The Permian Period is a geologic period corresponding to the last subdivision of the Paleozoic Era.
It began 299.9 million years ago and ended approximately 251 million years ago.
Permian is named after the region of Perm located in Russia, where rocks from this period were first studied.
The period was named back in 1841 by geologist Sir Roderick Murchison.
The Permian Period was a time of dramatic changes in the Earth’s climate.
At the start of the period, all of Earth’s continents were fused to form a supercontinent called Pangea.
The contiguous strip of land resulted in seasonal and geographical variations across the planet.
Expectedly, the changes in the Earth’s climate triggered an evolution of biological life as well.
The extensive forest ecosystems formed during the Carboniferous started breaking down as new plant groups rose to replace the ancient varieties.
The Permian Period was characterized by remarkable diversification and evolution of animal life as well, both in the oceans and on land.
One of the most significant events in the Permian Period was the rise of the reptiles and synapsids (ancestors of modern mammals).
These groups were better equipped to thrive in the drier conditions of the Permian, and they soon rose to dominance in place of the amphibians.
Unfortunately, the Permian Period ended with the largest mass extinction event in Earth’s history.
The “Great Dying” resulted in the loss of the vast majority of plant and animal life that evolved during the Paleozoic.
In this post, we’ll go over the details of the key events that occurred during the rise and fall of Earth’s ancient supercontinent at the end of the Paleozoic.
Timeline of the Permian Period
The Permian Period is a 47-year period beginning from the end of the Carboniferous Period till the beginning of the Mesozoic Era — the Triassic Period.
It started approximately 298.9 million years ago and ended 252.2 million years ago, making it the last period of the Paleozoic Era that began 541 million years ago.
The Permian Period is grouped into three main subdivisions based on rock layers, fossil assemblages, and the significant events that took place throughout the period.
They include:
- Cisuralian Epoch (299 to 272.3 million years ago)
- Guadalupian Epoch (279.3 to 272.3 million years ago)
- Lopingian Epoch (272.3 to 251 million years ago)
Cisuralian Epoch (299 to 272.3 Million Years Ago)
By the time the last epoch of the Carboniferous Period ended 299 million years ago, Earth’s landmasses already formed a supercontinent called Pangea.
This supercontinent was mostly concentrated in the Southern Hemisphere, but parts of it straddled the equator and extended into the Northern Hemisphere.
Major tectonic activities were going on as the continents continued to merge.
The climate, which was warm and humid during the Early Carboniferous Period, became arid early in the Permian.
The arrangement of the continents as single vast land masses meant very little oceanic influences.
Localized variations in climatic conditions also began to emerge as the epoch progressed.
The Carboniferous forests formed by early conifers, cycads, and seed ferns still covered the land but were starting to break down due to changing climatic conditions.
Amid this, the first true gymnosperms (seed-producing plants) appeared, and they became dominant later in the epoch.
In the oceans, marine life continued to thrive.
Invertebrate groups like the brachiopods, ammonoids, and bivalves were still abundant, but trilobites started declining and eventually became extinct.
Fish continued to evolve, with some developing bony plates and spines for protection.
On land, early reptiles, including the iconic sail-backed Dimetrodon, emerged and started to dominate early in the Permian Period.
Insects, which had first appeared during the Carboniferous, increased dramatically during the Early Permian but declined later in the period.
Guadalupian Epoch (279.3 to 272.3 Million Years Ago)
The interior of the supercontinent Pangea was characterized by vast dry areas during the Middle Permian.
There were climatic variations, with some regions experiencing clear tropical conditions while others became colder and temperate.
Changes in sea levels led to the formation of shallow seas that supported diverse marine ecosystems.
As a result of this, marine life continued to thrive, with the presence of diverse invertebrates, including corals, sponges, and mollusks.
Plant life diversified significantly during this subperiod of the Permian, with an increase in the abundance and diversity of plant species.
New plant groups, such as glossopterids, a type of early seed-producing plant, emerged during this period.
On land, reptiles further diversified.
Variations in atmospheric conditions meant the reptiles (being cold-blooded) had to evolve adaptations that would favor their survival.
Some of them, such as the primitive pelycosaurs, evolved giant sails on their back which served thermoregulatory functions.
Others, like the therapsids, became warm-blooded.
This group of mammal-like reptiles was important because they would eventually give rise to true mammals in the later periods.
Lopingian Epoch (272.3 to 251 Million Years Ago)
Mountain-building activities due to the consolidation of the continents continued throughout the Lopingian Epoch.
As the continents neared their final positions for the Permian Period, the climate continued to change and varied even more.
While the interior of Pangea remained dry, some of the coastal regions had more humid conditions.
Towards the end of the epoch, the climate became progressively warmer, but inland Pangea was still quite dry.
Plant diversity continued to increase during this epoch.
More specifically, plant species that were better adapted to drier conditions started to emerge.
On land, reptiles remained the dominant group.
However, early prehistoric life was starting to decline by the end of the Permian.
