The Permian Mass Extinction Event
The Permian mass extinction event, often referred to as the “Great Dying,” stands as the most severe extinction episode in the history of life on Earth, and is still greatly studied, with much to teacah us.
Occurring approximately 252 million years ago at the boundary between the Permian and Triassic periods, this cataclysmic event resulted in the loss of an estimated 90% of marine species and 70% of terrestrial species, fundamentally altering the composition of ecosystems and the trajectory of life on our planet.
The magnitude of this biodiversity collapse is unparalleled in the geological record, with impacts far surpassing those of other well-known mass extinctions, such as the Cretaceous-Paleogene extinction that led to the demise of the non-avian dinosaurs. Consequently, the Permian mass extinction event serves as a critical case study for understanding the underlying mechanisms and drivers of mass extinctions, as well as the subsequent recovery and resilience of ecosystems in the wake of such devastation.
In this extended post, we will delve into the intricacies of the Permian mass extinction event, examining the prevailing theories and hypotheses regarding its causes, and evaluating the evidence that supports each.
Through this analysis, we aim to not only shed light on the factors that contributed to Earth’s greatest biodiversity collapse, but also emphasize the importance of understanding past extinction events in order to inform our ongoing efforts to conserve biodiversity and protect ecosystems in the face of modern anthropogenic challenges.
Contents of this post:
Setting the Stage: The Permian Mass extinction event
- Tectonic and Climatic conditions during the Permian
- Dominant Flora and Fauna of the Permian
- Permian Ecosystems
The Great Dying
Comparing the Great Dying to other Mass extinction events
The Aftermath of the Permian Mass extinction event
Recovery and Continued Diversification
Theories and Hypotheses for the cause of the Great Dying
- Volcanic activity and the Siberian traps
- Oceanic Anoxia and Euxinia
- Climate change and greenhouse gasses
- Other potential contributing factors and synergies
Conclusion
Setting the stage: The Permian Mass Extinction Event
The Permian Period, spanning approximately 298 to 252 million years ago, marked the final chapter of the Paleozoic Era, preceding the Triassic Period and the subsequent Mesozoic Era. This geological period was characterized by significant tectonic, climatic, and biological changes that would ultimately set the stage for the catastrophic mass extinction event that transpired at its conclusion.
Understanding the context of the Permian Period is essential in order to appreciate the magnitude of the ecological transformation that occurred during the Great Dying and to properly evaluate the various hypotheses surrounding its causes.
The Permian Period itself can be divided into two distinct epochs: the Early Permian, or Cisuralian (298–272 million years ago), and the Late Permian, or Lopingian (272–252 million years ago).
These epochs witnessed the assembly of the supercontinent Pangea, the expansion and subsequent contraction of vast tropical and temperate forests, and the evolution of diverse and complex terrestrial and marine ecosystems, which supported a myriad of organisms that would ultimately be affected by the mass extinction event at the end of the period.
In the following sections, we will explore the tectonic and climatic conditions, as well as the dominant flora and fauna of the Permian Period, to provide a comprehensive understanding of the backdrop against which the Great Dying unfolded.
Tectonic and Climatic conditions during the Permian
The Permian Period was marked by significant tectonic activity, which played a crucial role in shaping the Earth’s geography, climate, and ecosystems, with the most notable tectonic event during this time was the formation of the supercontinent Pangea. As a result of the gradual convergence of the Earth’s major landmasses, Pangea encompassed nearly all the continental crust and was surrounded by the immense global ocean, Panthalassa.
This amalgamation of landmasses had profound effects on the Earth’s climate, resulting in a predominantly arid and seasonally extreme environment across much of Pangea’s vast interior, with the vastness of the continent leading to the development of large, high-pressure systems that prevented moisture-laden air from reaching the interior. Consequently, deserts and semi-arid regions expanded, while the once-extensive tropical and temperate forests began to contract.
