The History of Earth's Mass Extinctions
The four billion year history of earth has witnessed five mass extinctions, and some scientists believe that we are on the verge of the sixth.1 If we are in the midst of the next mass extinction, we are in the very early stages of an evolving, and escalating process. The most recent, or fifth mass of the extinctions occurred 65 million years ago at the boundary between the Cretaceous and Tertiary periods. Images of an asteroid colliding with the planet, decimating the dinosaur population have been in circulation since the early 80’s.2 Being the most recent mass extinction, thousands of scientists around the world have investigated it, and elementary school children are familiar with it.
While the asteroid-collision hypothesis has not been proven concretely, it has been widely assimilated into, and accepted by the popular culture. Palaeontologists, sedimentologists, palaeoceanographists, geochemistrists, and experts in numerous other related fields have recently stepped up investigative efforts concerning the mass extinctions.3 Knowledge about these previous mass extinctions would not only give us a better understanding our past, but it could be vital in the study and recognition of a sixth mass extinction.
Geologists studying basalt flats in Siberia are discovering evidence that a massive lava eruption in that region 250 million years ago may have been more devastating than previously believed. In their latest figures, the investigating scientists believe that 85% of all aquatic species, and 70% of all species living on land became extinct at this juncture in time. Figures three times that of the Cretaceous-Tertiary extinction.4 The belief is that the lava poisoned the atmosphere by releasing sulfur dioxide, carbon dioxide, and hydrogen fluoride. These gasses would have radically distorted the climate conditions, suffocated plants and animals, blocked out the sunlight, and generally made the planet inhospitable.5
The man-hours dedicated to field research and analysis of collected data are staggering. Experts have put together various theories about previous mass extinctions and their findings have led some to believe that we are in the early stages of the sixth. One finding that has worried scientists throughout the world is the rate at which species of plants and animals have been going extinct. Previous research had discovered that the number of species of birds around the world has been on a steady decline for some time.6 While this detection did raise some red flags, it was not evidence that the next mass extinction had been launched.
While birds are abundant both in sheer population and number of species scientists needed to discover the decline of more than one selection of animals. More than half of the detected species of animals on earth are insects.7 If scientists wanted substantial, tangible evidence that there was a widespread...