The CHILLING TALE of the Ordovician-Silurian Mass Extinction

Summary

This video introduces the concept of evolution and explores the five major mass extinction events in Earth's history. The focus is on the Ordovician-Silurian extinction, the second deadliest event, which wiped out 80% of marine species around 445 million years ago. The extinction unfolded in two phases: first, global cooling caused by glaciation, and later, rising temperatures leading to marine anoxia. The video dives into the causes, impacts, and aftermath of this extinction, while also providing insight into the biodiversity and geological landscape of the Ordovician period.

Takeaways

• 🌱 Life on Earth has endured for billions of years due to evolution, the process by which species adapt to their environments.
• 🌍 Evolution is slow, and rapid environmental changes can lead to population declines or even extinction.
• 🦖 There have been five major mass extinction events in Earth's history, with the least devastating being the one that wiped out the dinosaurs.
• 📉 Each mass extinction led to the loss of 70-90% of life on Earth, fundamentally altering ecosystems.
• 🌊 The Ordovician-Silurian extinction, around 445 million years ago, was the second most devastating mass extinction, primarily affecting marine life.
• ❄️ This extinction was partly triggered by a significant global cooling event and glaciation, causing sea levels to drop and habitats to disappear.
• 🌡️ The cooling was potentially caused by increased continental weathering and the expansion of land plants that drew down CO₂ levels.
• 🪨 The extinction occurred in two major pulses: the first caused by glaciation and falling sea levels, and the second by global marine anoxia (lack of oxygen).
• 🌊 Anoxic conditions suffocated marine species, especially those living in epicontinental seas and other specific regions.
• 🐚 The extinction led to the loss of 80% of marine species, including many trilobites, brachiopods, and other endemic species, drastically impacting biodiversity.

Q & A

What is the significance of the Ordovician period in Earth's history?

The Ordovician period was significant as it was the second geological period of the Paleozoic Era and the Phanerozoic Eon, lasting from approximately 485 to 444 million years ago. It was a time when life on Earth was mostly confined to the oceans, with some evidence suggesting that plants may have begun to emerge onto land.

What were the main types of marine life during the Ordovician period?

During the Ordovician period, marine life was dominated by trilobites and brachiopods. Other animals such as bryozoans, snails, and clams were also abundant. By the late Ordovician, fish began to evolve, including the first jawed fish.

How did the continents look during the Ordovician period?

During the Ordovician, the continents were arranged differently than today. Antarctica, Australia, Africa, South America, and parts of Europe were joined together in the southern hemisphere as the supercontinent Gondwana. Other continents like Siberia, Baltica, and Laurentia occupied the remaining parts of the Southern Hemisphere, with the Paleo-Tethys Ocean between them and Gondwana. The entire Northern Hemisphere was covered by the Panthalassic Ocean.

What was the climate like during the Ordovician period?

The climate during the Ordovician period was generally warm, with temperatures ranging between 43 to 49°C (110 to 120°F). However, it cooled significantly towards the end of the period, which was one of the causes of the end-Ordovician extinction.

What caused the end-Ordovician mass extinction?

The end-Ordovician mass extinction was likely caused by a combination of factors over approximately 1.4 million years. These included glaciation, falling sea levels, and global climate change, possibly triggered by factors such as increased continental weathering and the cooling effect of land-invading plants.

How did the end-Ordovician glaciation affect marine life?

The end-Ordovician glaciation led to a significant drop in sea levels, causing habitat loss for many marine species, especially those that thrived in epicontinental seas. The glaciation of Gondwana and the subsequent sea level drop are referred to as the late Ordovician mass extinction interval 1 (LME-1).

What happened during the second interval of the end-Ordovician mass extinction?

The second interval, known as the late Ordovician mass extinction interval 2 (LME-2), was characterized by a sudden expansion of marine anoxia and increased levels of hydrogen sulfide. These anoxic conditions spread globally, suffocating many of the species that survived the first interval.

How severe was the end-Ordovician mass extinction in terms of species loss?

The end-Ordovician mass extinction was the second most devastating in Earth's history, with around 60% of all marine genera and 25% of all marine families going extinct. Overall, it is estimated that 80% of all marine species were wiped out.

What was the impact of the end-Ordovician mass extinction on biodiversity?

The end-Ordovician mass extinction had a profound impact on biodiversity, particularly affecting endemic species that were confined to certain regions. However, the ecosystems of the following Silurian period did not appear drastically different from those before the extinction, suggesting some level of resilience and recovery.

How long did it take for life to recover from the end-Ordovician mass extinction?

It took several million years for life to fully recover from the end-Ordovician mass extinction. Some species that survived became more widespread, such as the Laurentia endemic brachiopods, which expanded during the Silurian period as they sought new habitats.

