Guest post by David Middleton
Sixth Mass Extinction or Sixth Mass Genesis?
Animals and plants are seemingly disappearing faster than at any time since the dinosaurs died out, 66m years ago. The death knell tolls for life on Earth. Rhinos will soon be gone unless we defend them, Mexico’s final few Vaquita porpoises are drowning in fishing nets, and in America, Franklin trees survive only in parks and gardens.
Yet the survivors are taking advantage of new opportunities created by humans. Many are spreading into new parts of the world, adapting to new conditions, and even evolving into new species. In some respects, diversity is actually increasing in the human epoch, the Anthropocene. It is these biological gains that I contemplate in a new book, Inheritors of the Earth: How Nature is Thriving in and Age of Extinction, in which I argue that it is no longer credible for us to take a loss-only view of the world’s biodiversity.
[…]
Climate change has brought tree bumblebees from continental Europe to my Yorkshire garden in recent years. They are joined by an influx of world travellers, moved by humans as ornamental garden plants, pets, crops, and livestock, or simply by accident, before they escaped into the wild. Neither the hares nor the rabbits in my field are “native” to Britain.
Many conservationists and “invasive species biologists” wring their hands at this cavalcade of “aliens”. But it is how the biological world works. Throughout the history of the Earth, species have survived by moving to new locations that permit them to flourish – today, escaped yellow-crested cockatoos are thriving in Hong Kong, while continuing to decline in their Indonesian homeland.
Nonetheless, the rate at which we are transporting species is unprecedented, converting previously separate continents and islands into one biological supercontinent. In effect, we are creating New Pangea, the greatest ecological pile-up in the Earth’s long history. A few of the imported species cause others to become extinct – rats have driven some predator-naïve island birds to extinction, for example. Ground-nesting, flightless pigeons and rails that did not recognise the danger were no match for a deadly combination of rodents and human hunters.
But despite being high-profile, these cases are fairly rare. In general, most of the newcomers fit in, with limited impacts on other species. The net result is that many more species are arriving than are dying out – in Britain alone, nearly 2,000 extra species have established populations in the past couple of thousand years.
[…]
There is no doubt that the rate at which species are dying out is very high, and we could well be in for a “Big Sixth” mass extinction. This represents a loss of biological diversity. Yet, we also know that the Big Five mass extinctions of the past half billion years ultimately led to increases in diversity. Could this happen again? It seems so, because the current rate at which new animals and plants (such as the apple fly, the Italian sparrow and Oxford ragwort) are coming into existence is unusually high – and it may be the highest ever. We are already on the verge of Genesis Number Six – a million or so years from now, the world could end up supporting more species, not fewer, as a consequence of the evolution of Homo sapiens.
[…]
Chris D Thomas, Professor of Evolutionary Biology, University of York
This article was originally published on The Conversation. Read the original article.
For starters, the use of the phrase Anthropocene is, at best, silly. The Holocene *is* the Anthropocene. And, the description of the current species extinction rate as a “mass extinction” is totally wrong. Mass extinctions are marked by the loss of not just species; but by entire genera, families, orders, classes and sub-phyla.
The Late Pleistocene to Early Holocene extinction is not classified as a mass extinction, despite the loss of many genera.
It’s been quite a while since a genus was declared extinct, and it might actually be extant… just hiding…
Entire Mammal Genus on Brink of Extinction
Critically endangered African antelope is last species of its kind.
By Christine Dell’Amore, National Geographic News
PUBLISHED NOVEMBER 8, 2011
For the first time in 75 years, an entire genus of mammal may go the way of the dodo—unless a new conservation effort shepherded by Somalian herders succeeds.
The hirola, a large African antelope known for its striking, goggle-like eye markings, is the only remaining species in the genus Beatragus—and its numbers are dwindling fast, conservationists say.
The last mammal genus to blink out was Thylacinus, in 1936, with the death of the last Tasmanian tiger. A genus is a taxonomic ranking between species and family.
[…]
There are 30 genera of antelope and that doesn’t count American antelope, which technically aren’t antelope… So the demise of the hirola won’t be the death knell for antelope.
Reports of the Tasmanian tiger’s extinction might be just a bit premature.
The current mass extinction isn’t exactly taking a huge toll on any taxonomic units above the species level.
