Will the Nautilus survive the sixth great extinction?


But first a few words about life long learning. That’s an expression that’s overused, or not used enough, or rather used but not understood. In fact, there’s probably not a school or college that doesn’t mention life long learning in its brochure materials.

What’s going on here? Well it’s simple, we would prepare our students to become in their own lives life long learners. That’s the bottom line, more bottom than even the monstrous, obscene, sometimes life long debts the students are accumulating while attending their schools and colleges.

But are there lifelong learners out there among the graduates of our schools and colleges? How does one judge their presence? Are there any lifelong learners among the millions of Americans who are going to vote for Donald Trump? Those who would vote for Trump what can they possibly know about the history of the West, about the Enlightenment, about art and music, about literature, about math and science, all those subjects that ought to have a greater place in our lives out of school than in school, those subjects that ought to be what life long learning is all about.

The greatest irony is that now, in the 21st century it has never been easier to learn. The incredible achievements of mathematics and science, the great works of art and music and literature, the histories of times past, the nature of other civilizations, of other cultures, of other ways of life have never been so readily accessible, so completely within our reach.

While thousands of brave individuals, hundreds of thousands are making these treasures available by means of the ever new electronic media, putting the knowledge of most everything out there within the reach of most everyone, it’s just not happening, that people are becoming more enlightened, more open, more tolerant, more liberal and/or more conservative.

People seem rather to be closing up within themselves, shutting themselves off from others who are different, from most of the wide world, wanting to hold tight to whatever they may have from the past rather than going out into what is fast becoming without them the bravest new world that men have ever seen.

I’m reminded again of Richard Feynman’s question, of the relation of science to modern society —Why is it possible for people to stay so woefully ignorant and yet reasonably content in modern society when in fact so much knowledge is available to them?

I stumbled upon the article below just this morning in the Review, Cosmos. And I might just as well have stumbled upon any number, thousands, tens of thousands of other no less interesting and informative articles. As I say it’s never been so easy to find out more about our world. We are no longer just cave dwellers putting the best of ourselves on to the walls of a cave in southwestern France.

I think it’s our greater and greater knowledge of our world that saves us, that brings out our humanity, that makes us (well not all of us, helas! but perhaps the life long learners among us) more inclusive, more tolerant, the very sort of qualities that what life long learning should be all about.

Anyway, here’s just one example of the millions of doorways, in this instance a magazine article, leading to new knowledge. Here the subject is extinction. What does that mean? Is it the same as death? What did it mean to the cave dwellers? Did they even know the word? What does it mean to us now?

For even today, with all the knowledge available to us, we still have to come up with our own answers, just like the cave dwellers. We’ll have to decide what meaning to give to extinction, and in particular to the so-called sixth extinction that is now going on and for which we are probably mostly to blame.

The big five mass extinctions

Viviane Richter is a freelance science writer based in Melbourne

Biologists suspect we’re living through the sixth major mass extinction. Earth has witnessed five, when more than 75% of species disappeared. Palaeontologists spot them when species go missing from the global fossil record, including the iconic specimens shown here. “We don’t always know what caused them but most had something to do with rapid climate change”, says Melbourne Museum palaeontologist Rolf Schmidt.

End Ordovician, 444 million years ago, 86% of species lost
— Graptolite 2-3 cm length

Graptolites, like most Ordovician life, were sea creatures. They were filter-feeding animals and colony builders. Their demise over about a million years was probably caused by a short, severe ice age that lowered sea levels, possibly triggered by the uplift of the Appalachians. The newly exposed silicate rock sucked CO2 out of the atmosphere, chilling the planet.
060715_holodeck_1Credit: JAIME MURCIA / MUSEUM VICTORIA

Late Devonian, 375 million years ago, 75% of species lost
— Trilobite, 5 cm length

Trilobites were the most diverse and abundant of the animals that appeared in the Cambrian explosion 550 million years ago. Their great success was helped by their spiky armour and multifaceted eyes. They survived the first great extinction but were nearly wiped out in the second. The likely culprit was the newly evolved land plants that emerged, covering the planet during the Devonian period. Their deep roots stirred up the earth, releasing nutrients into the ocean. This might have triggered algal blooms which sucked oxygen out of the water, suffocating bottom dwellers like the trilobites.
Credit: Chip Clark / Smithsonian Institution

End Permian, 251 million years ago, 96% of species lost
— Tabulate coral, 5 CM

Known as “the great dying”, this was by far the worst extinction event ever seen; it nearly ended life on Earth. The tabulate corals were lost in this period – today’s corals are an entirely different group. What caused it? A perfect storm of natural catastrophes. A cataclysmic eruption near Siberia blasted CO2 into the atmosphere. Methanogenic bacteria responded by belching out methane, a potent greenhouse gas. Global temperatures surged while oceans acidified and stagnated, belching poisonous hydrogen sulfide.  “It set life back 300 million years,” says Schmidt. Rocks after this period record no coral reefs or coal deposits.
060715_holodeck_3Credit: JAIME MURCIA / MELBOURNE MUSEUM

End Triassic, 200 million years ago, 80% of species lost
— Conodont teeth 1 mm

Palaeontologists were baffled about the origin of these toothy fragments, mistaking them for bits of clams or sponges. But the discovery of an intact fossil in Scotland in the 1980s finally revealed their owner – a jawless eel-like vertebrate named the conodont which boasted this remarkable set of teeth lining its mouth and throat. They were one of the first structures built from hydroxyapatite, a calcium-rich mineral that remains  a key component of our own bones and teeth today.  Of all the great extinctions, the one that ended the Triassic is the most enigmatic. No clear cause has been found.

Credit: Paul Taylor / Natural History Museum

End Cretaceous, 66 million years ago, 76% of all species lost
— Ammonite 15 cm length

The delicate leafy sutures decorating this shell represent some advanced engineering, providing the fortification the squid-like ammonite required to withstand the pressure of deep dives in pursuit of its prey. Dinosaurs may have ruled the land during the Cretaceous period but the oceans belonged to the ammonites. But volcanic activity and climate change already placed the ammonites under stress. The asteroid impact that ended the dinosaurs’ reign provided the final blow. Only a few dwindling species of ammonites survived. Today, the ammonites’ oldest surviving relative is the nautilus. Will it survive the sixth great extinction?


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