Nevertheless, there were also areas along Pangea’s eastern coast that experienced relatively higher humidity and precipitation due to the influence of the Tethys Ocean, a narrow seaway that separated the southern and northern landmasses of Pangea, and this resulted in the development of extensive coal deposits that are now part of the Permian-aged strata found in the eastern parts of present-day North America and Europe.
Additionally, the formation of Pangea led to the development of an extensive continental shelf along its western margin, which created favorable conditions for the proliferation of shallow marine ecosystems. However, the overall reduction in shallow marine habitats, as well as the isolation of some seas and ocean basins, significantly impacted marine biodiversity and contributed to the vulnerability of marine organisms during the mass extinction event.
Dominant Flora & Fauna of the Permian
During the Permian Period, both terrestrial and marine ecosystems were characterized by a diverse assemblage of flora and fauna, which played important roles in shaping the ecological landscape and setting the stage for the mass extinction event that would follow.
Terrestrial Flora
The flora of the Permian Period was dominated by seedless vascular plants such as ferns, horsetails, and clubmosses, particularly in the humid, swampy environments along the eastern coast of Pangea.
These ecosystems were characterized by extensive peat-forming forests, which would eventually form the coal deposits that are a hallmark of the period, and in drier, more upland environments, seed-bearing gymnosperms, including early conifers and glossopterids, became increasingly abundant. Glossopterids, in particular, were a dominant tree lineage in the southern part of Pangea (Gondwana), forming vast forests that played a significant role in the global carbon cycle.
Terrestrial Fauna
The terrestrial fauna of the Permian Period was marked by the diversification of both invertebrates and vertebrates, with Invertebrates, including insects and arachnids, diversifying in response to the changing vegetation patterns, and the availability of novel ecological niches.
Vertebrate life during the Permian was dominated by the synapsids, a group of amniotes that would give rise to mammals, and various reptile lineages. Among the synapsids, the pelycosaurs (such as the iconic sail-backed Dimetrodon) were dominant during the Early Permian, while the therapsids, a more advanced group of synapsids, became increasingly abundant during the Late Permian. Additionally, early reptile lineages, such as parareptiles and eureptiles, began to diversify and adapt to various ecological niches.
Marine Flora and Fauna
Similar to those habitats on land, the marine ecosystems of the Permian were equally diverse, with a rich array of invertebrates, including brachiopods, bivalves, gastropods, trilobites, ammonoids, and various groups of reef-building organisms such as corals and sponges. Marine vertebrates were represented by several groups of fish, including cartilaginous fish (sharks and their relatives) and bony fish, as well as early marine reptiles, such as mesosaurs.
Permian reefs were particularly diverse and complex, with a wide range of organisms contributing to their construction, and Rugose and tabulate corals, sponges, bryozoans, and various types of algae and microbialites played key roles in building the intricate structures that supported a wealth of marine life. These reef ecosystems were hotspots of biodiversity and served as important sources of ecological stability within the expanding marine realm.
Permian Ecosystems
As we have briefly covered, the Permian witnessed several significant evolutionary milestones that played crucial roles in shaping the trajectory of life on Earth. Among these developments, and possibly most important, were the radiation of gymnosperms, which provided new ecological opportunities for terrestrial herbivores and led to the diversification of plant-eating synapsids and reptiles.
This expansion of gymnosperms also facilitated the spread of insects, as these plants offered new food sources and habitat niches for insect communities.
Additionally, the Permian saw the emergence of early reptiles, such as the aforementioned parareptiles and eureptiles, which would later give rise to important reptilian lineages, including turtles, lizards, snakes, and archosaurs, the group that would eventually include dinosaurs, pterosaurs, and crocodilians.
Emergence of New Species and Ecosystems
The Permian Period also saw the emergence of new species and ecosystems in response to the shifting geological and climatic conditions. One notable example is the evolution of therapsids, a group of synapsids that thrived during the Late Permian.
