Posts Tagged ‘mass extinctions’

3rd great “mass extinction” was due to an ice age and not to global warming

March 8, 2017

A new paper addresses the drivers behind the 3rd great “mass extinction” around 250 million years ago. It finds that it was due to an ice age and not due to global warming as many have speculated.

Björn Baresel, Hugo Bucher, Borhan Bagherpour, Morgane Brosse, Kuang Guodun, Urs Schaltegger. Timing of global regression and microbial bloom linked with the Permian-Triassic boundary mass extinction: implications for driving mechanisms. Scientific Reports, 2017; 7: 43630 DOI: 10.1038/srep43630

Universite de Geneve Press Release:

The Earth has known several mass extinctions over the course of its history. One of the most important happened at the Permian-Triassic boundary 250 million years ago. Over 95% of marine species disappeared and, up until now, scientists have linked this extinction to a significant rise in Earth temperatures. But researchers from the University of Geneva (UNIGE), Switzerland, working alongside the University of Zurich, discovered that this extinction took place during a short ice age which preceded the global climate warming. It’s the first time that the various stages of a mass extinction have been accurately understood and that scientists have been able to assess the major role played by volcanic explosions in these climate processes. This research, which can be read in Scientific Reports, completely calls into question the scientific theories regarding these phenomena, founded on the increase of CO2 in the atmosphere, and paves the way for a new vision of the Earth’s climate history. 

Teams of researchers led by Professor Urs Schaltegger from the Department of Earth and Environmental Sciences at the Faculty of Science of the UNIGE and by Hugo Bucher, from the University of Zürich, have been working on absolute dating for many years. They work on determining the age of minerals in volcanic ash, which establishes a precise and detailed chronology of the earth’s climate evolution. They became interested in the Permian-Triassic boundary, 250 million years ago, during which one of the greatest mass extinctions ever took place, responsible for the loss of 95% of marine species. How did this happen? for how long marine biodiversity stayed at very low levels? 

Researchers worked on sediment layers in the Nanpanjiang basin in southern China. They have the particularity of being extremely well preserved, which allowed for an accurate study of the biodiversity and the climate history of the Permian and the Triassic. “We made several cross-sections of hundreds of metres of basin sediments and we determined the exact positions of ash beds contained in these marine sediments,” explained Björn Baresel, first author of the study. They then applied a precise dating technique based on natural radioactive decay of uranium, as Urs Schaltegger added: “In the sedimentary cross-sections, we found layers of volcanic ash containing the mineral zircon which incorporates uranium. It has the specificity of decaying into lead over time at a well-known speed. This is why, by measuring the concentrations of uranium and lead, it was possible for us to date a sediment layer to an accuracy of 35,000 years, which is already fairly precise for periods over 250 million years.”
Ice is responsible for mass extinction

By dating the various sediment layers, researchers realised that the mass extinction of the Permian-Triassic boundary is represented by a gap in sedimentation, which corresponds to a period when the sea-water level decreased. The only explanation to this phenomenon is that there was ice, which stored water, and that this ice age which lasted 80,000 years was sufficient to eliminate much of marine life. Scientists from the UNIGE explain the global temperature drop by a stratospheric injection of large amounts of sulphur dioxide reducing the intensity of solar radiation reaching the surface of the earth. “We therefore have proof that the species disappeared during an ice age caused by the activity of the first volcanism in the Siberian Traps,” added Urs Schaltegger. This ice age was followed by the formation of limestone deposits through bacteria, marking the return of life on Earth at more moderate temperatures. The period of intense climate warming, related to the emplacement of large amounts of basalt of the Siberian Traps and which we previously thought was responsible for the extinction of marine species, in fact happened 500,000 years after the Permian-Triassic boundary.

This study therefore shows that climate warming is not the only explanation of global ecological disasters in the past on Earth: it is important to continue analysing ancient marine sediments to gain a deeper understanding of the earth’s climate system.

We now have more living species than ever before. The number of “garbage” species is very high and a new “mass extinction” (the sixth) is needed to clear out the rubbish. A Herculean task and hopefully humans will not be one of the “garbage” species. When it comes it is more likely to be due to a global cooling than a global warming.

There are thought to have been 5 great “mass extinctions” in the past. A “mass extinction” removes around 30 – 50% of extent species and can be seen as a self-correcting method for getting rid of the detritus remaining from failed evolution.

