¿Fueron 5 las extinciones masivas en la Tierra?
Summary
TLDREn este video, Aldo explora el tema de las extinciones masivas, esos eventos que han acabado con gran parte de la vida en la Tierra. Detalla cinco grandes extinciones, sus posibles causas, y cómo afectan la biodiversidad. Menciona fósiles emblemáticos y teorías sobre una posible sexta extinción, que podría ser provocada por el impacto humano. Reflexiona sobre las consecuencias de la pérdida de especies, el cambio climático, y la importancia de ser conscientes de nuestro papel en la protección del planeta. Termina con un llamado a evitar el sensacionalismo y a tomar medidas para un futuro más sostenible.
Takeaways
- 🌍 Las extinciones masivas han ocurrido varias veces en la historia de la Tierra, con al menos cinco eventos importantes identificados.
- 🦖 Más del 90% de todas las especies que han existido en la Tierra están extintas, y solo tenemos un conocimiento limitado de cómo eran debido a los fósiles.
- 🦕 Algunas criaturas extintas, como el atopodentatus y el helicoprion, tenían apariencias muy extrañas según los fósiles.
- 🧊 La primera extinción masiva identificada ocurrió hace 444 millones de años al final del Ordovícico, donde el 86% de las especies marinas desaparecieron debido a una breve pero severa glaciación.
- 🌱 Durante la extinción del Devónico, las plantas terrestres recién desarrolladas podrían haber causado la proliferación de algas, lo que provocó la muerte de muchas especies marinas.
- 🔥 La peor extinción masiva, conocida como la extinción del Pérmico, ocurrió hace 250 millones de años y acabó con el 96% de las especies marinas debido a erupciones volcánicas y emisiones de gases tóxicos.
- 🌋 Las erupciones volcánicas, los impactos de asteroides y los cambios en el nivel del mar son las principales causas de las extinciones masivas en la historia de la Tierra.
- 🐕 En las extinciones masivas, la distribución geográfica de las especies no siempre garantiza su supervivencia; los eventos son tan catastróficos que pueden afectar a todas las especies.
- 📉 Nos enfrentamos a una posible sexta extinción masiva, acelerada por la actividad humana y el cambio climático, lo que afecta tanto a las especies como a los ecosistemas.
- ☄️ Aunque hay especulaciones sobre asteroides acercándose a la Tierra, es más probable que el cambio climático y la actividad humana continúen siendo las mayores amenazas para la biodiversidad y nuestra propia supervivencia.
Q & A
¿Cuántas extinciones masivas han ocurrido en la historia de la Tierra?
-Se han identificado cinco grandes extinciones masivas, aunque algunos científicos creen que han habido hasta ocho eventos de extinción.
¿Qué factores han causado las extinciones masivas en el pasado?
-Las causas más probables incluyen erupciones volcánicas masivas, impactos de asteroides, caídas del nivel del mar y eventos anóxicos donde los océanos pierden su oxígeno.
¿Cómo sabemos que han ocurrido extinciones masivas?
-Gracias al registro fósil y a estudios como los realizados por el paleontólogo Jack Sepkoski, quien creó un gráfico que mostró cinco eventos catastróficos en la biodiversidad oceánica.
¿Cuál fue la peor extinción masiva de todas?
-La extinción del Pérmico, hace 250 millones de años, donde el 96% de las especies marinas y el 70% de las especies terrestres desaparecieron.
¿Qué eventos podrían desencadenar una nueva extinción masiva?
-Una nueva extinción masiva podría ser causada por el cambio climático, erupciones volcánicas masivas, impactos de asteroides o un colapso de los ecosistemas debido a la actividad humana.
¿Qué animales sobrevivieron a la última extinción masiva?
-Pocos animales más grandes que un perro sobrevivieron a la última extinción masiva. Entre ellos, algunas especies de aves, reptiles pequeños y mamíferos pequeños.
¿Por qué no todas las especies con amplia distribución geográfica sobreviven a las extinciones?
-Los eventos físicos como asteroides o erupciones volcánicas son tan devastadores que incluso las especies más extendidas pueden ser aniquiladas.
¿Qué impacto podría tener la desaparición de una especie en un ecosistema?
