the initial location of rock formation). Based on the newly discovered evidence, scientists successively proposed the theory of seafloor spreading and plate tectonics, enriching our understanding of the ocean and the earth.

Image source network

Land and ocean both belong to our only planet. While we see the magnificent mountains and rivers on land, we should also pay attention to the ocean and the underwater world. The ocean, which accounts for 71% of the earth's surface, has too many places that humans have not set foot on and too many unknowns to humans. The unknown world under the sea still needs to be explored continuously to add a touch of color to the colorful earth.

(The main academic viewpoints of this article are quoted from Introduction to Oceanography by Alan P. Trujilo and Harold V. Thurman, published by Electronic Industry Press)