But I would argue instead that mass extinctions are necessary and unavoidable. They are necessitated by the ineffectiveness of the process of evolution itself. They provide the self-correction necessary to cope with the mass of “rubbish” species created by the hit-and-miss process of evolution. The external shock is only incidental and acts as the trigger for the extinction of the highly-stressed “rubbish” species. None of the historical mass extinctions ever posed any threat to the continuation of life. Instead they have served to muck out the dung from the evolutionary stables.

The fossil record shows that biodiversity in the world has been increasing dramatically for 200 million years and is likely to continue. The two mass extinctions in that period (at 201 million and 66 million years ago) slowed the trend only temporarily. Genera are the next taxonomic level up from species and are easier to detect in fossils. The Phanerozoic is the 540-million-year period in which animal life has proliferated. Chart created by and courtesy of University of Chicago paleontologists J. John Sepkoski, Jr. and David M. Raup.

The fossil record shows that biodiversity in the world has been increasing dramatically for 200 million years and is likely to continue. The two mass extinctions in that period (at 201 million and 66 million years ago) slowed the trend only temporarily. Genera are the next taxonomic level up from species and are easier to detect in fossils. The Phanerozoic is the 540-million-year period in which animal life has proliferated. Chart created by and courtesy of University of Chicago paleontologists J. John Sepkoski, Jr. and David M. Raup.

The clue lies here:

Wikipedia: Although there are 10–14 million species of life currently on the Earth, more than 99 percent of all species that ever lived on the planet are estimated to be extinct.

Evolution fails in over 99% of its attempts to create species that can survive. The 1%  of species that do and have survived may seem to be perfectly tailored for the prevailing conditions but that is putting the cart before the horse. Evolution has no direction and does not seek excellence. It only throws up a plethora of species where just 1% of those species happen to suit the prevailing conditions. One round peg out of a 100 different shapes may happen to fit a round hole but the round peg itself was not designed to fit – it happened to be the only one of many which did. For every species which is just good enough to survive, evolution gives another 99 which are not. As a process it is a remarkably ineffective one. Humans are not the result of “intelligent design”. They are just the 1% of all the species created by evolution which happened to fit the round hole of the prevailing environment.


 

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Raging biodiversity – “One trillion species on earth”

May 3, 2016

A new paper now estimates that there could be up to one trillion species on earth.

Kenneth J. Loceya, and Jay T. Lennona. Scaling laws predict global microbial diversity. PNAS, 2016 DOI: 10.1073/pnas.1521291113

It seems logical to me that for any environment there has to be an optimum (perhaps many possible such) number of species for the sustainability of those species. Biodiversity is not always good and the current “wisdom” that increasing biodiversity is always a good thing, is not just flawed – it is plain stupid. Evolution is highly inefficient (though it has been effective) and produces far more species than are necessary for the sustainability of life. Since over 99% of all species that have ever existed are now extinct, it follows that evolution has failed every one of those extinct species; and failed each to the point of destruction. Mass extinctions are merely the way in which the detritus of failed evolution is cleaned out. Currently probably some 30% of all species need to go extinct.

I have never yet heard a satisfactory explanation of why ever-increasing biodiversity, which is so politically correct, is a good thing. “The good of the eco-system” is often quoted – but what on earth is that? Is it better to have a multitude of species or a multitude of individuals in a fewer number of species? Is it better for external forces to change an environment (long, slow geologic processes or short sharp catastrophic events) or for the species within the environment to change it? There is a mindless worship of biodiversity which is not logical.

It seems almost self-evident to me that, for any given environment there must be an optimum number of species, with particular combinations of characteristics, which allow the ecosystem or biosphere to be in a self-sustaining equilibrium (not growing or declining but self-sustaining). This optimum will vary depending upon the characteristics and interactions between the particular species existing and the available space in the prevailing environment. Then, having fewer than the optimum number of species in that environment would mean that all the complex interdependent, interactions between species that seem to be necessary for sustaining each of the participating species would not be fully developed. I say “seem” because it is not certain that all interdependencies are necessarily of benefit to individual species. “It is the entire ecosystem which benefits” I hear some say, but even that is more an assumption than a conclusion.

 

The press release from the University of Indiana

Earth could contain nearly 1 trillion species, with only one-thousandth of 1 percent now identified, according to a study from biologists at Indiana University.

