How did life begin? Abiogenesis. Origin of life from nonliving matter.

Summary

This script explores the origins of life on Earth, distinguishing between abiogenesis and evolution. It delves into the 'RNA world hypothesis,' lipid membranes' role in cell formation, and the challenges of RNA polymerization. The video discusses the possibility of life's chemical evolution driven by entropy, as proposed by Jeremy England, and the ongoing pursuit of understanding life's beginnings without concrete proof, but with plausible scientific theories.

Takeaways

• 🌏 The Earth's current diversity is a result of billions of years of evolution by natural selection, but it all began with the process of abiogenesis.
• 🔬 Abiogenesis is distinct from evolution and refers to the origin of life from nonliving matter, which is considered the 'primordial soup' from which life emerged.
• 🧬 All living organisms share a trinity of elements: nucleic acids (DNA/RNA), proteins, and lipids, which are essential for life's basic functions.
• 💧 Lipids, forming cell walls, are critical for encapsulating and organizing the components necessary for the first life forms, and their self-assembly is influenced by their hydrophilic and hydrophobic properties.
• 🔑 The formation of lipids from simple compounds like carbon monoxide and hydrogen in the presence of minerals suggests that the building blocks of life could have been present on early Earth.
• 🚫 The presence of certain ions, such as salts or magnesium, can disrupt lipid structures, but recent research shows that amino acids can stabilize lipid spheres in salty conditions.
• 🧬 The 'RNA world hypothesis' posits that RNA, a simpler molecule than DNA, likely came first and played a crucial role in the early stages of life before DNA took over genetic storage and replication.
• 🔬 The formation of the first RNA molecules from nonliving chemicals is still not fully understood, but research suggests that clay surfaces and meteoritic organic molecules could have facilitated this process.
• 🥚 Proteins, the workhorses of the cell, were likely present early in Earth's history, as amino acids, their building blocks, can be formed under conditions simulating the early atmosphere.
• 🤔 While precursors to life are understood, the exact mechanism of how these molecules came together to form a self-replicating, living cell is still a mystery.
• 🔄 MIT professor Jeremy England's research suggests that chemical evolution may be driven by entropy, with molecules restructuring to dissipate more energy, potentially leading to life forms over time.

Q & A

What is the difference between abiogenesis and evolution?

Abiogenesis is the process by which living organisms arise from nonliving matter, while evolution is the process by which living organisms develop and diversify from earlier forms of life. Abiogenesis does not explain the origin of life but rather the first formation of life, whereas evolution explains the changes in species over time.

What are the three fundamental components of life according to the script?

The three fundamental components of life are nucleic acids (DNA or RNA), proteins, and lipids. Nucleic acids contain the blueprints of life and are self-replicating molecules, proteins perform important functions within the body, and lipids encapsulate the cells of the body.

Why are lipids considered a critical component for abiogenesis?

Lipids are critical for abiogenesis because they can self-assemble into spherical structures that encapsulate other molecules, providing a boundary within which chemical interactions can occur. This encapsulation is necessary for the formation of a primitive cell that could potentially self-replicate.

How can lipids form naturally from nonliving materials?

Experiments have shown that lipids can form when carbon monoxide and hydrogen are heated up with minerals commonly found in Earth's crust. This suggests that lipids could have been present in the early Earth, possibly in underwater hydrothermal vents.

What is the 'RNA world hypothesis' mentioned in the script?

The 'RNA world hypothesis' theorizes that RNA, which today plays roles in expressing genes, was the essential precursor that led to the first living matter. It suggests that RNA came before DNA and was the molecule that initiated the first forms of life.

What is the challenge in replicating the formation of RNA from nonliving chemicals?

The challenge lies in the difficulty of forming bonds between the bases and ribose of RNA in the absence of enzymes that are present in modern cells. Replicating this process in the lab has been largely unsuccessful, making it a major stumbling block in abiogenesis theories.

What is the significance of the 2009 study by researchers at Rensselaer Polytechnic Institute?

