The end of the Permian period is also the end of the Paleozoic Era. The fossil record shows the biggest drop in the diversity of marine and land organisms in life’s history on Earth. Many forms that flourished in the Paleozoic Era did not pass through to the Mesozoic Era. The reasons for the mass extinction are debated, but it is likely an enormous outpouring of magma and gases during volcanism in Siberia contributed to dramatic changes in the atmosphere, hydrosphere and biosphere.
Summary of the Permian Mass Extinction
The lecture travels to the Permian to show the configuration of continents and the various plants and animals that were abundant at that time.
In contrast, the earliest Triassic has reduced biodiversity and is characterised by disaster taxa.
The coincidence of the mass extinction with the vast outpouring of lava and gas in Siberia is examined. The interaction of molten rock with coal (C), evaporite salts (NaCl) and limestone (CaCO3) in a sedimentary basin, unlocked carbon and other elements sequestered in the geosphere and released these gases into the atmosphere, hydrosphere and biosphere. Gases included Cl-rich, ozone-depleting gases, greenhouse gases, CO2 and CH4 and SO2. Both CO2 and SO2 add to acid rain and also ocean acidification. These factors are thought to be a major contributor to a change in climate and mass extinction.
This is a long lecture. Nearly like a real live lecture! Grab a beverage, relax and do some time travelling
Select one of the below.
- Could huge volumes of molten rock alone cause a mass extinction?
- Yes
- Incorrect. It seems unlikely that any molten rock alone, even large quantities could cause a mass extinction. The gas content of the magma is very important and the rocks the magma interacts with have in this case released gases that feed into greenhouse warming and acidification scenarios.
- No
- Correct. That is correct. Any molten rock will release lava which cools and possibly particles which can get into the atmosphere, but molten rock must have more sulfur or carbon-rich gas to be able to influence climate. In the case of the Siberian Traps it was the extra elements, normally held in the rocks that were released quickly (in geological time) and contributed to a greenhouse climate and hydrosphere acidification.
Other Factors
We have only presented one of the possible contributors to this serious mass extinction event. Conditions on Earth were conspiring to create problems for the biosphere at that time.
- Continents stretched from pole to pole with a large mountain range near the equator.
- This configuration reduced world ocean circulation and upwelling, possibly creating anoxia (low to no oxygen) in the oceans. As well as this, there was reduced continental shelf areas (home to most marine biota today).
- The continental configuration also caused increasing aridity and heating of the atmosphere and also the oceans. Deserts spread and occupied the middle latitudes.
- Greenhouse gases increased, due to reduced biota. Heating may also have allowed the mass release of methane normally locked in ice in the ocean substrate (methane clathrate) adding to the greenhouse effect.
- You may like to read this BBC article, which further explains the impact of rising temperatures in the ‘Great Dying’.
From all of this, you can see that things were already difficult for life, even without the added calamity of the gases released in huge quantities during the voluminous eruptions of Siberia!
The end Cretaceous mass extinction (K-Pg)
This is a short lecture on the end of the Cretaceous, 66 million years ago, which saw the demise of the Dinosaurs. Popular culture has taken up the idea that the Dinosaurs fell foul a large meteor/asteroid impact. But geologists are not so sure that this is the full story.
More on Dinosaurs
Did you know that there were two main forms of dinosaurs?
It’s all in the hips!
The images to the right, you can see the two hip configurations of dinosaurs. The first set of hips belongs to the “lizard-hipped” dinosaurs or Saurischians, where the pubis and ischium are separated. The second set of hips belongs to the so-called “bird-hipped” dinosaurs or Ornithiscians. Where the pubis and ischium are together. Tyrannosaurus Rex was a Saurischian and the Muttaburrasaurus and many other herbivorous dinosaurs were Ornithischians.
Birds actually evolved from the Saurischians.
Many dinosaurs are now known to have been feathered. Recently some scientists purchased amber (fossilised tree resin) at a market in Myanmar. The scientist were very excited to find intact baby dinosaur feet encased in the amber. The feet were covered in brown feathers.
The evolution of feathers, suggests that some dinosaurs were hot rather than cold-blooded.
