10 teorías del origen de la vida (fácil de entender). Biología🦠
Summary
TLDREl video analiza las principales teorías sobre el origen de la vida, desde la generación espontánea hasta la creación por un ser divino. Se mencionan propuestas como la sopa primordial, la panspermia, y la vida creada por electricidad, así como la hipótesis de la primera vida bajo el hielo y la formación de polímeros orgánicos. También se destacan ideas más recientes, como la teoría del 'mundo de ARN' y las redes metabólicas, y se compara el creacionismo con las teorías evolucionistas. El video invita a los usuarios a compartir su opinión sobre cuál teoría apoyan.
Takeaways
- 🌍 La Tierra se formó hace aproximadamente 4.5-5 mil millones de años, y los fósiles más antiguos datan de hace 3.5 mil millones de años.
- 🦠 La teoría de la generación espontánea proponía que los seres vivos podían surgir de la materia no viva, pero fue refutada por los experimentos de Francesco Redi y Louis Pasteur.
- 💧 La teoría del caldo primitivo sugiere que la vida se originó a partir de una evolución química gradual, donde las moléculas inorgánicas reaccionaron y formaron compuestos orgánicos.
- 🌌 La panspermia plantea que la vida podría haber llegado a la Tierra desde el espacio en forma de esporas o semillas que germinaron bajo las condiciones adecuadas.
- ⚡ La teoría de la vida por electricidad sugiere que una chispa eléctrica pudo haber proporcionado la energía necesaria para organizar los compuestos orgánicos y formar moléculas complejas.
- ❄️ La teoría de la vida bajo el hielo propone que la vida pudo haber surgido en el océano cubierto de hielo, protegiendo los procesos biológicos de la radiación solar.
- 🧪 Sidney Fox demostró que los aminoácidos podían polimerizarse en proteínas al calentarse, lo que pudo haber ocurrido en la Tierra primitiva.
- 🧬 La hipótesis del mundo del ARN sugiere que el ARN fue la primera molécula autocatalítica capaz de replicarse y transmitir información genética.
- 🔥 La hipótesis del metabolismo primero plantea que las primeras formas de vida consistieron en redes metabólicas autosuficientes, que precedieron a los ácidos nucleicos.
- 🙏 El creacionismo sostiene que un Dios creó la vida y el universo, en contraste con las teorías científicas de la evolución.
Q & A
¿Cuál es el período en el que se formó la Tierra según los registros científicos?
-La Tierra se formó hace aproximadamente 4.5 a 5 mil millones de años.
¿Qué son los fósiles más antiguos conocidos y de qué época datan?
-Los fósiles más antiguos conocidos corresponden a cianobacterias encontradas en Australia Occidental, y datan de al menos 3.5 mil millones de años.
¿Por qué no se han encontrado fósiles más antiguos que los de las cianobacterias?
-Muchos científicos creen que otras formas de vida anteriores pudieron haber existido, pero los fósiles se destruyeron debido al calor y a los cambios en las rocas durante el Precámbrico.
¿Cuál es la teoría de la 'generación espontánea' sobre el origen de la vida?
-La teoría de la 'generación espontánea' sostenía que los seres vivos podían surgir de materia inerte, como insectos que aparecían en el barro o la carne en descomposición. Esta teoría fue desacreditada por científicos como Francesco Redi y Louis Pasteur.
¿Cómo refutaron Francesco Redi y Louis Pasteur la teoría de la generación espontánea?
-Redi demostró que las larvas no surgían espontáneamente en la carne a menos que los insectos adultos depositaran sus huevos, y Pasteur mostró que los microorganismos solo podían provenir de otros microorganismos preexistentes.
¿Qué plantea la teoría del 'caldo primitivo' propuesta por Oparin y Haldane?
-La teoría del 'caldo primitivo' sugiere que la vida en la Tierra surgió a través de una evolución química gradual, donde moléculas inorgánicas reaccionaron para formar compuestos orgánicos que, con el tiempo, se organizaron en estructuras más complejas capaces de replicarse.
¿Qué es la panspermia y quién propuso esta teoría?
