|Ancestors of Living Creatures Edition: Silurian|
We have now come to the third edition of the Silurian Age. This period started from 443 to 416 million years ago, which is quite short when compared to the previous period.
At this time Gondwana still continues to dominate the south and continues to grow, while the northern hemisphere is still filled with oceans. Although one of them, Siberia, is now getting farther away, approaching the Devonian period, Baltica and Laurentia have instead united to form the continent of Euramerica.
With the end of the Ordovician Period, during which parts of Gondwana formed glaciers, the climate of the Silurian period began to warm and become more stable. As a result, all the ice there melts and makes sea levels rise again.
The land of Gondwana is smaller than during the Ordovician period. So what is the conclusion from rising sea levels? Life there is flourishing again!
Not only that, even the formation of ice that used to make many animals extinct, melting even left new life on land and freshwater ecosystems appeared in the estuaries that were formed.
Since those who moved to land have not seen it, we still talk a lot about what is in the sea. The first marine plants. As I said earlier, various corals are starting to grow a lot.
Algae and bryozoa from ancient times also still exist. Trilobites reached their peak of species diversity only until the Ordovician epoch. The diversity of its species in the Silurian period is decreasing. In addition, we will find more Eurypterids, of course, more developed.
Now let's open the meet-and-greet session for the Silurian-age species guest:
Smaller than their grandfather Megalograptus, I introduce the species Eurypterus. Arthropods that have small elongated tails make them different from their cousins.
What makes me more suspicious is that they don't have big claws like their other siblings, but instead have big forelegs like turtles.
Regardless, Eurypterus remained a carnivore. With their small claws, they can crush and devour their prey. Their true tiny feet (two tortoise-like legs are just a type of flipper) also aid them in gripping prey beneath them.
Unlike the Eurypterus species whose origins are questionable, Pterygotus is a dangerous predator in the Silurian seas.
With two tiny eyes on the top and two on the bottom, Pterygotus' eyesight was practically as sharp as a spider's. Supported by their quick response, they can catch their prey all at once. Though the way they eat is only camouflage and waiting on the ground.
At number three is the veteran gastropod, namely Platyceras. The shell has evolved from the creature that carried the house above the previous body, namely the Cameroceras species. What was once long, big, and strong, turned into a curvy. The size is also smaller, only about an inch.
Apart from information about the symbiosis between Platyceras and Crinoids (sea animals similar to plants), unfortunately, there is no further information about these tiny creatures. Even more realistic illustrations could not be found. Naturally, their new family will be more developed in the future which I will write about later in the Devonian period.
Still a jawless fish again, his name is Jamoytius. This half-eel-shaped catfish was originally associated with anapsid reptiles (animals without curved bones, such as turtles). However, after the discovery of more and more fossils, Jamoytius finally entered the same group as lampreys, etc.
Shaped like a marlin fish, there are long fins all over his body. For their way of eating, although associated with lamprey fish, they are known as detritivores, namely carrion eaters.
With the end of the Silurian period, fish began to diversify. Jawless fish are getting more and more, and jawed fish are starting to appear and exist.
Although still the same as Jamoytius, both jawless fish, Thelodus this type of food is more carnivorous. Overall, the morphology of this fish is quite modern for its time. With larger fins that extend downward, Thelodus' swimming ability was more advanced than that of the other Agnathas.
There is one more animal that currently holds the title as the first land animal. Say hello to Myriapoda (centipedes and the like) by the name of Pneumodesmus!
They were millipedes measuring only one centimeter in size, but despite their size, they were the first creatures to adapt to land air. And of course this is a great innovation! What allows us today to set foot on land, instead of floating our bodies in the ocean.
The first plant finally appeared and lived during the Silurian age, namely Cooksonia!
Broadly speaking, they are the forerunner of all land plants. They are quite small, only a few inches, and quite simple in shape, of a long stalk with sporangia on top. They have roots, but no leaves.
Cooksonia grows by absorbing extra sunlight. Then in terms of reproduction, they spread the spores they produce. In this way, Cooksonia could cover the entire Silurian landmass! You can imagine, the land was all yellow at that time.
Note: There are no major events in the period between the Silurian and Devonian. But extinctions still exist, albeit on a small scale.
The next period that I will write about in the next article is quite special, you could say a special period where fish are rampant. As I said earlier, freshwater ecosystems are starting to develop. Plus the road for land plants is already there, let time and evolution go by, tall trees will appear and spread roots quickly.
That's all I'm talking about this Silurian era. If you have any questions, disclaimers or additions, you can comment here. For the future, I guarantee it will be very unique and interesting to wait for, just wait for my next writings about this edition.