Outlines

00:00

🌏 Evolution and the First Mass Extinction

This paragraph introduces the concept of evolution as the process that allows life to adapt and survive in changing environments. It explains that when environmental changes occur too rapidly, life forms may not be able to adapt quickly enough, leading to population decline or extinction. The paragraph then delves into the topic of mass extinctions, highlighting that there have been five such events in Earth's history, with the most well-known being the KT extinction that wiped out the dinosaurs. The focus then shifts to the first of these events, the Ordovician-Silurian extinction, also known as the End-Ordovician or Late Ordovician extinction. The paragraph sets the stage by describing the world during the Ordovician period, noting that life was predominantly marine and that continents were arranged differently than today. It discusses the climate, marine life, and the continents' configurations, providing a backdrop for understanding the causes and effects of the extinction event.

05:01

❄️ The Ordovician-Silurian Extinction: A Tale of Two Intervals

This paragraph delves into the details of the Ordovician-Silurian extinction event, which occurred over approximately 1.4 million years during the Hirnantian age of the Ordovician and the Rhuddanian age of the Silurian. The extinction is believed to have happened in two major pulses, with a possible minor phase preceding them. The first pulse, known as the Late Ordovician glaciation of Gondwana, is theorized to have been caused by increased continental weathering and possibly by land-invading plants that drew down atmospheric carbon dioxide, leading to global cooling. This resulted in glaciation and a significant drop in sea levels, causing habitat loss for many marine species. The second pulse, or LOME II, occurred during the end of the Hirnantian and continued into the Rhuddanian, and was characterized by a sudden expansion of marine anoxia and increased levels of hydrogen sulfide, which further decimated the surviving species. The paragraph concludes by noting the severity of the extinction, with approximately 60% of marine genera and 25% of marine families going extinct, and 80% of all marine species being wiped out.

10:01

⚠️ Informal Information Disclaimer

This paragraph serves as a disclaimer, emphasizing that the information presented in the video is informal and should not be used for professional or educational purposes without further verification from other sources or experts. It highlights the importance of cross-referencing the content with reliable sources or consulting with educators to ensure the accuracy and validity of the information.

Keywords

💡Evolution

Evolution is the process by which species of organisms change over time through genetic variation and natural selection. In the context of the video, evolution is the mechanism that has allowed life to endure for billions of years by adapting to different environments. The script discusses how life on Earth has evolved and adapted to survive, but also how rapid environmental changes can outpace this adaptation, leading to mass extinctions.

💡Mass Extinctions

Mass extinctions refer to events in Earth's history where a large number of species become extinct in a relatively short geological period. The video script describes five such events that have occurred during the reign of complex life over the past half a billion years, causing the loss of 70 to 90% of all life on Earth. The first mass extinction discussed in the script is the Ordovician-Silurian extinction event.

💡Ordovician-Silurian Extinction

The Ordovician-Silurian Extinction, also known as the end Ordovician Extinction, is the first of the five mass extinctions discussed in the video. It is characterized by a drop in global temperatures and sea levels, leading to habitat loss and the extinction of many marine species. The script details this event as the second most devastating mass extinction in Earth's history.

💡Gondwana

Gondwana was a supercontinent that existed during the late Ordovician period, composed of present-day Antarctica, Australia, Africa, South America, and parts of Europe. The script mentions that glaciation of Gondwana played a significant role in the Ordovician-Silurian mass extinction, as the expansion of ice sheets led to a drop in sea levels and habitat loss.

💡Epicontinental Seas

Epicontinental seas are shallow seas that cover continental crust, typically found along continental shelves. In the video script, these seas are mentioned as being particularly affected by the drop in sea levels during the Ordovician-Silurian extinction, leading to the loss of habitats for many marine species.

💡Glacial Period

A glacial period is a time in Earth's history when ice sheets and glaciers cover more of the Earth's surface than usual. The script describes the late Ordovician glaciation of Gondwana as a significant factor in the Ordovician-Silurian mass extinction, causing a drastic drop in global temperatures and sea levels.

💡Marine Anoxia

Marine anoxia refers to a condition where oxygen levels in the ocean are depleted, often leading to the creation of 'dead zones' where most marine life cannot survive. The script mentions that a sudden expansion of marine anoxia during the second interval of the Ordovician-Silurian extinction played a significant role in the extinction of many marine species.

💡Hirnantian

The Hirnantian is a stage in the geological timescale that marks the end of the Ordovician period. The script discusses the Hirnantian as the time when the second pulse of the Ordovician-Silurian extinction occurred, characterized by a sudden rise in sea levels and the expansion of marine anoxia.

