Easter is historically a festival celebrating the resurrection of Jesus Christ after His crucifixion, when, on the third day after His death, He was alleged to have risen again and lived on. Some say that the festival itself predates Christianity and actually has its roots in the worship of Ishtar, the Babylonian goddess of love, war, fertility, and sexuality, though there is little evidence to support this theory. It is also said to be linked to a pagan festival dedicated to the worship of Eostre, the Anglo-Saxon goddess of spring, though solid verification of this fact is also as elusive as the Easter Bunny. One thing that all of the theories appear to have in common is that the festival celebrates the new life, fecundity and rebirth that flourishes in the natural world during the season of Spring.
Death and rebirth is a concept that occurs both literally and metaphorically in every area of our daily lives, however, and not just in the months of Spring. As Mahatma Gandhi once mused: “Each night, when I go to sleep, I die. And the next morning, when I wake up, I am reborn."
Each different stage in our personal physical and spiritual development could be called a form of rebirth, as we rise, phoenix-like, from the ashes of our former selves.
In nature, death and rebirth are an ever-present force driving the cycle of life on this constantly evolving planet. This force affects all forms of life: animals, plants, birds, fish, even bacteria, and not just individuals but sometimes whole species. In fact, extinction is considered to be a common occurrence throughout the earth’s past, with over 99% of the species that have ever lived believed to have become extinct.
At certain points in history, however, so-called "mass extinction" events have occurred, periods when huge numbers of species die out simultaneously or within a limited time frame.
The Earth is known to have undergone at least five mass extinction events in its history, the Cretaceous-Tertiary (or K-T) extinction event being the most legendary as it was responsible for the disappearance of the dinosaurs. This event is commonly thought to have been caused by flood basalt eruptions covering large areas with hardened lava and changing the global climate, combined with drastic drops in sea level and topped off by a huge asteroid or comet blasting the seabed near the Yucatan Peninsula in Mexico.
Other, less well-known but equally as devastating events included the Ordovician-Silurian mass extinction, which had two peak dying times separated by hundreds of thousands of years. Marine life was badly affected, with up to 85 per cent loss of life in the oceans. The event has been attributed to an ice age causing climate change, a drop in sea levels and altered sea-water chemistry.
During the Late Devonian mass extinction over 75 per cent of all species died out; this extinction saw the sea bed become so devoid of oxygen that only bacteria could survive there, and it was thought to have been caused by asteroid impact, climate change and the impact of new plant life altering soil content.
The Triassic-Jurassic mass extinction occurred during the last 18 million years of the Triassic period, and featured two or three extinction phases that combined to form the whole event. Climate change, volcanic eruptions and asteroid impact have also been mooted as possible causes for this episode, which resulted in the disappearance of a wide variety of species including a large amount of marine life. Around half of all life forms existing on earth died out, though oddly the majority of plants seemed to survive.
The most severe mass extinction event of all time, however, occurred at the end of the Permian period when 96 per cent of all species on Earth perished, and all forms of life that have existed since are known to have evolved from the remaining four per cent of surviving species.
Many possible causes for the incredible loss of life have been put forward by scientists, including the usual suspects: asteroid impact, flood basalt eruptions, catastrophic methane release, fluctuations in oxygen or sea levels, or a combination of all of these, though recent evidence has suggested the involvement of a very different and unexpected factor.
The cause of the event is now thought to have come from a relatively innocuous source that spiralled out of control and decimated the planet.
The culprit was a microscopic, methane-producing life form called Methanosarcina that originated in the oceans. As populations of the tiny terror escalated, vast quantities of methane were released into the atmosphere, elevating global temperatures and acidifying the oceans. The environmental changes were severe enough to wipe out almost all of the life on earth, as existing species were unable to adapt quickly enough to the new and inhospitable conditions.
This is the theory put forward after the results of a recent study published in the journal Proceedings of the National Academy of Sciences, which analyzed geological carbon deposits and found a significant boost in levels of carbon-containing gases – either carbon dioxide or methane – at the time of the mass extinction. It was concluded that such high levels of these gases could not have been produced solely by volcanic eruptions.
