The Mesozoic Era

The Jurassic Period is a time period were new dinosaurs were being discovered and found. It was about 199.6 to 145.5 million years ago. Some of the species that were found in the Jurassic Period are the Stegosaurus, Ceratosaurus, Brachiosaurus, and Allosaurus. Each dinosaur had their own characteristics for survival.

During the Cambrian Period there was an explosion of life forms. Most of these were in the water. Many animals with no backbones lived in the shallow seas. These animals were invertebrates.

The Cretaceous period is a period of time within the Mesozoic Era lasting from 146 million years ago to 65.5 million years ago. It is one of three periods in the Mesozoic Era along with the Triassic and Jurassic periods. The Cretaceous period is well known for the amount of dinosaurs it had, and the event that put an end to the dinosaurs reign, the K-T mass extinction. During the K-T mass extinction, a huge asteroid hit earth and caused tons of dust to infiltrate the air. Only a small portion of dinosaurs died on impact Instead, the dust blocked out sunlight which caused plants to die. Without plants, many dinosaurs did not have a food source, so the died out. Carnivore dinosaurs, such as the Tyrannosaurus Rex, survived a little longer

It was four feet in length and first they thought it might be a crocodile. Nevertheless, over the next year, at the tender age of 12, Mary painstakingly uncovered the rest of it, to discover a giant marine reptile called the 'ichthyosaurus'.

The Mesozoic Era is an interval of geological time from about 252 to 66 million years ago. It is also called the Age of Reptiles, a phrase introduced by the 19th century paleontologist Gideon Mantell .

Stromatolite forms and is the first organisms on the earth they were formed by very thin layers of single-celled organisms.

According to a live science, an article written by Mary Bagley, "The Cretaceous Period was the last and longest segment of the Mesozoic Era. It lasted approximately 79 million years, from the minor extinction event that closed the Jurassic Period about 145.5 million years ago to the Cretaceous-Paleogene extinction event dated at 65.5 million years ago"(Mary Bagley, LS). In the cretaceous period, the continent of Pangea was still breaking away from itself, forming what we now know as the seven world continents. In the many eras of dinosaurs, the cretaceous era was responsible for evolving some, but not all the dinosaurs from full land dinosaurs to some who were able to live both on land and in water, semi-aquatic carnivorous dinosaurs. This era had produced some of the dinosaurs that maybe us non- paleontologist are more familiar with like the all mighty tyrannosaurus rex or the long neck. Well let me tell you, there were a lot more dinosaurs than just those two. Although the tyrannosaurs rex was an enormous dinosaur, a bigger dinosaur was discovered in 1912, the Spinosaurus. This discovery would change peoples, kids, and paleontologists view on which dinosaur was bigger than the other. This semi-aquatic dinosaur, Spinosaurus, was much larger than the T-rex due to its sail like backbones that stuck out of its back. Furthermore, spinosaurus had a huge advantage that the tyrannosaurus-rex did not.

The fifth, and one of the largest and most well known extinctions in Earths history was the Cretaceous period, where many species, including the dinosaurs, pterosaurs, and large marine reptiles, disappeared. This period was widely known as the K-T period, K being the traditional abbreviation for the Cretaceous Period derived from the German name Kreidezeit, and T being the abbreviation for the Tertiary Period (a historical term for the period of time now covered by the Paleogene and Neogene periods). It was a relatively warm climate and had high global sea levels. The oceans and seas were populated with now extinct marine reptiles, ammonites and rudists, and the land by dinosaurs. At the same time, new groups of mammals and birds as well as flowering plants appeared. The early part of the Cretaceous showed a cooling trend that had been

The Cro-magnon people lived about 100,000 to 10,000 years ago. The average temperature -2 degrees celsius (28.4 degrees Fahrenheit).The temperature sometimes reached lows of -4 or highs of 4 degrees celsius (24.8 or 39.2 degrees Fahrenheit). They lived in the epoch known as the Pleistocene epoch. The Pleistocene epoch was the first epoch occurred in the Quaternary period and the sixth epoch in the Cenozoic era.The Cenozoic era occurred during the Phanerozoic eon (the current eon). This epoch is best known as the “last ice age” and it lasted from 2.2 million to 11,000 years ago. The “last ice age” began its climate decrease at the start of the Pleistocene epoch (2.2 million years ago) and reached its peak about 20,000