Conclusion
In this learning pathway we have considered the dire consequences for life when there are major imbalances in Earth Systems. Biosphere collapse was driven by rapid (on a geological time scale) changes wrought by Earth’s own geosphere or extra-terrestrial influences. Everything discussed had nothing to do with humans (except the dodos).
Humans: Earth Shapers has covered a breadth of topics. Initially, we looked at Earth systems: geosphere, hydrosphere, atmosphere and biosphere and discussed how these systems function and interact. We pondered how these systems have been dynamic over geological time. We learnt to read rocks and explored the fossil record, where there is evidence for major mass extinction events that happened long before humans evolved.
Humans, like all biota, interact with and impact on their environment. As human populations expanded and changed lifestyles they have a had an accelerating impact on Earth’s systems. Today some of these impacts are on metal cycling, earth moving, land use, removal of primary productivity (e.g fishing), as well as the nitrogen cycle and the carbon cycle which are driving climate change. These changes are happening on scales often greater than in nature and in much shorter time frames. These drivers are causing stress on natural systems and organisms. Organisms can only respond to these stresses in four ways: tolerate the change, evolve to become something else that can tolerate the change, migrate to somewhere more suitable or if organisms cannot do any of these things then they will become extinct. Although the evidence is still inconclusive, if many organisms become extinct and the extinction rate is elevated we will be in the sixth mass extinction. And this time humans are implicated.
So does this matter? The philosophy part of this unit has asked you to reflect upon this. Humans are the authors of these changes, but we are also subject (as are all organisms) to the impacts of these changes. We cannot divorce ourselves from this and this has a moral dimension. As humans, and some argue that humans are the only creatures who can argue these questions, do we have a moral responsibility to ourselves and other organisms? You were invited to think about questions of your own and other peoples’ personal values? Which of these values has authority and how can these values be put into practice and policies?
Policies lead to a discourse on governance. Governance is essential to making changes at global scales. In the unit we examined old and current governance. In many cases, these appear to be failing to deal with the looming environmental issues and the tragedy of the commons in general. New governance will be required to implement the changes we need to keep Earth habitable. These new modes of governance will arise from the markets, community, entrepreneurship and social movements.
So, armed with all this breadth of information on science, governance and philosophy, we invite to consider how you will be shaping Earth into the future?
You must be logged in to post to WEnotes.
Note: Your comment will be displayed in the course feed. Remembering mastodon.oeru.org is also an option to share your thoughts.
Learning pathway complete
Congratulations. You have just completed all the learning pathways for Understanding Earth Shaping, ETHS101.
If you haven’t already, we would recommend you think about the Assessment. The assessment is based on all the learning you have just engaged with, and by completing the assessment you will gain credit towards the full Human Earth Shapers unit, that is part of the Diploma of Sustainable Living.
Thank you for participating in this OERu course, and we look forward to reading your assessment submissions.
The end of the Permian period is also the end of the Paleozoic Era. The fossil record shows the biggest drop in the diversity of marine and land organisms in life’s history on Earth. Many forms that flourished in the Paleozoic Era did not pass through to the Mesozoic Era. The reasons for the mass extinction are debated, but it is likely an enormous outpouring of magma and gases during volcanism in Siberia contributed to dramatic changes in the atmosphere, hydrosphere and biosphere.
Summary of the Permian Mass Extinction
The lecture travels to the Permian to show the configuration of continents and the various plants and animals that were abundant at that time.
In contrast, the earliest Triassic has reduced biodiversity and is characterised by disaster taxa.
The coincidence of the mass extinction with the vast outpouring of lava and gas in Siberia is examined. The interaction of molten rock with coal (C), evaporite salts (NaCl) and limestone (CaCO3) in a sedimentary basin, unlocked carbon and other elements sequestered in the geosphere and released these gases into the atmosphere, hydrosphere and biosphere. Gases included Cl-rich, ozone-depleting gases, greenhouse gases, CO2 and CH4 and SO2. Both CO2 and SO2 add to acid rain and also ocean acidification. These factors are thought to be a major contributor to a change in climate and mass extinction.
This is a long lecture. Nearly like a real live lecture! Grab a beverage, relax and do some time travelling
Lecture Review
Select one of the below.
Other Factors
We have only presented one of the possible contributors to this serious mass extinction event. Conditions on Earth were conspiring to create problems for the biosphere at that time.
