As science digs for answers to the history of this planet, the earth in its own time is giving up some clues as to the why and how these events that wiped out species which inhabited the earth took place. Fossil records are difficult to read as we dig deeper for answers. Most of the species from long ago did not have a hard body which makes it challenging to track the extinction record. But as equipment and test grow more sophisticated, additional secrets are being revealed.
It appears that in all cases two events took place that ended over an over populated species from depleting its natural resources and those two events were climate change leading to food shortages.
Cataclysmic events, such as volcanoes combined with collision courses with terrestrial objects such as comets and asteroids are part of the answer however it is not the complete story. These events had effects on the natural behavior that led to the natural selection of certain species but these events in themselves did not cause mass extinction.
Although volcanoes have spewed out molten rock from the bowels of earth and acid dust into the atmosphere, wrecking havoc on life, this only contributed to the picture of change that blanketed this planet.
Tectonic plates grumbled and groaned as they opened gaping fissures in the earth’s crust. In other places they pushed upward toward the heavens giving rise to mountain ranges.
The earth has had more impact with terrestrial forces, comets, meteors, asteroids than the moon. There are approximately 120 crater impacts still visible on the planet. Mineral debris from other unseen impacts has now been detected. These impacts created more dust and debris being tossed into the atmosphere. This again seems only to add to the story being reveled about the cause of mass extinction.
There have been at least ten mass extinction events, five being major natural selection events on this planet; the Ordovician period (approximately 435 million years ago), the Devonian period (357 Million years ago), the Permian period (250 million years ago), the Triassic period (198 million years ago) and the Cretaceous period (65 million years ago).
The most famous of these events has been the Cretaceous period, the age of the dinosaurs, in which the dinosaurs plus many other plants and animals along with up to 75% of marine life were lost. The most devastating but less famous event was the Permian period where an estimated 95% of marine species and 8 of 27 insect orders were lost.
Science has found that mass extinction is of selective life forms. Not all the thunder lizards, commonly called dinosaurs died. There are still lizards, turtles and the like inhabiting the earth. Although the megalodon is all but forgotten sharks still swim in the oceans. Mass extinction is the process of eliminating one order to make way for a new order of species.
Fossil records have shown changes and the extinction of plant life in the seas as well as the land. Plants are the life support of all of earth’s inhabitance. Some of the changes were amazingly fast. A few degrees in ocean currents will change many things from migration to food sources as will the air currents on land.
With these records being verified, what did caused these mass extinctions?
This planet is vulnerable to many forces from above and below. All of these forces have brought the planet to climate changes. Dust from natural event layer the sky blocking the suns warming rays, in some areas holding the heat in with harmful ultra violet rays thus changing the climate.
Climate is the force of nature that sustains life. With a few degrees of change in the temperature, organisms can thrive, die or change. A late frost can destroy tons of produce. Warm air can make snow capped peak barren, flooding or bogging low laying areas. A few degrees up or down can cause insects, birds and other life forms to alter their natural habits which in turn can lead to extinction or a major decrease in their numbers. Put this on a model on a global scale, the changes are slow but sure.
A drier climate will also affect other life forms, decreasing plants, in turn decrease herbivores, in turn decreasing predators.
From the fall out from volcanic ash as well as the natural release of green house gases such as methane and carbon dioxide have all added chapters to story of climate change, extinction and evolution. Climate change affects all orders of life, as it effects the food chain. So the one must conclude that with climate change comes changes in the food source, changes in the food sources means life or death to any life form.
Mass extinction seems to follow another rule, and that is the natural selection of the dominate species to make way for a newer life form. Approximately 99% of life forms on this planet have become extinct. From fossil records, extinction eliminates a large percentage of whatever species is over populated thus putting the planet back on track for survival.
One must remember that we live in fragile ecosystem not unlike a jungle, coral reef, swamp, desert, forest or whatever the topographical landscape maybe on this planet. Anything that disturbs the natural scheme of things makes a big ‘shock wave’ on the planet. Mass extinction, through climate change is nature’s way of ensuring the continuation of life on this planet.
In the end climate and food resources are the causes for mass extinction on this planet. One cannot flourish with out the other, that is without a stable climate food sources will dwindle.
