The K-T extinction, abbreviation of Cretaceous-Tertiary Extinction, also known as the K-Pg Extinction or the Cretaceous-Paleogene Extinction, was one of the major mass extinctions that marked the end of the dinosaurs. This event wiped out three quarters of all animal species on Earth and many of those species played important roles throughout the Mesozoic Era. Yet out of the "Big 5" mass extinctions this one only ranks #3.
Over the centuries there have been many hypotheses to what caused the K-T extinction. However, only a few have been seriously taken into consideration... Hypotheses such as tectonic drift, increased volcanic activity, widespread disease, outcompeted by mammals, and gamma-ray bursts (GRBs) from a nearby supernova. In 1980 a new theory was proposed by Luis Alvarez and Walter Alvarez that a comet or asteroid struck the planet and triggered a series of events that carried out the mass extinction. This theory has some good credibility to it, but still, even today there are various opinions.
About 66,000,000 years ago a large asteroid 6-9 miles (10-15 kilometers) in diameter struck the Yucatán Peninsula in Mexico creating the Chicxulub Crater, an impact crater that is 112 miles (180 km) in diameter and 12 miles (20 km) in depth. The explosive energy of the impact is estimated to be equal to 100 teratons of TNT compared to the most powerful nuclear weapon ever detonated Tsar Bomba of 50 megatons and "Little Boy" (the atomic bomb dropped on Hiroshima, Japan in WWII) of a mere 15 kilotons.
The explosive impact sent megatsumanis across the Gulf of Mexico and onto the North American coasts. The height of these waves could have reached upto 100 meters (330 feet) compared to the 10 meter (33 foot) tall waves produced by the Japan Tsunami in 2011. However, the waves caused by the asteroid's impact could have reached a whopping 3 miles (5 km) high if only the asteroid landed in deep ocean and not a shallow sea like it did. A massive cloud of super-heated dust, ash, and steam would have immediately spread from the crater. Debris from the asteroid and the direct area shot into the atmosphere by the sheer force of the impact. Upon reentry, the material was heated to incandescence; scorching the Earth's surface and potentially igniting global wildfires. On top of that, the returning ejecta into the atmosphere sent out a powerful pulse of infrared radiation lasting for a few hours -- killing the exposed life. Plus, the astronomical shockwaves from the impact triggered earthquakes, tsunamis, and volcanic eruptions that wrecked havoc across the planet.
Judging by the elliptical shape of the Chicxulub crater, the asteroid struck Earth at an angle of about 30° meaning most of the dust and debris was shot to the northwest. To make things worse, the asteroid struck a region of sulfur-rich carbonate rocks, much of which was vaporized, and threw sulfuric acid aerosols into the stratosphere. This made the rain and ocean waters acidic and the acidification of the oceans killed many marine organisms that built their defensive shells from calcium carbonate. Also, it would have blocked out the sun for months, years, even up to a decade. With little to no sunlight many plants and phytoplankton would not have survived...and with so little to eat the larger herbivores died and soon the carnivores would fall. Scavengers had a bit easier of a time, but after awhile even they began to struggle. Large animals failed to survive the strict conditions and in fact, most animals over 20 pounds did not survive.
Even after this catastrophe life found a way... the planet eventually recovered and the survivors experienced adaptive radiation. Now that the non-avian dinosaurs were gone the mammals were free to do as they pleased and quickly spread across the planet. Birds, fish, and reptiles also underwent adaptive radiation. This is a new beginning. Life after the dinosaurs.
The Cretaceous period is the last period of the Mesozoic era and lasted for 79,000,000 years from the end of the Jurassic to the beginning of the Paleogene Period 66mya.
In the Cretaceous period the supercontinent Pangaea finished breaking up into the seven continents that we know today. However, at the beginning stages of the Cretaceous, Gondwana had yet to break up into Antarctica, South America, Africa, Australia, and Mauritia (the microcontinent containing India and Madagascar). All of this tectonic commotion created both the South Atlantic and Indian Oceans. Meanwhile, the Atlantic Ocean continued to widen, the Tethys Sea (the sea that separated Laurasia from Gondwana) continued to narrow. The Earth at this time was experiencing a warm climate and because of this underwent high eustatic sea levels thus creating various shallow inland seas. And in North America and Europe shallow inland seas advanced, the most popular being the Western Interior Seaway of North America. Many organisms inhabited these seas and oceans, the most noteworthy being the marine reptiles, ammonites, an abundance of fish, and others.
On land, the dinosaurs continued to rule and some all-time favorites such as Tyrannosaurus and Triceratops made an introduction at the closing of this period. The Cretaceous introduced some new faces as well...new groups of mammals and birds appeared, along with the first flowering plants. Speaking of the evolution of angiosperms, bees also evolved to assist the new flowers. This is a prime example of coevolution.
Unfortunately, about 66 million years ago a massive asteroid, the size of Mount Everest, will strike the planet -- erasing three quarters of all life on Earth.
Facing too many sadness for the past few months, life is really unexpected and vulnerable. So cherish whatever or whoever by your side at this moment, don't wait because the next second is totally unpredictable...
