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The word "extinction," like many other evocative terms, is often used nowadays, in large part because of groups like the Extinction Rebellion, for whom the issue is of utmost importance. It is easy to comprehend why fearing extinction can be a problem. In your opinion, it's probably the worst thing that could occur. With the extinction of a species, something unique is removed from the face of the planet.
What Is Extinction?
The term "extinct" refers to a species that has perished. In many cases, we may infer from the fossil record that this happened only a few years after the event. Even though a species is not legally extinct, it may be unsustainable due to its small population. Unfortunately, such species are facing extinction.
Over five billion species have gone extinct during the history of our planet, making up 99% of all life that has ever existed. This does not include certain species that have disappeared from the wild but are still alive in captivity.
What About Instances of Extinction?
The majority of the time, the word "extinction" conjures up images that are more catastrophic than the usual slow-moving process of natural selection. When several different species go extinct at the same time, it is referred to as a "mass extinction." It is characterised by a sharp decline in biodiversity, which measures how greatly forms of life vary.
"Diversification," the process by which biodiversity expands between extinctions as surviving lifeforms adapt to the new status quo, is contrasted with extinction.
Marine Species Disappearing
Animals that live on land have experienced several of the most well-known extinctions. On the other hand, it's possible that the fossilised remains of certain marine animals will never be found. Since the majority of the globe is covered by water and the oceans are vital to supporting ecosystems on land, marine conservation may be more important than any other form.
Events on the Scale of Extinction
How often have extinction-level events taken place? It's difficult to know for sure. For a certain time period to be eligible, no precise number of extinctions is required. The fact that the fossil record still has a lot of gaps indicates that there may be other events that we are not aware of.
1. Ordovician-Silurian Period
The "big five" disasters, which have wiped off 85% of marine species, started with this one. Although scientists are still attempting to determine what caused it, we do know that it occurred in two distinct stages: a significant cold period followed by a rapid warming.
2. Devonian Period
About half of all taxa on Earth were eliminated during this extinction, which happened in the late Devonian Epoch (genera being the plural of genus, which is one taxonomic rank up from species).
3. Permian-Triassic Period
We can state with certainty that this is the worst extinction disaster in recorded history. It was known as "The Great Dying" and was most likely brought on by the eruption of massive volcanoes in Siberia about 252 million years ago.
4. Triassic-Jurassic Period
Roughly 201 million years ago, the Triassic period came to an end with the extinction of all archosaurs and about one-third of marine life, with the exception of dinosaurs, pterosaurs, and crocodiles (large reptiles).
5. Cretaceous-Paleogene Period
In addition to three-quarters of all life on Earth, this one also wiped off the dinosaurs (or, at the very least, the dinosaurs that did not develop into birds). It was set off by a big asteroid. We'll return to it soon.
6. Holocene Period
We are now living through the Holocene extinction (and very likely perpetuating). Because scientists have just recently realised how quickly things are unravelling, it is frequently referred to as the "sixth" big extinction event.
What About the Meteor That Wiped Out the Dinosaurs?
The Yucatan peninsula in modern-day Mexico was struck by an asteroid 65 million years ago. The Chicxulub crater was left behind, along with 48,000 cubic miles of debris and energy equivalent to one billion atomic bombs.
Anybody would have a terrible day if they were struck by an asteroid. However, rather than the impact itself, the majority of the extinction that followed was brought on by the event's aftereffects.
As the atmosphere of the planet filled with dust and soot, the number of plants that depend on sunlight fell precipitously. The only animals and plants that survived were those that consumed dead ones. For instance, birds consumed mostly dead and decaying insects.
Final Thoughts
Extinction is horrible, but it is inevitable. Darwin's celebrated "tree of life" has certain branches that must die for others to grow. In the absence of such actions, life as we know it would not be conceivable and there would be no selection process. The natural world we know and love today would not have existed if the dinosaurs had survived.
Written By: Dharchini Priya P
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