So, this image is totally meaningless for at least three reasons:
- It’s denominated in species.
- It fails to address the rate of new species evolving and/or being discovered.
- It would not be resolved in the fossil record – as the five real mass extinctions are.
Earth Is Not in the Midst of a Sixth Mass Extinction
“As scientists we have a responsibility to be accurate about such comparisons.”
PETER BRANNEN JUN 13, 2017
At the annual meeting of the Geological Society of America, Smithsonian paleontologist Doug Erwin took the podium to address a ballroom full of geologists on the dynamics of mass extinctions and power grid failures—which, he claimed, unfold in the same way.
[…]
I had written to Erwin to get his take on the contemporary idea that there is currently a sixth mass extinction under way on our planet on par with the so-called Big Five mass extinctions in the history of animal life. Many popular science articles take this as a given, and indeed, there’s something emotionally satisfying about the idea that humans’ hubris and shortsightedness are so profound that we’re bringing down the whole planet with us.
[…]
Erwin says no. He thinks it’s junk science.
“Many of those making facile comparisons between the current situation and past mass extinctions don’t have a clue about the difference in the nature of the data, much less how truly awful the mass extinctions recorded in the marine fossil record actually were,” he wrote me in an email. “It is absolutely critical to recognize that I am NOT claiming that humans haven’t done great damage to marine and terrestrial [ecosystems], nor that many extinctions have not occurred and more will certainly occur in the near future. But I do think that as scientists we have a responsibility to be accurate about such comparisons.”
[…]
“So you can ask, ‘Okay, well, how many geographically widespread, abundant, durably skeletonized marine taxa have gone extinct thus far?’ And the answer is, pretty close to zero,” Erwin pointed out. In fact, of the best-assessed groups of modern animals—like stony corals, amphibians, birds and mammals—somewhere between 0 and 1 percent of species have gone extinct in recent human history. By comparison, the hellscape of End-Permian mass extinction claimed upwards of 90 percent of all species on earth.
[…]
The Atlantic and WUWT
Note that the “Big 5” and other real extinction events put significant dents into the number of genera and how biodiversity has literally exploded since the end of the Jurassic Period:
The K-T (End-Cretaceous mass extinction) was just a “bump in the road” compared to the End-Permian extinction.
So, rather than whine about the occasional loss of a toad species that looks just like the un-endangered toad species in the next valley, we should celebrate the Carbon-Fed* Sixth Mass Genesis… We could even call it the Anthropocene Explosion!
*Pretty well all life on Earth is carbon-fed in one way or another.
I’ll just close with George Carlin’s best-ever standup routine…
(WARNING: Lots of F-bombs)…
The total number of species on the planet isn’t a particularly good measure of biosphere health, particularly considering its dependence on geographical isolation. Frankly, it would more enlightening to look at some estimate of total biomass.
Particularly since the definition of “species” is quite expansive.
Yet the regulation agencies have got away with stopping development, farming and other business activity because they found a snail or fish they deemed endangered in a local area.
Without humans on Earth species would be going extinct and evolving into new species probably at about the same rate they are today. Some of the species are on the verge of extinction regardless of humans and will go extinct now matter what humans do. Sure we have pushed some over the edge but often they were on the decline anyway. Just like death is the end result of life, extinction is the ultimate end for a species. The idea of species are a human invention. We make really dumb decisions supposedly trying to avoid a species or subspecies going extinct. What is ironic is that after bringing raptors back from the brink in the USA, the USFWS has issued a “take permit” for wind farms across the USA. Present wind farms kill between 100K and 325K per year. One wind farm in the late great golden state, in operation for 25 years, has killed 2,900 golden eagles alone.
I think humans clearly accelerate this process. We accelerate or retard a lot of processes.
All lifeforms do this. We just happen to be the only lifeforms, so aware of our own impacts, that some of us are willing to commt economic suicide in order to erase our footprint.
Nice piece, although an article on verbal accuracy is diminished by “biodiversity has literally exploded since the end of the Jurassic Period”.
I don’t see how the numbers of animals can increase if they keep exploding, wouldn’t they diminish? Perhaps they only explode after they have passed reproductive age? Nature’s version of menopause?
