Chapter 4: Rising oxygen levels in the ocean and the appearance of animals


    The scorching sun of the sixth day set in the sky and the night of the seventh day came. The Violet Herograss still flourished in the ocean.


    It has eliminated 99% of the other species, sessfully surviving the second mass extinction and dominating the entire ocean. It was the perfect species to thrive in the harsh environment where the sun and moonspassage took 5,000 years.


    At the same time, due to its massive spread, the photosynthesis of ocean nts has increased dramatically. This caused the oxygen content of seawater to greatly rise. The conditions suitable for the birth of marine creatures were in ce.


    Soon, the first invertebrates began to appear in the ocean. They were a group of ck beetles, simr in shape to the ancient species, the horseshoe crab.


    At this point, marine creatures have finally appeared on evolutions grand stage, and the state of nt-life has beenpletely stable after the Radiant Age. Life within the sandbox greeted a great evolutionary explosion. Species diversified.


    "Animals have finally appeared. I''ve had to wait for such a long time, too. Through two mass extinctions"


    The moment he saw the creatures appear, Xu Zhi smiled happily. His tired body that had no rest for a day and night finally couldn''t take it anymore, and so he returned to his room,y down, and fell asleep.


    When he woke up, it was the eighth day of creation in the evolutionary sandbox.


    "Ugh, gotta wash my face and brush my teeth."


    Xu Zhi got up from his bed, he was really hungry.


    If he did not take proper care of his body while being terminally ill, then he was just asking for an early death. He left thepound and rode on his bicycle while enjoying the bright sunshine. The countryside path was nked by neat paddy fields, and the air was indescribably fresh and natural.


    He went into town and ate breakfast before returning home. It was a little after nine o''clock in the morning when he got back.


    He continued to observe the sandbox.


    After one night, the forty square meters miniature ocean,parable to the size of a swimming pool, has changed dramatically. The ocean was alive with sea creatures! They were everywhere.


    The Violet Herograss had evolved into all sorts of strange and bizarre aquatic nts, some of which looked nothing like their great ancestor.


    As the dominant nt species, all of the oceans nt-life was its offspring.


    As for 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.


    They were the first creatures to evolve eyes. With their revolutionary visual system and their sturdy shell, all organisms were their prey!


    "Theyve already evolved the game-changing organ  the eyes" Xu Zhi had just returned from breakfast and was a little shocked to see that there were already such creatures.


    Most living creatures had eyes, this wasmon sense in the modern world.


    But in the Cambrian period, the first marine species were all blind. All living creatures were eyeless and swam blindly in the sea. For those who had evolved eyes, beating a group of sightless creatures was all too easy. They instantly ascended to the top of the food chain and prospered.


    The species with eyesight became the food chains mightiest creatures and started to reproduce inrge quantities, quickly eliminating the species that couldn''t evolve eyes. The entire ocean soon entered into a new era where all creatures had the gift of sight.


    But even with the evolution of eyes, the age of the invertebrates did notst 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.


    Xu Zhi spotted a ck fish swimming in the ocean.


    Different from the invertebrates of this era which had sturdy exoskeletons armoring their vulnerable flesh, vertebrates had skeletons enveloped in soft flesh instead.


    It might seem foolish of them to evolve in the opposite direction by putting their weak flesh on the outside and their hard bones on the inside, but thanks to a flexible skeletal structure built around their vertebral column, they were extremely dexterous.


    "One side has heavy full body armor with high defense, but is slow. The other side has light armor with low defense, but due to their superior dexterity, you can neither outrun them or eat them." Xu Zhi was sitting in the chair next to the ocean, peeling an apple. Heughed upon seeing this scene. It was a very interesting, yet also reasonable evolution.


    Both sides were in a stalemate.


    On the tenth day, this bnce was broken.


    A vertebrate species  a red colored fish  had evolved teeth and jaws, bing the first fish species with jaws in the world.


    Its axial skeleton now consisted of a spine connected to a skull, with powerful jaws and teeth that could easily bite through an invertebrates outer armor.


    The second revolutionary organ of the animal kingdom  the teeth  has appeared!


    The teeth, the most powerful weapon of the era after the eyes, changed the ecosystem of the entire ocean in an instant.


    Those armor-d ancestors of trilobites, shrimps, and crabs were preyed upon, their 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 has finallye!


    This fish-like species had a mouth and swam by using its spine to move its tail. It could already be considered a true fish species.


    It was not only the ancestor of all fish species, but also the ancestor of all vertebrates, including mankind.


    Even hundreds of millions of yearster, vertebrates would still dominate the food chain.


    At the moment, this little fish was still leisurely swimming in the sea,pletely ignorant of the glorious future that awaited it descendants.


    "Already, some animals are beginning to leave the great mother, the origin of all life  the ocean." As Xu Zhi looked on, he found that there were already marine animals that had started to be unsatisfied with thepetitive ocean environment and have evolved into amphibians, relocating to the empty coast.


    Marine nts have also started to climb ashore, bing terrestrial nts, and filling the barren, yellowedndscape with patches of greenery.


    However, due to Xu Zhi''s imposed gic limits, they evolved to be ant-sized, and even thergest nts were only finger-sized.


    After all, bigger was not better.


    The Hive Mother of the previous generation has stated before her death that there were mysterious life forms with enough power to destroy the world despite having tiny bodies. Compressed power gets concentrated and distilled. Energypressed into a small body will undergo a qualitative change.


    These tiny primordial species had extraordinary potential!


    As Xu Zhi made that observation, he started a new page in his evolutionary records. Taking notes with his clear and beautiful handwriting, he named the new era the Revival Age.


    "The Revival Age ushered in new life. This era saw the explosive birth of many animal species. The appearance of the first marine animals started an age of great prosperity and heroicpetition. Invertebrates relied on their hard carapaces to dominate the ocean for a time, briefly bing the masters of the era. Then vertebrates were born, and with their superior dexterity, they defeated the invertebrates, and became the true masters of the Revival Age, ruling for many long epochs!"


    Xu Zhi finished writing down everything and closed the notebook silently.


    He also turned around and walked away from the harshlypetitive sandbox world.


    "Itll be quick now. In the time it takes for me to finish breakfast, the spores should finish leaving the ocean and evolve into terrestrial species"


    Even when granted such a small patch ofnd to reproduce in, the Tyranis spores had evolved into many diverse species, and formed the beginnings of an ecosystem.


    Xu Zhi suddenly frowned, "However, who knows how long itll take for intelligent life to appear. Since theres already an ecosystem, why don''t I do some tests?"


    He looked at his hand and considered cutting his finger and letting his blood drip into the sandbox. The species that absorb his genes would be able to quickly evolve into intelligent humanoid creatures


    But after a moment of thought, he rejected this idea; human experimentation made him feel a little uneasy. "I remember there''s a zoo in town. I could quietly collect the fur of a few monkeys and acquire their gic samples"


    He immediately headed out.