Earth Before Dinosaurs-part 2

Earth Before Dinosaurs-part 2

Earth Before Dinosaurs: We talked about this in part one. Now we will continue the same discussion. A summary of the previous topics is as follows:

• Pentecopterus: Early arthropod with long spiked tails and grabby claws, reaching over 5 1/2 feet in length; terrifying but not the top predator.
• Cameroceras: A predatory cephalopod, related to modern octopuses and squids, reaching up to 23 feet in length; top of the food chain, feasting on armored arthropods like sea scorpions.
• Algae Evolution: Primitive algae, present since the Cambrian, evolved and spread onto damp land areas as moss during the Ordovician period.
• Flora's Impact: These early plants absorbed carbon dioxide and released oxygen, setting the stage for the eventual transformation of Earth’s atmosphere and ecosystems.
• Ordovician Mass Extinction: The period ended around 443 million years ago with a mass extinction event caused by an ice age.

Now we go back to the continuation.

Earth Before Dinosaurs: a millipede the size of a car

Earth Before Dinosaurs: Take the Arthropleura, a millipede the size of a car. Seriously, this thing could've reached a terrifying 8 1/2 feet long. Fortunately for any smaller critters around at the time, millipedes have always been vegetarians. Phew, not that many critters were exactly small, even among those with wings.

The aptly named Meganeura was one of the largest flying insects to ever live, with a wingspan of 2 1/2 feet. That's about the same size as an American crow. The tetrapods also exploded in diversity, both on land and in the water.

The early amphibian Diplocaulus evolved in this era and was a complete weirdo. This three foot long freak sported a strange boomerang-shaped head that experts suggest could've helped it to glide through the water or deter predators.

It'd be hard for anything to swallow this guy. But it was outside of the water that the tetrapods made their next giant leap. See, no matter how much time they'd been spending on land, they were still forced to return to the water to give birth.

That was, until an incredible evolutionary adaptation changed everything. Terrestrial tetrapods started laying eggs with hard shells. These fancy new eggs were able to keep amniotic fluid inside their walls, negating the need to be laid directly in water, and the shells also protected the young inside from predators.

With that, tetrapods would uncouple themselves from life in the water for the first time ever. These were the very first amniotes, the ancestors to most modern land animals. Plus, we're only a few hundred million years out from the first omelet.

Earth Before Dinosaurs: until around 335 million years ago

Earth Before Dinosaurs: It's pretty lucky that the tetrapods developed this amazing adaptation when they did, because the end of the Carboniferous period would change the planet entirely, again. Earth's various land masses had been gradually shifting over the preceding millions of years, until around 335 million years ago they all collided together and formed one super continent, Pangea. But what exactly did this mean for life on Earth?

Well, the lush rainforests that covered the planet suddenly found themselves struggling. They became fragmented and scattered, and the formation of the supercontinent meant trees that once had access to copious water now found themselves inland and quickly dried up. This destroyed habitats and consequently lowered the incredible oxygen levels in the atmosphere.

Couple this with dropping temperatures and a wave of oncoming glaciation, and the rainforests were done for. The formation of Pangea had started a domino effect that brought the Carboniferous period crashing down around 299 million years ago. In its wake was a much drier, less forested world largely unrecognizable to what had come before.

Many species went extinct due to this massive climate change, including the giant arthropods who relied on lots of oxygen. But the amniotes stayed strong. With no need to return to water to reproduce and a scaly body to prevent water loss, the stage was set for them to take over the world.

Earth Before Dinosaurs: sauropsids

Earth Before Dinosaurs: Split into synapsids, the group that would become mammals, and sauropsids, the group that would evolve into reptiles and birds, it was all coming together. The next era, the Permian, began with a rise in temperature. The glaciers that had formed at the end of the previous period slowly melted away, with the most inland areas becoming dry deserts.

