What Was the Earth Like after Dinosaurs?

Imagine yourself as a dinosaur walking across the endless savannah in search of food about 66 million years ago. In a blink of an eye, the bright sunny day becomes even brighter. Lifting your large head in confusion, you notice your tribe running away in panic. A rock measuring six miles across, which will only be named by ape descendants 66 million years later, falls on your home. In a split second, everything you've ever known disappears. Literally. Everything in the 900 mile radius turned to dust. Just like you, your species, and the entire savannah. What can we say? That was a bad day. But life goes on, right? How did such catastrophic events define the course of evolution and life on earth? How was life preserved? And what did it become after the dinosaurs? A cataclysm caused by an asteroid impact, more precisely the Cretaceous-Paleogene extinction, became a turning point when one domineering species is replaced by another. Because death is always the beginning of a new life for someone or something else. But what took place of the giant reptiles first? This is where we come across our first pitfall, faced by everyone who took interest in the fate of dinosaurs. Many people think that the asteroid crash resulted in all dinosaurs becoming extinct within one or two days after the impact. But that's far from the truth. The species that were outside of the 900 mile zone of instant destruction had to face challenges. Huge tsunamis reaching 300 feet in height, endless forest fires caused by the flow of scorching hot air, and trillions of tons of earth and rock launched into the atmosphere, making the planet practically uninhabitable. But the actual extinction is a very long process. At first, the planet was launched into almost complete darkness. Trillions of tons of dust and soot lifted into the atmosphere, shielded the planet from sunlight for literal years. Furthermore, research indicated that the first 600 to 700 days after the impact, the dust concentration was so great, the sky was entirely covered. An eternal night of sorts. Except without the moon or stars. As a result, the lack of photosynthesis, which in a very short time killed most of the plant species, including the royalty of the floral world at the time, the ferns, which in itself is already a terrible ecological catastrophe. But perhaps the main consequence of the remaining living beings was the global cooling. The thing is, the Yucatan Peninsula that sustained the impact of the asteroid has been, and still is, rich in minerals containing sulfur. As the sulfur aerosols lifted into the atmosphere, they practically turned it into a climate blanket, preventing the energy generated by the sun to heat the surface of the earth. This type of darkness continued for years, but the actual cooling has only happened for a short period. From the geological point of view, only a million years. But during this time, it significantly influenced the species diversity on the entire planet. Now let's get our facts together. The long and very destructive night that killed the majority of nutritious plants resulted in the large part of herbivorous dinosaurs being on the edge of extinction. Which in turn meant these large predators started losing their source of food, which made dinosaur extinction just a matter of time. It isn't known exactly when the very last dinosaur died, whether that was a few decades or a half million years later. We know one thing for sure. Between the start of extinction and the end of planet cooling, all large animals have disappeared. We're talking about anything weighing upward of 55 pounds. This number is more nominal, but it reflects the fact that beings with larger body mass and faster metabolism just couldn't find enough food to sustain them. The era of giant lizards was steadily coming to its end. But what came next? The most sophisticated viewers might say it was mammals. Small, savvy creatures that in the dinosaur era rarely surpassed the size of a mouse conquered the world. But it's not quite what happened. The truth of the matter is any significant climate event rearranges the food chain. However, the unbearable living conditions and the absence of available food resulted in surviving organisms forming isolated enclaves where life slowly developed and evolved on a relatively small scale. This way, the space at the top of the food chain remained vacant after the fall of the dinosaurs for the next 15 million years. That's how long it took for the planet's ecosystem to restore and enable larger creatures, including mammals, to exist. Only after some time when significant areas of earth have changed from dense jungle to sparse forest, life out in the open contributed to mammals increasing in size. Before that, all of our mammal ancestors were small, omnivorous beings, something between rodents and lizards. We deliberately highlighted their omnivorous diet. It was one of the key factors that resulted in their effective survival. It's worth noting that the first therapsids, which was the name given to the first proto-mammals, didn't come to existence after the dinosaurs or even at the dawn of their existence. Formerly, they branched off the pelicosaur species, which was a common ancestor of mammals and dinosaurs 272 million years ago. This is what our common ancestor looked like, by the way, which over time evolved into something much more familiar. For millions of years, mammals were at the bottom of the food chain, becoming prey to larger and more aggressive tetrapods, the dinosaurs. However, the asteroid made some changes over the next few million years, and slowly but surely mammals filled the vacant population niches, predominantly on the ground and next to large bodies of water. Only a few managed to get established in the air or in the deep water. But why? Up there, animals had their own special struggle for a place under the sun. It's particularly telling that the sky is the only environment where the only direct relatives of dinosaurs known as Maniraptorus has survived. A small number of them managed to survive, and over the next 15 million years produced the offspring resembling modern birds. That might strike you as odd. A pigeon or a penguin didn't look very similar to a T-Rex, but the connection is there, right down to the bone structure. When the extinction occurred, the traits developed by birds over millions of years became the deciding factor in their survival. Entire groups of avians, including the toothed birds known as the Ananthiornans, became extinct. It's unlikely that only one trait decided their fate, and yet survival in a mass extinction event often relies on luck, and the beak was like an ace for some birds. By the end of the Creotius period, birds with a beak had a more diverse diet than their toothed counterparts. These birds didn't focus on insects or other live prey, which enabled them to harvest seeds and nuts. When the animal world has significantly reduced in size because of the extinction event, this type of food allows the beak birds to survive the hard times. What's funny is that today the closest direct relative of the dinosaurs, that's the creature that underwent