💡Endemic Species

Endemic species are those that are native and restricted to a certain geographic region. The video script notes that many endemic species were hit exceptionally hard by the Ordovician-Silurian extinction, as they were confined to specific regions and unable to adapt or migrate when their habitats were destroyed.

💡Brachiopods

Brachiopods are a group of marine animals that lived during the Ordovician period, characterized by a shell-like structure. The script mentions that brachiopods were among the species that were hit hard by the Ordovician-Silurian extinction, with many species going extinct.

💡Trilobites

Trilobites are a group of extinct marine arthropods that lived during the Paleozoic Era. The video script discusses how trilobites, along with other marine species, were severely affected by the Ordovician-Silurian extinction, with many species either declining or going extinct.

Highlights

Life's ability to adapt is called Evolution.

Evolution is the reason life has endured for billions of years.

Mass extinctions are catastrophic events affecting the entire globe.

There have been five mass extinctions during the half a billion year reign of complex life.

Each mass extinction wiped out 70 to 90% of all life on Earth.

The KT Extinction event, which wiped out the dinosaurs, is the most well-known but not the most devastating.

The average person is not aware of the multiple mass extinctions.

The first mass extinction event is the Ordovician-Silurian Extinction.

The Ordovician Period was the second geological period of the Paleozoic Era.

Life on Earth was mostly confined to the ocean during the Ordovician Period.

Trilobites and brachiopods made up much of the marine life during the Ordovician Period.

The continents looked alien compared to today during the Ordovician Period.

The climate was very warm during the Ordovician Period, ranging from 43 to 49°C.

The Ordovician-Silurian Extinction was caused by many uncertain factors.

The extinction took place over about 1.4 million years.

The first pulse of the extinction was the late Ordovician glaciation of Gondwana.

The second pulse of the extinction was the late Ordovician mass extinction interval 2.

Around 60% of all marine genera and 25% of all marine families went extinct.

80% of all marine species were wiped out forever.

Despite the major effects on marine biodiversity, ecosystems did not appear drastically different after the extinction.

It took several million years for life to truly recover from the Ordovician-Silurian Extinction.

The video series aims to inform about the five mass extinctions and their impact on Earth.

The information provided is informal and should be cross-checked with other sources for professional or educational purposes.