The 2009 study showed that current-day RNA could have formed on the surface of clays, which act as catalysts to bring RNA bases together. This finding offers a potential mechanism for the formation of RNA from nonliving chemicals.

How did the amino acids, the building blocks of proteins, likely form on the early Earth?

The amino acids, which are the components of proteins, likely formed through natural processes under the atmospheric conditions of the primordial Earth, as demonstrated by the experiments of Stanley Miller and Harold Urey in the 1950s.

What is the role of entropy in the process of chemical evolution as proposed by Jeremy England?

Jeremy England proposed that the driving force for chemical evolution may be entropy, the tendency of systems to increase their state of disorder. He mathematically showed that when exposed to an external energy source, any group of molecules will restructure themselves to dissipate more energy, which could lead to the formation of living organisms over time.

Why is the probability argument by Fred Hoyle and Chandra Wickramasinghe considered an oversimplification?

The probability argument is an oversimplification because it does not account for the incremental and gradual formation of simpler precursors to life. It also ignores the vast number of opportunities for chemical interactions over millions of years, which increases the likelihood of the formation of life's building blocks.

What evidence supports the idea that life could have originated on Earth's early oceans?

Research suggests that lipid spheres and amino acids could have coexisted in the presence of each other, and that the building blocks of RNA and proteins could have polymerized in shallow ponds with a wet/dry cycle. This, along with the fact that all necessary components were available on early Earth, supports the idea that life could have originated in such environments.

Outlines

00:00

🌏 The Puzzle of Life's Origin

This paragraph delves into the concept of abiogenesis, the origin of life from nonliving matter, and distinguishes it from the process of evolution. It emphasizes the necessity of a primordial 'soup' containing nucleic acids, proteins, and lipids for life to begin. The paragraph highlights the critical role of lipids in forming cell membranes, which could have facilitated self-replication. It also touches upon the historical belief that lipids could only be produced by living cells and the subsequent discovery that they can form through chemical reactions involving carbon monoxide, hydrogen, and minerals. The discussion points to the complexity of forming the first living cell, especially considering the presence of ions that can disrupt lipid structures but are necessary for RNA function.

05:02

🔬 The Interdependence of Lipids and Proteins

The second paragraph focuses on the mutual necessity of lipids and proteins in the formation of life. It discusses recent research indicating that lipid spheres do not disassemble in the presence of amino acids, which are precursors to proteins. This finding is significant as it suggests that the first cells could have formed in an ion-rich environment, contrary to previous beliefs. The paragraph also explores the 'RNA world hypothesis,' which posits that RNA came before DNA and played a crucial role in the emergence of life. It outlines the challenges in understanding how the first RNA molecules could have formed, mentioning the difficulty of replicating the bond formation between ribose and the bases of RNA in a lab setting. The discussion includes recent studies that propose possible environments and mechanisms for RNA formation, such as clay surfaces acting as catalysts and the polymerization of RNA building blocks in shallow ponds influenced by meteorites and interplanetary dust.

10:06

🧬 The Quest for Understanding Protein and RNA Formation

This paragraph continues the exploration of the building blocks of life, discussing the formation of proteins and RNA. It references the classic experiments by Stanley Miller and Harold Urey, which demonstrated the natural formation of amino acids and other organic compounds under the conditions of primordial Earth. The paragraph also addresses the challenge of understanding how complex molecules could come together to form a self-replicating living cell. It mentions the creationist argument against the spontaneous formation of life and counters it by highlighting the incremental and gradual nature of life's emergence. The discussion introduces the concept of chemical evolution driven by entropy, as proposed by MIT professor Jeremy England, which suggests that molecules exposed to an external energy source will restructure to dissipate more energy, potentially leading to the formation of life. The paragraph concludes by emphasizing the plausibility of life's natural origin through a slow process of chemical and molecular evolution, despite the lack of definitive proof.

