The History of the Mesozoic Era

The History of the Mesozoic Era

 The dinosaur age, and Earth’s second main geological era, the Mesozoic Era, spans from about 252 million years ago to about 66 million years ago. As stated, dinosaurs were the main species of this era along with huge reptiles and other giant animals. This era was known for the geologic and biological evolution. The most commonly known periods of this age were the Triassic, Jurassic, and Cretaceous Periods. Mass extinction actually occurred in the Paleozoic Era, the era before the Mesozoic Era. Despite the fact that mass extinction occurred, certain plants and animals continued to evolve during the Mesozoic time. Plants and animals that exist today have ancestors that links back to this time.

 The Triassic and Jurassic periods, were commonly known as the Age of Cycads. Cycads are plants described to be short and stout. They also have palm-like leaves and produce large cones. Those plants grew abundantly amongst those periods, hence the name “Age of Cycads”. An animal that was commonly known in both the Paleozoic and Mesozoic was the reptile. Since reptiles were distinguished in the Permian Period of the Paleozoic Era, they underwent alterations, or mutations, in order to survive the Mesozoic Era. Those changes occurred so that some could live in the sea and others on land. Other reptiles grew wings, which enabled them to fly.

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 Both the Triassic and Jurassic periods had mass extinctions to occur. It affected life both on land and in water. During that time, half of the marine invertebrate went extinct. About 76 percent of marine and terrestrial species died. About 20 percent of the taxonomic families went extinct as well.

 In the course of the Triassic Period, it was typically dry. Rise of the reptiles and first dinosaurs were present in this period of the era. Pangaea, or the supercontinent, was still in affect during this time as well. Sea floor spreading started to occur later on in the Triassic Period. It occurred in the Tethys Sea, which led to the separation of Pangaea from the northern and southern portions. Pangaea then separated into two continents known as Laurasia and Gondwana. Around the mid-to late Triassic period, stony corals began to show up. No major changes really occurred in plants or insects during this time. Organisms that survived were gymnosperms, mosses, and ferns. Because of the Permian Extinction, the conifer forests had to recover. Spiders, scorpions, millipedes, and centipedes are insects that also survived. During the earliest time of the Triassic period, Therapsids, were the most dominant animal. Therapsids are a group of mammal-like reptiles. Most of the Therapsids, by the mid-Triassic, had become nonexistent. As the Therapsids died off, the Archosaurs became the dominant species. The earliest mammal appeared towards the end of this period. Those mammals were small and a few inches long. They were mainly herbivores and insectivores. Scientists did not know how to separate both the therapsids and the early mammals since the therapsids were mammal-like.

 As we transition over into the Jurassic Period, we learned that the climate changed from dry and hot to more of a subtropical temperature. More reptiles appeared in this period. Those included pterosaurs, which are flying reptiles. Dinosaurs were dominant on land while mammals continued to evolve. Two dinosaurs that were prominent during this time were the Apatosaurus and Stegosaurus. Both were plant eating animals. They fed on cycad seeds and conifer trees. Other animals that were present were huge marine reptiles. They had gigantic paddle-like limbs and ate fish from the sea in order to survive. Other marine animals that were present were giant marine crocodiles, sharks, rays, fishlike ichthyosaurs, squid like cephalopods, and coil-shelled ammonites. Because there were so many sea animals and marine life, this is how scientist discovered that oceans began to ascend. This was due to layers of dried magma covering the seafloor. Because of this, landmasses continued to do fragmentation. By the middle of the Jurassic period, North America began pulling away from Eurasia and Gondwana. Towards the end of the Jurassic period, Africa separated from South America. Australia and Antartica then separated from India. In the Pacific region, ocean basin deposits can be found from the Jurassic time period today.

 The Cretaceous period is the home and start of the Triceratops, Tyrannosaurus rex, and the Parasaurolophus. This period is also the last of the Mesozoic Era. The Triceratops are rhino like dinosaurs. The Tyrannosaurus rex, also known as the T. Rex, was a carnivore. It played the same ecological role back then as lions do today. The Parasaurolophus was a dinosaur with a long crest, and it was billed like a duck. Since the crest was much bigger than the skull of the Parasaurolophus, scientists figured that it must have been used for mating or helping members of a herd find one another. During this time, Pangaea no longer existed. Each continent had drifted off to shape how the world exists today. The Cretaceous period ended with one of the greatest extinctions of all time. This extinction led to the ending of the dinosaurs, marine and flying reptiles, and many of the marine invertebrates. Sea levels were extremely high during this period of time. Because of this, it led scientist to think that this is how water was placed in ocean basins from ocean ridges. Seas were also formed because of those high sea levels. Those were formed in North America, South America, Europe, Russia, Africa, and Australia. The Mesozoic Era, itself, shaped the world forever.

 During this Mesozoic Era, a lot of physical changes helped shaped the Earth today. Because a marine incursion occurred, the Muschelkalk Sea covered Europe’s interior. Seas began to exceed the continents during the early and late Jurassic period. It also continued over into the Cretaceous period. The flood left behind sandstone, ironstone, clays, and limestone. Because of the rise in sea levels, the results of this had caused two effects. It caused the temperature to become warmer. Sea floor spreading, as previously talked about, is the second thing that occurred because of the flood. Ocean ridges uprooted and placed large amounts of ocean water onto land.

 The real question of the matter is, “Could humans survive the way of life and it’s environment during the Mesozoic Era?” In my opinion, I do not think that humans would have survived. I say this because there were a lot of different changes going on in this era. Also, the animals that were present were dangerous. The T. Rex could be compared to a lion. Really nice to look at and be fascinated with, but not so nice to be in the presence of. Also, the climate and it’s change probably would have been unbearable for humans. The weather started off as hot and dry, but then it changed to a subtropical environment. There was not any water present until the Jurassic period, which means that humans would have waited years before water would exist on land. Food or a source of nutrition would have been scarce as well. They could have hunted animals, but those animals or dinosaurs, at that time, would have been hunting the humans.  It would have been survival of the fittest. Eventually, something would become limited and die out. The plants were not exactly how they are today, so I can not really say if they would have been safe to eat. To answer that question, no I do not think humans would have survived during this time.

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