And the supercontinent would only get hotter as the period went on. Life was difficult, so the animals that thrived were the ones capable of conserving water most effectively. Those synapsids and sauropsids I mentioned earlier had diversified and spread across Pangea, becoming the dominant land animals. But it was the synapsids that truly ruled the Permian. They were slowly but surely evolving and becoming more like mammals.

Dimetrodon was one such creature, a big mean boy. Probably the most iconic animal of the time, this thing was so menacing that it's often misconstrued as a dinosaur. In reality, it's more closely related to you and me. It was the top predator of the early Permian, reaching intimidating lengths of 15 feet. It'd be tough not to be top dog when you're as big as an SUV.

Consensus is still split on what that big old sail was used for. Some scientists say it helped regulate body temperature, while others believe it was used to attract potential mates. Personally, I like to think it was a handy place to hang Christmas decorations.

Despite enjoying great success, Dimetrodon did eventually die out though after its 16 million year tenure. Taking the crown as the middle to late Permian's apex pred was another group of synapsids, the gorgonopsians. No, they're not Star Trek villains. These ugly mugs weren't as big as Dimetrodon, the largest species, Inostrancevia came in at only 11 feet long, but they were deadly.

Earth Before Dinosaurs: Gorgonopsians

Earth Before Dinosaurs: Gorgonopsians had a mouth filled with six inch long, saber-like canines, probably used to shear the skin off their prey. That's freaking terrifying. And they'd have turned these teeth on animals like the lumbering sauropsid Scutosaurus, slow, armored herbivores that had to walk for miles to hunt down scant vegetation.

But enough of the lame Scutosaurus, the Permian era also gave birth to the greatest animal to ever live. You ready? Okay, let me introduce you to the Cotylorhynchus. Damn, just look at his tiny little head. No neck at all on that lad.

What an adorable little plant munching freak. But don't get too attached to him. Remember when I said that the Permian would only get hotter? I meant it. Over the course of a million years, a series of extensive volcanic eruptions began to tear through what is now Siberia.

These eruptions spread unbelievable amounts of burning hot lava across the planet. I'm talking, giant lava beds half the size of the United States, all spewing colossal amounts of carbon dioxide into the atmosphere. All this CO2 trapped heat within the ozone layer, raising the Earth's temperature dramatically and forcing animals to adapt or die.

Marine animals fared no better than those on land. The ocean absorbed some of the carbon dioxide, making the water dangerously acidic. Then the hotter temperatures ignited wildfires on land that burned down what foliage remained, incinerating forests and exposing previously hidden rocks.

Earth Before Dinosaurs: an explosion of life

Earth Before Dinosaurs: These quickly eroded and the nutrients left behind ran off into the ocean, unwittingly causing an explosion of life. Oh, awesome. I was getting worried. So, things all turned around, right? Well, no. Actually, the overwhelming number of new lifeforms turned out to be less a blessing and more of a curse.

They absorbed what little oxygen remained in the sea, suffocating any creatures that had survived the initial onslaught.

By the end of the Permian around 251 million years ago, this apocalyptic event had reached a fever pitch. Since termed the Great Dying, it was the single most devastating mass extinction the world has ever seen, and the closest life has ever come to disappearing entirely. A shocking 70% of land animals and 90% of sea creatures were wiped from the face of the Earth. Yikes.

The tiny number of beasties that survived these end times were left with a husk of a world. All the periods of prehistory we've covered so far were grouped into an overarching era known as the Palaeozoic meaning ancient life. With the Great Dying, it wasn't just the Permian that ended, but the entire Palaeozoic with it. That's a nearly 300 million year span. But history didn't just end.

Earth Before Dinosaurs: synapsids

Earth Before Dinosaurs: Life carried on, and with it, the dawn of a new era—the Mesozoic Era, a time that would eventually see the reign of the dinosaurs. However, the start of the Mesozoic was far more modest. It began with the Triassic period, a time when life was still recovering from the devastating mass extinction known as the Great Dying.

