I recently spent a day on Twitter with a couple of theists who held the frighteningly common belief that humankind has not evolved from apes and we are now as we have always been from day six! Now I know what you’re all thinking… it would have been easy to shoot them down.
Well, yes, of course, but no matter how much evidence for evolution and the origin of man you present, if they won’t listen to anything but ‘God created the heaven and the earth’, you are unlikely to get much further. This situation will ring true with many readers.
I won’t embarrass either American gentleman (I use the term loosely since one, in particular, had a limited vocabulary generously interspersed with ‘bitch’ and ‘homo’) by using their twitter handles but, if you are interested, look on my timeline and have a good laugh. They parade their love of ‘microevolution’ yet, when given links and details of accepted scientific theory, they run for the hills.
They did, however, inspire me to write this blog on Extinction Level Events (ELE) as both of them would disagree these natural phenomena could ever have happened. There are two ELEs whigh they may have mentioned had I been inclined to ask. The Flood (for which, to put it kindly, there is little evidence) and the End of the World (again, let’s be kind and suggest Revelation’s description lacks scientific credibility). I allude to both stories in previous blog posts which you can read here :-
So let’s learn more about ELEs which are also known as Mass Extinctions or Biotic Crises. Based on fossil records, an average of between three and five minor events occur every million years or so. There have been 5 major events that we know of:
THE ORDOVICIAN-SILURIAN EXTINCTION
Around 439 million years ago, as Earth’s climate cooled and glaciers formed, there was a significant drop in sea levels. During this extinction event we lost 60% of marine genera
THE LATE DEVONIAN EXTINCTION
This occurred around 364 million years ago and its cause is still unknown. However, warm water marine species were worst affected which leads many palaeontologists to believe it was an episode of global cooling. There are glacial deposits of this age in Northern Brazil.
The date evidence is inconclusive and still under debate but what is known is that this mass extinction killed around 22% of marine families and 57% of marine genera
THE PERMIAN-TRIASSIC EXTINCTION
Occurring around 251 million years ago, this was Earth’s worst mass extinction to date. 95% of all species, 53% of marine families, 84% of marine genera and an estimated 70% of land species such as plants, insects and vertebrate animals were killed. Direct evidence hasn’t been found but scientists believe a comet or asteroid impact let to this extinction. Some scientist believe it was a volcano triggered in Siberia, itself triggered by the asteroid.
THE END TRIASSIC EXTINCTION
This occurred around 199 million years ago and caused by massive floods of lava erupting from the central Atlantic magmatic province which triggered the break up of Pangaea and opening of the Atlantic Ocean. This led to global warming. Rocks from the eruptions have been found in the U.S, Easter Brazil, North Africa and Spain. 22% of marine families, 52% of marine genera and an unknown percentage of vertebrate deaths were the result.
THE CRETACEOUS-TERTIARY EXTINCTION
This occurred around 65 million years ago and is thought to have triggered by an asteroid several miles wide which created the Chicxulub crater in the Yucatan Peninsula beneath the Gulf of Mexico. 16% of marine families, 47% of marine genera and 18% of land vertebrate families including the dinosaurs.
TODAY 99.9% OF ALL SPECIES ON EARTH ARE NOW EXTINCT
AND THE SIXTH MASS EXTINCTION HAS BEGUN
Right now animals are going extinct 100 to 1,000 times faster than previous background extinction rates, that is to say 10-25 species a year.
Many researchers are claiming we are in the middle of a mass extinction faster than the Cretaceous-Tertiary extinction which wiped out the dinosaurs.
We cannot blame a meteorite or a volcanic eruption, the decline of biodiversity is the result of five human activities :-
- Habitat destruction
- Invasive species
- Human over-population
- Over Harvesting
Once a mass extinction has occurred it takes 10-30 million years to recover and when it does there is a whole new cast of characters.
By 2100 AD half of the earth’s species will be gone. Scientists have been warning us for decades that human actions are pushing us to a mass extinction. We have only ourselves to blame. As a leading geologist Mr Mark Williams has said :-
We have to recognise that our impact is game changing on this planet, that we are all responsible and that we have to become stewards of nature, rather than behaving like children in a candy store
It isn’t a matter of if, but when…
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