The age of the planet Earth is estimated to be about four point six billion years old. Life on Earth is estimated to have started one billion years later. Evolution has taken place since then. Evolving life from simple forms into more complex forms through the course of time. It all began with single celled organisms, prokaryotes. Later evolving in a period of two hundred million years, cyanobacteria began to produce photosynthesis. And life went on, evolving, adapting to its home. However through this course of time, mass extinctions have taken place on planet Earth. One of the most recent mass extinctions, has as a matter of fact left various amounts of evidence of the creatures which roamed the Earth at that time. Such magnificent creatures which varied from a very small size to giant sizes. Creatures which are now known to humanity as dinosaurs. The name of this extinction was the Cretaceous-Tertiary Mass Extinction. This extinction took place roughly sixty five million years ago. It has not been too long since this incident compared to the life span of the Earth. And yet it is still unclear how this extinction occurred. Paleontologists to this day, debate on how this extinction occurred. A major factor on what caused this extinction to occur was an impact of an asteroid. Another theory such as sea level regression is considered to be the blame for the extinction. Sea level regression is the drop of sea levels which aids to explain the marine mass extinction, however

Space scientists are attempting to comprehend which far-off worlds may have livable environments. To aid in this research a team has been studying the Earth past, “during the Archean era, one through half a billion years early ().” Earth atmosphere was unlike the present day Earth, possible because of different level of elements in the air. Astronomers find the Archean era Earth is the most unfamiliar world in their records. Haze in this world’s environment could play host to various elements, and block ultra violet radiation from the sun.

This class has been great! I have learned a lot about the Mesoamerica period and have gained a new incite to what has happened in this period with the forming of many new groups of people. The part that has affected my outlook the most is seeing how much we can learn from the past like the Spanish and the Aztec people coming from different parts of the world. I can see a new light to seeing people from different cultures coming to America that that we need to respect their traditions even if we have different believes and help people understand the United States traditions that we have. It is amazing what the Spaniard and Aztecs showed me that even though they came from different parts and cultures there has been an integration to many now traditional celebrations.

The Precambrian era does not have a previous era.But the era after the Precambrian was the Paleozoic. The Precambrian era was from 4.8 to 4.5 million years ago with the paleozoic era before it and then the Mesozoic era after. The time periods in the paleozoic era were Cambrian, Ordovician, Silurian, Devonian, Mississippian, Pennsylvanian, Carboniferous, and Permian.The precambrian era did not have a previous Geologic era. The precambrian era had different periods which are Proterozoic, Archaean, and Hadean my major climate was the the ice age.my main geologic period was formation of earth and life for an example plants.The continents that the precambrian era had were pangia, animals that lived in the geologic era was waptia Dickinsonia protozoa

Jurassic is a period of time with Dinosaurs, rodents and birds. There were also island seas consisting of sharks, sea monsters and blood-red planktons. The existing plants in that period were cycads, ferns and conifers. The Mesozoic era was about 245 million years ago to 65 years ago, so it almost lasted about 180 years in total. The Mesozoic era is divided into three periods of Triassic, Jurassic and Cretaceous. Mesozoic era means middle animals and it is the era, which the word’s fauna has changed from what is in the Paleozoic era and the most famous organisms of this era are dinosaurs. In the Mesozoic era, the extinction of more than 90 percent of species in the earth was observed and the reason behind it was mostly volcanic eruptions and climate changes. On the other hand, this era had massive changes that represented ecological niches and rise to new creatures such as rodent-size mammals and first dinosaurs. In Triassic, which was the first period of Mesozoic, the mammals and first dinosaurs existed. Later than that, the second period was Jurassic, which giant shaped dinosaurs and other kinds of dinosaurs were developed. Besides that the first flowering plants and primitive birds, with long teeth appeared in that era as well.

These techniques led to the discovery of the boundary between the two eras. A single thin layer of clay found within predominantly limestone rocks established this. By comparing the marine life found in, above, and below the clay, the marine life, like the dinosaurs, had been terribly affected by the extinction event. The percentage of life in the upper layers was dramatically lower than that in the lower. This was far more compelling than what was suggested by dinosaur’s fossils.