Transcripts

life is a fragile thing it changes and

adapts so specifically to survive in the

environment it's placed in this ability

to adapt is called Evolution and it's

the reason that life has endured for the

past few billion years but evolution

takes a long time so when environments

change too quickly for the inhabitants

to keep up the result is a drop in

population or at the worst

Extinction and some of these changes can

be so big that they affect the entire

globe

leading to some of the most catastrophic

events in our planet's history mass

extinctions five times during complex

life half a billion year reign the

forces of nature have conspired against

it leading to the five mass extinctions

in each of these great dying anywhere

from 70 to 90% of all life on Earth was

completely wiped out forever they are

some of the most significant events in

the history of life and yet I'm willing

to bet that most of you only really know

about One the KT Extinction event which

WIP out the dinosaurs which funnily

enough is the least devastating of all

the mass extinctions despite the

importance of these events the average

person isn't really aware that many of

them took place so I decided to start

this five-part video series looking into

the five mass extinctions and how they

Rock The Globe so from the chilling tale

of the end orishan Extinction to the

Astra that wiped out the dinosaurs these

are the stories of the great

dying today we will be looking at the

first of these five extinctions the

order of Solan mass extinction event

otherwise known as the end orishan

Extinction or the late orishan

Extinction event but before we explore

the causes and effects of this chilling

tragedy we must first take a look at the

world that it fell

upon the ovian period was the second

geological period of the Paleo era and

of the phoro Eon it lasted from

approximately 485 million years ago to

to 444 million years and was followed by

the saluran

period at this time during the Earth's

history life on Earth was still mostly

confined to the ocean although we have

some evidence that some plants may have

begun crawling out of the water by this

point however these land invading plants

may not have boated well for the

stability of the oceans as we will see

soon a huge array of trites and codons a

group of eike vertebrates characterized

by the tooth likee apparatus they used

for feeding

made up much of the ovine marine life

other animals such as brackup pods

snails and clams also r on the seaf Flor

by the late ordovician the forish fish

began to evolve most notably basil seop

Poots continued to adapt and by the

middle to late ovian would evolve into

monsters such as the 9 M 30t long apex

predator

croas like everything else in the world

at the time the continents look alien

compared to how they are today and

Antarctica Australia Africa South

America and parts of Europe were joined

together in the southern hemisphere as

the massive supercontinent of Guana

other paleo continents such as Siberia

Bala and laurentia took up the remaining

portion of the Southern Hemisphere and

between them and gondwana was a body of

water known as the Paleo teus ocean

meanwhile the entire Northern Hemisphere

was taken up by a massive sea known as

the panthal lastic ocean where most of

the marine life lived at the

time

the climate was very warm ranging from

between 43 to 49° C 110 to 120 fenhe

although it would cool drastically

towards the end of the period which as

we will see was one of the biggest

causes of the end orishan Extinction due

to these higher temperatures the

atmosphere was very moist as

well life was good and stable for the

inhabitants of these early Paleozoic

seas that was until around 445 million

years ago during the her in Canadian age

at the end of the order of

isan like many Extinction events we

can't exactly pinpoint a single reason

for the orishan solarian mass extinction

like the asterid that killed the

non-avian dinosaurs at the end of the

Cretaceous instead the extinction seems

to have been caused by many uncertain

factors that ultimately came together to

form this terrible event the extinction

took place over about 1.4 million years

during the heronian age of the ovian and

the routing age of the saluran beginning

around 445 million years ago and ending

a little under 444 million years ago it

likely happened over two major pulses or

intervals some scientists suggest the

possibility of a more minor phase that

took place before the two major pulses

possibly caused by Falling carbon

dioxide levels resulting from the

erosion of silicate rock this may have

triggered a global cooling which took

place before the major

glaciations this phase may have affected

members of the troby brachiopod and grap

toly

families the first pulse of the

extinction was the late orishan

glaciation of gondwana we don't exactly

know what caused this but the theory

suggests that an increase in Continental

weathering could have been responsible

land invading plants may have also

played a role in the cooling by drawing

too much carbon dioxide from the air

regardless of the cause the orishan

Earth cool to a shockingly low 8.5 de C

16.7 F which resulted in the glaciation

of the African and South American

portions of gondwana as that the

freezing temperatures were not enough

the expansion of gandana ice sheets also

resulted in the seed levels Falling by

50 to 160 m 164 to 525 ft this in turn

led to a change in ocean currents as

well the combination of these frigid

conditions and the plummeting sea levels

like led to mass habitate loss for many

species organisms that thrived on

epicontinental Seas bodies of water that

lie on continents or over Continental

shelves were especially hit hard by the

dropping water levels as their habitats

became drained this interval is often

referred to as the late orishan mass

extinction integral 1 or L

mei1 this orishan glaciation lasted for

a long time but despite these harsh

conditions some life would adapt and

diversify to form the short-lived

hernadia life was just beginning to

bounce back once disaster struck again

in the form of the second

interval the next pulse or interval of

the oran salarian Extinction is known as

the late ovian mass extinction interval

2 or L Mei 2 it took place during the

very end of the hernadi age of the

ordovician and continued into the rudian

age of the solarian period period

similar to the preceding glaciations we

don't know for certainty what caused it

the warming of the orishan climate led

to the depletion of the gondon and

Continental ice sheets and subsequently

a rise in sea level this return of a

warmer climate condition was for some

reason followed by dire consequences a

sudden expansion in Marine anoxia or

depletion of oxygen and yenia raised

levels of hydrogen sulfide struck the

already we Earth these aquatic anoxic

conditions spread globally suffocating

many of the few remaining species that

survived the

loi1 after a little while conditions

would return to the norm required to

sustain life but not before the global

anoxic conditions could take a heavy

toll the order ofish solarian mass

extinction event ended approximately

443.101 species such as brachiopods

endemic Dorena were hit exceptionally

hard by the extinction in fact endemic

species made up much of the life loss in

this Great die out many species of

trilobites B Valves corls and

brachiopods were either hit hard or

completely vanished altogether around

60% of all marine jera and 25% of all

Marine families went extinct overall

though a shockingly high figure of 80%

of all marine species were wiped out

forever

it may have only been the first but it

was the second most devastating mass

extinction in the history of our

planet despite the major effects of the

extinction on Marine biodiversity the

ecosystems of the ensuing saluran period

did not really appear to be that much

different from the biospheres preceding

the extinction this is likely because

most of the species lost during the end

orishan Extinction were endemic which

means they were confined to a certain

region the endemic species which

survived however take the laurentia

endemic brachiopods mentioned earlier

became more widespread during the Salan

due to the extinction which forced them

to find new habitats life would begin to

bounce back from this Devastation

throughout the early saluran but it

would take several million years to

truly recover from this

tragedy so there you have it that was

the chilling tale of the orishan saluan

mass extinction event the first but

second most deadly Extinction to ever

Rock The Globe I have to say this was

actually an incredibly fun video to make

I love paleontology and being able to

share it with others so I look forward

to the second video in the series which

will be covering the late devonian

Extinction but until then thanks for

watching please keep in mind that this

is an informal source of information

while the sources used are considered

reliable this Source should not be used

for professional or educational purposes

except if the information presented can

be confirmed by other sources or an

expert

educator