the least change on the chromosome level, and that's a chicken. So if you want to have a short tour into the fauna of the Creotius period and observe the way real dinosaurs used to act, take a look at the nearest chicken coop. But if you want to know what the first birds looked like, you should take a trip to the Amazon rainforest. The only living representative of one of the oldest avian species that originated 64 million years ago is the Huatzen bird. If you take a close look at this incredible bird, you'll see the resemblance between a Huatzen and the reconstructed model of a semi-bird, semi-reptile creature created based on excavated bones. Young Huatzen birds have an interesting vestige inherited from the proto birds, namely the two claws on the bones supporting their flight feathers, kind of like hands. If the baby bird falls out of the nest, which is a common cause of death for a young bird, the Huatzen offspring can use the claw to get to safety. The mass extinction affected the deep blue seas too. Down there, the extinction created vacancy for the unique species niches. The world's oceans experienced their own revolution, where the monstrous mosasaurs and megalodons were replaced by fish. More precisely, ray-finned fishes or actinophergy, named for bony spines on their fins arranged like rays of light. Again, the ability to quickly adapt to the new situation played its part, just as it did with the proto birds. Today, the ray-finned fish make up over 95% of all fish species known to science. The fish were gradually taking over the sea just as the mammals took over the land after dinosaurs went extinct. Scientists quote the disappearance of the majority of the ammonites as one of the main reasons for the successful population of ray-finned fish. Ammonites are the relatives of the modern calamilari, octopi, and other cephalopods. They were a very prolific species and insatiable customers of tiny plankton, which was the main food supply of regular fish. In a way, they presented as much danger to the fish as giant water reptiles. The sequence of events that triggered their extinction is very simple, not unlike what happened on land. Due to the absence of photosynthesis, the large number of phytoplankton, which feeds the regular zooplankton, had died. And without it, supporting the voracious population of ammonites was simply impossible. It is interesting that when studying the fossils from that time period, the scientists discovered that the population of ancient Carleogenus fish, which includes species like sharks and rays, didn't suffer a significant reduction in size. We can't know for sure, but it appears that the sharks did not pose a serious danger to the ray-finned fish, which allowed the latter to fill almost all the vacant niches. Perhaps it's due to its relatively small population size. Whatever it was, this baby boom in the population of ray-finned fish was so significant, it became known as the new era of fish. Why new? Because at one point, the water-dwelling dinosaurs already took this title from the sharks. The first fish era took place during the Devonian period, which lasted from 417 to 354 million years ago. This is when the first fish came to exist, including sharks and rays. This new era of fish lasted for at least the first 24 million years of the Cenozoic era, which followed the Creeaxus period. After this, fish made space for certain mammals, such as whales and cachalots, that decided to venture into the water. To this day, ray-finned fish are the most diverse water-dwelling vertebrates. While other animals may seem larger or more advanced, fish are still the most predominant species in evolutionary terms. But let's get back to the land, where yet another fourth evolutionary battle for survival was happening at the time. Despite the vast diversity of gymnosperms, mostly evergreen plants and ferns, their heyday is suddenly interrupted at the end of the Creeaxus period. At the same speed as the gymnosperms disappeared, the flowering plants entered the arena. Let's take a look at how it happened and how it affected the evolution of the animal population during the Cenozoic era. The thing is, ancient species of gymnosperms and ferns were designed to exist in a wet climate, and when they found themselves in unsuitable living conditions, they quickly started to die off. All the while, the young species of flowering plants managed to adapt to the new environment and quickly took over the land. One of the main factors in the victory of the flowering plants was the development of so-called double fertilization, which contributed to their vitality and adaptability to the new environmental conditions. The transition from gymnosperms to flowering plants was without exaggeration one of the most important leaps in the history of plant life. Their evolutionary fight for survival radically changed the face of plant life on earth and caused a real revolution in nature. The gloomy and monochrome forest made up of gymnosperms and ferns were replaced with flowering plants, diverse in both shape and color. Besides, the flowering plants created a more nutritious, undoubtedly better food supply for the animals. Around the same time, during the Cenozoic era, the first grain plants came to exist. As such, the evolution of many animal species revolved around their interaction with the first flowering plants. The entire groups of living beings, such as carnivorous and seed-eating monkeys, could continue living surrounded only by flowering plants. In turn, animals became the most effective method for transporting fruit and seed across long distances. The influence of flowering plants was so great, we can confidently state that they played a major role in the development of great apes, and consequently you and me. People. Homo sapiens. The Cenozoic era is an incredible period in earth's history. It was if the crash of the asteroid destroyed a colorful puzzle where giant reptiles ruled the world. After breaking into a million pieces, the puzzles came back together but revealed an entirely new picture, where you can clearly see the remnants of the past. This is the era of amazing creatures that look like they came directly from ancient myths and tales. The saber-toothed metatherian tiger called Thylacosmalus that reached the size of a jaguar. The walking whale known as Ambulocetus, which only 20 million years later, after the catastrophe, would finally come to live under the water, reproducing descendants like orcas, whales, and cachalots. The saber-toothed elephant, Deanotherium, and the hippo ancestor that looks more like a giraffe known as the Paraceratherium. That's just a fraction of the species diversity that expanded in such an explosive fashion, allowing the mammals to take the key position in the food chain. Though this tight and mutually beneficial interaction, the flora and the fauna revived after a global cataclysm that destroyed the mass majority of life on this planet. The Cenozoic era marked the end of existence for some species, gave way to others more complex and diverse organisms, confirming yet again the cynical yet endlessly true thesis that death is not the end, but the beginning of something new.