Tectonics as we know deals with large earth mass, its movement of the continents or plates into some configurations can cause or contribute to extinctions in several ways, but we would look at the major extinction events and causes too.
Extinction of species:
Mass extinction or extinction event is a phenomenon in which large numbers of species of life/organisms on planet earth become extinct in a relatively short period of time.
Image source: Pixabay
Mass extinction:
Refers to an extinction affecting a great/many, different organisms occupying a diverse and widespread environment.
At least five major and global mass extinction events have occurred during the past 542 million years ago.
Some authorities argue for as many, like about 20 mass extinction.
Many scientists believed that the earth is presently undergoing mass extinction, the sixth extinction ( or the Holocene).
• Cambrian Extinction (450 million years ago) & Ordovician-Silurian Extinction (400mya)
• End Permian, (251 million years ago)
• Late Devonian (300 million years ago) & Permian extinction (200mya)
• Triassic Extinction (200mya)
• End Cretaceous extinction (66mya)
Cambrian Extinction (450 million years ago) & Ordovician-Silurian Extinction (400mya):
Trilobite, 5 cm length
CREDIT: JAIME MURCIA / MUSEUM VICTORIA
End Cambrian Extinction (about 450 million years ago)
A series of mass extinction of the Cambrian-Ordovician transition eliminated many briachopods and conodonts.
End Permian, (251mya):
This extinction is known as “the great dying”, this was by far the worst extinction event ever seen/recorded; it nearly ended life on Earth. The tabulate corals were lost in this period.
Today’s corals are an entirely different group. What caused the extinction? it was caused by perfect storm of natural catastrophes, a cataclysmic eruption near Siberia blasted CO2 into the atmosphere, Methanogenic bacteria responded by belching methane out, the methanogenic is an active greenhouse gas.
Global temperatures surged while oceans acidified and stagnated, belching poisonous hydrogen sulfide. “It set life back 300 million years,” says Schmidt. Rocks after this period record no coral reefs or coal deposits.
Late Devonian (300Mya) & Permian extinction:
Tabulate coral, 5 CM
CREDIT: CHIP CLARK / SMITHSONIAN INSTITUTION
Invertebrates like trilobite were the most abundant animals that appeared in the Cambrian explosion about (550mya), their multifaceted eyes and their sparky armour helped them survive the first extinction but were wiped by the second extinction.
The end of the Frasnian age in the later part(s) of the Devonian period, a series of prolong extinctions which eliminated about 19% of all families, 50% of all Genera and at least 70% of all species.
Triassic Extinction (200mya)
End Triassic Extinction (about 200 million years ago). At the time of the Triassic-Jurassic transition, about 20% of all marine families as well as most non-dinosaurian, archosaurs, most therapsids (except the order from which mammal descended) and the last of the large animal were eliminated.
Conodont teeth 1 mm
CREDIT: JAIME MURCIA / MELBOURNE MUSEUM
End Cretaceous extinction:
This extinction was formerly called the K-T extinction/K-T boundary, about 76% species were eliminated/extinct.
About 17% Of all families, 50% of all Genera became extinct in the period. Dinosaurs may have ruled the land during the Cretaceous period but the oceans belonged to the ammonites.
Timeline of Cretaceous–Paleogene extinction event.
Image source
Ammonite 15 cm length
CREDIT: PAUL TAYLOR / NATURAL HISTORY MUSEUM
Only a few dwindling species of ammonites survived. Today, the ammonites’ oldest surviving relative is the nautilus.Read more?
Causes of mass extinction
Impact events: Asteroid impacts from outer space fell to the earth and ended the dinosaurs and provided the final blow.
Rapid transistions in climate may be stressing the environment to the point of extinction.
Climate change: Climate change posed great stress to certain organisms like the Ammonites.
Volcanism activities: The formation of large igneous provinces through the outflow of up to millions of cubic kilometers of lava in short duration is likely to pose great stress to animal.
Gamma-ray burst:
Gamma-ray burst (less than 6000 light years away). It was said that the Gamma-ray with this intensity depleted the ozone layer and radiation from the sun was too much. It was suggested that a supernova or gamma ray burst caused the End-Ordovician extinction.
• Global warming
• Global cooling and many more
• Global tectonics: Movement of the continents or plates into some configurations can cause or contribute to extinctions in several ways:
• By ending ice ages;
• By changing ocean and wind currents and thus altering climate at that time.
• By opening seaways or land bridges which expose previously isolated species to competition for which they are poorly adapted, and loss of their habitats.