Therapsids were mammal-like reptiles that displayed a wide range of morphological and ecological adaptations, occupying a variety of niches, from herbivores and carnivores to burrowers and aquatic forms, and the massive diversity and dominance of therapsids during the Late Permian foreshadowed the later success of mammals, which would eventually evolve from this group.
In the marine realm, the development of Permian reef ecosystems was marked by the ongoing, and rapid diversification of various reef-building organisms, such as corals, sponges, and bryozoans, where these complex structures supported a wealth of marine life, including various types of fish, ammonoids, and brachiopods. Permian reefs also provided crucial habitats for the early marine reptiles, such as the mesosaurs, which were among the first reptiles to adapt to a fully aquatic lifestyle.
Furthermore, the unique tectonic and climatic conditions of the Permian Period allowed for the emergence of highly specialized ecosystems, such as those found in the Tethys Ocean, and other locations. The Tethys Ocean, which separated the northern and southern parts of Pangea, was characterized by tropical shallow seas that supported diverse communities of marine life, including ammonoids, brachiopods, and corals, and these ecosystems were highly important centers of marine biodiversity, serving as critical refugia for many species during times of environmental stress.
The Great Dying
The Permian mass extinction event, often referred to as the Great Dying, was the most severe extinction event in Earth’s history, and resulted in the loss of an estimated 90% of all marine species and 70% of terrestrial species, significantly altering the course of life on our planet. This catastrophic event affected virtually all major groups of organisms, from marine invertebrates, such as brachiopods, ammonoids, and trilobites, to terrestrial plants and vertebrates, including synapsids and early reptile lineages.
Marine ecosystems were particularly hard hit, with the collapse of complex reef systems and the disappearance of numerous groups of marine invertebrates. For example, trilobites, which had thrived for over 250 million years, were completely wiped out during the Permian mass extinction.
Similarly, the extinction event also brought an end to the rugose and tabulate corals, which had been among the major reef builders during the Paleozoic Era, and on land, in terrestrial ecosystems, the Great Dying led to the decline of many dominant plant lineages, such as glossopterids and seed ferns, which were replaced by gymnosperms and, eventually, angiosperms in the Mesozoic Era.
The vertebrate community was also heavily impacted, with the extinction of many synapsid lineages, including the once-dominant pelycosaurs and numerous therapsid groups, though these losses paved the way for the rise of other vertebrate groups, such as archosaurs, which would go on to dominate the Mesozoic Era, giving rise to dinosaurs, pterosaurs, and crocodilians.
Comparing The Great Dying to other Mass extinction events
In order to fully appreciate the severity of the Permian mass extinction event, it is helpful to compare it to other major extinction events in Earth’s history. There have been five significant mass extinctions in the geological record, commonly referred to as the “Big Five.”
These events include the Ordovician-Silurian, Late Devonian, Permian-Triassic (the Great Dying), Triassic-Jurassic, and Cretaceous-Paleogene extinctions. Each event was characterized by significant losses in biodiversity, but the Permian extinction stands out as the most devastating.
Ordovician-Silurian Extinction: ~443 million years ago
The Ordovician-Silurian extinction resulted in the loss of approximately 60–70% of marine species, primarily affecting brachiopods, trilobites, and corals. This event was likely driven by rapid climate changes, including mass glaciation and the subsequent sea level fluctuations.
Late Devonian Extinction: ~359 million years ago
The Late Devonian extinction led to a loss of around 70–75% of marine species, with brachiopods, trilobites, and reef-building organisms among the most severely affected groups. The causes of this extinction event are still debated, but likely factors include climate change, ocean anoxia, and the rise of land plants, which may have altered global nutrient cycles.
Triassic-Jurassic Extinction: ~201 million years ago
The Triassic-Jurassic extinction event resulted in the loss of approximately 70–75% of species, both marine and terrestrial, though the event particularly affected marine reptiles, early dinosaurs, and various synapsid groups. The causes of this extinction event are still under debate, but possible factors include volcanic activity, climate change, and ocean anoxia.