"A rapid initial injection of carbon dioxide from a volcano would be followed by a gradual decrease," said US scientist Dr Gregory Fournier from the Massachusetts Institute of Technology (MIT). "Instead, we see the opposite: a rapid, continuing increase. That suggests a microbial expansion. The growth of microbial populations is among the few phenomena capable of increasing carbon production exponentially, or even faster."
It can take the influence of very small environmental variations to initiate such a change: a combination of two factors are thought to have encouraged Methanosarcina to proliferate, according to the study. Genetic changes allowed it to become a major producer of methane from accumulations of carbon dioxide in the oceans, and then an explosion of volcanic activity created a an excess of nickel, a vital nutrient that helped to propagate the microbial growth.
A similar situation could now be gradually occurring on Earth, as populations of greenhouse-gas-producing bacteria are being encouraged to grow by increases in global temperatures caused by climate change.
Mankind certainly appears to be sleepwalking towards the demise of his own species, with climate change alone having the potential to wipe out life as we know it and relatively little being done to combat its effects. Our planet is therefore considered to be currently undergoing its sixth mass extinction event, creating the worst spate of species die-offs since the loss of the dinosaurs 65 million years ago.
The problem is that, although extinction is essentially a natural phenomenon, it has previously occurred at a natural rate of about one to five species per year; however scientists estimate that species are now dying out at 1,000 to 10,000 times the average rate, with literally dozens going extinct every day. This directly correlates to the development and increase of the human population: this mass extinction event is caused solely by the influence of humanity.
So, is an artificially initiated mass extinction event any different to those caused by naturally occurring phenomena?
History suggests that extinction encourages new life forms to develop, and ensures the resilience of ecosystems. Is an asteroid blast artificial or just an unhappy accident? Man could be considered to be just another species that has briefly gained the ascendancy on Earth, only to be the victim of his own short-lived success.
Whether or not Man manages to survive the effects of his own myopic industrial progression is almost irrelevant; our occupancy of Earth is barely a snapshot in its history and, whilst we may wish to fight for existence, we are no more entitled to survive than any other species that has gone before us. What is almost certain, unless conditions on Earth become totally hostile to all life forms, is that there will be a radiation of new life forms managing to adapt to the changing environmental conditions. The same effect has been observed by scientists researching fossilised remains from each post-extinction era: mass extinctions are invariably followed by periods of adaptive radiation and bio-diversification where previously unknown species suddenly blossom into being.
So, what is the role of mass extinction events in evolution? How has life on our planet been "resurrected" after these catalcysms, and have these events had positive or negative impacts on the evolution of life today?
Extinction is certainly the driving force for innovation in the natural world and it has been a powerful mechanism in encouraging evolutionary diversity, allowing the constant rise and fall of dominant species. It has provided the opportunity for new and varied life-forms to spring into existence and has been a valuable tool to initiate novelty in nature. From the death of those species that have gone before, new and previously unseen life has blossomed.
Even the loss of one species alters the ecosystem it once survived within, though no single species is optimally adapted to its environment; however the fight for survival sorts out those who are better able to adjust to changing circumstances, particularly in mass extinction scenarios.
Those life forms that do manage to adapt rapidly, known as "disaster species", are usually generalists who are displaced by more specialized species over time. Man could be termed a "generalist", though the fragile infrastructure that currently makes up much of the world’s human eco-system has rendered many of us ill-equipped for survival outside of its comfortable confines.
As one of the species that may now be facing possible extinction, Man should be using every facet of his adaptability and ingenuity in order to survive.
The difference between this latest extinction event and those that have gone before us is that Man is well aware of the effects of his own actions, and has the option to try and reverse those effects before the damage is irretrievable. But should we try to reverse what now seems almost inevitable, or should we allow the consequences of our own actions to take their natural course, allowing our brief reign on Earth to disappear into the history books like the dinosaurs?
What do you think? In global terms, does Man have any more right to survive than any other species?
Wishing all our subscribers and readers a Happy Easter – hopefully we have given you some food for thought in addition to your chocolate eggs.
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