Keywords

💡Abiogenesis

Abiogenesis refers to the process by which living organisms arise from nonliving matter. It is distinct from evolution, which describes the development and diversification of life from existing life forms. The concept is central to the video's theme, as it explores the origins of life on Earth. The script discusses the possibility of abiogenesis through various chemical processes, such as the formation of lipids and RNA, which are essential for life.

💡Natural Selection

Natural selection is the process by which organisms with traits that are better suited to their environment are more likely to survive and reproduce, leading to the spread of those traits in subsequent generations. While the video acknowledges the role of natural selection in the diversification of life, it emphasizes that this process does not explain the initial origin of life, which is the focus of abiogenesis.

💡Primordial Soup

The term 'primordial soup' refers to the hypothetical environment in which organic molecules necessary for life first formed. It is used in the script to describe the conditions that may have existed on early Earth, where a 'soup' of nonliving chemicals could have given rise to the first living organisms. The concept is integral to understanding the conditions that may have led to abiogenesis.

💡Lipids

Lipids are a class of organic compounds that include fats, waxes, and sterols, which are crucial for the formation of cell membranes. In the context of the video, lipids are highlighted as critical components for abiogenesis because they can self-assemble into spherical structures, potentially encapsulating other molecules and creating an environment conducive to the emergence of life.

💡RNA World Hypothesis

The RNA world hypothesis proposes that early in evolution, self-replicating RNA molecules preceded DNA as the genetic material and played a central role in the origin of life. The video script mentions this hypothesis as a widely accepted scientific theory, suggesting that RNA, with its simpler structure compared to DNA, could have been the first self-replicating molecule that eventually led to the development of more complex life forms.

💡Proteins

Proteins are large biomolecules composed of amino acids and are essential for the structure, function, and regulation of the body's cells, tissues, and organs. The script discusses the importance of proteins in the context of the 'trinity' of elements necessary for life, alongside nucleic acids and lipids. The formation of proteins from amino acids is a key step in the development of life from nonliving matter.

💡Self-Replication

Self-replication refers to the ability of a molecule or a system of molecules to produce an exact copy of itself. In the video, self-replication is a critical concept in understanding how life could have originated, as it is a fundamental characteristic of living organisms. The script explores how RNA, in particular, may have been the first self-replicating molecule.

💡Chemical Evolution

Chemical evolution is the process by which complex organic molecules are formed from simpler inorganic precursors, leading to the origin of life. The video script discusses chemical evolution as a precursor to biological evolution, suggesting that a series of chemical reactions over time could have led to the formation of the first living organisms.

💡Thermodynamics

Thermodynamics is the study of the relationships between heat and other forms of energy in a system. The script mentions Newton's second law of thermodynamics, particularly the concept of entropy, as a driving force for chemical evolution. It suggests that the tendency of molecules to restructure themselves to dissipate more energy could have led to the emergence of life.

💡Molecular Evolution

Molecular evolution refers to the changes in the molecular composition of organisms over time. The video script touches on the idea that molecular evolution could have driven the transition from simple organic molecules to the complex molecules necessary for life. It is part of the broader process that led to the diversity of life forms we see today.

💡Fossil Record

The fossil record is the collection of all preserved remains and traces of past life found within the Earth's crust. The script briefly mentions the fossil record as evidence of the early diversity of life on Earth, which supports the idea that life originated and evolved through natural processes over billions of years.

Highlights

The origin of life from nonliving matter is termed abiogenesis, distinct from evolution.

All life forms share a trinity of elements: nucleic acids, proteins, and lipids.

Lipids, forming cell walls, are critical for encapsulating and organizing the building blocks of life.

Lipid molecules self-assemble into spheres due to their hydrophilic and hydrophobic properties.

Lipids can be synthesized from carbon monoxide and hydrogen in the presence of Earth's crust minerals.

The presence of ions like salts or magnesium can disrupt lipid structures.

Amino acids prevent lipid spheres from disassembling in the presence of ions.