It all came to a calamitous close about 251 million years ago with an extinction event that wiped out over 90% of all marine species and 70% of land animals.
Climate and Geography of the Permian Period
One of the most notable events of the Permian Period was the formation of the supercontinent Pangea.
Pangea was formed by two big supercontinents, Pangea and Laurussia, along with several smaller land masses.
The continents merged into a vast stretch of land, forming extensive interior regions with no significant coastlines.
Most of the landmass of Pangea was in the Southern Hemisphere, surrounded by shallow seas.
The interior of Pangea consisted of arid and desert-like landscapes, while the coastal regions had more varied ecosystems.
In addition to the geographical variations, the climate of the Permian Period also fluctuated significantly throughout the period.
It transitioned from a stable, arid climate to a less stable one, where conditions varied locally as the period progressed.
In some parts of the Earth, the temperature would drop below freezing at night and rise to over 100 degrees Fahrenheit (38 degrees Celsius) during the day.
The variations increased further as the Permian Period progressed.
Regions along the coast and in low-lying areas experienced tropical and subtropical conditions.
These regions supported lush vegetation and diverse ecosystems.
The sea levels also fluctuated throughout the Permian Period.
Shallow seas covered large areas of land, then receded after some years.
These shallow seas were crucial in supporting marine life and creating unique coastal environments suitable for amphibians.
Towards the end of the Permian Period, the climate began to shift towards a more uniformly warm and humid state.
This warming trend continued into the subsequent Triassic Period, leading to further changes in global climate patterns.
Key Events and Developments of the Permian Period
The Permian Period was a time of significant changes in Earth’s geology and biology.
As geological events forced a change in the Earth’s continental configuration, it introduced key developments that would shape the progression of life on the continents and in the surrounding marine ecosystems.
Some of the key events that took place during the Permian include:
Supercontinent Formation
The formation of Pangea technically started before the start of the Permian Period.
However, it continued throughout the period and can be considered one of the critical events that shaped the progression of the Earth’s climate and biological trajectory.
In Pangea, the landmasses of the Earth formed a thickened “C-Shaped” configuration.
The landmasses of Europe and Asia formed the top curve of the “C.” Africa was the inside of the curve, while the landmass of North and South America formed the curved back.
The low curve included the landmass of present-day Antarctica, Australia, and India.
Climate Variability
The Permian Period experienced fluctuations in climate.
This happened because Pangea was so immense and far out from the ocean that the oceanic current had little to no effect on its climate.
As a result, the interior portions of the continent were much cooler and drier compared to the previous period.
It began with arid conditions in the interior of Pangea, but as the period progressed, the climate became more diverse, with some regions experiencing tropical and subtropical conditions.
The south was also closer to the South Pole, so it was colder and more arid.
Northern regions were subject to significant seasonal variations with fluctuating wet and dry conditions.
Geological Processes
The Permian Period was also characterized by significant geological processes.
This includes volcanic activity, mountain building, and sedimentation that sculpted the Earth’s landscape and also contributed to changing climatic conditions.
Some experts believe geological processes may have been the cause of the extinction events that occurred at the end of the Permian Period.
Major Groups of Organisms in the Permian Period
Although the Permian is more popular for the catastrophic end to most of Earth’s living species that occurred at the end of the period, the period was also characterized by the emergence of several new groups and the diversification of many others.
Some of the major groups of organisms known from this period include:
Reptiles
The Mesozoic Era is rightly regarded as the “age of the reptiles,” but the events that paved the way for the dominance of reptiles began long before then.
The Permian Period marked the rise of reptiles as they became the dominant land vertebrates in place of amphibians.
Early reptiles, including iconic species like Dimetrodon and Edaphosaurus, emerged during this time.
They had thicker skin that could retain moisture which made them better suited to the desert-like habitats that were more common in the Permian.
Therapsids
Therapsids were a group of mammal-like reptiles that flourished during the Permian Period.
They were the first group of animals to evolve the ability to conserve heat generated internally through the breakdown of food (warm-blooded animals).
Therapsids are important because they play a crucial role in the evolutionary path of mammals.
Brachiopods
Brachiopods were abundant and diverse in the marine habitats of the Permian Period.
They were filter-feeding marine organisms that resembled clams but were not closely related to them.
Brachiopods were important members of marine ecosystems, inhabiting a wide range of environments from shallow seas to deep waters.
Conifers
Conifers are a group of seed-producing plants (gymnosperms) that emerged during the Permian.
They were well-adapted to the drier conditions that prevailed during this period because they developed seeds protected by cone structures.
This allowed them to reproduce and disperse more efficiently than earlier plant groups.
Notable Species from the Permian Period
Dimetrodon
Dimetrodon is one of the most iconic and recognisable animal species from the Permian Period.
They’re known for the sail-like structures on their back, which were used for thermoregulation.
Although it is often mistaken for a dinosaur, this carnivorous reptile belonged to a group known as synapsids.
Edaphosaurus
Edaphosaurus was another prominent synapsid species that was alive during the Permian Period.
It was a herbivore that also had sail-like structures on its back. The sail of the Edaphosaurus was elongated and spiky.
Gorgonopsids
Gorgonopsids were a group of large, carnivorous therapsids that thrived during the Permian Period.
They were the top predators of their time and had a unique skull structure with large canine teeth.
Gorgonopsids are often considered one of the most advanced predators that lived during the Permian.
Glossopteris
Glossopteris was a genus of seed ferns that were quite abundant in the forests of the Permian.
These plants had large, tongue-shaped leaves and are considered an important component of the Permian flora.
Proetus
Proetus was a genus of trilobite that persisted into the Permian Period.
These trilobites had a distinctive spiny appearance and were adapted to a variety of marine habitats.
Although the trilobites did not survive beyond the Permian, the presence of Proteus and other trilobites in the Permian shows just how persistent this group of marine arthropods was.
Fossils and their Significance in Understanding the Permian Period
The paleoenvironment of the Permian Period was unique and characterized by significant variations across the continents.
Fossils from the Permian Period provide evidence of these variations and the changes they caused during one of Earth’s most important periods.
By studying the changes in the plants, terrestrial and marine organisms that lived during the Permian, scientists have been able to better understand the Permian paleoenvironment and the fluctuations that existed on both local and global scales.
These fossils also serve as indicators of the distribution of life, climate patterns, and changes in habitats that occurred during this period due to the environmental pressures faced by the plant and animals of the Permian.
The Permian Period is also characterized by several evolutionary transitions in various groups of organisms.
For instance, the transition from early reptiles to more advanced forms, such as mammal-like reptiles (therapsids), is well-documented in Permian fossils.
Studying these fossils aid our understanding of the evolutionary pathways and the origins of some of the important organisms still alive today.
The Permian represents the last gasp for several early prehistoric species, and we only know this by studying the fossil deposits from that period.
Fossils from the Permian Period provide evidence of this mass extinction event, allowing scientists to study its magnitude, timing, and impact it had on the different groups of organisms that were alive at the time.
Carboniferous Rainforest Collapse and Its Impact on Evolution in the Permian
The collapse of the Carboniferous rainforest occurred during the transition from the Carboniferous Period to the Permian Period roughly 299 million years ago.
During the Carboniferous, vast regions of the planet were covered by tropical rainforests that supported a rich terrestrial ecosystem.
Towering tree ferns, horsetails, and giant lycopods dominated these rainforests.
However, as the Permian Period began, significant changes in climate and environmental conditions led to the collapse of these rainforests.
The tropical rainforest plants that thrived during the Permian were replaced with plants that are better suited to the drier conditions of the Permian, such as the cycads, conifers, and gymnosperms.
The plants of the Permian forest had evolved seeds with cone structures which were more efficient in terms of their reproduction and dispersal.
This significant evolutionary shift had far-reaching implications for both plant and animal groups.
The emergence of conifer-dominated ecosystems created new ecological opportunities for new animal groups, such as herbivores.
Plant-eating insects, reptiles, and mammal-like reptiles diversified during this period, and many of them adapted to feed on the new vegetation types.
This diversification of herbivorous organisms laid the foundation for subsequent evolutionary radiations that occurred during later periods.
Extinction Events and Their Effects on the Permian Period
The Permian Period ended with the most devastating extinction events in Earth’s history.
The Permian-Triassic extinction event, also known as the “The Great Dying,” wiped out about 90 to 95% of marine organisms and up to 70% of all land organisms.
Trilobites, a group of arthropods that have been quite dominant since the beginning of the Cambrian, were eventually wiped out by the end-Permian event.
Brachiopods and corals were also nearly wiped out by the event.
On land, many groups, such as the mammal-like reptiles (therapsids) and large amphibians, were severely impacted.
Although the cause of this event is still being debated, scientists have theorized that the Permian-Triassic extinction event was probably triggered by a combination of environmental factors, such as volcanic activity and the release of greenhouse gasses into the atmosphere.
Intense volcanic eruptions, such as those associated with the Siberian Traps, may have released massive amounts of carbon dioxide and other gasses into the air, leading to global warming and other significant changes in ocean chemistry.
It took Earth several million years to recover from the effect of the Permian extinction.
The event caused a massive loss of genetic diversity, and many specialized species were lost forever.
However, the subsequent recovery and adaptive radiation that followed during the Early Mesozoic also gave rise to new lineages and transformed the planet’s biological composition forever.
Sources
- https://www.britannica.com/science/Permian-Period
- https://en.wikipedia.org/wiki/Permian
- https://www.nationalgeographic.com/science/article/permian
- https://ucmp.berkeley.edu/permian/permian.php
- https://www.nps.gov/articles/000/permian-period.htm
- https://www.livescience.com/43219-permian-period-climate-animals-plants.html
- https://natmus.humboldt.edu/exhibits/life-through-time/visual-timeline/permian-period
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