A recent news article published in the international journal Nature Geoscience cites a new reason for the earlier mass extinction, also known as the “Late Ordovician Mass Extinction”
This suggests that the colder climate may have changed the pattern of ocean circulation. It disrupted the flow of oxygenated water from the shallow seas to the deep oceans, causing mass extinction of marine life.
Back to Basics: Mass Extinction
Mass extinction occurs when species become extinct much faster than mutations.
It is generally defined as extinct in less than about 75% of the world's species - in less than 2.8 million years.
Incidents of Mass Extinction
First mass extinction:
About 445 million years ago the Ordovician mass extinction destroyed about 85% of all species.
Second mass extinction:
The Devonian Mass Extension (about 375 million years ago) destroyed about 75% of the world's species.
Third mass extinction:
Permian mass extinction (about 250 million years ago) also known as “Great Dying”, which caused more than 95% of all species to become extinct.
Fourth mass extinction:
The Triassic Mass Extinction (about 200 million years ago) wiped out about 80% of the Earth's species, including some dinosaurs.
Fifth mass extinction:
It is known for the extinction of the non-avian dinosaur ‘Cretaceous Mass Extinction’ (about 65 million years ago).
About the latest findings
New Interpretation:
There are many theories behind each mass extinction and with advances in new technologies researchers are uncovering more complex details about these phenomena.
Traditional Ideas:
The prevailing view for decades has been that volcanic induced global warming leads to a shortage of oxygen in the oceans and thus affects the ability of marine habitats and potentially destabilizes the entire ecosystem.
New School of Thought:
- Increasing evidence in recent years points to many events in Earth's history when oxygen levels dropped in cold climates.
- During that period, Oxidation of the surface of the sea and the oceans of the oceans occurred in response to global cooling due to the ordovician climate and marine algae cycles.
- Due to this ‘Deep Sea Anoxic’ affects the movement of the Sea.
- Thus, the newspapers concludes that the cooling of the climate may have altered the circulation of nutrients, and that the primary productive communities may have eventually led to the ‘Late Ordovician Mass Extinction’.
The current sixth ‘mass extinction’ and its effects
Sixth ‘Mass Extension’:
- Some researchers have indicated that we are currently experiencing a sixth “Mass Stimulant” as a result of human-induced climate change.
- Currently only an estimated 2% of all species are alive, but the total number of species is higher than before.
- It has been described as the most serious environmental problem, as the loss of species will be permanent.
- This species is being harmed when human ancestors developed agriculture 11,000 years ago. Since then, the human population has grown from about 1 million to 7.7 billion.
Possible effects:
- Species extinction is affected by crop pollination and loss of water treatment.
- In addition, if a species performs a specific function in the ecosystem, damage can have serious consequences for other species by affecting the food chain.
- The effects of extinction will exacerbate genetic and cultural variability that will change the entire ecosystem.
- When genetic variability and flexibility are reduced, its contribution to human welfare may end.
Q. 1) Consider the following statements about mass extinction.
1. The effects of extinction will exacerbate genetic and cultural variability that will change the entire ecosystem.
2. The cooling of the climate may have altered the circulation of nutrients and the primary productive communities may have finally inspired the ‘Late Ordovician Mass Extinction.
3. Growing evidence in recent years points to many incidents of Earth's history when oxygen levels dropped in cold climates.
4. Fifth mass extinction: It is known for the extinction of the non-avian dinosaur ‘Cretaceous Mass Extinction’ (about 65 million years ago).
Which of the above statements is correct?
(A) 1,2,3 (B) 2,3,4
(C) 1,2,4 (D) 1,2,3 and 4
Welcome to IQ Curator’s General Knowledge - All Competitive Exams Questions - Answers Section. This section is a various topics & category-wise archive of IQ Curator’s GK (General Knowledge) Questions – 2021-2022 in Short MCQs format on various subjects and states. This section is suitable for aspirants preparing for UPSC-IAS, SSC-CGL and State Level Examinations of various states and also UPSC conducted NDA/ CDS/ IFS/ IES / CSE, SSC, Banking / IBPS, IAS, NTSE, CLAT, Railways, NDA, CDS, Judiciary, UPPSC, RPSC, GPSC, MPSC, MPPSC ,etc. examinations.
Please Click Here for : IQ Curator - Shakti 2021: 6th Edition of India-France Military Exercise
You may also Click Here for : General Knowledge - All Competitive Exams
Good Luck!