RNA is simpler than DNA and is hypothesized to have come first in the 'RNA world hypothesis'.

RNA's formation from nonliving chemicals is challenging to replicate, a major hurdle for abiogenesis theories.

Clays may have acted as catalysts for RNA base assembly in early Earth conditions.

RNA building blocks could have polymerized using organic molecules from meteorites in shallow ponds.

Amino acids, the building blocks of proteins, could have formed naturally under primordial Earth's conditions.

The probability of life forming by chance is often overstated, ignoring incremental and widespread chemical reactions.

Chemical evolution may be driven by entropy, as molecules restructure to dissipate energy.

RNA and DNA are efficient at absorbing UV light, potentially aiding in early life's energy conversion.

While there's no single accepted theory for life's origin, natural processes likely led to simple life forms over time.

Biological evolution then took over, leading to the diversity of life we see in the fossil record and today.

Our understanding of life's origins is evolving, driven by scientific pursuit and decreasing ignorance.

Transcripts

If, in an instant, you could magically transport yourself to the ancient earth

4.5 billion years ago, and then in the next instant, you magically transported

yourself to now. you may say that only magic, or a supernatural force could have

transformed the earth to its present day from its humble beginnings. The diversity

of earth today can be explained largely through evolution by natural selection, a

process that occurred over billions of years. But this diversity must have had a

seed of some kind, the first semblance of life at some

point must have had a beginning, a start from the primordial soup. And it must

have started from nonliving matter. But how is it that the seemingly

unremarkable processes of geology, chemistry, and physics could have

combined in precisely the correct sequence to produce the first living

matter, from nonliving matter. This seems to many people utterly impossible.

There must have been a blueprint. There must have been an architect, they say. How

could such vastness of diversity, functionality, and beauty come from the

physical processes of the cosmos and nature? And how could it have happened on

its own? that's coming up right now...

The origin of living organisms from inorganic, or nonliving material is

called abiogenesis. It's important to distinguish this from

evolution. Abiogenesis is not evolution. Evolution is the process of development

or diversification of living things from earlier forms of living things. Evolution

does not say anything about how life first originated. So how did the first

life originate? Despite the incredible variations that we see today, at the

fundamental level all living things contain a trinity of elements. First,

nucleic acids, which make up the DNA or it's simpler form called RNA. These

contain the blueprints of life and are self-replicating molecules. Second, there

are proteins, which are the workhorses that perform the important functions of

your body. And third, are lipids which encapsulate the cells of your body.

Before any living things existed, before animals, plants and even bacteria existed,

these three things had to have been present in the primordial soup in order

for life to start. Some argue that the most important component of this Trinity

are the lipids, which make up the cell walls. Why would this be the most

important?...because without the wall, or a way to encapsulate certain elements

within the soup, there would just be a soup of material that would just be

disorderly and floating around in a sea of liquid. It would not be functioning

inside something that could potentially self-replicate. But because these lipid

membranes could potentially form around other elements, they could bring

disparate parts of various chemicals together, that could potentially interact,

combine, react and work together to perhaps eventually form a machinery for

self replication. So these fatty membranes composed of lipids were

critical components for abiogenesis. So any study of abiogenesis should

perhaps start with a closer examination of lipids. Lipid molecules have a unique

structure. There is a round part and a long tail part. It so happens that the

round part loves water. It's hydrophilic. The tail part however,

hates water. It's hydrophobic. So what tends to happen

is, when a bunch of lipids are floating around in water, they tend to gather

together and self assemble in spheres. Why does this happen?...because the

tail part of the molecule, since it wants to get away from water,

automatically faces other tails that also dislike water. And the round part

which likes water, exposes itself to the water outside and inside the sphere. It

is what these types of molecules do naturally. So it has a tendency to

self-assemble into natural spheres. But where do lipids come from? It was once

thought that they could only be produced by living cells. But experiments have

shown that when carbon monoxide and hydrogen is heated up with minerals

commonly found in Earth's crust, lipids can form. All components were available

in the early Earth and could have happened in underwater hydrothermal

vents. You might at this point say aha that's it! That's how the first cell must

have formed! Not so fast. It turns out that while lipids do have

this quality of self-assembly, when there are certain ions present, such as salts

or magnesium, it destroys the lipid structure they disintegrate. But the

problem is that RNA and other functions of a cell require these ions, and since

the early Earth was believed to have salty oceans, and since these spheres

can't form in these salty oceans, this theory always had a gaping hole.

