The scorching sun of the sixth day set in the sky, and the night of the seventh day arrived. The Violet Herograss continued to flourish in the ocean.
It had eliminated 99% of the other species, successfully surviving the second mass extinction and dominating the entire ocean. It was the perfect species to thrive in the harsh environment shaped by the passage of the sun and moon over 5,000 years.
At the same time, due to its massive spread, the photosynthesis of ocean plants increased dramatically, causing the oxygen content of seawater to rise significantly. Conditions were now suitable for the emergence of marine creatures.
Soon, the first invertebrates began to appear in the ocean. They resembled a group of black beetles, similar in shape to the ancient horseshoe crab.
At this point, marine creatures finally appeared on evolution's grand stage, and the state of plant life had stabilized completely after the Radiant Age. Life within the sandbox experienced a great evolutionary explosion, leading to a diversification of species.
"Animals have finally appeared! I've waited so long for this, even through two mass extinctions," Ethan exclaimed, smiling happily at the sight of the creatures.
However, his tired body, which had gone without rest for a day and night, could take no more. He returned to his room, lay down, and fell asleep.
When he woke up, it was the eighth day of creation in the evolutionary sandbox.
"Ugh, I need to wash my face and brush my teeth," he said to himself.
Ethan got up from his bed, feeling quite hungry. If he did not take proper care of his body while battling terminal illness, he was only inviting an early death. He left the compound and rode his bicycle, enjoying the bright sunshine. The countryside path was flanked by neat paddy fields, and the air was fresh and invigorating.
After eating breakfast in town, he returned home a little after nine o'clock in the morning.
He resumed observing the sandbox.
After one night, the forty-square-meter miniature ocean—comparable to the size of a swimming pool—had changed dramatically. The ocean was teeming with sea creatures! They were everywhere.
The Violet Herograss had evolved into various strange and bizarre aquatic plants, some of which bore little resemblance to their great ancestor. As the dominant plant species, all the ocean's plant life was its offspring.
Among the oceanic creatures, the dominant species at the top of the food chain were the arthropods. With their sturdy exoskeletons, they possessed the strongest armor and had no natural enemies.
The strongest of them all, an ancient trilobite-like insect, dominated the oceans.
These were the first creatures to evolve eyes. With their revolutionary visual system and sturdy shells, they turned all organisms into their prey.
"They've already evolved the game-changing organ—the eyes!" Ethan said, shocked to see such creatures appearing so soon after breakfast.
In the modern world, most living creatures had eyes, making this fact seem trivial. However, during the Cambrian period, the first marine species were all blind. They swam blindly in the sea, and for those with eyesight, defeating a group of sightless creatures was all too easy. They quickly ascended to the top of the food chain and thrived.
Species with sight became the mightiest creatures in the food chain, reproducing rapidly and swiftly eliminating those that could not evolve eyes. The entire ocean soon entered a new era where all creatures possessed the gift of sight.
However, even with the evolution of eyes, the age of the invertebrates did not last long. Another 5,000-year cycle of sun and moon passed, and on the ninth day, the true dominant species of the ancient era—the vertebrates—appeared.
Ethan spotted a black fish swimming in the ocean.
Unlike the invertebrates of this era, which had sturdy exoskeletons protecting their vulnerable flesh, vertebrates had skeletons enveloped in soft tissue.
It might seem counterintuitive for them to evolve in the opposite direction, with their delicate flesh on the outside and hard bones on the inside, but their flexible skeletal structure built around their vertebral column granted them extreme dexterity.
"One side has heavy, full-body armor with high defense but is slow. The other side has light armor with low defense, but thanks to their superior agility, they are neither easy to catch nor outrun," Ethan observed, sitting in a chair beside the ocean and peeling an apple. He laughed at this intriguing yet reasonable evolution.
Both sides were in a stalemate.
On the tenth day, this balance was broken.
A vertebrate species—a red-colored fish—evolved teeth and jaws, becoming the first fish species in the world to possess jaws.
Its axial skeleton now consisted of a spine connected to a skull, equipped with powerful jaws and teeth capable of easily biting through the exoskeletons of invertebrates.
The second revolutionary organ of the animal kingdom—the teeth—had emerged!
These teeth, the most powerful weapon of the era after the eyes, transformed the ecosystem of the entire ocean in an instant. The armor-clad ancestors of trilobites, shrimps, and crabs became prey, their once-mighty defensive shells cracked open to reveal the tender flesh within. The carapace was no longer invincible.
On the tenth day, the era where vertebrates reigned had finally begun!
This fish-like species, equipped with a mouth, swam by using its spine to propel its tail. It could already be considered a true fish species. Not only was it the ancestor of all fish species, but it was also the ancestor of all vertebrates, including mankind.
Even hundreds of millions of years later, vertebrates would still dominate the food chain.
At that moment, this little fish was leisurely swimming in the sea, completely unaware of the glorious future that awaited its descendants.
"Some animals are already beginning to leave the great mother—the origin of all life, the ocean," Ethan noted, observing that certain marine creatures had become dissatisfied with the competitive ocean environment and had evolved into amphibians, relocating to the empty coast.
Marine plants had also begun to climb ashore, transforming into terrestrial plants and filling the barren, yellowed landscape with patches of greenery.
However, due to the genetic limits imposed by Ethan, they evolved to a diminutive size, with even the largest plants measuring only finger-length.
After all, bigger is not always better.
The Hive Mother of the previous generation had stated before her death that there were mysterious life forms with enough power to destroy the world despite their tiny bodies. Compressed power becomes concentrated and distilled; energy compressed into a small body undergoes a qualitative change.
These tiny primordial species held extraordinary potential!
As Ethan made these observations, he began a new page in his evolutionary records. With clear and beautiful handwriting, he named the new era the Revival Age.
"The Revival Age has ushered in new life. This era witnessed the explosive birth of many animal species. The appearance of the first marine animals initiated an age of great prosperity and heroic competition. Invertebrates relied on their hard carapaces to dominate the ocean for a time, briefly becoming the masters of the era. Then vertebrates emerged, and with their superior agility, they defeated the invertebrates, becoming the true masters of the Revival Age, ruling for many epochs!"
After completing his notes, Ethan closed the notebook silently.
He then turned away from the fiercely competitive sandbox world.
"It will be quick now. In the time it takes for me to finish breakfast, the spores should complete their emergence from the ocean and evolve into terrestrial species."
Even when granted such a small patch of land to reproduce in, the Tyranis spores had evolved into many diverse species and formed the beginnings of an ecosystem.
Ethan suddenly frowned. "However, who knows how long it will take for intelligent life to appear? Since there's already an ecosystem, why don't I conduct some tests?"
He considered cutting his finger and letting his blood drip into the sandbox. The species that absorbed his genes could quickly evolve into intelligent humanoid creatures.
But after a moment of thought, he rejected this idea; the notion of human experimentation made him uneasy. "I remember there's a zoo in town. I could quietly collect the fur of a few monkeys and acquire their genetic samples."
He immediately headed out.