The IU scientists combined microbial, plant and animal community datasets from government, academic and citizen science sources, resulting in the largest compilation of its kind. Altogether, these data represent over 5.6 million microscopic and nonmicroscopic species from 35,000 locations across all the world’s oceans and continents, except Antarctica. ……

….. Microbial species are all forms of life too small to be seen with the naked eye, including all single-celled organisms, such as bacteria and archaea, as well as certain fungi. Many earlier attempts to estimate the number of species on Earth simply ignored microorganisms or were informed by older datasets that were based on biased techniques or questionable extrapolations, Lennon said. ……

……. The study’s results also suggest that actually identifying every microbial species on Earth is an almost unimaginably huge challenge. To put the task in perspective, the Earth Microbiome Project — a global multidisciplinary project to identify microscope organisms — has so far cataloged less than 10 million species.

“Of those cataloged species, only about 10,000 have ever been grown in a lab, and fewer than 100,000 have classified sequences,” Lennon said. “Our results show that this leaves 100,000 times more microorganisms awaiting discovery — and 100 million to be fully explored. Microbial biodiversity, it appears, is greater than ever imagined.”

Abstract

Scaling laws underpin unifying theories of biodiversity and are among the most predictively powerful relationships in biology. However, scaling laws developed for plants and animals often go untested or fail to hold for microorganisms. As a result, it is unclear whether scaling laws of biodiversity will span evolutionarily distant domains of life that encompass all modes of metabolism and scales of abundance. Using a global-scale compilation of ∼35,000 sites and ∼5.6⋅106 species, including the largest ever inventory of high-throughput molecular data and one of the largest compilations of plant and animal community data, we show similar rates of scaling in commonness and rarity across microorganisms and macroscopic plants and animals. We document a universal dominance scaling law that holds across 30 orders of magnitude, an unprecedented expanse that predicts the abundance of dominant ocean bacteria. In combining this scaling law with the lognormal model of biodiversity, we predict that Earth is home to upward of 1 trillion (1012) microbial species. Microbial biodiversity seems greater than ever anticipated yet predictable from the smallest to the largest microbiome.


Related:

ktwop on biodiversity

The fossil record shows that biodiversity in the world has been increasing dramatically for 200 million years and is likely to continue. The two mass extinctions in that period (at 201 million and 66 million years ago) slowed the trend only temporarily. Genera are the next taxonomic level up from species and are easier to detect in fossils. The Phanerozoic is the 540-million-year period in which animal life has proliferated. Chart created by and courtesy of University of Chicago paleontologists J. John Sepkoski, Jr. and David M. Raup.

The fossil record shows that biodiversity in the world has been increasing dramatically for 200 million years and is likely to continue. The two mass extinctions in that period (at 201 million and 66 million years ago) slowed the trend only temporarily. Genera are the next taxonomic level up from species and are easier to detect in fossils. The Phanerozoic is the 540-million-year period in which animal life has proliferated. Chart created by and courtesy of University of Chicago paleontologists J. John Sepkoski, Jr. and David M. Raup.


 

Mass extinctions correct for evolution’s greater than 99% failure rate

April 23, 2015

There are said to have been 5 great mass extinctions in the last 540 million years (the Phanerozoic) and a new paper claims  – without carrying much conviction – that it was really six (with two being very close together). The Alarmists claim that humans are causing a new great mass extinction (the 6th or the 7th) and that this threatens a catastrophic collapse of biodiversity. This contradicts the fact that there are more species alive today than ever before. Moreover, why this high level of biodiversity is necessary or a “good thing” remains a mystery.

The mass extinctions of the past are generally put down to various external events which provided a sharp shock to the environment in which highly stressed species existed. Nearby supernovas, asteroid impacts, sudden tectonic plate shifts, glaciation, and super-dooper-volcanic eruptions are among the “shocks” suggested.

But I would argue instead that mass extinctions are necessary and unavoidable. They are necessitated by the ineffectiveness of the process of evolution itself. They provide the self-correction necessary to cope with the mass of “rubbish” species created by the hit-and-miss process of evolution. The external shock is only incidental and acts as the trigger for the extinction of the highly-stressed “rubbish” species. None of the historical mass extinctions ever posed any threat to the continuation of life. Instead they have served to muck out the dung from the evolutionary stables.

The fossil record shows that biodiversity in the world has been increasing dramatically for 200 million years and is likely to continue. The two mass extinctions in that period (at 201 million and 66 million years ago) slowed the trend only temporarily. Genera are the next taxonomic level up from species and are easier to detect in fossils. The Phanerozoic is the 540-million-year period in which animal life has proliferated. Chart created by and courtesy of University of Chicago paleontologists J. John Sepkoski, Jr. and David M. Raup.