However, just this year, in 2019 researchers at the University of

Washington showed that lipid spheres do not disassemble if they are in the

presence of amino acids, which are precursors to protein molecules. In

addition, the enclosing of amino acids within cell walls allows amino acids to

concentrate within the walls and interact with each other to form

proteins, which is part of the Trinity one of the essential components of life.

What is remarkable about this research is that it turns out that nonliving

lipid cell walls and non living proteins need each other to exist in an

ion rich or salty water. So now we see that lipids and proteins can potentially

form in the presence of each other. What about DNA and RNA? These are the key

self-replicating molecules, the blueprints of all living things.

Today, genetic information is stored in DNA. And RNA is created from DNA to put

that information into action. RNA can direct the creation of proteins and

perform other essential functions of life in a cell. The simplicity

of RNA compared to its cousin the DNA is the reason that most people

think RNA came first. This is part of the "RNA world hypothesis." which theorizes

that RNA, the molecule that today plays roles in expressing genes, was the

essential precursor which led to the first living matter. Only later did it's

more complex cousin, DNA, take over the task of storing and replicating genetic

information. This hypothesis has gained wide acceptance by scientists. So let's

look at RNA. How did the first RNA molecule form from nonliving chemicals?

Well, the answer to this is not as clear-cut. And this has been a major

stumbling block to any theory of abiogenesis. So here is what some of the

latest research points to regarding RNA. RNA is made up of three chemical

components - the sugar ribose the bases and phosphate. A ribose-base-phosphate

unit links together with other ribose-base-phosphate units to form RNA polymer.

Figuring out how a bond between the bases and ribose first formed has been

difficult to replicate in the lab. Attempts to show how ribose bonds can

form with the bases of RNA have been largely unsuccessful. This is because

cells in your body require complex enzymes to bring RNA building blocks

together before they combine to form polymers. But in a 2009 study,

researchers at Rensselaer Polytechnic Institute in Troy New York, showed that

current-day RNA could have formed on the surface of clays which act like catalyst

to bring RNA bases together, as shown in this animation. A 2017 paper by

scientists from McMaster University in Canada, and the Max Planck Institute in

Germany, showed that the building blocks of RNA could have polymerized in the

early Earth using organic molecules from meteorites and interplanetary dust in

shallow ponds. The wet/dry cycle of these ponds, they showed, are conducive to RNA

polymerization. They also theorized that such polymers were probably present

on earth shortly after its formation as early as 4.17 billion

years ago. So now we have ways that two of the Trinity could have formed - RNA and

lipids. But what about protein? How did they form? In the 1950s, several

experiments by Stanley Miller and Harold Urey verified that the natural formation

of amino acids, components of proteins, and other organic compounds, out of

organic materials, was possible under the atmospheric conditions of the primordial

earth. So the precursors of proteins were likely present in the very early Earth.

It turns out that it's pretty easy to form many kinds of organic molecules in

a wide range of environments. But so far, I have only presented ways that can

result in potential precursors needed for life. You might say, "Well, that's fine

and dandy," but having all the precursors get together inside a lipid cell wall

does not necessarily mean they will all come together to form a self-replicating

living cell. How do the complex molecules come together to self replicate and

become a living organisms? And if I'm being honest, this is currently not well

understood, and there's no experiment or smoking-gun evidence, right now, that

points to a precise mechanism of how this could have happened.