-La pérdida de una especie puede desencadenar efectos imprevisibles en otras especies debido a la compleja red de interacciones que existen en los ecosistemas.
¿Qué papel juega el cambio climático en las extinciones modernas?
-El cambio climático, causado principalmente por la actividad humana, está acelerando lo que podría ser la sexta extinción masiva, al afectar negativamente a los hábitats y especies en todo el mundo.
¿Qué podemos hacer para evitar una futura extinción masiva?
-Es crucial reducir nuestra huella ambiental, combatir el cambio climático y tomar medidas para proteger las especies y ecosistemas vulnerables si queremos evitar una futura extinción masiva.
Outlines
🌏 Masas Extintivas: El pasado y el futuro
Aldo nos habla sobre las masas extintivas, momentos en los cuales la mayoría de la vida en la Tierra se extinguió. Explica que han habido varias masas extintivas y plantea la posibilidad hipotética de una nueva. Aborda la idea de que el 90% de los organismos que han vivido en la Tierra ya están extintos y menciona la importancia de los fósiles para entender su apariencia. Presenta ejemplos de criaturas antiguas como el Atopodentatus, el Helicoprion y la Opabinia. Además, habla sobre la importancia de los fósiles en museos y cómo solo representan una pequeña fracción de la vida que ha existido. Finalmente, menciona la investigación de Jack Sepkoski y cómo su trabajo mostró cinco eventos catastróficos en la biodiversidad.
🔥 Las cinco masas extintivas y sus causas
Este párrafo profundiza en las cinco masas extintivas conocidas y las posibles causas de cada una. Se describe la extinción en el Ordovícico, donde se perdieron el 86% de las especies debido a un glaciar severo. Luego, se habla de la extinción en el Devonico, donde se sugiere que las plantas terrestres recién emergentes contribuyeron a la muerte de criaturas marinas como los trilobites. Se detalla la extinción Permiana, la peor de la historia, causada por erupciones volcánicas que llevaron al aumento de la temperatura global y a la acidificación de los océanos. Se menciona la extinción Triásica, cuyas causas son enigmáticas. Finalmente, se habla de la extinción Cretácica, causada por un meteorito que acabó con los dinosaurios.
🌱 La sexta extinción y su relación con el cambio climático
El tercer párrafo se enfoca en la sexta extinción, que estamos provocando por nuestra actividad humana. Se cuestiona qué animales y especies sobrevivirán y se destaca la importancia de la distribución geográfica en la supervivencia durante las masas extintivas. Se menciona que incluso las especies ampliamente distribuidas pueden ser aniquiladas por eventos catastróficos. Se enfatiza la necesidad de ser conscientes de las consecuencias del cambio climático y la destrucción de la biodiversidad. Finalmente, se hace un llamado a la acción para que las nuevas generaciones hagan cambios significativos y se insta a la ciencia a ayudar a evitar más extinciones.
Mindmap
Keywords
💡Extinciones masivas
💡Fósiles
💡Graptolitos
💡Trilobites
💡Extinción del Pérmico
💡Calentamiento global
💡Anoxia oceánica
💡Extinción del Cretácico
💡Sexta extinción
💡Tardígrados
Highlights
Mass extinctions have occurred multiple times throughout Earth's history, wiping out most life forms.
Over 90% of all organisms that have ever lived on Earth are now extinct.
There have been five major mass extinction events, though some scientists suggest there could have been as many as eight.
Fossils, though rare, are crucial in understanding what extinct organisms looked like.
The first mass extinction occurred at the end of the Ordovician period, where 86% of species were lost due to a severe ice age.
The second extinction, in the Devonian period, wiped out 75% of species, with terrestrial plants possibly being the culprits.
The Permian extinction, 250 million years ago, was the most devastating, wiping out 96% of marine species and 70% of terrestrial species.
Volcanic eruptions and asteroid impacts are the most likely causes of mass extinctions, by disrupting the atmosphere and blocking sunlight.
Dinosaurs appeared after the Permian extinction and were wiped out during the fifth mass extinction, likely due to an asteroid impact.
The possibility of a sixth mass extinction is looming, driven by human activities like global warming and habitat destruction.
Antarctica, once a green land, could be hiding countless unknown species from millions of years ago under its ice.