I hope the author meant “metaphorically exploded”, although the picture of beasties spontaneously exploding as they amble along is amusingly Pythonesque.
I was more going for Douglas Adams-esque
The Bird Mass Extinction
A few comments on C vs E…
There is no “debate,” just a flame war. (Thank you Charles, for hitting it with a fire hose).
This particular argument is ridiculous: “It’s just a theory,” vs “No! It’s a fact!”
In science, there is no hierarchy from theory to fact. A scientific theory is a systematic, comprehensive, predictive explanation of the facts (observations). Scientific theories are so powerful, they can predict as-yet unobserved facts. The scientific theory of evolution is one of the most powerful, robust, comprehensive and predictive theories ever devised by man.
To refer to it as “just a theory” or to insist that it has somehow been promoted from theory to fact belies an ignorance of the concept of scientific theory.
Directly-observed genetic evolutionary processes are facts (observations).
The fossil record consists of facts (observations).
The integration of these two sets of facts, combined with basic principles of geology and geochronology leads to the scientific theory of evolution.
Regarding punctuated equilibrium (punk eke) vs slow genetic drift, the fossil record clearly supports punk eke.
Evolution is a fact as well as a theory explaining that fact. That the fact and the theory have the same name doesn’t imply a hierarchy. Similarly, there are the fact of gravity and the theory of universal gravitation.
Speciation and the formation of new genera have been observed, indeed new species and genera are created in labs as well as in nature. So evolution is a fact.
Some other evolutionary events and processes which have been inferred from other facts, as per your comment.
Gradual evolution doesn’t occur only via genetic drift, but from processes such as natural selection as well.
Punctuated equilibrium occurs, but it’s not the main tempo or mode of evolution. Rapid evolution can be followed by long intervals of gradual evolutionary change. Just as modern geology includes both catastrophism and uniformitarianism, modern biology recognizes both periods of rapid and gradual change.
Human evolution provides instances of both rapid and gradual change. Single mutations are responsible both for upright walking and brain enlargement, but both developments then underwent further evolution. The pelvises, legs and feet of our ancestors gradually became better adapted to bipedalism. And after the change in the brain growth gene, our ancestors’ cerebral volume increased a slow, steady pace for over a million years.
The inability to grasp the difference between observations of evolutionary processes and the overarching scientific theory of evolution is fundamentally unscientific.
David,
I beg to disagree.
For Darwin, the origin of species was evolution, although he never used that term himself.
Hence, speciation is evolution. And speciation has been observed hundreds if not thousands of times. Thus, evolution is an observation, that is, a scientific fact.
It’s common for scientific theories to be named for the facts which they try to explain. Besides the theories of gravity and evolution, there are for instance the germ theory of disease and the atomic theory of matter.
What is now called evolution, in the sense of the history of life on earth, was known as “development” in the early 19th century, that is, the observation or scientific fact that fossil assemblages change dramatically in rocks of different ages, generally from simpler to more complex and diverse, with interruptions.
In the sense of the origin of species by descent with modification via natural selection and other evolutionary processes, it was then called “transmutation”, and generally rejected by natural philosophers for lack of a plausible mechanism, which of course Darwin and Wallace provided with their discovery of natural selection.
Which is one of the most eloquent, robust scientific theories ever devised by man.
David,
Yes, of course evolution is a theory, comparable to the theory of universal gravitation, although it is much better understood than gravity.
But evolution also refers to the repeatedly observed fact of evolution, ie new species from existing species, as well as all the other evolutionary processes, such as the natural selection which has created the terrible problem of MRSA.
I looked for but could not find a clip from the episode of “Monk” that introduced Natalie Teeger as his new assistant.
The Captain held up a type of goldfish and wondered why someone would think it was valuable and try to steal it.
Lt Disher said, “Maybe it’s extinct.”
Captain Stottlemeyer replied, “How could it be extinct if we’re looking at it?”
(The clip was better.)
Gotta love Ted Levine as Leland Stottlemeyer.
You’re an idiot.
Bruce,
It’s unclear to me to whom you refer. If to David, then please be specific, lest I conclude that you are an idiot. Because he’s right.
I’m tired tonight and I’m going to close this thread for a day or so while I compose a solid answer to the burning question.