There are creationist arguments such as the one that says if I put all the parts

of a watch in a big vat, and keep stirring it for a million years, a

functioning, ticking watch is not going to magically form inside the VAT. And

some cite an estimate by scientists Fred Hoyle and Chandra Wickramasinghe

that the probability of all the chemicals in a simple bacterium arising

on their own by chance is something on the order of one in 10 to the 40,000

power, which is more than the Planck volume of the entire universe. So that is

a virtual impossibility. But this number and the clock-parts-in-a-vat argument

are oversimplifications. They ignore the fact that sophisticated life forms, like

current-day bacteria, almost certainly did not arise spontaneously, but arose in

much simpler incremental steps, that had a much higher chance of occurring. There

are stats such as the one that says the odds of creating a protein molecule by

chance is 1 in 10 to the 45 power. Odds such as these and others not only ignore

the idea of simpler precursors, but also ignore the fact that it

was not just one set of amino acids, at one place, at one time, but it was

trillions upon trillions of amino acids reacting in countless places, over

millions of years, that resulted in simple protein molecules. There are about

4x10^47 molecules of water in Earth's oceans.

Even if there was one amino acid among 1 million water molecules, that would be

10 to the power 41 molecules of amino acids that had the opportunity to interact with

each other, and to form proteins in numerous environments, in numerous places,

and in numerous trials, over millions of years, to produce proteins. The actual

probability is not how the hundreds of complex chemicals can come together to

form a modern-day bacterium, but the probability of a few chemicals, may be 10

or 20, forming and coming together to form the precursors of life, that can

chemically evolve over time to form the simplest kind of life form, that likely

looked nothing like any evolved life form we recognize today. But showing how

even this chemical evolution could have happened is problematic. Chemical

evolution is not the same as biological evolution, which is driven by favoring

organisms that have the best chance of survival and reproduction. Scientists have had

trouble figuring out what could have driven chemicals to evolve the

complexity needed for biological functioning. But in 2014

Jeremy England, physics professor at MIT, showed mathematically that the driving

force for chemical evolution may be hidden in physics, in Newton's second law

of thermodynamics. that's our old friend "entropy." From a physics point of view, the

one thing that distinguishes living things from nonliving things is its

ability to capture energy and convert it to heat. England argues that when exposed

to an external source of energy, such as the sun, any group of molecules will

restructure themselves to dissipate more and more energy. This, he says, is the

driving force for chemical evolution. And this can, over time, result in living

organisms, such as those we see today - organisms that are super efficient at

dissipating energy. This theory is further supported by a

2011 paper by Karo Michaelian, that showed that RNA and DNA are the most

efficient of all known molecules for absorbing the intense ultraviolet light

of the Sun. While there is no single generally accepted theory of the origin

of life, all credible proposals show that life under natural conditions by a slow

process of chemical and molecular evolution, could have plausibly resulted

in simple life forms over a long period of time, and that this evolution of

chemistry was probably the biggest hill to climb for life to have occurred on

earth. But once this happened, biological evolution took over and relatively

quickly, resulted in exceptional diversity of life forms. We see that in

the fossil record of early Earth, and of course, we see that on earth today. Do we

have proof that this is how life came about? No...at least not yet. Is it

plausible?...absolutely. Just like chemical and biological evolution, our knowledge

too is evolving in a slow process over hundreds and thousands of years, driven

by the pursuit of science, and hopefully, ever decreasing ignorance.

Hey guys, video is sponsored by the newly released sci-fi novel "New Eden" by Kishore Tipirneni.

New eden is a mind-boggling story of quantum entanglement and the origins of

life. Follow physicist Joshua Andrews and journalist Rachel Miller as they

discover that entangled particles were created the moment of the Big Bang,

creating a universe-wide communication network. So if you love sci-fi based on

some real science, I highly recommend New Eden. It's available now from Amazon. The

link is in the description below. And if you want to support us and see

more videos like this, then please subscribe, ring the bell icon, and give us

a like. Or support us on patreon. I'll see you in the next video.