-La panspermia es la teoría que sugiere que las semillas de la vida están dispersas por el espacio cósmico y germinan cuando encuentran condiciones favorables en un planeta. Fue propuesta por el científico August Arrhenius en 1908.
¿Cómo se vincula la electricidad con el origen de la vida según Miller y Urey?
-Miller y Urey demostraron que una descarga eléctrica en una atmósfera primitiva podría haber formado moléculas orgánicas como aminoácidos, apoyando la idea de que la vida pudo haberse originado gracias a una 'chispa eléctrica' que organizó compuestos inorgánicos.
¿Qué propone la teoría del origen de la vida 'bajo el hielo'?
-Esta teoría sugiere que la vida pudo haberse originado en aguas profundas cubiertas por una gruesa capa de hielo, la cual protegía los procesos biológicos que dieron lugar a las primeras formas de vida.
¿En qué se diferencia la hipótesis de 'genes primero' de la hipótesis de 'metabolismo primero'?
-La hipótesis de 'genes primero' sugiere que las primeras formas de vida fueron ácidos nucleicos autorreplicantes como el ARN, mientras que la hipótesis de 'metabolismo primero' plantea que las primeras formas de vida consistieron en redes metabólicas autosostenibles que precedieron a los ácidos nucleicos.
Outlines
🌍 El origen de la vida y su estudio a través del tiempo
Este párrafo describe cómo la humanidad ha intentado explicar el origen de la vida desde hace siglos. Se menciona que la Tierra se formó hace unos 4.5-5 mil millones de años y que los fósiles más antiguos datan de al menos 3.5 mil millones de años. A pesar de la falta de fósiles anteriores, se cree que formas de vida podrían haber existido antes, pero fueron destruidas por procesos geológicos. Se enumeran teorías sobre cómo surgieron los primeros organismos, comenzando con la 'generación espontánea', la cual fue desacreditada por los experimentos de Redi y Pasteur. Finalmente, se plantea la evolución como una explicación de cómo los organismos simples dieron lugar a formas de vida más complejas.
🔬 Evolución química y el caldo primario
Este párrafo describe la teoría de la evolución química, propuesta por Oparin y Haldane en los años 1920. Según esta hipótesis, la vida en la Tierra surgió a partir de la materia inanimada en un proceso gradual, bajo condiciones de una atmósfera reductora. Los rayos y la luz solar habrían facilitado la formación de moléculas orgánicas que se acumularon en los océanos, creando un 'caldo primario'. Estas moléculas más tarde se habrían combinado para formar estructuras más complejas como proteínas y ácidos nucleicos.
💫 La teoría de la panspermia y otras hipótesis
Este párrafo aborda la teoría de la panspermia, propuesta por August Arrhenius en 1908, que sugiere que las semillas de la vida están distribuidas por todo el espacio y germinan cuando las condiciones en un planeta son favorables. Además, se menciona la teoría del origen de la vida por una chispa eléctrica, apoyada por los experimentos de Miller y Urey, que demostraron que una descarga eléctrica bajo ciertas condiciones atmosféricas podría generar moléculas orgánicas como los aminoácidos. También se incluye una teoría menos conocida que propone que la vida surgió en aguas oceánicas profundas cubiertas por una capa de hielo.
🧪 El papel de los polímeros en el origen de la vida
Este párrafo se centra en cómo los científicos comenzaron a investigar la polimerización de los compuestos orgánicos, lo que condujo a la creación de proteínas. En 1950, Sidney Fox y su equipo demostraron que los aminoácidos podían unirse para formar proteínas bajo ciertas condiciones experimentales. También se menciona la teoría de Cairns-Smith, que sugiere que el ARN pudo haberse formado en superficies de arcilla que actuaron como catalizadores, organizando moléculas en patrones definidos.
