Every Dinosaur Period Explained in 10 Minutes

0:00 Triacic period. It's 252 million years ago and the Peran Triacic extinction event, also called the Great Dying, has just happened, wiping out an estimated 96% of marine species and 70% of terrestrial vertebrate species. It's thought to have been caused by massive prolonged volcanic eruptions in the Siberian traps in modern-day Russia. These eruptions released enormous amounts of greenhouse gases that triggered climate change. Around this time, Earth was essentially depleted and had just one single superc continent called pangia. It was mostly composed of desert with arid conditions. While more coastal regions experienced strong seasonal rains and winds. However, even though the conditions were this harsh, not all forms of life went extinct. Within the small percentage that survived, we can find some resilient

0:45 plants like these ones and most importantly synapsids, the group that includes mammals and their ancient relatives and arosaurs. Now, what we really care about is the arcosaurs. You see, at that time there were no real dinosaurs in the proper sense of the word, but rather their predecessors. You could have seen creatures like ichthyosaurs and proterosucus. By contrast, mammals still played a marginal role at the time, existing as small and likely nocturnal creatures. The real change, however, happened around 230 million years ago in the southern part of Pangia, which is now modern-day South America. Here, the first examples of dinosaurs appeared, such as Eoraptor and Herrerasaurus. However, they didn't look like how you might imagine them. They were really small. For example, Eoraptor was about 3.3 ft long, much much smaller than a human. However, this wasn't necessarily a disadvantage. Their small stature made

1:31 them incredibly agile. This was supported by an impressive evolutionary feet they developed. Their legs were positioned directly beneath their bodies rather than sprawling outwards like contemporary lizards. This allowed them to stand on two legs, giving them much more speed and stamina, both for running away and for chasing. While dinosaurs weren't very diversified at the beginning, they started to diversify as the triacic period progressed. Therapods, the group of typically two-legged meat- eatating dinosaurs that would later include some of the giants we'll talk about later, started to appear. Soropotamorphs, the dinosaurs characterized by long necks and large size, also began emerging. A first trend of change occurred when Platoaurus, a long necked sorropottomorph from Europe that was 10 m long, began to thrive. It signaled a broader trend toward increasing size and herbivy in some lineages. However, just as Earth was

2:18 beginning to repopulate and these new forms of life were developing, a new catastrophic event occurred around 20 million years ago. The Entryacic extinction brought an end to all of this. The leading hypothesis attributes this extinction to massive volcanic activity associated with a huge area of volcanic rock that formed as pangia began to rift apart. Once again, these eruptions released vast amounts of greenhouse gases, destabilizing the climate. Most life on Earth was wiped out. About 76% of all species, including most large amphibians, the remaining large synapsids, except the lineage leading to mammals, many marine reptiles, and crucially, the large terrestrial arcosaur competitors of the dinosaurs, such as the Rowisukians. The main survivors were turtles, crocodilians, early mammals, paterosaurs, and most importantly, dinosaurs. With their main rivals gone,

3:04 these survivors had a fresh start to take over the world. Jurassic period. Following the entryic extinction event, a new period began. It's called the age of giants because this is when we finally witnessed the definitive rise of dinosaurs. The superc continent pangia continued its slow fragmentation, primarily splitting into two major land masses. Lorasia in the north, comprising future North America and Eurasia, and Gonduana in the south with the rest of the world. This rifting created new coastlines and shallow inland seas leading to a generally warmer, wetter, and more stable climate compared to the harsh idity of the triacic. In a sort of chain reaction, this caused extensive forests to flourish, which provided abundant food sources crucial for supporting large herbivores. Everything seemed to aid the dinosaurs growth as the dominant species, and in fact, they

3:51 rapidly diversified and grew to enormous sizes. Two main groups of dinosaurs started to dominate the landscape. The first was the soropods, the iconic long- necked four-legged herbivores that descended from the smaller soropottomorphs of the triacic like platiosaurus. These guys achieved colossal dimensions. For example, Brachiosaurus, which was one of them, had a neck so long that he could look over trees to scout the area. Diploicus and Apodosaurus, two other iconic dinosaurs, were also soropods. Their immense size not only served as a defense against predators, but also as a necessity for processing vast quantities of relatively low nutrition plants in extensive digestive systems. The second major group was the theropods, which came straight from the triacic period. These guys roamed on two legs and were carnivores, having all the traits of