Marine creatures have played a key role in understanding past extinctions through fossil records.
Even widespread species are not immune to mass extinction events due to their global impact.
Species' geographic distribution does not guarantee survival during extinction events, as seen in the Triassic extinction.
Tardigrades, microscopic organisms, are seen as one of the most resilient species, capable of surviving extreme conditions.
Transcripts
Hi, I'm Aldo and today we're going to talk about something quite shocking
mass extinctions, the times when most of life on earth
became completely extinct
they were several times, how many were these times?
What would happen if there were a new mass extinction tomorrow at 7 o'clock at night?
Do not believe those things, how will tomorrow be at 7 o'clock?
is seven o'clock in the evening the same in all countries? No, it isn´t
but I bet some of you tomorrow at 7 o'clock at night will be like this
More than 90% of all organisms that have lived on earth are extinct
we have an idea of how some of them looked thanks to the few fossils that we have been able to find
but think about that 90 percent, how many of those animals
we will never be able to see or we will never be able to discover?
imagine what shape they would have had, maybe some of them looked pretty out of this world for us
for example the atopodentatus, what does it look like? like a shoe? or the helicoprion
well this one looks like a shark but with a can opener in its mouth, it does not really seem so strange but what about the opabinia
If this is a computer-made image obviously, how can we have an idea of what these animals were like? because of the fossils
and here I present the fossils of the animals that we have just seen
ah but Aldo, that looks small, why don´t you better not show us a big fossil
100% real not fake, that is exhibiting in a museum that does not exist, does it? sure, we have several of them, for example
sue the most complete tyrannosaur skeleton you can find in the field museum of natural history in Chicago
the head is a replica
it weighed too much to be put on the top of the skeleton, remember that fossils do not have the same consistency as bones, they are not bones
the whole real head is also in the museum but separated in a showcase
yes, as they were found
these remnants of monsters can be found around the world but only represent a small portion of all the animals that have lived
We have only discovered a few during our brief existence here
Imagine everything that Antarctica can be hiding down there since millions of years ago
it was quite green, imagine the remains of species that can be found on the ocean floor
and it's thanks to the ocean floor
or it's thanks to the sea creatures actually that we know there have been mass extinctions on earth
in 1970 paleontologist Jack Sepkoski began to investigate in depth about all the creatures
oceanic known until then, his studies resulted in what is perhaps the most popular graphic in paleontology
East
Oh no that no. East
a record through time that revealed five catastrophic events in the past biodiversity of the inland and out of the ocean
The bad thing about this graph is that it is based on observations of animals that could somehow leave a footstep and that is very
little compared to all the animals that may have existed
does not take into account either the much smaller organisms that are unable to leave traces so there is no way to know if it could
have a much more massive extension than those shown in the graph
in fact some consider that there were eight mass extinctions instead of five others say they were three
but what happened happened and what caused all these massive extinctions
Well, the causes were several, the most likely are basalt floods product of volcanic eruptions
asteroid collisions and sea level drops, although other events that are more familiar to us that can also contribute
those include global warming pre global cooling
the methane productions and the anoxic events that is when the oceans of the earth lose their oxygen
in the case of volcanic eruptions
massive and astroid collisions. these would be responsible for expelling tons of debris into the atmosphere
darkening the sky for at least months for lack of sunlight the plants of the creatures that feed on them
would die quickly, now let's look at some of the situations that could have been considered only five massive extinctions
this is a graptolite an organism at the end of the ordovician
444 million years ago here it is estimated that 86% of the species that existed were lost
the graptolites measure between one and three centimeters and since most of the Ordovician life were marine creatures, their disappearance during
approximately one million years was probably caused by a short but severe ice age that reduced sea levels
triggered by the uprising of the Appalachian Mountains
the newly exposed silicate rock absorbed a large part of the carbon dioxide from the atmosphere
cooling the planet
Let's go now to the late Devonian period ago
375 million years
here it is estimated that 75% of the species that existed in that period were lost, the trilobites
or trilobites with only five centimeters long were the most diverse and abundant animals that appeared in the Cambrian explosion
550 million years ago
yes, these animals survived the first great extinction but they were almost
exterminated in the second. Studies suggest that terrestrial plants that had just begun to develop
they were the culprits since they covered the planet during the Devonian period
its deep roots would have stirred the earth releasing nutrients to the ocean this could have triggered
the birth of algae that sucked oxygen from the water, causing inhabitants like trilobites to die suffocated
but the worst mass extinction of all time occurred about 250 million years ago
the Permian extinction event where 96% of marine species and 70% of terrestrial species died
the image shows the fossil of an extinct tabulated coral that existed in that period
there is a consensus that a volcanic eruption
cataclysmic near Siberia blew carbon dioxide into the atmosphere
some bacteria responded by throwing methane which is as we saw in other videos a powerful greenhouse gas
global temperatures rise, while the oceans acidified and stagnated, releasing hydrogen sulfide
poisonous, which should put us on alert considering that we are ridding a large amount of carbon dioxide in the atmosphere
and there are people out there saying that global warming does not exist (cof cof: v).