The first five million years of the Triassic were spent in a slow process of rebuilding, with ecosystems gradually stabilizing and evolving. During this time, life struggled to re-establish itself, but eventually, new dominant species emerged.

As species adapted and evolved, the groundwork was laid for the rise of the archosaurs, and soon after, the early dinosaurs that would go on to conquer the world. However, in these early days of the Triassic, Earth’s ecosystems were still fragile, and it took time for life to fully bounce back.

Despite the slow start, this period marked the beginning of a remarkable transformation in the history of life on Earth—one that would shape the planet for millions of years to come.

This new world was a supremely difficult place to live, and the few species that stood a chance would need to be pretty darn resilient. Most of the synapsids, sadly, didn't have what it takes. They were utterly devastated by the Great Dying. And though a handful did survive to eventually evolve into modern mammals, they'd take a backseat for a long time.

The sauropsids on the other hand, well, they were perfectly suited. Given their ability to survive away from water due to their hard-shelled eggs, and retain moisture with those scales, they not only recovered, they utterly dominated the planet.

Indeed, the Triassic saw sauropsids diversify and evolve at a rapid rate never seen before. Some took to the empty oceans, evolving into the very first marine reptiles like Ichthyosaurs, a bizarre and terrifying fish-like beasts that hunted using some of the largest eyes in the animal kingdom. Alongside them, the plesiosaurs would eventually patrol the seas too.

Earth Before Dinosaurs: Sharivopteryx

Earth Before Dinosaurs: The Triassic period was full of strange and fascinating evolutionary experiments. Among the more bizarre creatures were those with monumentally long necks, which likely gave them an edge in hunting by allowing them to approach prey stealthily. These marine reptiles thrived for millions of years, adapting to their environments in remarkable ways.

On land, creatures like the Drepanosaurus took a different route, evolving to live in trees. This strange, tree-dwelling reptile may have behaved like modern lemurs or sloths, possibly hanging from its tail much like the curious aye-aye.

Drepanosaurus had a distinctive adaptation—a super long claw that was perfect for poking around inside insect nests on tree branches. With its monkey-like behavior, Drepanosaurus was essentially a "monkey lizard."

But life in the trees wasn’t the final evolutionary frontier for these reptiles. Some ventured into the skies, experimenting with early forms of flight. One of the more peculiar attempts at this was the Sharovipteryx, a small reptile that, unlike any flying creature we know today, had wings on its hind limbs rather than its front ones.

This odd design didn't allow for true flight—Sharovipteryx could only manage a clumsy glide through the air. As expected, this experimental body plan didn’t last into the modern era.

However, by the late Triassic, the evolution of flight had been perfected in the form of pterosaurs. These flying reptiles had hollow, air-filled bones, making them light enough to sustain proper flight.

Their wings stretched from their forearms, across their bodies, and all the way to their ankles, allowing for efficient, graceful movement through the air. This innovation was key to the success of pterosaurs, marking them as the first true flying vertebrates.

In essence, the Triassic period was a time of wild experimentation in both the air and trees, leading to the remarkable evolution of creatures that would come to dominate their respective environments for millions of years.

Earth Before Dinosaurs: Sharivopteryx

Earth Before Dinosaurs: In other words, the archosaurs were game changers. While their distant relative, Sharovipteryx, may have been an early example of a gliding reptile, the archosaurs took things to a whole new level. But let's not just stay in the air and sea—it's time to talk about what was happening on dry land.

After the Great Dying, a mass extinction event, the once-dominant synapsids (the ancestors of mammals) were mostly wiped out. This opened the door for another group to rise to power—the sauropsids, and more specifically, a new subclass known as the archosaurs.

The archosaurs were incredibly successful for a number of reasons. One major factor was their highly efficient respiratory system. Oxygen levels were likely low during the Triassic, due to the enormous amounts of CO2 lingering in the atmosphere after the mass extinction event.

Many species struggled in these harsh conditions, but the archosaurs thrived. Their unique respiratory system allowed them to efficiently extract oxygen from the air, even in environments where it was scarce, giving them a crucial advantage over other species.