4:37 standard predators. Sharp and recurved teeth, powerful claws, and agile movement on two legs. One of the most common dinosaurs from this group was Allosaurus, a predator so effective that it's said to have hunted soropods or Stegosaurus. They're usually confused with T-Rexes, but they're not the same. They're just long-distant relatives. Another iconic dinosaur from the therapod group that developed around this time was seratosaurus, famous for the horn on its snout. However, not all dinosaurs were necessarily incredibly big. Smaller ones continued to exist. And matter of fact, one of the smallest dinosaurs of all time is found in this era. Compsson, a dinosaur that was as big as a chicken and hunted small lizards and insects. As a fun fact, birds originated specifically from the theropod group with archopterics possessing feathers alongside reptilian

5:22 features like teeth and a bony tail. It's important to note, however, that while therapods and sorropods were the two main groups of dinosaurs, there was an important third one, the ornithysians. These guys, also known as the birdhipped dinosaurs, were entirely herbivorous and developed interesting strategies for feeding and defense. Stegosaurus, for example, developed a distinctive double row of plates along its back, likely for display or thermmorreulation, and a spiked tail to defend itself from predators. The first examples of armored dinosaurs were also part of the ornithysians group, like the earliest ancestors of the later Ankyosaurs, which had bony plates for protection. Around this time, the seas were dominated by placaurs and plyosaurs, while the skies were ruled by pasosaurs, which diversified greatly, ranging from the long-tailed ramper hinkus to the short-tailed

6:07 pterodactylus. Mammals on the other hand remained marginal just like in the triacic period being mostly nocturnal and insectiviverous. However, around 145 million years ago, another significant ecological transition occurred. This wasn't as brutal as the previous mass extinction events, but it did bring about substantial change. Likely due to rising sea levels, environmental shifts, climate fluctuations, and the continued drifting apart of pangia, the world transformed. Many iconic Jurassic dinosaur groups like stegosaurs and certain large soropod lineages declined or went extinct. This marked the beginning of a new era, Cretaceous period. This is probably the most interesting period for dinosaurs. Not only did diversity reach its peak, but it's also when the most famous and iconic species appeared. During the Cretaceous period, continental drift

6:53 continued and the superc continents Laurasia and Gonduana fragmented further, moving toward the modern arrangement of continents. This separation created vast new coastlines and global sea levels were incredibly high, contributing to a generally warm greenhouse climate worldwide. This brought about another important change, the spread and diversification of flowering plants. Because of this, new insects like bees and butterflies began to appear. As for therapods, Tyrannosaurus Rex with its massive skull and powerful bite dominated late Cretaceous North America. While other large carnivores like Carnotaurus, known for its horns, and Spinosaurus, a massive semi-aquatic predator, thrived elsewhere, smaller feathered therapods related to birds such as Velociraptor and True Dantids, also became quite important. While older soropods like

7:38 Brachiosaurus declined and disappeared, a new group became important within the soropod family, the titanosaurs. They were called this because they were enormous with species like Argentinosaurus and Patagotatin reaching lengths over 98 ft and weights possibly exceeding 154,000 lb making them the largest land animals ever known. Ornithysians however were the most diverse group of all during this period. Dinosaurs like Edmontosaurus and Parasaurolophus which belonged to a subgroup called duckbuild dinosaurs became common and showed signs of complex social behaviors such as hering and nesting colonies. The horned dinosaurs called sereratopsians like the famous Triceratops flourished in North America and Asia. Also, boneheaded dinosaurs like patchy sephilosaurus characterized by their thickened skull domes possibly used in headbutting

8:25 contests began to thrive. Unfortunately, ichthyiosaurs, which we mentioned previously in the triacic period, declined and disappeared early in the Cretaceous. However, pleiosaurs continued alongside the rise of mosasaurs. Enormous marine lizards related to modern monitor lizards which became apex predators in many marine environments. In the skies, terasaurs persisted producing gigantic forms like quitzel katlas with wingspans rivaling small aircraft. Mammals on the other hand while still playing a marginal role began diversifying with some becoming herbivores or small carnivores. It was around this time that the ancestors of modern placental, marsupial and monotream mammals emerged. This incredibly diverse ecosystem, however, was brought to an abrupt end 66 million years ago with the Cretaceous Paleogene extinction event. A large asteroid or

9:11 comet approximately 10 km wide struck the Yucatan Peninsula, creating the Chickixel Crater. This impact triggered catastrophic environmental consequences, including widespread wildfires, tsunamis, and the ejection of massive amounts of dust and aerosols into the atmosphere. This blocked sunlight and caused a prolonged winter, leading to the collapse of global food chains. The event resulted in the extinction of roughly 75% of all species on Earth, including all non-bird dinosaurs, paterosaurs, mosasaurs, and plesiosaurs. However, survivors included birds, mammals, crocodilians, turtles, lizards, snakes, amphibians, fish, insects, and flowering plants. This set the stage for the subsequent cenazoic era known as the age of mammals. But that's a topic for another video. If you like this video,

9:57 subscribe for similar ones or join my Discord to suggest another.