It seems to me that productivity in terms of video game strategy guide and walkthrough creation is directly proportionate to whatever formula you are actively using for what you do. For example the quality of output for a writer is inversely squared to the measure of actual entertainment and/or enjoyment one accumulates from the project currently active. Put another way - you lot are going to find that our most recent project - the Collectibles Guide for Microsoft's Platformer and Action-Adventure jaunt ReCore - is bloody brill!
Here we are, in the Jurassic Period, which is perhaps the most recognizeable geological period to most people. It is right in the middle of the Mesozoic Era between the Triassic and Cretaceous Periods and lasted for approximately 56 million years; coming to an end about 145,000,000 years ago. Two extinction events took place during this time, however, neither one of them ranks among the "Big Five". At the beginning of the Jurassic the famous supercontinent, Pangaea, had separated into two landmasses; Laurasia in the north and Gondwana in the south. This continental breakup created more coastlines and turned the land's climates from being arid, like in the Triassic, to humid with lush rainforests.
In terms of fauna, the dinosaurs mushroomed during the Jurassic and are now the dominant lifeforms on land. The scrawny prosauropods of the Triassic evolved into the famed sauropods such as Apatosaurus, Brachiosaurus, Camarasaurus, Diplodocus, and many others. "Long-neck" dinosaurs weren't the only staples of the Jurassic... Ornithischian like the stegosaurs and ornithopods also played important herbivorous roles. But you cannot have a functional ecosystem without the carnivores, large theropods like Allosaurus and Ceratosaurus would have stalked the landscapes. The flying reptiles, known as the pterosaurs, continued to evolve as well and at this point in time have complete rule of the skies yet their position would soon be contested by the appearance of the first birds at the end of the Jurassic like Archaeopteryx which evolved from small coelurosaurian dinosaurs. Meanwhile, the aquatic world primarily consisted of fish and marine reptiles -- most noticeably the ichthyosaurs and plesiosaurs and even various marine crocodiles.
The Jurassic flora was also quite different than today... Sometimes you see pictures of dinosaurs like Stegosaurus next to palm trees and flowers, but this is not the case as there were no palm trees nor flowering plants at this time. Instead, the plants mostly consisted of ferns, ginkgoes, bennettitaleans, cycads, and the very common conifers. It is also worth noting that the first true mammals were scurrying amongst the undergrowth at this time, trying their best to elude detection...
So, I am back... I don't know if anyone I know in the past will be reading this, but i'm sorry with the way I acted as a kid. This place is an important place to me. I regret my actions and how immature I was. I had a lot of fun, and the drama was meaningless, but it was how we all got together lol Most of all, I regret not giving the effort into trying to get in touch with everyone. Hit me on PM? Maybe we could talk outside from Neoseeker? I welcome you guys with open arms lol Thank you guys for being a part of my childhood!
This series will be a much shorter continuation of the 'Before the Dinosaurs' series. You can read more on the Triassic Period here.
The Triassic Period is notorious for the appearance of the first dinosaurs which appeared at the end of this period. Small carnivorous theropods such as the herrerasaurids were among the earliest known dinosaurs although there is some uncertainty to where exactly these animals lie on the dinosaur evolutionary tree. Although the earliest, yet most distinct theropods were the Coelophysoidea. These small and agile dinosaurs that included Coelophysis were quite successful and even survived up until the Early Jurassic Period as the ceratosaurs.
Another key group of Triassic dinosaurs were the prosauropods. Prosauropods were relatively large, semi-quadrupedal herbivorous dinosaurs that included the common Plateosaurus. In conclusion, the late Triassic period was no walk in the park for the dinosaurs and by around 201,000,000 years ago another mass extinction swept across the planet that affected all life. And by the time this extinction caled down, the Earth was in the Jurassic Period and the dinosaurs were free to rule.
First aid kits recover all of your energy, while "food" recovers only some (half or less). Recovery items, extra lives, and ammunition reappear when you leave and return to the area they are found in. Destroy Compys. Raptors are a lot bigger when you're outside a building. If you see a Triceratops, don't just run. Get out of the way. Don't get hit by Dilophosaurus spit. Pachycephalosaurus may be territorial, but Alan Grant is more so! Just shoot them. Shoot the Gallimimus. They will stampede anyway. You cannot kill a T-Rex. Don't jump over a dead raptor. Other dead dinosaurs, it's fine. Don't listen to Dennis. Raptors will attack you whether you shoot them or not. Mr. DNA lies to you! If you're inside a building and you hear what sounds like someone sniffling or kicking at gravel, it's probably a Dilophosaurus spitting. If you're inside a building and a raptor attacks you from behind, run to the nearest exit. Even if you get a chance to turn around before it kills you, you won't be able to see it. If you're on a roof, look out for raptors, because at least one will jump up there. Don't pick up raptor eggs. Ian will try to kill you. Last of all, don't heed the above advice. It is based solely on my own observations and was written in jest.
Usually when you think of the mammals that lived alongside the dinosaurs, you usually think of small, nocturnal, shrew-like animals. But not Repenomamus. This animal was quite large for a Mesozoic mammal at around 1 meter (3 ft 3 in) in length and an estimated weight of 12-14 kg (26-31 lb) for the larger species; R. giganticus. The teeth and jaws of Repenomamus suggest that it was carnivorous, but when a specimen of R. robustus was uncovered it revealed the fragmentary remains of a baby Psittacosaurus within its stomach.
Repenomamus lived in what is now prehistoric China during the Early Cretaceous period.