Cretaceous-Paleogene Extinction: ~66 million years ago
The Cretaceous-Paleogene extinction, the most famous of the mass extinction events, led to the loss of approximately 75% of all species, including the non-avian dinosaurs. The extinction event was triggered by a combination of factors, stemming from the impact of an asteroid.
Compared to these other events listed above, the Permian mass extinction event stands out due to its unparalleled scale and severity, with an estimated 90–96% of all species lost.
The causes and consequences of the Great Dying are still the subject of ongoing research, but it is clear that this event had a profound and lasting impact on the course of life on Earth, reshaping ecosystems and opening new ecological niches for the organisms that survived.
The Aftermath
The Permian mass extinction event had profound and lasting effects on ecosystems and the biosphere, as the surviving organisms struggled to adapt and fill the ecological voids left by the extinction. The following points are some of the key consequences of the Great Dying on Earth’s ecosystems:
Collapse and Rebuilding of Marine Ecosystems
The marine ecosystems were severely affected by the extinction event, as evidenced by the loss of complex reef systems and the extinction of numerous marine invertebrates. In the aftermath of the Great Dying, the recovery of marine ecosystems was slow and protracted, taking millions of years to rebound.
New reef-building organisms, such as scleractinian corals and calcareous sponges, emerged to replace the extinct rugose and tabulate corals, eventually leading to the establishment of modern coral reef ecosystems.
Terrestrial Ecosystem Shifts
On land, the extinction event resulted in significant shifts in terrestrial ecosystems, and the loss of many dominant plant lineages, such as glossopterids and seed ferns, allowed gymnosperms to become the dominant plant group in the Mesozoic Era.
These new plant communities supported the emergence of various herbivorous vertebrates, including dinosaurs, which would come to dominate terrestrial ecosystems in the following periods/
Rise of New Vertebrate Groups
The extinction of numerous synapsid and early reptile lineages during the Great Dying opened up ecological niches for the surviving vertebrates. The most notable example is the rise of archosaurs, which as we have mentioned, gave rise to dinosaurs, pterosaurs, and crocodilians.
These groups would go on to become the dominant vertebrates in the Mesozoic Era, shaping the course of terrestrial ecosystems for millions of years to come.
Recovery, and continued diversification
The recovery and diversification of life following the Permian mass extinction event was slow and uneven, as ecosystems were drastically altered and many previously occupied niches were left vacant. It took approximately 5–10 million years for the biodiversity to begin recovering, and even longer for many of the complex ecosystems to be re-established.
This period of recovery, occuring during the Early Triassic, was characterized by a relatively low diversity of species, many of which were widespread in distribution. Over time, however, the surviving organisms diversified and adapted to the new conditions, eventually giving rise to the diverse and vibrant ecosystems of the Mesozoic Era.
Early Triassic: Initial Recovery
The Early Triassic period (252–247.2 million years ago) represents the initial phase of recovery following the Great Dying. During this time, biodiversity remained relatively low, and the ecosystems were simplified compared to the complex communities of the Permian period.
One notable feature of the Early Triassic is the prevalence of cosmopolitan species with wide geographic distributions, such as the hardy Lystrosaurus, a herbivorous synapsid that thrived in the aftermath of the extinction event.
Middle Triassic: Increasing Biodiversity and Ecosystem Complexity
The Middle Triassic period (247.2–237 million years ago) marked a turning point in the recovery process, as biodiversity began to increase and ecosystems grew more complex. During this time, new groups of marine invertebrates, such as ammonoids and bivalves, diversified, and the first scleractinian coral reefs began to form.
On land, gymnosperms continued to spread, providing a foundation for the expansion of terrestrial ecosystems.
The archosaurs, which had first appeared in the Early Triassic, began to diversify and occupy various ecological niches, eventually giving rise to the first true dinosaurs.Middle Triassic: Increasing Biodiversity and Ecosystem Complexity
The Middle Triassic period marked a turning point in the recovery process, as biodiversity began to increase and ecosystems grew more complex, and during this time, new groups of marine invertebrates, such as ammonoids and bivalves, diversified, and the first scleractinian coral reefs began to form.
