Mass Extinctions have been part and parcel of millions of years of history of our earth. From the Dinosaurs to the Woolly mammoth have all disappeared as part of mass extinctions in the past. Today morning I read an article by Jeremy Hsu titled “Mass Extinction Threat: Earth on Verge of Huge Reset Button?”
Some scientists have speculated that effects of humans — from hunting to climate change — are fueling another great mass extinction. A few go so far as to say we are entering a new geologic epoch, leaving the 10,000-year-old Holocene Epoch behind and entering the Anthropocene Epoch, marked by major changes to global temperatures and ocean chemistry, increased sediment erosion, and changes in biology that range from altered flowering times to shifts in migration patterns of birds and mammals and potential die-offs of tiny organisms that support the entire marine food chain.
Imagining that we might be the beginning of a new epoch because of our actions is beyond belief to me. But I can see how it could be, as we are seeing several species disappearing before our very eyes.
The write up is based on an analysis by John Alroy a Paleobiologist from Macquarie University Sydney, Australia. His analysis is detailed in the Sept. 3 issue of the journal Science, is based on almost 100,000 fossil collections in the Paleobiology Database (PaleoDB)
In the past, researchers have typically counted species in the fossil record by randomly drawing a set number of samples from each time period – a method that can leave out less common species. In fact two studies using the PaleoDB used this approach.
Instead, Alroy used a new approach called shareholder sampling, in which he tracked how frequently certain groups appeared in the fossil record, and then counted enough samples until he hit a target number representative of the proportion for each group.
“In some sense the older methods are a little like the American voting system – the first-past-the-post-winner method basically makes minority views invisible,” said Charles Marshall, a paleontologist at the University of California, Berkeley, who did not take part in the study. “However, with proportional systems, minority views still get seats in parliament.”
One of the few consistent patterns is that growth spurts in diversity can apparently happen at any time, according to Alroy. He added that the background extinction of individual species has also remained consistent – the average species lasts just a few million years.
This means today’s species matter for environments around the world, and so humans can’t simply expect replacements from the diverse species of the future.
“If we lose all the reef builders, we may not get back the physical reefs for millions of years no matter how fast we get back all the species diversity in a simple sense,” Alroy said.
Read the entire article here
Check out the video of animals which went extinct in the 20th century: