What Killed the Dinosaurs

Introduction: I have decided to answer this question, as the extinction of dinosaurs has interested me since I was very young and I thought that by answering it, I could learn a lot more about what happened and broaden my knowledge of the subject! Answering about the dinosaurs would also keep me interested in the topic as I am working on it and I do not fully understand many parts so as I work on the case study I can learn more and stop myself from becoming bored. 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 "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:

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.