After this great event
the dinosaurs appeared.
The fourth mass extinction occurred then at the end of the Triassic
200 million years ago and it is estimated that it ended up with 80% of the species that existed, of all the great extinctions
which presents the Triassic is the most enigmatic
no clear cause has been found and the scientists are like whaat happened here exactly what caused the fifth mass extinction
remains in the mystery. but a large part scientists agree that 66 million years ago a meteorite ended with barney
yes the one we see now is not real sorry children (stupid my childhood: 'v)
that meteorite killed the dinosaurs that lived at that time as we know we still live with dinosaurs and I'm not referring
to the monster of Loch Ness or
to those who show the videos that say "the dinosaurs that still live these days" no, those I do not mean the
birds this we have already clarified in another video which I recommend that you see if you want to understand well about this
But what would happen in a future extinction?
one that is approaching apparently the sixth that we are causing ourselves (Tomorrow 7: v?) What animals, what species would survive
let's leave us aside because if we continue like this with this behavior
half stupid I do not think we can do much, if we continue with this behavior there is always hope
alarmingly few animals larger than a dog survived the last extinction
Does this mean that dogs would be saved? not necessarily
some may think that the animals that are most scattered in most of the geographical
they would have more opportunities to save themselves since between the extinction events a wide geographic distribution
it seems to offer a considerable life insurance,
Well, not necessarily.
Recently it was discovered that the geographic range had no effect on the number of terrestrial vertebrate species
survivors in the end the mass extinction
of the Triassic, the physical events that cause mass extinctions, be they asteroids, mass volcanic eruptions and other physical factors
they are so disturbing and have such global consequences that even the most widespread species can be
annihilated, therefore quite difficult to make generalizations and predictions what is sure
is that nothing is certain unless it is clear that you are a
tardigrade, those little animals do have it pretty easy I've also made a video about them on the other channel if they can stand the voice see it
as we face the prospect of the sixth mass extinction that is accelerated by our fault
It is good to keep in mind that extinctions can increase rapidly in unpredictable ways.
the loss of a species for example, may have consequences
unforeseen for many others since ecosystems are connected by a complex network of interactions that are not always
we understand very well.
For some time now, world cataclysms and ends of the world have been the favorite themes of some channels
sensationalists and one or another youtube channel
the last one that came out is that in October of this year a great meteor is approaching
very close to the earth and probably going to destroy this meteorite is the size of a house
will happen very close to the earth according to the calculations but at a distance that is quite safe which would not cause any danger
for our planet
even so all the scientists are wrong and the asteroid hits the earth would not completely exterminate us
I would destroy a few cities, if they would be exterminated of course, I would have to have bad luck if it falls on your eye.
That does not mean that we do not have to be alert to a threat that nature simply
we do not have to be carried away by so many sensationalist news one of the main problems we have now is global warming
if we do not make an effort to have a cleaner planet, we will not be so far from disappearing but it's not just about us
We share the planet with other beings and it is indisputable that our wrongdoing has been and is being the cause of the extinction of several species
we do not need an asteroid that comes to destroy us we only need political leaders denial,
corporations and selfish and an epidemic indifference on the part of all of us
let's hope that the new generations
radically change the damage that is being done
let's hope it's not too late, let's hope that science advances enough to make humanity not exterminate or continue to exterminate
thanks for watching this video and see you next time
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