What Killed the Dinosaurs free essay sample

The subject has no concrete answer and probably never will but I hope to find my own personal opinion of what happened at the end and enjoyed and use what I have learnt in the future. Background Science: Before I get into my arguments I will explain a bit of background behind dinosaurs, so you can have a better understanding of my case study and what I am trying to express. Dinosaurs are often brought up in the media and normal life and are also constantly referenced in relation to other animals and films but not many people actually know what a Dinosaur is! The word dinosaur actually means â€Å"terrible lizard†. Dinosaurs were actually reptiles, this means when they were hatched and born, they had no fur. Dinosaurs and lizards are in a way similar but also very different. The main difference between the two is how their legs join to the hips. Lizards have legs in a squatted position, with the legs going outwards. However dinosaurs have legs similar to humans where they go straight down! The dinosaurs were first around about 245 million years ago, during the Mesozoic Era; which is often called the Age of the Reptiles. This era was split up into three sections, the Triassic which was from 245 million years ago to 208 million years ago, and then the Jurassic which was 208 million years ago to 146 million years ago and finally the Cretaceous period which lasted from 146 million years ago to 65 million years ago when dinosaurs started to die off. Over many years scientists have developed many different theories to why the dinosaurs became extinct; some are much more known while others and thought to be the truth and others and not known and thought to be a lie. This list of theories include; volcanoes, an asteroid impact, an ice age, comet and cosmic rays, mammals killing them, diseases, climate change and even obesity! Asteroid Impact: This is where the asteroid hit. One of the main theories, if not the main theory believed to have caused the extinction of dinosaurs is linked to the 15km asteroid which crashed into the Yucatan Peninsular causing mass destruction around the world! Scientists believed that the Asteroid would have travelled 150 times faster than a jet airliner! The original impact would only have killed a tiny percentage of the dinosaurs; however the after effects would be catastrophic. For months dense clouds of dust would block of the suns rays which would darken and chill the earth, so most of the world’s plants and animals would die. Then once the dust had settled, greenhouse gases would cause the temperature on Earth to skyrocket over usual levels. Due to these freezing and sweltering conditions in only a few years, all dinosaurs and 70% of the plants and animals would become extinct. However there are a few issues with this theory and why it might not be true! A well established scientist, Gerta Keller has carried out research for 20 years with her team and she believes that the dinosaurs were dying out 300 thousand years before the impact of the asteroid, which if true, almost destroys the asteroid theory! Due to this many people now believe that volcanoes may be the true reason for the extinction of dinosaurs which I will talk about next. Volcanoes: Volcanoes are one of the main suggested theories for the extinction of dinosaurs and are this theory is generally accepted by many scientists. Massive beds of ancient lava have been found around the world between 65 and 70 million years ago. If these massive eruptions really occurred, there would have been so much gas that the sun’s rays would not have been able to reach the surface of Earth and subsequently would mean poorly adapted creatures; like the dinosaurs would die. Even dinosaurs which survived would have lost many sources of food and could not survive. Scientists have found several pieces of evidence to back up the theory including; large lava flows in India which would be caused by volcanoes and fractured crystals which are caused by high impact or explosions, both asteroids and volcanoes could have caused this. However, some scientists believe that this theory cannot be correct; one reason is that there is a very large amount of iridium found where the asteroid hit and this layer is found all over the world which can only be explain by the asteroid impact. Another reason may be that not all parts of the world have volcanoes so; some parts of the world may not have been affected. Scientists also found that there was a global fall in temperature around the time dinosaurs died out, but massive volcano eruptions would have the opposite effect. Mammal Competition: Mammals could have been the reason for the extinction of dinosaurs. Mammals were quickly evolving and became fierce competition for the dinosaurs. Some packs of smaller mammals would take the dinosaurs food and carnivorous mammals would eat the eggs of dinosaurs. This would mean dinosaurs would have a harder time of getting food and even having babies! Dinosaurs would slowly become less and less dominate and eventually extinct. Unfortunately, this theory isn’t thought to be the real reason for the extinction of dinosaurs. Most mammals would not have been able to defend themselves against the dinosaurs and would have struggled to compete with the dinosaurs for some foods. This theory is also believed to be a contributing factor rather than a main one. Continental Drift/Climate Change: Some scientists believe that continental drift could have killed of all the dinosaurs. The continents were being moved upwards by the movement of tectonic plates which would cause the sea levels to fall and parts of the world were rising by thousands of feet. This would means that the climate would be a lot drier and cooler. The ecosystem providing for the dinosaurs would provide much less food for the dinosaurs and they would not be able to survive. This is another theory which scientists don’t believe is significant enough to wipe out the dinosaurs. There is no solid proof that the tectonic plate movement directly caused the global temperature to drop and many other theories have much more evidence to back themselves up including the asteroid impact and volcano theories. Yet again like the mammal competition theory, it may have been a contributing factor in the extinction of dinosaurs. Alternative Theories: Along with the theories previously mentioned, there are many more â€Å"less known† theories which are either not yet recognized or proven to be correct to a certain degree. It is extremely concerning that a theory could be found that almost comprehensively proves what caused the extinction of dinosaurs but because of how the media works, it may not be recognized or even forgotten over a long period of time. The first theory I will mention is an ice age wiping out all of the dinosaurs, however there has been no solid evidence of an ice age occurring during the life of the dinosaurs. Another theory is mammals out-competed the dinosaurs and forced them into extinction. Some evidence points to a simultaneous evolution between dinosaurs and mammals and some scientists believe some mammals ate dinosaur eggs. However, mammals and dinosaurs had different diets and could not wipe each other out. Furthermore, there were no more marine animals at the time and this means the marine reptiles could not be wiped out by this theory. My final alternative theory is the dinosaurs were never killed but they evolved into birds. Scientists agree there is significant evidence that suggests dinosaurs such as Velociraptors could have evolved into birds but that does not explain the extinction of several types of dinosaur, like the Tyrannosaurus Rex, which disappeared with no evolutionary trace. To finish, each of the theories contains a chance of proving the extinction of dinosaurs. Unfortunately, none of them provide enough evidence to be considered on a larger scale and much more evidence and information would have to be found to be considered like other theories such as the asteroid impact. Conclusion: The reason for extinction of dinosaurs has been debated for centuries and we still haven’t got a solid conclusion and it will probably never be found. Every person you meet can have a slightly different opinion on a topic and this clearly happens with what killed the dinosaurs. As the extinction of dinosaurs happened such a long time ago, unless huge technologic advancements occur where we can find evidence from millions of years ago and link to how they really died, we will never find the true answer. Another problem is when someone finds a new lead another scientists finds one to cancel it out for example; the volcanoes looked like the answer but then scientists saw the global temperature had been lower than usual which could is extremely unlikely due to all of the eruptions from the earthquakes! I really hope that in the future we can find the reason for the extinction of the dinosaurs, as it would not only be ground breaking in the aspect of opening the doors to extreme amounts of information and also helps us in our preservation of mankind if such a thing happened to us but at this current time, it seems we will not be able to find a solid reason on why the dinosaurs are extinct. However, in my opinion, I believe that the extinction of dinosaurs was not just one theory, but multiple theories which all contributed towards the extinction. I think that volcanoes started erupting in various places around the world as well as super volcanoes erupting; which killed off a large proportion of the dinosaurs, and then the continents start to rise and make the earth very cold, this would mean many life forms could not survive including most species of dinosaur. Then finally, the asteroid hit the Yucatan Peninsular and caused the final blow to the dinosaurs where the impact killed some dinosaurs the dust brought up would lower the temperature even further and surely met the end of the dinosaurs and they would soon become extinct.