Palaeontology is the study of old life. It doesn’t exactly jump for attention. We have something against old stuff. Even the iPad I’m typing on right now is a testament to our dislike of the old and our constant need for new and fresh. Anyone who has ever splashed out a few bucks on an original Atari 2600 (nerd reference alert) or a vintage 1980s stonewashed jacket knows that old has another connotation. It can also mean classic. Ok, maybe not the best examples of classics, but you get the drift. Today I decided to learn about the classics. The organism both great and humble that through multiple evolutionary combinations attained a form that enabled their survival for millions of years. Incidentally, I don’t consider humans part of this ‘classics’ subset. A few million years doesn’t quite pass muster.
Since their origins in the Silurian period, land plants have been through a few ‘bad patches’. Probably the most commonly known is the Cretaceous extinction, or the dinosaur killer in common parlance. The end of the Cretaceous featured an unfortunate synchrony of very unpleasant geological and extraterrestrial events that must have made the living quarters a little unpalatable for most organisms. These events were, in no particular order, the impact of a large meteor in Mexico, eruption of the Deccan traps in India and unexplained anoxia of the oceans. Most people have heard of the chicxulub crater (probably not by name), but the other two events are almost muttered under the breath. I’d never heard of the Deccan traps or indeed the Siberian traps till my brother, who loves to give me nightmares, decided to tell me that lava can pour out of the ground for 30,000 years or more. Definitely beyond the timeline of most disaster movies. These events were so global in their effects that a layer of soot and a rare element, iridium, were deposited in the Earth. The soot and dust thrown up by the combination of volcanism and impact shock waves would have blocked sunlight and rendered it almost impossible for plants to photosynthesise. And therein lies the mystery. Without photosynthesis, how could plants survive and yet some species came through the extinction event unscathed. Without plants, how could animals survive and yet some did. For reasons that are not fully understood, some plants and animals emerged from one of the worst global environmental catastrophes and many others did not.
Letter on possible causes of oceanic anoxia
Eddie: What if we’re the last animals left alive? We’ll have to repopulate the earth.
Crash: How are we supposed to do that? Everyone here is either a dude or our sister.
Now I’ll get to the concept of a classic. The earth has undergone several climatic upheavals which should have led to total extinctions, yet some species persist. These are the species on the edge. The survivors. Evolution is not a steady stream of linear changes but rather it follows a more punctuated pattern. Extreme conditions seem to force evolutionary change. Following the major extinctions of the Cretaceous and Permian, life flourished with apparent ease and new species quickly filled ecological niches. Some species such as crocodiles, mammals, ferns seem to have the ability to weather the storm of changes and maintain their ecological foothold. This doesn’t necessarily equate to them having a more complex or sophisticated body plan but rather that they have a robustness of design. In particular plants have an incredible arsenal of survival skills. Many plants can adjust leaves, stems and roots to cope with low water levels. Some plants can withstand fires and indeed rely on being razed to the ground to disperse their seeds. Plants have developed a particularly formidable arsenal of chemical substances which can be used to prevent herbivory, to signal to other plants and to initiate reproduction. The gamete carrying pollen of angiosperms is particularly tough when subjected to environmental challenge. Even when doused with hydrofluoric acid (breaking bad fans will recall its destructive force), pollen has retained it’s viability. It seems unsurprising in this case that angiosperms recovered well from the late
For our sake, I hope the Deccan traps stay quiet, and that meteors swing past us and our oceans remain relatively oxygen rich. I wouldn’t like to anticipate the odds of our survival. We are newbies, with all the fragility that that entails and we are facing into a period of serious environmental change. The mystery of life came through catastrophic extinction events is something we should be taking heed of, to safeguard our own future.
The day the world nearly died
Svalbard world seed bank- just in case, but who’ll be around to sow them?