Mesozoic History - Essay Example

The only two Cephalopod classes which are present in my set are Nautiloidea and Coleoidea. Most of the present subclasses of Cephalopods have become extinct.

The Nautiloidea class exists from Cambrian or Holocene. Mollusks of this class are highly developed. They are very active swimmers. Coleoidea on the other hand, exists from the Devonian age. They have 8 to 10 arms. Squids and octopuses belong to this category.

Ammonoids are very good index fossils because their age can be easily traced from their appearance. The ammonite pattern is the main thing that helps the researchers in understanding their age.

Dinosaur Bone Fossil:

The dinosaurs belong to the reptile class. There are some well-established processes which are followed for preserving the dinosaur’s bone. Excavation is the first step in which the bones are collected. But careful excavation is of utmost importance. The sediment part from the bone is removed. Acid is used for preservation but in a very little amount as the bone is constructed of calcium carbonate and calcium phosphate. Ascetic acid and formic acid are commonly used for this purpose.

The dinosaur bone that I own is from the Mesozoic period. Dinosaur bones are very helpful as index fossils and there are some specific reasons behind this phenomenon. First of all, dinosaur bones can be traced very easily. Understanding the age to which they belong is not hard if someone deals with index fossils.

Lives in Mesozoic

Invertebrate Life: there were a few life forms existing during this period. Shells of silica and calcium carbonate are the two main forms. Class Sardonica was very important during this time. Marine invertebrates developed rapidly during the Mesozoic period.

Vertebrate Life: there were three distinguished sections in Mesozoic vertebrate life and they were: sauropod, theropod, and ornithischian dinosaurs. Dinosaurs were among the best-known creatures which dominated the world at that period.

Plant Life: this was the era when some of the major plants existed. Among them, the mentionable ones are ginkgoes, ferns, and cycads. There were also some flowering plants present in the Mesozoic era too. Insect pollination was one of these plants’ characteristics.

Mass Extinction

Mesozoic was a period in the dinosaurs are believed to have become extinct from the world. Among the main creatures which entirely vanished from this planet are Iguanodon, Ouranosaurus, Dilophosaurus, Protoceratops, and Maiasaura. The Ordovician Period was the time when the process of extinction started and by the end of Meso, zoic the process was complete. It is believed that collision with the comets is the main reason behind this extinction. Conjured by Raup and Sepkoski, this theory is known as Nemesis Hypothesis.

Angiosperms: Angiosperms had a very primary life during the Mesozoic period. Understanding these particular primitive angiosperms’ origin is a very difficult task. The ancestry of angiosperms is not clear to date.

Pangaea Breakup and Its Influence on World’s Biota:

Triassic and Jurassic ages were the period when the breakup of Pangaea took place on this planet. It led to many changes in the world’s biota. The continents were separated from each other. Some of them, however, remained connected. Australia and America were formed during this time. They both are two separate lands where evolution took place differently rather than in the other parts of the world. This is why the creatures of these continents are different from the rest of the world today.