On land, gymnosperms continued to spread, providing a foundation for the expansion of terrestrial ecosystems, and the archosaurs, which had first appeared in the Early Triassic, began to diversify and occupy various ecological niches, eventually giving rise to the first true dinosaurs.
Late Triassic: The Emergence of Iconic Mesozoic Groups
The Late Triassic period (237–201.4 million years ago) saw the further diversification of life, with the emergence of many iconic Mesozoic groups. In the oceans, ichthyosaurs and plesiosaurs began to dominate as marine reptiles, while on land, the first true mammals evolved from their synapsid ancestors.
The dinosaurs continued to diversify and grow in size and complexity, eventually coming to dominate terrestrial ecosystems.
What caused the Permian Mass Extinction Event: Theories and Hypotheses
Following are the main hypotheses for the Permian mass extinction event, with many believing that all played a role, in contrast to one simple defining event.
Volcanic activity and the Siberian traps
The Siberian Traps are a large igneous province formed by extensive volcanic eruptions that occurred around the end-Permian period, approximately 252 million years ago. This massive volcanic event produced an estimated 3 to 5 million cubic kilometers of basaltic lava, covering an area of approximately 2 million square kilometers.
The scale of the eruptions and their potential impacts on the environment make the Siberian Traps a strong candidate for a major driving force behind the Permian mass extinction.
The eruptions associated with the Siberian Traps took place over a relatively short geological time frame, lasting around 1 million years. The timing of these eruptions closely coincides with the end-Permian mass extinction event, suggesting a potential causal link. The vast quantities of lava, ash, and volcanic gases released during the eruptions would have had wide-ranging impacts on the environment, including:
Global Warming: The release of massive amounts of greenhouse gases, particularly carbon dioxide and methane, likely led to significant global warming, causing extreme heat stress for many organisms.
Ocean Acidification: The increased atmospheric carbon dioxide would have also led to ocean acidification, which can have severe effects on marine life, particularly organisms with calcium carbonate shells.
Anoxia: The warming of the oceans could have led to stratification and reduced mixing of oxygen-rich surface waters with deeper, oxygen-poor waters, resulting in widespread anoxic conditions that would have been detrimental to marine life.
Disruption of Photosynthesis: The release of sulfur dioxide and other aerosols into the atmosphere could have led to a decrease in sunlight reaching the Earth’s surface, disrupting photosynthesis and further stressing both terrestrial and marine ecosystems.
There is a considerable body of evidence supporting the hypothesis that volcanic activity associated with the Siberian Traps played a significant role in the Permian mass extinction. Some key markers include:
Geochronology: Precise dating techniques have shown that the timing of the Siberian Traps eruptions closely aligns with the end-Permian extinction event.
Geochemical Signatures: The isotopic signatures of carbon and sulfur in end-Permian sediments provide evidence of massive volcanic outgassing and the release of vast quantities of greenhouse gases.
Fossil and Sedimentary Records: Fossil and sedimentary records reveal abrupt changes in the composition of ecosystems and the deposition of volcanic ash layers that coincide with the end-Permian extinction event.
Oceanic Anoxia and Euxinia
Another leading hypothesis for the cause of the Permian mass extinction is widespread oceanic anoxia and euxinia. These events are characterized by a severe depletion of dissolved oxygen and the presence of toxic hydrogen sulfide in ocean waters, respectively, which can have devastating consequences for marine life and ecosystems.
In this section, we will explore the mechanisms behind anoxic and euxinic events, the evidence from rock records and geochemical data, and the potential impacts on marine life and ecosystems.
