Five Extinctions and Counting-
The question - Can we assume that life on earth as we know it can continue no matter what the environmental conditions? Or are we setting the stage for an eventual sixth extinction—our own?
We live in the period of the greatest extinction of plant and animal species since the extinction of the dinosaurs some 65 million years ago (9, 56, 143, 246). The history of life on earth has included at least five periods during which huge numbers of species vanished forever, primarily due to changes in climate and sea level. Some scientists worry that a sixth extinction has begun because of humanity's gross misuse of the earth's resources.
I was reading the above and I thought about whether planet earth would be better off with pea brained dinosaurs or a self conscious humanity today with one of the largest size of brain/body mass ratio, all designed very carefully, after all life is such a great gift, the following list extinctions provoked me to search for answer to a burning question, from time zero or the big explosion to the first cellular life, I see stage being set for a better and efficient kinder, gentler, all around species.
How could we have co-exist with dinosaurs, our size was too small to domesticate them or they would not let us survive, logic was not their strong point, their size of brain too small to survive as changes were happening and planet earth was being readied for our specie grand entrance, very modest and ape like in the beginning of course.
May be one can argue that natural selection led to extinction, the number of species have reduced but our dependency on gentler, co habitable, kinder species have increased considerably, dogs and cats are companions of man as never before, they are domesticated and bring a lot of joy to lot of people, so have other bovine species that can help excel human protein intake have multiplied, may be it is life natural destiny on this planet earth from time immemorial that encourages extinction of outdated species! Definitely a tough call but worth examining, instead of self extinction we may be a unwilling partner of greater scheme, the best bet is that we can be sure of better grounds for our future generation not worst, nothing form the past suggest any thing contrary! ..
A tour de force of our journey as highlighted gives me an indication that we are not preparing for our sixth extinction all these pre extinctions if they happened were natural disasters not related to the activities of few harmless species inhibiting the planets
First extinction: End-Ordovician. About 440 million years ago. This was the second-most severe extinction yet discovered. About 85% of all species were wiped out.
Second extinction: Late Devonian. About 365 million years ago. Marine species were particularly hard-hit in an extinction that took place in two waves a million years apart.
Third extinction: End-Permian. About 251 million years ago. With an estimated extinction of 96% of all species, this is the largest mass extinction of all. It dealt a near fatal blow to mammal-like reptiles that had ruled life on land for 80 million years. The dinosaurs stepped into their place as the dominant species.
Fourth extinction: End-Triassic. About 205 million years ago. An estimated 76% of all species, mostly marine creatures, vanished.
Fifth extinction: End-Cretaceous. About 65 million years ago. This is the most famous mass extinction of all because it signaled the end of the dinosaurs, which had dominated the land for 140 million years. Probably between 75% and 80% of all species disappeared during this time.
Sixth extinction? Since 1950 some 600,000 species have disappeared (164), and nearly 40,000 more currently are threatened (116). The pace of extinction may increase under the weight of human consumption and pollution of natural resources and, with global warming and resulting rising sea levels, take on alarming proportions. |