🧬 Hipótesis de los genes y el metabolismo en el origen de la vida
Aquí se describen dos hipótesis principales sobre el origen de la vida. La primera, conocida como la 'hipótesis de los genes primero', sugiere que los primeros seres vivos podrían haber sido ácidos nucleicos autorreplicantes como el ARN. La segunda, llamada 'hipótesis del metabolismo primero', propone que las primeras formas de vida consistían en redes metabólicas autosuficientes que existieron antes de la aparición de los ácidos nucleicos. Ambas hipótesis exploran cómo pudieron surgir sistemas autocatalíticos que eventualmente formaron células.
📜 La vida por necesidad y el papel de la creación
Este párrafo explora la teoría de que la vida surgió por necesidad, siguiendo las leyes de la naturaleza, según investigadores del MIT. Se sugiere que los átomos al ser expuestos a una fuente de energía, como el sol, se reorganizan para disipar la energía de manera más eficiente, lo que podría haber llevado a la formación de vida. Finalmente, se menciona el creacionismo, una teoría respaldada por parte de la sociedad que sostiene que Dios creó la vida. Se destacan las diferencias entre creacionistas bíblicos y creacionistas de la 'tierra antigua', y cómo estas visiones contrastan con las teorías de la evolución.
Mindmap
Keywords
💡Teorías del origen de la vida
💡Generación espontánea
💡Caldo primitivo
💡Panspermia
💡Electricidad y origen de la vida
💡Polímeros orgánicos
💡Mundo de ARN
💡Hipótesis del metabolismo primero
💡Creacionismo
💡Evolución química
Highlights
Theories of the origin of life aim to explain how living things originated.
The Earth formed about 4.5-5 billion years ago, and the oldest fossils, found in Western Australia, date back 3.5 billion years.
Many scientists believe that earlier life forms may have existed, but their fossils were destroyed by geological changes.
Theories like spontaneous generation proposed that life could arise from non-living matter, which was eventually disproven by experiments from Francesco Redi and Louis Pasteur.
Darwin and Wallace’s theory of evolution by natural selection introduced the idea that complex beings evolved from simpler unicellular organisms.
Oparin and Haldane’s theory of the 'primordial broth' suggested that life arose from chemical evolution in Earth's early reducing atmosphere.
The panspermia theory proposed by August Arrhenius in 1908 suggested that 'life-bearing seeds' may have come from outer space.
Miller and Urey’s experiments demonstrated that electrical discharges in early Earth’s atmosphere could form organic molecules like amino acids.
A less known theory suggests life might have originated under the ice of Earth's oceans, which protected biological interactions.
Sidney Fox’s experiments in the 1950s showed that heating amino acids in the absence of water could lead to the formation of proteins.
Alexander Cairns-Smith proposed that clay surfaces may have helped catalyze the formation of RNA, promoting the emergence of life.
The 'RNA world' hypothesis suggests that self-replicating RNA molecules may have been the first catalysts for life’s formation.
The 'metabolism first' hypothesis argues that metabolic networks formed before nucleic acids, leading to the first cellular life forms.
MIT researchers suggested that the origin of life might have been inevitable, driven by energy dissipation according to natural laws.
Creationism posits that life and the universe were created by a divine power, contrasting with evolutionary theories based on natural selection.
Transcripts
The theories of the origin of life try to explain how living things originated.
How life as we know it arose is a question that many philosophers,
theologians and scientists have asked for many years, in fact, we could
say that almost since man is man. Different scientific records establish that
the earth was formed about 4.5-5 billion years ago and that the oldest known fossils,
corresponding to remains of cyanobacteria found in Western Australia,
date from at least 3.5 billion years ago.
Although there are no fossil records or older geological evidence,
many scientists agree that other life forms may have existed before,
but that the fossils may have been destroyed by the heat and changes in
shape of many rocks during the Precambrian. What happened during the nearly 2 billion
years between the origin of the earth and the occurrence of the first fossils?
It is the biological events that occurred at that time that made
the emergence of life possible and that are so debated today in the scientific community.
Next we will find some of the main hypothetical theories proposed
by different authors to explain the origin of the first living organisms, from
which the most “advanced” forms of life presumably evolved.
