Whenever we hear the name Dinosaur, the first picture that comes to our mind is a giant animal with a long neck, a huge mouth and a long tail. A snapshot from the Jurassic Park movie, maybe! It is pretty apparent because, more than seeing in pictures the fossils and remains of the giant animal that once existed on Earth, we tend to recall the moving character of the movie.
Yes, dinosaurs existed and lived on the same Earth that we live on now. The place where you are reading this might be the resting place of a giant Dinosaur some million years ago, or it could be where the last living Dinosaur breathed last. It sounds fascinating and scary for some, but it is true that they were there, lived but could not survive for long.
- Credit: Pixabay
The Dinosaur: A Believable Mystery
Although the exact origin and time of the evolution of the Dinosaurs are not clear, the giant reptile species was an obvious animal during the middle and late Triassic Period of the Mesozoic Era. It was about 233 to 243 million years ago. However, the Dinosaurs are the dominant species in the Jurassic and Cretaceous periods, from which the name of the movie Jurassic Park has derived.
The studies report that today, the only species the closest to the extinct species are the birds that have evolved from the Feathered Dinosaurs.
Dinosaurs are a species that existed in the prehistoric period of the planet, and their existence traces back to about 230 million years ago. Thus, dinosaurs are a significant part of the reptile clade Dinosauria.
It is a diverse group of reptiles that includes species of different shapes and sizes. They existed in the world for more than 140 million years, and in some parts, they have even survived for 20 million years more. The reptile group includes around 300 genera and more than 700 species. This diversified group consists of dinosaurs like Spinosaurus, which is enormous, and species like Microraptor, which is as small as a chicken. Even being reptiles, the Dinosaurs had an upright stance with their legs positioned under their bodies. It made their weight more balanced, irrespective of their size.
- Credit: ABC news
Dinosaurs are members of a subclass of reptiles called the archosaurs. This subclass includes crocodiles and birds as well. So it very well justifies the similarity we see between the Dinosaurs and crocodiles.
Like the other reptile species, dinosaurs used to lay eggs for reproduction. The entire reproduction and genetic production process is very similar to birds. They also build their nests, sit on the eggs after laying and brood them like any bird today. However, dinosaurs are believed to be very special in terms of parental care. The adults care for their younger newly hatched ones for the first several months. After that, they feed them, make them learn skills and, finally, after being able to live on their own, the adults set them free.
While dinosaurs were originally bipedal, several ancient groups featured quadrupedal animals, and some were able to switch between them. All dinosaur groups shared elaborate display features such as horns or crests, while some extinct species evolved skeletal changes like bone armour and spines.
Classification of Dinosaurs
While the present avian lineage is usually tiny due to flying limitations, several prehistoric dinosaurs had enormous bodies. The biggest sauropod dinosaurs are believed to have measured 39.7 metres (130 feet) in length and 18 metres (59 feet) in height, making them the largest terrestrial creatures of all time. The widespread belief that non-avian dinosaurs were consistently massive stems in part from preservation bias, since huge, strong bones are more likely to survive until they are fossilised. Many dinosaurs were relatively tiny, with some only reaching 50 centimetres (20 inches) in length.
How Do We Know About Dinosaurs?
Palaeontology is the subject of the sciences that study ancient life. Here, researchers study the lives of the planet that existed from the prehistoric period, or even before that. The study includes mammals, reptiles, plants, aquatic life, fungi, insects and even microspecies. The study of Dinosaurs also features under the curriculum of Paleontology.
During the 1820s, the first-ever traces of giant dinosaurs were discovered in the countryside of England. People presumed it to be the bones of a colossal land reptile or a giant lizard. However, the term ‘Dinosaur’ was first coined by Richard Owen, the renowned palaeontologist from Britain, in 1842.
Studies on Dinosaurs
Owen, during his study, observed a few significant differences which made the species distinct from the other reptiles. He studied the bones of three different species – Megalosaurus, Iguanodon and Hylaeosaurus. He found that all three species are land reptiles, have a different and upright body structure and, above all, much larger than any living reptile of the time. His examination and research of the bones resulted in creating a new reptile group, ‘Dinosauria’. The word comes from two ancient Greek words – ‘dinos, meaning terrible, and Saurus, which means reptile or lizard.
The traces of dinosaurs are sporadic. Usually, an animal or a living creature in the ancient period is found from its fossils. But, there are very few traces of Dinosaur fossils that could provide more information. Moreover, it is a land animal, and it becomes more challenging to find the remains of an animal who lives on land. Therefore, scientists have reported that the physical remains of the Dinosaurs ever found must have lived near a river or a lake or any large water body.
