Earth 200 million years ago was a very different place from now, for starters, Earth only had one continent Pangaea which later with tectonic plates moving split into many more continents that we have today. So, all of today’s continents can fit inside Pangaea almost perfectly.
Pangaea was surrounded by a gigantic ocean Panthalassa or old Pacific which covered 70% of the whole surface.
Source: File: Pangea continents and oceans.svg – https://en.wikipedia.org
So, then what would be going back in time and spending a day on earth 200 million years ago were like, it should be noted that a day in earth 200 million years ago was around 23 hours not 24 hours. So, let’s put you in the North American part of Pangaea which was ruled by dinosaurs as well as the whole surface. Generally, reptiles and cold-blooded creatures were all over Pangaea. So, let’s say, you were roaming around in one of the forests where it would be quite an experience you would see many aliens like species or at least many different species that didn’t survive or adapt and are not present in today’s world. I mean Just think about, it is estimated that 99% of all species that ever existed on earth went extinct and 20 million years ago many more mass extinction events were to come. So, just in the forests, you would see many species of fascinating trees, insects, and reptiles that didn’t get to survive, and you would see how they move, eat, and live. It would be the greatest throwback in time but, there would be no flowers, bees, ants, snakes, any mammals, and tons upon tons of species and nurse that are present today. The whole surface would look somewhat different many mountains have been formed that are not here today, as well as many ancient deserts. Interestingly part of Antarctica was not covered in snow, there was no snowy wasteland. Since, that Antarctica was a bit closer to the equator, meaning there maybe was a huge chunk of the desert as well as parts that were covered with vegetation. So, today’s Antarctica is nothing alike old Antarctica which possibly had forests with many organisms living in it. The climate of the whole planet was as well the very different distribution of cold and warm temperature because of continents which changed wind paths. Occasionally while roaming around Asian forests a group of flying reptiles Pterosaurs with their 10-meter wingspan would fly over.
Source: File: Pteranodon sternbergi pair.jpg – https://en.wikipedia.org
Finding dinosaurs on Pangaea as well wouldn’t be very hard since they are the top predators before mammals from finding a Raptor theropod dinosaurs which are actually just 1 meter in length not that big to finding the biggest dinosaurs and biggest organisms to have ever walked the surface of the earth. Argentinosaurus huinculensis and many other gigantic dinosaurs they were 39 meters in length which is comparable to the height of the ten-story building.
Source: File:Wintonotitan.png – https://en.wikipedia.org
Still, you should keep a distance from these giants but, if they spot you they likely wouldn’t try to eat you, because they only ate vegetation. Who knows what would go through their brains after seeing a creature from future but, there were predatory dinosaurs too, so keeping a distance is good. So then let’s travel to see Panthalassa the big ocean in which water seems inviting as always but, this time it has more sharks and other species that are predators, just a hundred meters off the coast the danger will rise drastically. Taking a deep dive again same as in the surface there would be unrecognizable species living in the ocean from large sharks to reptile like fish to other unknown species. So, this would be all great but the big problem is that just a single human could contaminate the whole world with, its viruses from the future which we are immune to. At this time there was the earliest evidence of virus presence through cells being infected so you might pick up some type of virus that is deadly to today’s humans. Still, there might have been even earlier viruses that are poorly understood and we can’t even decide whether or not they are alive. So, then we can see that if we had a time machine it would be worth it to go back in time 200 million years ago to see what was before the existence of whole humanity which arises very early compared to organisms that were here before us. It would be one of the best throwbacks we never got to experience.