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The Ecology of Pangaea
The Ecology of Pangaea
Published by MrILoveTheAnts
09-25-2012
Default 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 Ė 250 million years ago. Its start is marked as having the largest diversification of life in earthís history. Its end is naturally marked by the largest mass extinction in earthís 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 didnít 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 donít 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 2í long. These insects were so much larger than because of the increased oxygen levels. Insects actually donít 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 theyíre not as well known.) Itís 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 donít 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 thatíd 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.
  #1  
By Rebek56 on 09-26-2012, 06:50 AM
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Great project! Reading through it, something else occurs to me: is the current ease of travel contributing to a different sort of Pangaea, with species wandering (invading) in all sorts of places?
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  #2  
By MrILoveTheAnts on 09-26-2012, 12:58 PM
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Quote:
Originally Posted by Rebek56 View Post
Great project! Reading through it, something else occurs to me: is the current ease of travel contributing to a different sort of Pangaea, with species wandering (invading) in all sorts of places?
Well it's an unnatural spread that I'm against unless its a food crop pretty much everyone knows. And I say pretty much everyone knows because people who follow permaculture and food foragers (forest foragers?) seem to find nutrition in just about everything from bamboo shoots, to dandelion. But then I have to make an exception there because there are plenty of native plants the general public isn't eating, such as gooseberry.

When the plant is being imported just for its looks though, that should be banned. Exotic pets fall under this catagory too, how many venomous snakes, and tropical fish does one need? Why are we importing lady bugs when we have over 400 native species? Why is the Chinese Praying Mantis used and not the 20 native Mantises we have in North America. Honeybees make sense because they're a food crop in their own right, an essential for monocultural farming.

Going back to ornamental plants though, a lot of them are tame and perfectly safe in the landscape. However a few of the insect pollinated species we've imported are only tame because their ideal pollinator hasn't yet jumped the ship. Now adding another pollinator species to the 4,500 North America already has doesn't sound all that bad but because nothing is controlling the spread of this plant and it has a pollinator who 9 out of 10 flower visits will produce a viable seed it's easy to see how a new weed is born. We're just adding and adding species onto less and less land.

Back when the continents were all connected this didn't matter all that much. But as they've separated the species have all gone their separate ways, with their pollinators, with their lepidoptera, and on up the food chain.

Where the land is still connected, or had only recently vanished is where we see species that are related to one another closest. Raspberries and I think Strawberries for example are found in both Canada and the norther US, as well as Russia, Asia, and the northern parts of Europe. So has happened in the past but doesn't really happen on its own anymore. Islands are a different issue. The Oceans, Lakes and Rivers too.

Now where this all falls apart is a billion years in the future or whenever all the continents eventually bump back into one another. When that happens, species jumping from one land mass to the other will be unavoidable. It would certainly be an event worthy of marking a different era. But thinking this simply negates all conservation efforts is like skipping ahead to the end of a book and not enjoying the bit in the middle.
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  #3  
By Rebek56 on 09-27-2012, 05:47 AM
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I didn't mean to imply that invasive species are no problem (geologic time and our time are very different, after all), rather that perhaps human intervention has created a new (and negative) sort of Pangaea.
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  #4  
By turttle on 10-22-2012, 07:47 PM
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One thing I think is really cool is the concept of "aeroplankton". Lichens are truly global in their speciation, bounded by latitude rather than continental boundaries, because their spread is controlled by the wind. They simply release spores into the wind and they can be carried anywhere that wind goes. Where the fungus part of the lichen ends up, it then has to wait for the right algae from the aeroplankton to also land.

In a sense, air travel has made us all "aeroplankton", blowing in to places you wouldn't think we could go.

The problem with invasive plant species and all the ornamentals, is that the cat is too far out of the bag to ever get really put back in. And our North American plants are causing just as much trouble elsewhere as the Eurasian and African plants are doing here.

I would love to read a book on the subject by you!
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  #5  
By MrILoveTheAnts on 10-22-2012, 09:11 PM
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Originally Posted by turttle View Post
... And our North American plants are causing just as much trouble elsewhere as the Eurasian and African plants are doing here.

I would love to read a book on the subject by you!
How our native plants behave in other countries is something I'd love to read about, let alone write. The only one I've really herd about is as being invasive is actually our beloved Black Cherry Tree, Prunus serotina, in Europe. Apparently the only reason it's so tame in North America is because of a fungal pathogen in the soil that restricts germination. Though that's just going on my memory.
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  #6  
By Rebek56 on 10-27-2012, 06:36 AM
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Our eastern gray squirrel is causing serious problems for the British red squirrel. http://www.nytimes.com/2007/10/07/ma...anted=all&_r=0
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