Main theories of the origin of life 1- Life by spontaneous generation
From the Greeks to many scientists of the mid-nineteenth century, the
proposal that living beings could arise spontaneously, without other parental organisms,
from "non-living" matter was accepted. . Therefore, for many centuries,
various thinkers were convinced that insects, worms, frogs, and other
vermin formed spontaneously on mud or decaying matter.
These theories were discredited more than once by the experiments carried
out by Francesco Redi (1668) and Louis Pasteur (1861), for example.
Redi proved that unless adult insects lay their eggs on a piece of meat,
the larvae do not spontaneously arise on it. On the other hand, Pasteur
later showed that microorganisms could only come from pre-existing microorganisms.
Furthermore, it must be said that this theory was also ignored because in different
historical contexts “spontaneous generation” referred to two quite different concepts, namely:
- Abiogenesis: the notion of the origin of life from inorganic matter and
- Heterogenesis : the idea that life arose from dead organic matter,
just as worms "appeared" on decomposing meat.
Darwin and Wallace, a little earlier, in 1858, independently published their theories
on evolution by natural selection, by means of which they made it understood that the
most complex living beings had been able to evolve from more “simple” unicellular beings.
Thus, the theory of spontaneous generation disappeared from the scene and the
scientific community began to wonder how those "simplest unicellular beings" that
evolutionists spoke of emerged. 2- Theory of the primary broth
and gradual chemical evolution In 1920, the scientists A. Oparin
and J. Haldane proposed, separately, the hypothesis about the origin of life on
earth that today bears their names and through the which established that life on earth could
have arisen "step-by-step" from non-living matter, through "chemical evolution".
Both researchers suggested that the "initial" earth must have had a reducing atmosphere
(poor in oxygen, in which all molecules tended to donate electrons), a condition that
could perfectly explain some events: - That some inorganic molecules reacted
with each other to form the organic structural “blocks” of living beings, a process directed
by electrical energy (from rays) or light (from the sun) and whose products accumulate
in the oceans forming a “primary broth”. - That these organic molecules were
subsequently combined, assembling more complex molecules, formed by fragments
of simpler molecules (polymers) such as proteins and nucleic acids.
- That these polymers were assembled into units capable of replicating themselves, either
in metabolic groups (Oparin's proposal) or inside membranes that formed
"cell-like" structures (Haldane's proposal). 3- Panspermia
In 1908, a scientist named August Arrhenius, proposed that "life-bearing seeds"
were scattered throughout cosmic space and that they fell on the planets and "germinated"
when conditions there were favorable. This theory, also known as
the panspermia theory (from the Greek pan, which means "all" and sperma, which means "seed"),
was supported by different scientists and we can also find it referred to in some texts
as "the extraterrestrial origin of life". 4- Life by electricity
Later, part of the scientific community insinuated that the origin of life proposed by
Oparin and Haldane could have started on earth thanks to an electrical "spark" that provided
the necessary energy for the "organization" of the fundamental organic compounds from
inorganic compounds (a form of abiogenesis). These ideas were supported experimentally
by two American researchers: Stanley Miller and Harold Urey.
Through their experiments, both scientists demonstrated that, from
inorganic substances and with some special atmospheric conditions, an electrical discharge
was capable of forming organic molecules such as amino acids and carbohydrates.
This theory proposed, then, that with the passage of time the
most complex molecules that today characterize living beings could have been formed; which is why it
was very supportive of Oparin and Haldane's "primary broth" theories a few years earlier.
5- Life under the ice Another theory, perhaps a
little less known and accepted, proposes that life arose in deep ocean waters,
whose surface was presumably covered by a thick and thick layer of ice, since the
Sun of the earth initial probably did not impinge as strongly on the surface as it does now.
The theory proposes that the ice could have protected any
biological phenomenon that occurred in the sea, allowing the interaction of the different compounds
that originated the first living forms. 6- Life from organic polymers
Proteins After it
could be demonstrated in a laboratory that organic compounds such as amino acids
could be formed from inorganic matter under certain conditions, scientists
began to wonder how the polymerization process of the compounds took place organic.
