Growing up in India, my only encounter with archaeology was a poignant one. During my seventh grade summer vacation, I received that dreaded call my from Dad informing the demise of my friend. His dad was an archeologist, they had an accident on their way to an excavation site. Since then I have been oblivious to anything related to archaeology or paleontology in India until I read this fascinating piece. (and Jeff Wilson's website here)
"Throughout most of the 545 million years during which there has been visible life on Earth (the Phanerozoic Eon), Greater India was not part of Asia, and it was not a peninsula. The majestic Himalayas, the mighty Indus and Ganges Rivers, and the expansive Deccan Plateau did not yet exist. These geographical features, which are integral to modern characterizations of Greater India, did not emerge until well after the extinction of dinosaurs at the end of the Mesozoic Era, 65 million years ago. The Greater India that was known to early dinosaurs and their antecedents was interlocked with Antarctica, Africa, Madagascar, Australia, and South America. These conjoined southern landmasses were called “Gondwana” or “Gondwanaland”, owing to their shared flora and fauna (du Toit 1937; Sorkhabi 1996). The break-up of Gondwana later in the Mesozoic Era remains a fascinating event in Earth history because it led to the creation of islands, each initially seeded with a common flora and fauna, that became progressively isolated from one another. Greater India in particular is interesting because it rifted from Gondwana and drifted across the equator some 6,000 km to Asia. The evolutionary changes and extinction events manifest during that journey remain the subject of investigation by many paleontologists.
"Throughout most of the 545 million years during which there has been visible life on Earth (the Phanerozoic Eon), Greater India was not part of Asia, and it was not a peninsula. The majestic Himalayas, the mighty Indus and Ganges Rivers, and the expansive Deccan Plateau did not yet exist. These geographical features, which are integral to modern characterizations of Greater India, did not emerge until well after the extinction of dinosaurs at the end of the Mesozoic Era, 65 million years ago. The Greater India that was known to early dinosaurs and their antecedents was interlocked with Antarctica, Africa, Madagascar, Australia, and South America. These conjoined southern landmasses were called “Gondwana” or “Gondwanaland”, owing to their shared flora and fauna (du Toit 1937; Sorkhabi 1996). The break-up of Gondwana later in the Mesozoic Era remains a fascinating event in Earth history because it led to the creation of islands, each initially seeded with a common flora and fauna, that became progressively isolated from one another. Greater India in particular is interesting because it rifted from Gondwana and drifted across the equator some 6,000 km to Asia. The evolutionary changes and extinction events manifest during that journey remain the subject of investigation by many paleontologists.
Dinosaurs are one of the best groups for studying the potential effects of paleogeographic changes on evolution because dinosaurs were large animals that were capable of traversing continent scale-distances. For example, early in the Mesozoic Era, when the Earth's continental landmasses were connected, dinosaur faunas worldwide are generally similar. Carnivorous dinosaurs from North America, for example, bear striking resemblance to those from southern Africa, and herbivorous dinosaurs from China resemble those from South America. Later in the Mesozoic Era, however, this is not the case. Dinosaur faunas worldwide became more distinctive from one another due to evolutionary changes and extinction associated with increased isolation."
No comments:
Post a Comment