From all of this, you can see that things were already difficult for life, even without the added calamity of the gases released in huge quantities during the voluminous eruptions of Siberia!
The end Cretaceous mass extinction (K-Pg)
This is a short lecture on the end of the Cretaceous, 66 million years ago, which saw the demise of the Dinosaurs. Popular culture has taken up the idea that the Dinosaurs fell foul a large meteor/asteroid impact. But geologists are not so sure that this is the full story.
More on Dinosaurs
Did you know that there were two main forms of dinosaurs?
It’s all in the hips!
The images to the right, you can see the two hip configurations of dinosaurs. The first set of hips belongs to the “lizard-hipped” dinosaurs or Saurischians, where the pubis and ischium are separated. The second set of hips belongs to the so-called “bird-hipped” dinosaurs or Ornithiscians. Where the pubis and ischium are together. Tyrannosaurus Rex was a Saurischian and the Muttaburrasaurus and many other herbivorous dinosaurs were Ornithischians.
Birds actually evolved from the Saurischians.
Many dinosaurs are now known to have been feathered. Recently some scientists purchased amber (fossilised tree resin) at a market in Myanmar. The scientist were very excited to find intact baby dinosaur feet encased in the amber. The feet were covered in brown feathers.
The evolution of feathers, suggests that some dinosaurs were hot rather than cold-blooded.
Conclusion
In this learning pathway we have considered the dire consequences for life when there are major imbalances in Earth Systems. Biosphere collapse was driven by rapid (on a geological time scale) changes wrought by Earth’s own geosphere or extra-terrestrial influences. Everything discussed had nothing to do with humans (except the dodos).
Humans: Earth Shapers has covered a breadth of topics. Initially, we looked at Earth systems: geosphere, hydrosphere, atmosphere and biosphere and discussed how these systems function and interact. We pondered how these systems have been dynamic over geological time. We learnt to read rocks and explored the fossil record, where there is evidence for major mass extinction events that happened long before humans evolved.
Humans, like all biota, interact with and impact on their environment. As human populations expanded and changed lifestyles they have a had an accelerating impact on Earth’s systems. Today some of these impacts are on metal cycling, earth moving, land use, removal of primary productivity (e.g fishing), as well as the nitrogen cycle and the carbon cycle which are driving climate change. These changes are happening on scales often greater than in nature and in much shorter time frames. These drivers are causing stress on natural systems and organisms. Organisms can only respond to these stresses in four ways: tolerate the change, evolve to become something else that can tolerate the change, migrate to somewhere more suitable or if organisms cannot do any of these things then they will become extinct. Although the evidence is still inconclusive, if many organisms become extinct and the extinction rate is elevated we will be in the sixth mass extinction. And this time humans are implicated.
So does this matter? The philosophy part of this unit has asked you to reflect upon this. Humans are the authors of these changes, but we are also subject (as are all organisms) to the impacts of these changes. We cannot divorce ourselves from this and this has a moral dimension. As humans, and some argue that humans are the only creatures who can argue these questions, do we have a moral responsibility to ourselves and other organisms? You were invited to think about questions of your own and other peoples’ personal values? Which of these values has authority and how can these values be put into practice and policies?
Policies lead to a discourse on governance. Governance is essential to making changes at global scales. In the unit we examined old and current governance. In many cases, these appear to be failing to deal with the looming environmental issues and the tragedy of the commons in general. New governance will be required to implement the changes we need to keep Earth habitable. These new modes of governance will arise from the markets, community, entrepreneurship and social movements.
Last thoughts!
So, armed with all this breadth of information on science, governance and philosophy, we invite to consider how you will be shaping Earth into the future?
You must be logged in to post to WEnotes.
Note: Your comment will be displayed in the course feed. Remembering mastodon.oeru.org is also an option to share your thoughts.
Learning pathway complete
Congratulations. You have just completed all the learning pathways for Understanding Earth Shaping, ETHS101.
If you haven’t already, we would recommend you think about the Assessment. The assessment is based on all the learning you have just engaged with, and by completing the assessment you will gain credit towards the full Human Earth Shapers unit, that is part of the Diploma of Sustainable Living.
Thank you for participating in this OERu course, and we look forward to reading your assessment submissions.
Content is available under the
Creative Commons Attribution Share Alike License.
Privacy Policy | Authors