The fossil record shows that biodiversity in the world has been increasing dramatically for 200 million years and is likely to continue. The two mass extinctions in that period (at 201 million and 66 million years ago) slowed the trend only temporarily. Genera are the next taxonomic level up from species and are easier to detect in fossils. The Phanerozoic is the 540-million-year period in which animal life has proliferated. Chart created by and courtesy of University of Chicago paleontologists J. John Sepkoski, Jr. and David M. Raup.

The clue lies here:

Wikipedia: Although there are 10–14 million species of life currently on the Earth, more than 99 percent of all species that ever lived on the planet are estimated to be extinct.

Evolution fails in over 99% of its attempts to create species that can survive. The 1%  of species that do and have survived may seem to be perfectly tailored for the prevailing conditions but that is putting the cart before the horse. Evolution has no direction and does not seek excellence. It only throws up a plethora of species where just 1% of those species happen to suit the prevailing conditions. One round peg out of a 100 different shapes may happen to fit a round hole but the round peg itself was not designed to fit – it happened to be the only one of many which did. For every species which is just good enough to survive, evolution gives another 99 which are not. As a process it is a remarkably ineffective one. Humans are not the result of “intelligent design”. They are just the 1% of all the species created by evolution which happened to fit the round hole of the prevailing environment.

Stewart Brand writes in Aeon that “the idea that we are edging up to a mass extinction is not just wrong – it’s a recipe for panic and paralysis”

Aeon: Many now assume that we are in the midst of a human-caused ‘Sixth Mass Extinction’ to rival the one that killed off the dinosaurs 66 million years ago. But we’re not. The five historic mass extinctions eliminated 70 per cent or more of all species in a relatively short time. That is not going on now. ‘If all currently threatened species were to go extinct in a few centuries and that rate continued,’ began a recent Nature magazine introduction to a survey of wildlife losses, ‘the sixth mass extinction could come in a couple of centuries or a few millennia.’

The range of dates in that statement reflects profound uncertainty about the current rate of extinction. Estimates vary a hundred-fold – from 0.01 per cent to 1 per cent of species being lost per decade. The phrase ‘all currently threatened species’ comes from the indispensable IUCN (International Union for Conservation of Nature), which maintains the Red List of endangered species. Its most recent report shows that of the 1.5 million identified species, and 76,199 studied by IUCN scientists, some 23,214 are deemed threatened with extinction. So, if all of those went extinct in the next few centuries, and the rate of extinction that killed them kept right on for hundreds or thousands of years more, then we might be at the beginning of a human-caused Sixth Mass Extinction.

Worrying about whether the 6th mass extinction has started or not is moot. A 6th mass extinction is needed.

A failure rate of 99% creates a terrible lot of dross. Over time, all the “rubbish” species produced by evolution accumulate and clutter the available environment. They restrict the space available for more suitable (worthy) species. The analogy with my desk fits perfectly. Only one of every hundred pieces of paper needs to be kept. Every once in a while – usually triggered by the shock of having to make my tax declaration – I clear out the rubbish. Mass extinctions are then due to the accumulation of too many “rubbish” species which are highly stressed – because they are not quite good enough to survive – and then which end up being susceptible to any external shock which tips them over into the dustbin of extinction – where they belong. It is mass extinctions which provides room for the “good enough” species to grow and even thrive. Mass extinctions provide the clean-up mechanism for a very sloppy and inefficient evolution process. A rather drastic clean-up method perhaps but no more drastic than diverting the Alpheus and Peneus rivers to muck out the Augean stables!

If it is in fact true that we have more species alive today than ever before then the number of “rubbish” species around is also probably at an all-time high. A new, 6th, mass extinction is probably necessary to clean up the mess. It is clearly overdue.

And that is really the problem with the alarmist conservationists who are wasting resources in trying to protect some of the “rubbish” species which are merely examples of the failures of evolution and which deserve to be consigned to the dustbin of extinction. Species which do not adapt to the dominating presence of humans are among the “rubbish”. It may be regrettable that tigers and elephants are on the “rubbish” list but the reality is that they are failed species unable to cope with their environments and which are now restricting the dominant species. It only emphasises that true conservation would not try to freeze these species into failed patterns but to genetically adapt them to be neo-tigers or neo-elephants which would no longer just be “rubbish”.


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