Oceanic anoxia and euxinia can be triggered by several interconnected mechanisms, often acting in concert. These mechanisms include:
Global Warming: Increased global temperatures, potentially due to volcanic activity, can lead to ocean stratification, with warm surface waters overlaying colder, denser waters. This stratification reduces the mixing of oxygen-rich surface waters with deeper, oxygen-poor waters, leading to the development of anoxic conditions.
Increased Nutrient Input: Elevated nutrient levels in the oceans, potentially due to increased weathering and erosion of continental rocks, can promote the growth of marine algae and other primary producers. When these organisms die and sink to the seafloor, their decomposition consumes oxygen, exacerbating anoxic conditions.
Stagnation: Tectonic events or changes in ocean circulation can lead to stagnation in certain areas of the ocean, reducing the exchange of oxygen between surface and deep waters.
Euxinia: In anoxic conditions, sulfate-reducing bacteria can thrive, producing toxic hydrogen sulfide gas as a byproduct. The accumulation of hydrogen sulfide in the water column leads to euxinic conditions, which are highly toxic to most marine life.
The hypothesis of widespread oceanic anoxia and euxinia as a driver of the Permian mass extinction is supported by various lines of evidence from rock records and geochemical data, including:
Black Shales: The deposition of black shales in marine sediments from the end-Permian period is indicative of anoxic conditions. These shales are rich in organic matter, suggesting low-oxygen environments that inhibited the decay of organic material.
Sulfur Isotopes: Sulfur isotope ratios in end-Permian rocks provide evidence of increased bacterial sulfate reduction, supporting the idea of widespread euxinia.
Trace Metal Concentrations: High concentrations of redox-sensitive trace metals in end-Permian sediments, such as molybdenum and vanadium, provide further evidence of anoxic and euxinic conditions in the oceans.
Impact of oceanic anoxia and euxinia on marine Life and Ecosystems
Widespread oceanic anoxia and euxinia would have had severe consequences for marine life and ecosystems, including:
Mortality: The lack of oxygen and the presence of toxic hydrogen sulfide would have directly caused the death of many marine organisms, particularly those with limited mobility or specialized oxygen requirements.
Habitat Loss: Anoxic and euxinic conditions would have rendered vast areas of the ocean uninhabitable, leading to the collapse of marine ecosystems and the extinction of species that were unable to adapt or migrate to more favorable environments.
Food Web Disruption: The loss of key species and the restructuring of ecosystems would have had cascading effects on marine food webs, leading to further extinctions and ecosystem shifts.
Climate Change and the Role of Greenhouse Gases
In addition to volcanic activity and oceanic anoxia, climate change driven by the release of greenhouse gases has been proposed as a contributing factor to the Permian mass extinction. This section will explore the effects of volcanic eruptions on the atmosphere, the release of methane from oceanic and terrestrial sources, and the feedbacks between climate change and ecosystems.
Effects of Volcanic Eruptions on the Atmosphere
The extensive volcanic activity associated with the Siberian Traps would have released vast quantities of greenhouse gases, such as carbon dioxide (CO2) and sulfur dioxide (SO2), into the atmosphere. These gases have the potential to alter the Earth’s climate in several ways:
Greenhouse Effect: The increased concentration of CO2 in the atmosphere would have contributed to the greenhouse effect, trapping heat and leading to global warming.
Aerosols: SO2 released by volcanic eruptions can form sulfate aerosols in the atmosphere, which can reflect sunlight and cause a temporary cooling effect. However, the long-term effects of sustained volcanic activity would likely have been dominated by the warming influence of CO2.
Release of Methane from Oceanic and Terrestrial Sources
Another potent greenhouse gas, methane (CH4), may have been released in large quantities during the end-Permian period from both oceanic and terrestrial sources. Potential sources of methane include:
Methane Hydrates: Methane hydrates, which are ice-like structures containing trapped methane molecules, are found in ocean sediments. Warming ocean temperatures could have destabilized these hydrates, leading to the release of methane into the atmosphere.
Terrestrial Wetlands: Wetland ecosystems, which can generate methane through the anaerobic decomposition of organic matter, may have expanded in response to increased precipitation and global warming, further contributing to atmospheric methane levels.