- Credit: Pixabay
How do the Dinosaur Fossils form?
The primary source to know about an ancient animal’s existence is by studying the fossils. When an animal dies, its body, along with various circumstances, turns into a fossil. So, even though the Dinosaurs lived 230 million years ago, we have gained quite a good amount of knowledge of them from fossils.
Fossils are the preserved remains of an animal. It is a very long process and needs much favour from natural phenomena to turn an animal into a fossil. Nevertheless, it is nature’s way of preserving the evidence of its ancient animals and living organisms.
For the formation of a fossil of an animal, there are specific criteria that we should meet. When an animal dies, the soft parts of the body rot away, and scavengers in nature consume a part of it. Therefore, for the formation of a fossil, the body must be buried by mud, sand or silt. If the body does not get buried under the sediment, it comes into contact with more oxygen, starts to decompose, and physical traces of the body do not remain.
After the burial, more sediment layers get formed above, which puts more pressure and turns it into sedimentary rock. Finally, with the contact of minerals in the water, the body’s remains turn into stones. However, the entire process takes millions of years.
The contact of water is significant in the formation process of the fossils. That is one of the reasons we do not witness many fossils of the Dinosaurs or any animal that lived on the land, as we see about the aquatic animals. However, from the fossils we have found of dinosaurs to date, the palaeontologists strongly believed that they must have lived near water bodies.
Types of Dinosaurs
Due to incomplete fossil records and lack of enough evidence, the researchers have not confirmed the exact numbers of the total species of Dinosaurs. However, some believe that there are over 300 genera and more than 700 valid species of them validated and named.
But, if we have to quote Mark Norell, the Macaulay Curator and chair in the Division of Paleontology. The quote goes, “Of the extinct Dinosaurs, the traditional Dinosaurs, that disappeared about sixty-five point four million years ago, there are about twelve or thirteen hundred different species which have been named. So, if you are talking about those, the twelve or thirteen hundred; if you are talking about the totality of dinosaurs, we would say that it is over ten thousand plus one thousand three hundred or so. So, it is an extraordinarily diverse group.”
However, there are some names of the selected species of dinosaurs you should know about. Have a look at the list.
From the Triassic period
- Coelophysis bauri
From the Jurassic period
- Plateosaurus engelhardti
- Allosaurus fragilis
- Apatosaurus excelsus
- Barosaurus lentus
- Camarasaurus lentus
- Camptosaurus dispar
- Diplodocus longus
- Mamenchisaurus hochuanensis
- Ornitholestes hermanni
- Stegosaurus stenops
From the Cretaceous period
- Albertosaurus libratus
- Anatotitan copei
- Ankylosaurus magniventris
- Argentinosaurus huinculensis
- Centrosaurus apterus
- Chasmosaurus kaiseni /belli
- Corythosaurus Casuarius
- Deinonychus anthiroppus
- Edmontonia rugosidens
- Edmontosaurus annectens
- Hesperornis regalis
- Hypacrosaurus altispinus
- Lambeosaurus lambei
- Microvenator celer
- Oviraptor philoceratops
- Pachycephalosaurus wyomingensis
- Prosaurolophus maximus
- Psittacosaurus mongoliensis
- Saurolophus osborni
- Sauropelta edwardsi
- Saurornithoides mongoliensis
- Struthiomimus Altus
- Styracosaurus albertensis
- Tenontosaurus tilletti
- Triceratops horridus
- Tyrannosaurus rex
- Velociraptor mongoliensis
- Credit: National Geographic
Names of Dinosaurs
Since you have already learnt about different types of dinosaurs, and some are very hard to pronounce, there is a way to find out about the species just by looking at the name.
Any species – living or extinct, has a scientific name for it. The Dinosaurs also have to follow this International Code of Zoological Nomenclature, according to which the scientific name should include two parts. The first part is called the genus, and the second part is called the specific epithet.
The name of the dinosaurs is according to their anatomical structure and behaviour. The names contain Greek and Latin roots and a particular part of each name contains the code of behaviour of the specific species of the Dinosaur. Let us have a look.
- Allo – Strange
- Apato – Deceptive
- Bronto – Thunder
- Cerat – Horned
- Compso – Pretty
- Deinos – Terrible
- Echino – Spiked
- Elasmo – Plated
- Mega – Huge
- Micro – Small
- Nodo – Lumpy
- Ops – Face
- Ornitho – Bird
- Raptor – Robber
- Rex – King
- Saur/Saurus – Lizard
- Stego – Roof
- Tri – Three
- Tyranno – Tyrant
Now that you know about the hidden meanings, you can find out the different characteristics and the behavioural differences of the Dinosaurs.
