Some Fun Facts About The Mesozoic Era That Will Leave You In Awe

Akinwalere Olaleye
Nov 01, 2023 By Akinwalere Olaleye
Originally Published on Jan 03, 2022
Earth was abundant with many coniferous trees

The term Mesozoic was coined by the English geologist John Phillips in the 1800s.

He was also the first person to create a global geological time scale. The term Mesozoic is derived from the Greek term for ‘middle life’, as the Mesozoic era falls in the middle of two different eras of the Phanerozoic timeline.

During the Jurassic period, there were several types of animals that were present on the Earth. This list includes giant herbivorous dinosaurs, smaller carnivorous dinosaurs, bird-like flying reptiles, rat-like mammals, and whale-sized marine reptiles.

Life went through a lot of diversification and adaptation during the Mesozoic era, which began around 252 million years ago after the end of the Paleozoic era. This era ended about 66 million years ago after a mass extinction, which gave rise to the Cenozoic era.

The three main periods into which the Mesozoic era are divided are the Triassic period, the Jurassic period, and the Cretaceous period respectively.

This era is famously known for being the age of dinosaurs, as they emerged and were annihilated during this era. They were the most powerful creatures that roamed our planet during the Mesozoic era.

Read on to know more about Mesozoic era animals. Afterward also check out Pisanosaurus: 19 facts you won’t believe and 55 Mesozoic era facts that are out of this world. 

What happened in the Mesozoic era?

The Mesozoic era is divided into three major periods: Triassic, Jurassic, and Cretaceous. The beginning of the Mesozoic era is marked by the largest mass extinction event which happened at the end of the Paleozoic era. This event wiped out almost 80% of living species from the face of the planet.

Ancestors of major groups of plants and animals surviving today are descended from primitive animals and plants which appeared during the Mesozoic era. The Mesozoic era also marked the beginning of a large scale of diversity which was occurring for the first time, mainly triggered by the previous extinction of older species.

One of the major events which took place in the Mesozoic era is the separation of Pangea. During that time, the Earth was a lot warmer compared to now and there were no polar ice caps.

All the continents of the Earth were a huge, single landmass, without any separate coastlines and seas in between. Hence, areas in the middle of the super-continent called Pangea were mainly covered with large expanses of deserts so Pangea experienced major temperature swings from time to time.

Continental rifting leading to the separation of the landmass into several fragments began in the late Triassic period. Pangea separated into two continents of Laurasia and Gondwana, which are roughly the northern and southern hemispheres in today’s age.

In the middle of the Jurassic period, these continents had drifted away to form more separated fragments, as Africa started to split from South America and India was separated from Antarctica and Australia.

Two of the largest volcanic eruptions in the history of Earth happened in the Mesozoic era.

These volcanic eruptions released a lot of carbon dioxide and harmful gases like sulfur into the air, which led to an imbalance in the food chain, and the extinction or decline of various life species during the era.

The Mesozoic era has also seen almost three mass extinctions, one which occurred at the very beginning, the second one at the end of the Triassic period, and the third occurred at the end of the Mesozoic era, which wiped out the entire species of dinosaurs from the face of the Earth.

During the Mesozoic era, the Earth was abundant with many coniferous trees and plants and the first flowering plants appeared in the late Cretaceous period. By the end of the Mesozoic era, the Pangea had separated into several continents which kept drifting away from each other.

Their positions ended up being quite similar to the continents as we see them today.

How did the Mesozoic era end?

The planet had already suffered great marine and biological losses during the mass extinction which occurred in the late Triassic period, about 201 million years ago. The event wiped out many species of amphibian animals, as well as plankton and major microbes which populated the waters of our planet.

The geological and fossil record reveals that because of this event, around the late Cretaceous period, there were some major changes taking place on our planet.

These changes were brought about by numerous volcanic explosions in some parts of the world; shifting of continental plates northwards into cooler climates, resulting in serious climate and environmental changes; and mountain building and falling sea levels due to this shift.

Fossil evidence suggests that these changes were significantly affecting plants as many of them started to go extinct; as well, the population of dinosaurs was declining.

All these factors culminated together in a climactic end when about 65 million years ago, a large asteroid hurtled towards the Earth and crashed, forming a giant crater.

This crater is present inside the Gulf of Mexico today and is named the Chicxulub crater. This asteroid impact led to the sudden extinction of many groups like ammonites and other microfossil species, which broke the balance of the marine life food chain.

The asteroid plunged the planet into darkness for a few months because of the ash it injected into the atmosphere.

Other effects were acid rain and wildfires which were followed by the planet heating up because of gases trapped inside the atmosphere.

This led to the literal suffocation of life on Earth, leading towards the end of the Mesozoic era in a mass extinction, which caused the death of all dinosaurs, one of the most powerful living things to walk on this planet.

Due to the fossil record being incomplete in many places, it is quite difficult to predict how these extinctions were caused, or how long it took to cause the ultimate effect.

Scientists also believe that fossils and geological evidence we have is incomplete, and it is impossible to discover the remains of all species which lived on our planet because of the ever-changing geological factors on Earth.

How did dinosaurs die?

Dinosaurs walked on this planet for about 175 million years. The first dinosaurs and marine reptiles like tortoises and lizards appeared during the Triassic period.

From that period, dinosaurs evolved into so many varieties which changed according to environmental changes, and their descendants adapted to their surroundings. Some of the most iconic dinosaurs existed during the third part of the Mesozoic era, the Cretaceous period, like the Triceratops, the Tyrannosaurus rex, and the Pteranodon.

