The Ecology of Pangaea

This is a work in progress. It started as an essay I wrote but lately I've been toying with the idea of expanding it into a book.





We start with the Paleozoic era which took place between 542 – 250 million years ago. Its start is marked as having the largest diversification of life in earth’s history. Its end is naturally marked by the largest mass extinction in earth’s history. Plant life at the time, possibly even before this time, was algae which only grew in water. Mosses, or Bryophytes, eventually made the jump onto land but still required water for at least one season of the year to reproduction much as it still does today. Mosses are simple and lack any vascular structure. Their successor would eventually become ferns which arose some 360 million years ago. This era also saw the rise of the Invertebrates. As plants didn’t flower yet the world lacked the butterflies, and bees, we know today. (There is a gap to be filled in here about them later.)

350 million years ago an event called the Carboniferous Rainforest Collapse occurred. Essentially this was the hay day of plant life on our planet because almost nothing was eating them! Evolution had struck again as the first Gymnosperms arose. These are plants that produce by seeds rather than spores. The benefit here is that seeds don’t require moisture for prolonged survival. Spores die almost instantly if they don't land in the correct spot and are at the mercy of the wind or water to decide where they will grow. Seeds can go dormant and stay viable for years, sometimes centuries after they've been made. Tree-like plants increased the stability of flood plains, rainforests quickly littered the planet. They created so much organic matter that vast deposits of Coal started occurred all over earth. This rich organic matter fueled the further rise of Invertebrates, some of whom became the first herbivores. This period's abrupt end has been contributed to everything from climate change, to meteorites. The cascade of extinctions contributed to the end of the Paleozoic era.

This is the time when we lost the giant millipedes and dragonflies of the day. The wing span to this massive insect was greater than 2’ long. These insects were so much larger than because of the increased oxygen levels. Insects actually don’t have lungs but rather breath through their exoskeleton, an adaptation from the earliest sponge-like relatives they had evolved from. When one finds a seemingly drown insect in a pool, often the insect can be brought back to life simply by letting them dry out.

By the end of this time, between 250 million and ~200 million years ago, the world existed as one geographical continent, Pangaea, which looked as we see in text books today. After that the continents had severely broken up and started going their separate ways. This is an important time in the world as the first Angiosperms (flowering plants) started appearing sometime between 245 and 202 million years ago. They quickly became the most dominant form of plant life on earth, with all of them being wind pollinated. However, 150 million years ago they started to incorporate insect help to achieve pollination and the first nectarivores were born. The world brightened up as flowers became fancier, shaping the evolution of their pollinating counterparts. As the world split its 7 ways, so did a lot of the plant and pollinator relations across the earth.

When the Paleozonic era ended 250 million years ago, the Mesozoic era began and continued up until 65 million years ago. This time period is known as the age of reptiles and marks the rise and fall of non avian dinosaurs. (There are a few lesser known plants and animals that go extinct by the end as well but they’re not as well known.) It’s odd thinking that a Tyrannosaurus rex may have indeed tasted like chicken, but sure enough modern day birds are all descendants of the dinosaurs. The earth would eventually become a much colder place which had a negative effect on cold blooded life the world over. Although reptiles are cold blooded there is some debate as to whether this was true of dinosaurs as well. During their decline 150 million years ago, we saw the first mammals appear. These were limited in size until the dinosaurs were either completely gone, or had transitioned more into birds, which are endothermic (warm blooded). Perhaps furrier mammals, which could often hibernate as well, flourished more so by finding refuge in the colder parts of the world.

While this speciation of animal life was going on, plants were just as prolific. Grasses were on the scene turning the world into one big savanna. Prior to this the world had mostly been one mighty rainforest some 350 million years ago. Grasses were successful at this time from the abundance of animal herbivores. It's unclear whether their dinosaur counterparts were able to keep woody forests at bay just 50 million years prior, (and frankly it's hard to picture too).

The Cenozonic era started 65 million years ago and continues to modern day. This is the age of mammals. Fueled by the prolific grassy meadows, great herds of animal grazers roamed 6 of the 7 continents. Constant grazing prevented most trees from growing into full forests though this does eventually become the end result. Thorn covered brambles and roses would shelter young saplings from browsing. The shade produced by the tree would encourage the brambles to grow outward and allow for more trees to grow about. Fire would sweep through the land and eliminate deciduous trees resulting in meadows rejuvenating back to life like a phoenix from the ashes. Conifers, though burned, are better able to grow back from fire damage, though often they don’t produce as much shade as deciduous trees do, and grasses and wildflowers are maintained longer than they are. In the absence of fire though, the deciduous hardwood trees tended to our last the conifers in most parts of the world. Another failing of conifers is they rarely grow well near water. Grazers are able to slow the process greatly though and much of the world looked like the South African savanna.

From here the trail turns more into more modern topics such as the rise of man, the mass extinction of many huge mammals, the onset of agriculture and land management, the burning of all that coal and oil that’d built up in the earth, and lastly globalization of the world economy. These events have finally leaded us to a very modern concept, The Invasive Species.