Facts about Dinosaurs
There are some interesting factors which you would like to know.
- The fossils of dinosaurs exist across all seven continents.
- The Non-Avian Dinosaurs went extinct about 66 million years ago.
- The skulls of the dinosaurs had a hole between the eye socket and nostril.
- Some of the dinosaurs had two holes behind the eye socket.
- The different species of dinosaurs could walk on two legs, four legs, and some could switch between both walking styles.
- No fossils of dinosaurs were found on the rocks younger than 65 million years ago.
- Credit: National Geographic
How did Dinosaurs go extinct?
The extinction of dinosaurs from the world is a big question mark to date. Despite many theories and factual evidence which somewhat conclude things, many scientists are still putting their efforts into researching the more convincing reasons for the extinction of such a dominant and powerful animal from the world.
The primary and widely accepted reason responsible for the mass extinction of the dinosaurs is the impact of an incoming object from outer space. In the books of Geology, the history of the Earth’s living organisms is divided into three broad periods – the Paleozoic, Mesozoic and Cenozoic. The Mesozoic is the era when the dinosaurs lived.
These periods are well-distinguished and can be observed in the formation of the rocks of the mountains. The rocks formed in the Mesozoic and Cenozoic periods are differentiated between a solid visible rock layer called the KT Boundary or Cretaceous-Tertiary Boundary. The distinct thicker layer of the rocks defines that the threshold of the two periods witnessed a significant change in the entire biodiversity of the planet. In addition, different rock formations in the KT Boundary also suggest that something huge happened at the end of the Mesozoic era, which has changed the whole biodiversity.
Research on Theories
This led to the scope of more research around the world and further resulted in the particles found in the KT Boundary containing radium to the extent that there must have been an external impact on Earth.
With all the research results in hand, Luis and Walter Alvarez from the University of California proposed a hypothesis that an asteroid from outer space might have hit the Earth, leaving all lives to death. He also proposes that the size of the asteroid was about 10 km in diameter, as large as Mt. Everest and weighed hundreds of billions of tonnes. Further research and studies have revealed that the hypothesis was absolutely correct. The impact crater was the Chicxulub crater that hit the Yucatan Peninsula in Mexico.
The asteroid impacted the Earth’s atmosphere at 80000 km/hr and heated the temperature of the planet several times more than the sun. The energy released by the impact is equivalent to 100 million nuclear bombs exploding at one time. The debris created from it has covered the Earth’s orbit and rained back to the surface. The debris blocked the sun for months, and the photosynthesis of the planet has stopped. The food chain has been affected widely across the planet. Everything depending on the sun for survival has been lost immediately.
Theories of Extinction
The whole ecosystem of the planet has been destroyed in a snap, taking the lives of all the living organisms. Within the 1000 kilometres around the impact, death came instantly. The dinosaurs living away died afterwards. Due to the size of the dinosaurs, they suffered the most impact. Bigger animals usually have a lower population and a lower reproduction cycle. That even accelerated the mass extinction of the dinosaurs.
Another theory that holds a valid standpoint is cholecalciferol deficiency among the species. This Vitamin D3 deficiency might have led to the malnourishment of the dinosaur’s eggs and could have caused death even before hatching. This hit hard on the reproduction process of the dinosaurs and caused the gradual extinction of them from the world. However, the asteroid’s impact is a more evidential reason responsible for the extinction of the dinosaurs.
Another theory that holds a valid standpoint is cholecalciferol deficiency among the species. This Vitamin D3 deficiency might have led to the malnourishment of the Dinosaur eggs and could have caused death even before hatching. Moreover, it hit hard on the reproduction process of the dinosaurs and caused the gradual extinction of them from the world.
After millions of years of their extinction, the dinosaurs remain one of the most fascinating species ever lived in the past. People get mesmerised by imagining its size, shape, and variety of species holding different behaviours and food habits.
Most of the dinosaurs were herbivores. They lived depending on the natural sources of the food chain. However, some predatory species were dependent on the herbivorous Dinosaurs to balance the ecological food chain.
Despite being a dominating animal, the Dinosaurs got extinct by leaving almost a negligible trace to know more about it. Due to size, the more giant species have much fewer fossil records available in the natural preservation. Again, with less contact with water, nature could not preserve the fossils of the animal.
In such a scenario, the only dinosaur we get to live with is the birds. And, if we want to experience the age when the Dinosaurs existed, the artificial imaginary Jurassic World Park is the only place to go. But, unfortunately, even though the reptile is practical and physical evidence, the only memory associated with the word Dinosaur is an animated character from the movie.