Around the end of the Cretaceous period, major volcanic activity was happening on what is today the Deccan Traps located in India. These volcanoes were spewing huge amounts of lava and volcanic ash into the atmosphere.

This was not the only volcanic activity happening on the Earth, as evidence suggests that for about two million years prior to the mass extinction, there were several volcanic activities happening around the world from time to time that caused major climate changes.

Apart from this, the continents were also fragmenting and drifting apart from each other, leading to increasing the space of oceans between the land and causing changes in the atmospheric pattern all around the world. These climatic and temperature changes had a severe effect on plants and animals inhabiting the Earth at the time.

The event which sealed the deal on the extinction of dinosaurs is most likely when the huge asteroid crashed onto the surface of the Earth, kicking up vast amounts of dust and gases which got trapped into the atmosphere.

It is believed that the impact of the crater caused so much dust and ash that it blocked the sunlight and caused darkness for months.

This stopped the photosynthesis occurring in plants, causing them to die.

This in turn disrupted the food chain and herbivorous dinosaurs and other creatures who depended on vegetation began to die. This starved carnivores who survived on herbivores.

Only a few scavenger dinosaurs might have made it for some time, but the number of toxins like sulfur and carbon dioxide in the air might have resulted in their extinction as well.

Subsequently, the whole food chain collapsed drastically to lead to a mass extinction, which killed off all dinosaurs and almost 80% of the life on the planet. Only a few dinosaurs that were adapted to severe temperature changes, as well as some birds and a few mammals and insects, made it out alive from this mass extinction.

Events That Happened In The Mesozoic Era

During the Mesozoic era, the climate on Earth was warm on average and there were no polar ice caps to reduce the temperature on the planet.

The Mesozoic era is said to be the period of transition, which caused a lot of diversity in species of this planet and made it easier for living beings to bounce back from the mass extinction at the end of the Mesozoic era.

The Mesozoic era also marks the new beginning after the world’s largest mass extinction, which wiped out almost 70% of terrestrial species and 90% of marine invertebrate species.

The beginning of the Mesozoic era saw the recovery of various species of life forms, ecosystems, and the population numbers which had declined seriously during the mass extinction. This population recovered to normal, almost close to what we find today.

The Triassic period saw the rise of the first dinosaurs to become the dominant terrestrial vertebrates, who were a descendant of lizards. Other species which were dominant during the Triassic period included Therapsids, which were mammal-like reptiles; and Theoconds, which were ancestors of crocodiles and dinosaurs.

The first true mammals emerged in the late Triassic period, as well as the first flying dinosaurs called Pterosaurs.

Oceans were thriving with mollusks like bivalves, ammonites, and gastropods. Marine reptiles like Plesiosaurs, Ichthyosaurs, and Nothosaurus swam along with other fish. The mass extinction which happened at the end of the Triassic period wiped out many of these species, close to 35% of all living life.

This event somehow pushed marine ecological life to diversify more rapidly in the Jurassic and Cretaceous periods of the Mesozoic era. This mainly happened because the increased predation caused preyed creatures to develop better defenses and predators to adapt to these defenses.

The changes which occurred during this period were extremely significant to the future of marine life and this event is termed as the Mesozoic marine revolution.

Triassic-Jurassic extinction was initiated by sudden climate change during this time leading to a large extinction event that resulted in almost 70% of the flora and fauna on the Earth being wiped out. During this time, temperatures also dropped a bit and Pangea started to split apart due to marine transgression and inflow of water.

This led to another increase in the temperature.

As a result, the desired humidity levels were again achieved during the Jurassic period. After a temporary decline in the level of water in the sea during the Cretaceous period, water levels increased again and were noted to be at their highest during the Phanerozoic eon.

The Jurassic period saw the rise of dinosaurs to become the dominant animal group on the planet. The extinction of various species previously allowed these dinosaurs to colonize and become the most powerful over millions of years, as they went through a lot of diversity during this time.

During this period, many groups of mammals evolved. As well, the earliest birds evolved from their reptilian ancestors.

Placentals and marsupials, two of the most important modern groups of mammals, also emerged during this period. Ancestors of small reptiles like salamanders, frogs, and toads also appeared for the first time during the Mesozoic era.

The final period of the Mesozoic era, the Cretaceous period, which happened about 145 to 65 million years ago, saw the largest and the most diverse range of dinosaurs. Some of the most heaviest and brutal dinosaurs, like the Tyrannosaurus rex, lived in the Cretaceous period.

The end of the Mesozoic era was marked by the mass extinction, wiping out dinosaurs from the Earth.

Here at Kidadl, we have carefully created lots of interesting family-friendly facts for everyone to enjoy! If you liked our suggestions for Mesozoic era then why not take a look at Pisanosaurus: 19 Facts you won’t believe or 55 Mesozoic era facts that are out of this world.

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Written by Akinwalere Olaleye

Bachelor of Arts specializing in English Literature

Akinwalere Olaleye picture

Akinwalere OlaleyeBachelor of Arts specializing in English Literature

As a highly motivated, detail-oriented, and energetic individual, Olaleye's expertise lies in administrative and management operations. With extensive knowledge as an Editor and Communications Analyst, Olaleye excels in editing, writing, and media relations. Her commitment to upholding professional ethics and driving organizational growth sets her apart. She has a bachelor's degree in English Literature from the University of Benin, Edo State. 

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