The Devonian Period started at the close of the Silurian (~419mya) and ends at the beginning of the Carboniferous (~360mya). During this time the supercontinent of Gondwana was located in the Southern Hemisphere while the continent of Siberia was to the North with the formation of the small Euramerica in between. The two continents of Gondwana and Euramerica were already predestined to collide together in the near future...and they'll one day form another super-continent; Pangaea.
In aquatic environments the fish continued to greatly diverse, giving the Devonian Period a nickname of the "Age of Fish". During this period we see the introduction of ray-finned and lobe-finned bony fish. Also in the Devonian; placoderms were able to dominate almost all marine environments. Creatures such as the trilobites and giant coral reefs were still quite common and even more new faces emerged such as the ammonites.
Meanwhile, on land, the free-sporing vascular plants spread throughout the lands, creating vast forests across the continents. By the middle of the Devonian several groups of plants grew leaves and developed true roots. Lastly, the earliest seed-bearing plants made their distribution at the end of the Devonian.
Terrestrial arthropods secured a strong foundation in their ecosystems.
But perhaps the biggest milestone of the Devonian was when the ancestors to all tetrapods (four-limbed vertebrates) adjusted their strong pectoral and pelvis fins to form legs -- these were the amphibians. Amphibians have soft skin that must be kept damp, this prohibited them from venturing too far from the water otherwise their skin would dry out. Nonetheless, this was still a big step for life on land.
The Silurian Period lasted for ±25 million years from the end of the Ordovician Period (~444mya) to the beginning of the Devonian Period (~419mya).
As evolution progressed the very first jaws appeared among bony fish. This feature will be a great evolutionary success and will continue to evolve for hundred of millions of years into the future. Meanwhile, on land, life continued to advance little by little... Terrestrial arthropods such as Pneumodesmus were first found in the Silurian rocks. The first vascular plants also evolved in the second portion of the Silurian, plants such as the small Cooksonia (as seen in the image above). Aside from these, terrestrial life will not significantly conquer the land until the Devonian Period...
The Ordovician will be the next period we cover. It spans from the end of the Cambrian (~485mya) to the beginning of the Silurian (~444mya) and just like its predecessor the Cambrian, the Ordovician will also be jam packed with new life... The marine environments consisted of various algae, graptolites, trilobites, brachiopods, cephalopods, some corals, crinoids, gastropods, primitive fish, and conodonts. The Ordovician truly marked the beginning of true vertebrates as well as fish, these fish were known as ostracoderms. Ostracoderms were jawless, armored fish with bony shields on their heads, small plate-like scales on their tails, and slit-like mouths. An example of this would be Astrapis. The Ordovician also started the colonization of the land. Fossils of some early, terrestrial arthropods are known in addition to microfossils of the cells, cuticles, and spores of early land plants -- although these were restricted to the shorelines...
However, the planet itself also had it's fair share of action... Europe, South America, Africa, Antarctica, and Australia formed the supercontinent Gondwana and was slowly moving towards the South Pole during the Ordovician Period. Meanwhile, North America was mostly submerged in the ocean and was stuck straddling the equator. As the Ordovician started coming to a close severe glaciation occurred in Africa, resulting in global sea levels to drop. This glaciation played a role in the disturbance of ecosystems worldwide and another mass extinction.
Woke up, had my daily lunch date with J. Daniels a little earlier than usual today.
Had to continue what seemed like a perpetual inebriation if I was going to make it until it was time for my 4 hours of sleep. Things were starting to get better, but I guess that was too unusual for me to let it continue. I felt like a stranger in my own body. Like if I was missing the inside joke that was my own existence.
Oh squiggly line in my eye fluid. I see you lurking there on the periphery of my vision. But when I try to look at you, you scurry away. Are you shy, squiggly line? Why only when I ignore you, do you return to the center of my eye? Oh, squiggly line, it’s alright, you are forgiven.
There are multiple ways terrorism is defined. Many different groups use and define it differently. Just because you pull a specific dictionary definition you want to use doesn't mean it might be the most correct version so stop being a c*unt. You know who you are
For those who haven't caught their own shiny Pokemon before and are discouraged, give the SOS method a shot. I've played Pokemon for a total of six years so far, and I've caught 4 shinies during that time, 2 of those being a shiny Grubbin and shiny Rockruff that I've caught about 4 days apart this month. You WILL get a shiny this way if you are patient. Good luck! :D
It all started with an inception. A united wake up call to a group of veteran game developers gathered under the banner of a simple vision: create fun and meaningful game experience again. We don’t ask for much. We don’t need much. We want to share with you the fruit of our passion. Introducing our “precioooousss”, EDEN – Renaissance:
News of cataclysm is spreading all around the world… Something is cooking. Governments are meeting each other, cities are in turmoil, and people can feel the tension around them everyday, expecting more bad news…
What could cause all this fuss worldwide? Planet warming is not at this critical stage yet. Something seems to be at the origin of it… something not yet discovered but yet feels so familiar…
Meanwhile, on the other side of the planet… studies are being done on a strange crystal formation at the heart of the icy earth. A young and motivated boy is working hard to uncover more knowledge and secret from this apparently simple rock. But what started as a mere rock referencing tedious task became much more for our young archeologist, Ran
Adventurous can be a dangerous trait when couple with curiosity…
Ran seems like he is getting closer to the truth of the crystal And maybe uncover deeper secret within the Earth?
Time is tight. But so is the mission. Ran can smell the reward… and yet cannot see it.
uh, uh.. it doesn't sound very good, does it? I don’t know, don’t look at me… and now.. without signal, without the professor, alone in the dark… with only shadows surrounding him... what is going to happen? Ran's journey is about to begin! Follow us, we will tell you all about it! To be continued…