But that wasn't the only trait that helped them rise to dominance. Archosaurs also made significant progress in evolving upright limbs—a seemingly small but transformative development. It might not sound like much, but this change gave them a massive advantage.

You see, most early tetrapods (four-limbed animals) had limbs that stretched outward from their bodies, similar to how modern lizards move. These animals walked by flexing their bodies from side to side, which had a big drawback: it shunted stale air back and forth between their lungs, preventing them from efficiently expelling old air and taking in fresh oxygen.

This limitation made it difficult for early tetrapods to breathe and walk at the same time. Not ideal for a predator (or prey) on the move! However, when archosaurs evolved upright limbs, it allowed them to walk with their bodies held more vertically.

This not only freed up their breathing mechanisms but also enabled them to move with greater endurance and efficiency. They no longer had to sacrifice breathing for movement. As a result, archosaurs could move faster, breathe easier, and survive in environments that were challenging for other species.

This evolutionary advantage allowed archosaurs to rise to the top of the food chain on land, and they became the precursors to some of the most iconic creatures in history—dinosaurs. Their superior respiratory system and upright posture set the stage for a future of dominance on Earth, ushering in a new era of terrestrial life that would eventually lead to the reign of the dinosaurs.

In short, the evolution of archosaurs was a game-changing moment in the history of life on Earth, and it all started with their ability to breathe better and move smarter.

Earth Before Dinosaurs: last part

Earth Before Dinosaurs: Archosaurs were truly the dominant force of their time, and among them, Postosuchus stood as one of the most formidable and fearsome creatures. This 15-foot-long apex predator was a nightmarish blend of what we now recognize as both a Tyrannosaurus rex and a crocodile:

a combination that undoubtedly struck terror into anything unfortunate enough to cross its path. With its large, razor-sharp teeth and a body built for ambush and power, Postosuchus ruled the land with unmatched ferocity.

Despite its intimidating appearance and size, Postosuchus was an incredibly effective predator not just because of its bulk, but also due to its stalking abilities. Experts suggest that Postosuchus primarily moved around on all fours, likely sneaking up on unsuspecting prey.

However, this beast had a terrifying trick up its sleeve. When it got close enough to its target, it could rise onto its hind legs, bringing its massive jaws down onto its prey's neck or spine with devastating accuracy and force. This combination of stealth, power, and adaptability made Postosuchus one of the most fearsome creatures of the Triassic period.

But Postosuchus wasn't alone in its dominance. In fact, it shared its reign with other archosaurs, a group that would soon produce the most famous and dominant creatures in history—dinosaurs.

The middle of the Triassic period saw a monumental turning point in Earth's evolutionary history. Among the many archosaurs roaming the land, there appeared a few new, seemingly unremarkable species that would ultimately change everything. These were the first dinosaurs.

At first glance, these early dinosaurs might not have seemed too different from their archosaur relatives. But they possessed one key advantage—an astonishingly fast breeding rate.

This rapid reproduction allowed them to spread and evolve quickly, adapting to different environments and conditions across the globe. As they multiplied, they began to outcompete their archosaur cousins, gradually taking over ecosystems and pushing even fearsome predators like Postosuchus to the brink.

With each generation, dinosaurs grew more diverse and specialized. Over time, they would rise to become the dominant force on Earth, ushering in a new age—the Mesozoic Era, often called the Age of Dinosaurs. This era would last for millions of years, with dinosaurs reigning supreme across the planet's continents.

The rise of dinosaurs marked one of the most significant evolutionary shifts in Earth's history. Their appearance was a testament to the adaptability and resilience of life, as they evolved from humble beginnings to become the kings and queens of their world.

Their story is not just one of survival but of conquest, as they gradually took over from creatures like Postosuchus and transformed the landscape of life on Earth forever.you can read more about Earth Before Dinosaurs Here. you can also watch more about Earth Before Dinosaurs: