Chapter 16, Problem 12STP

Summary Introduction

To explain: Land species and environments might change if the two American continents collided with each other.

Introduction:

The continents we see today were not present like this during ancient times. Around 200 million years ago there Pangea was a single landmass that existed. Later on, this Pangea split into two and gave rise to two continents Laurasia and Gondwana. Laurasia consisted of North America, Asia and Europe, whereas Gondwana consisted of the present-day continents of South America, Australia and Africa. This splitting of landmasses had affected biodiversity and animal migrations. This theory is called as Continental Drift theory.

Explanation of Solution

In the past, the South American continent was attached to the South African continent and the Indian continent was also part of the African continent. The animal diversity in these regions and the shape of the edges of these continents supports this. As the eastern edge of the South American continent is in relation to the western edge of the South African continent, both the North and South American continent is basically separated by a canal known as Panama Canal. This was created about 20 million years ago before which, the water from the Pacific and Atlantic flowed freely. At around 15 million years ago, a small trip of land bridge was formed between these islands. This hindered the free flow of water from these oceans and caused the enormous change in the environmental conditions as it changed the average temperature about 10^o C. This also made a change in the current biodiversity of both the continents as this land bridge allowed the movement/migration between these continents. The origin of animals like Opossum, armadillo, porcupine, etc. can be traced back to South America which is now part of North America, likewise, Racoons, Ilamas, cats, dogs, horses migrated to South America from North America. Therefore, if these continents collide again and become a part of one, there would be equal distribution of biodiversity. However, it will hinder the flow of the Pacific and Atlantic Ocean ad due to this, an enormous change in environmental conditions can be observed.

Conclusion

Biodiversity basically depends on environmental and ecological conditions. If there is a change in geographical or environmental conditions, this can affect the biodiversity of the organisms greatly. Continental drifting is very much realistic and according to data, two continents are drifting away from each other about 1 inch per year. This is due to the movement of plate tectonics and this can lead to the formation of new continents. If this happens, there will be a huge change in both the environmental conditions as well as in the Biodiversity of that continent.