Climate Feedbacks and Their Impact on Ecosystems
The release of greenhouse gases and subsequent climate change would have had numerous feedbacks and impacts on ecosystems, including:
Temperature Extremes: Rapid global warming could have led to extreme temperature fluctuations, with regions experiencing both intense heat and cold, creating inhospitable conditions for many species.
Precipitation Changes: Altered precipitation patterns, such as more intense rainfall or prolonged drought, could have disrupted ecosystems and caused habitat loss for both terrestrial and aquatic species.
Sea Level Rise: The melting of polar ice caps due to global warming would have caused a rise in sea level, potentially leading to coastal flooding and the loss of terrestrial habitats.
Ocean Acidification: The increased concentration of atmospheric CO2 would have led to a decrease in ocean pH, a process known as ocean acidification, which can negatively affect marine organisms, particularly those with calcium carbonate shells or skeletons.
Other Contributing Factors and Potential Synergies
In addition to the primary hypotheses discussed above, other contributing factors and potential synergies between them may have played a role in exacerbating the severity of the Permian mass extinction event.
Asteroid or Comet Impact
Though less widely accepted as a primary driver of the Permian mass extinction, the possibility of an asteroid or comet impact has been proposed as a contributing factor. Evidence for this hypothesis includes:
Impact Craters: Several impact craters dated to the end-Permian period have been identified around the world. However, the size and distribution of these craters suggest they may not have been sufficient to cause a global extinction event.
Iridium Anomalies: Elevated levels of iridium, a rare element often associated with extraterrestrial impacts, have been found in some end-Permian sedimentary layers. Nevertheless, the significance and global extent of these anomalies remain under heavy debate.
Tectonic Activity and Sea-Level Changes
Tectonic activity and associated sea-level changes may have played a role in shaping the end-Permian world, contributing to the extinction event through several mechanisms:
Continental Drift: The formation of the supercontinent Pangea during the Permian period would have altered ocean circulation patterns, potentially contributing to the development of anoxic conditions in marine environments.
Sea-Level Fluctuations: Tectonic activity may have caused sea-level changes, leading to the inundation or emergence of vast areas of land, which could have disrupted ecosystems and impacted species distributions.
Interactions between Different Causal Factors
The Permian mass extinction event may have been the result of a complex interplay between multiple causal factors, including volcanic activity, oceanic anoxia, climate change, asteroid impacts, and tectonic activity:
Feedback Loops: The various factors discussed may have acted synergistically, amplifying their individual effects through feedback loops. For example, global warming induced by volcanic greenhouse gas emissions could have destabilized methane hydrates, further exacerbating climate change.
Cumulative Stress: The simultaneous occurrence of multiple stressors may have overwhelmed the resilience of ecosystems, leading to a collapse in biodiversity. Species that may have been able to survive one or two stressors could have succumbed when faced with a combination of factors.
In summary to this section, while the primary drivers of the Permian mass extinction event remain a topic of ongoing research, it is likely that a combination of factors and their interactions contributed to the unprecedented loss of biodiversity.
Conclusion
The Great Dying remains an enduring mystery in the study of Earth’s history, and is one that is of great interest to me personally, so I imagine we will delve much deeper, when time allows.
In the meantime, I invite you to follow us here and keep up to date with our latest content, in the near future we will be covering a range of deep time topics, in addition to our “Exploration of Deep time” series.
Resources
Paleobiology Database (https://paleobiodb.org/)
National Center for Science Education (https://ncse.ngo)
Benton, M.J., & Twitchett, R.J. (Eds.). (2003). How to kill (almost) all life: The end-Permian extinction event. The Geological Society.
Erwin, D.H. (2006). Extinction: How life on Earth nearly ended 250 million years ago. Princeton University Press.
Wignall, P.B. (2015). The worst of times: How life on Earth survived eighty million years of extinctions. Princeton University Press.