Let us remember that cells are made up of large and complex types of polymers:
proteins (polymers of amino acids), carbohydrates (polymers of sugars), nucleic
acids (polymers of nitrogenous bases), etc. In 1950, the biochemist Sidney Fox and his group
discovered that, under experimental conditions,
if a set of amino acids were heated in the absence of water, they could join together to
form a polymer, that is, a protein. These findings led Fox to suggest
that in the "primitive broth" proposed by Oparin and Haldane amino acids could have been formed that,
when in contact with a hot surface, promoting the
evaporation of water, could form proteins. Ribonucleic acid and life on clay
Organic chemist Alexander Cairns-Smith later proposed that the first molecules
that made life possible could be found on clay surfaces, which not only
helped to concentrate them, but also promoted their organization into definite patterns.
These ideas, which came to light in the 1990s, claimed that clay could
serve as a "catalyst" in the formation of RNA (ribonucleic acid) polymers, acting,
in turn, as a catalyst support. 7- The "genes first" hypothesis
Taking into account the ideas of the "spontaneous" formation of essential organic polymers
, some authors took on the task of imagining the possibility
that the first forms of life were simply nucleic acids self- replicating,
such as DNA (deoxyribonucleic acid) or RNA. Therefore, it was suggested that other
important elements, such as metabolic networks and membrane formation, for example, be
added later in the "primordial" system. Given the characteristics of reactivity of RNA,
many scientists support the notion that the first
auto-catalytic structures were formed by this nucleic acid (obviously as ribozymes),
hypotheses known as "the RNA world". According to this, RNA could potentially
have catalyzed the reactions that allowed its own copying, making it capable of transmitting
genetic information from generation to generation and even evolving.
8- The “metabolism first” hypothesis On the other hand, different researchers
rather supported the notion that life took place first in “protein-type” organic molecules,
establishing that the initial life forms could have consisted of “self-
sustaining” metabolic networks ” prior to nucleic acids. The hypothesis implies that "metabolic networks"
could have formed in areas near hydrothermal vents, which maintained
a continuous supply of chemical precursors. Thus, the first simpler routes could
have produced molecules that acted as catalysts for the formation of
more complex molecules and, eventually, the metabolic networks could have been capable of
forming other, even more complex molecules, such as nucleic acids and large proteins.
Finally, these self-sustaining systems could have been "encapsulated"
inside membranes, thus forming the first cellular beings.
9- The origin of life by "necessity" Some researchers belonging to the Massachusetts Institute
of Technology (MIT, USA) have contributed to the formulation of a theory that
explains the origin of the first living beings by "necessity", in some way "following the laws
of nature" and not by "chance" or "chance". According to this theory, the emergence of
life was an inevitable matter, since it was established that matter generally
develops in "systems" that, directed by an external source of energy and surrounded by heat,
are more efficient in dissipating energy. energy. Experiments related to this theory have
shown that when a population of random atoms is exposed to an energy source,
they rearrange themselves to dissipate the energy more efficiently, suggesting that
this "re-patterning" would eventually end the formation of life. .
The alternate source of energy could easily have been the sun, although
other possibilities are not entirely ruled out. 10- Creationism
Creationism is another of the theories supported by an important part of today's societies,
mainly by act of faith. According to this school of thought, the universe
and all life forms in it were created out of "nothing" by a God.
It is a theory that interestingly contrasts with modern theories of evolution,
which seek to explain the origin of the diversity of living forms without the need
for a God or any other "divine power" and, many times, simply by "chance". ”.
There are two types of creationists: biblical and "old earth" creationists. The former
believe that everything stated in the chapter of Genesis in the Bible is literally true,
while the latter consider that a creator made everything that exists,
but without claiming that the story of Genesis is a literal story.
However, both types of creationists believe that changes in organisms
can lead to changes in a species, and they also believe in "downward" changes,
such as negative mutations, for example. However, they do not believe that these changes could have
led to the evolution of a "lower" species into a "higher" or much more complex species.
Creationism and evolutionism have been the subject of debates and disputes since
the publication of the first evolutionary theories and, even today,
both visions seem to be mutually exclusive. And which of these theories about the origin
of life do you support? Leave your opinion in the comments. See you soon.
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