{"id":88,"date":"2020-05-11T12:27:00","date_gmt":"2020-05-11T12:27:00","guid":{"rendered":"https:\/\/bvrtse.in\/blog\/?p=88"},"modified":"2021-05-18T09:23:13","modified_gmt":"2021-05-18T09:23:13","slug":"the-ancients-islands-of-coal","status":"publish","type":"post","link":"https:\/\/bvrtse.in\/blog\/the-ancients-islands-of-coal\/","title":{"rendered":"The Ancients: Islands of Coal"},"content":{"rendered":"\n
This is the eighth part of The\nAncients, a series of posts which, by this time, I\u2019m pretty sure all you\nnatural history buffs (Pretty sure you qualify for that by now) know, so I\u2019ll\nget straight to the point. Check out parts 1-7 before this one!<\/p>\n\n\n\n
Quick info:<\/p>\n\n\n\n
Name: Carboniferous<\/p>\n\n\n\n
Period: 358.9-298.9 m.y.a<\/p>\n\n\n\n
Average Temperature: 14 Celsius<\/p>\n\n\n\n
Atmospheric oxygen : 32.5%<\/p>\n\n\n\n
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Remember how there was a mass\nextinction during the Devonian? Well, guess what, there was another one during\nthis eon. WOOP-DE-DOO! Of course, there had to be another one. Luckily, this\none wasn\u2019t that bad; but more on that later. During the Carboniferous, most of\nthe coal deposits we use today were formed (That\u2019s why it\u2019s called the Carbon<\/strong>iferous).\nThe two continents that had slowly formed during the Devonian and Silurian,\nGondwana and Euramerica (because it\u2019s made up of land that will eventually form\nEurope and North America), were starting to join, forming the Appalachian and\nVariscan mountain ranges. Since all the land was near the South end of the\nEarth, an ice cap formed at the South pole, and, FINALLY, after SO MUCH\nEVOLUTION, four-legged vertebrates evolved in the coal swamps of the Equator.<\/p>\n\n\n\n
But\nfirst, the Carboniferous Collapse. Opportunistic ferns started to gain height,\nand rainforests started to shrink, each \u2018island\u2019 of rainforest developing their\nown animal species, when before, the same species existed throughout the\nrainforest. The rainforest patches were surrounded by an unsuitable habitat, which\nled to animals evolving in different ways inside each patch. Before the\nCollapse though, trees were everywhere, and oxygen levels rose, and something\nHUGE happened. But first, you have to understand a bit of Entomology ( study of\ninsects).<\/p>\n\n\n\n
Insects don\u2019t have lungs. That much is\nobvious. Now, while we humans have one trachea, insects have a whole system of\ntracheal tubes. Each tube has an opening on the insect\u2019s body, and oxygen is\nbrought in through the tubes, through a whole web-like system to reach all\ntissues, and carbon dioxide is brought out. As the insect get\u2019s bigger, the\ntubes elongate to reach longer limbs, and increase in either diameter or number\nto accommodate the additional oxygen needs. However, the openings can only get\nso big, and that limits growth. When there is a surplus of oxygen, an insect\ncan grow much bigger.<\/p>\n\n\n\n
Remember, in the Silurian, a giant\nmillipede called Pneumodemus<\/em>\n? Yeah, imagine tons of other insects the same size. Almost as big as a human.\nThey also grew because of the lack of terrestrial predators (That\u2019s why, in\nlater periods with similar oxygen levels, there were no giant insects). But,\nafter the Collapse, oxygen levels receded, and insects became smaller. Due to\nthe decrease in rainforests, the humidity also decreased, and so a hot, dry\nclimate evolved, killing off many species of amphibian, but promoting the\nevolution of reptiles. This event also promoted the creation of coal. How? Wait\nand see.<\/p>\n\n\n\n
Coal only forms when an organism\ndoes not decompose, and release all the carbon into the atmosphere, but\ninstead, the carbon is pressurized underground. The Carboniferous was full of\ncoal due to the abundance of swamps, which naturally inhibit decomposition.\nAnimals, plants and decomposing bacteria had also not evolved the specialized\nenzymes and chemicals to break down the substances present in the dead\norganisms. However, towards the end of the Carboniferous, fungi arose which\ncould break down said substances, and this made coal formation in the later\nperiods much rarer.<\/p>\n\n\n\n
Now, there were many species of\ntree in each patch of rainforest, but the three most prosperous, abundant, and\nones which made the biggest rainforests were, Lepidodendron<\/em>, Sigillaria<\/em>,\nand Calamites.<\/em> Lepidodendron<\/em> \nwas a tree which could grow over 30m in height, and probably only\nreproduced at the end of its lifespan. Sigillaria <\/em> was closely related to Lepidodendron<\/em>,\nand had a very short lifespan of around 13 years. Lastly, Calamites<\/em> were actually tree-ferns, specifically\nhorsetails. Now, for some crazy fish. Akmonistion<\/em> was related closely to sharks, and had a\ncrest which looked a lot like an anvil instead of the iconic dorsal fin. This\ncrest had barbs on it, and so did its forehead. Helicoprion<\/em> was another shark-like fish which lived very\nlong. Its lower teeth were arranged in a spiral pattern which could hang\noutside of its mouth. The species of reptiles, among others, were Hylonomus<\/em>,\na small, 20-centimetre long reptile which fed mostly on insects (before and\nafter they became supersized) and Archaeothyris<\/em>, which looked like a\nlizard, and could grow up to 50cm long. It was actually the ancestor of\nsynapsids, (soon-to-be modern-day mammals; don\u2019t worry, I\u2019ll explain in the\nnext blog!). The giant insects are next. Pulmonoscorpius<\/em> was a species\nof giant scorpion, almost 70 centimetres long. It ate small arthropods and\ncould kill some tetrapods as well. Arthropleura<\/em> was one of the biggest insects, at 2.3 metres\nin length and 50 centimetres wide. It had very few predators, and has actually\nherbivorous. It\u2019s like the insect version of an elephant! Lastly, Meganeura<\/em> was a genus of dragonflies, which could have\na wingspan of 65 centimetres.<\/p>\n\n\n\n
There\u2019s more to come. And it will\nget more confusing as we go on. Patience bears fruit, sweet or not, we will get\nto that some other time.<\/p>\n\n\n\n
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