Why is All Life Carbon Based, Not Silicon? Three Startling Reasons!

Summary

The video explores why carbon is the fundamental element for life on Earth, despite not being the most abundant or stable element. It attributes this to carbon's versatility in forming complex molecular structures, its relative abundance in the universe, and the stability of carbon-carbon bonds. The video also entertains the possibility of alternative life forms based on different elements under specific conditions, and promotes a course on Wondrium that delves deeper into organic chemistry.

Takeaways

• 🌿 **Carbon's Versatility**: Carbon is unique in its ability to form up to four covalent bonds, allowing for the creation of complex molecular structures necessary for life.
• 🌟 **Quantum Mechanics Influence**: The electron orbital configurations of carbon, as dictated by quantum mechanics, make it energetically favorable and stable when forming bonds.
• 🌌 **Abundance in the Universe**: Carbon is the fourth most abundant element in the solar system and is plentiful enough to serve as the backbone for life.
• 🔬 **Complexity of Carbon-Based Molecules**: Carbon can form diverse structures like long chains, closed rings, and various types of bonds, leading to millions of possible molecular configurations.
• 🧬 **DNA and Carbon**: DNA, which carries genetic information, relies on carbon's ability to form complex structures with its four nucleotides.
• ⚖️ **Stability of Carbon Bonds**: Carbon-carbon bonds are stronger than silicon-silicon or nitrogen-nitrogen bonds, providing a stable scaffold for organic molecules.
• 💠 **Noble Gases as Stability Benchmark**: Noble gases are chemically stable due to their complete outer electron shells, and carbon, through bonding, strives to achieve a similar stability.
• 🌐 **Elements' Bonding Trends**: The periodic table organizes elements by their maximum bonding capacity, with carbon being in a group that can form the most bonds.
• ⛰️ **Silicon's Limitations**: Despite silicon's ability to form four bonds, its bonds are weaker due to electrons being farther from the nucleus, making carbon a more suitable choice for life.
• 🌍 **Earth's Conditions for Life**: The conditions on Earth, including temperature and pressure, are conducive to carbon-based life forms and liquid water as a solvent.
• 🚀 **Potential for Artificial Life**: The advancement of technology may lead to the creation of silicon-based artificial life on Earth, demonstrating the potential for different elements to support life under varying conditions.

Q & A

Why is life on Earth based on carbon chemistry?

Life on Earth is based on carbon chemistry because carbon is capable of forming complex molecular structures necessary for life's complex chemistry. It can form up to four covalent bonds, allowing for the creation of long, non-repetitive chains, closed rings, and various types of bonds with other elements, leading to a vast array of possible molecular configurations.

Why is carbon preferred over more abundant elements like oxygen for the basis of life?

Despite oxygen's abundance, it can only form two bonds, limiting its ability to create complex molecular structures. Carbon, on the other hand, can form four bonds, enabling it to construct the intricate molecules essential for life's functions.

What role does quantum mechanics play in understanding why carbon is fundamental to life?

Quantum mechanics explains electron orbital configurations and their energy levels. It shows that noble gases are stable because they have complete outer shells of electrons. Carbon, with its ability to share up to four electrons to achieve a stable configuration, can form the stable and complex molecular structures that life requires.

Why are noble gases chemically inert?

Noble gases are chemically inert because they have a complete outer shell of electrons, which is the lowest energy configuration an atom can have. This makes them stable and typically unwilling to share, gain, or lose electrons to form bonds with other atoms.

How does the periodic table help us understand the bonding capabilities of elements?

The periodic table is arranged so that elements in the same column have similar bonding capabilities. It allows us to easily identify the maximum number of bonds an element can form with others, which is crucial for understanding the potential complexity of molecules that elements can create.

What is the significance of carbon's position in the periodic table?

Carbon's position in the periodic table (group 14) signifies that it has four valence electrons, enabling it to form four covalent bonds. This makes carbon versatile and capable of forming a wide variety of complex and stable molecular structures.

How does carbon's versatility contribute to the complexity of life?

Carbon's versatility allows it to form complex molecules such as long polymer chains, closed rings, and molecules with single, double, or triple bonds. This complexity is essential for life, as seen in DNA, which relies on carbon to form the backbone of its nucleotides and carry genetic information.

Why is silicon, despite its ability to form four bonds, not the backbone of life on Earth?

Silicon, while capable of forming four bonds, has its unpaired electrons on a higher energy level, making these bonds weaker and less stable compared to carbon. The carbon-carbon bond is stronger, which is crucial for the structural integrity of organic molecules in living organisms.

What are the top five most abundant elements in the solar system and how do they relate to the human body?

The top five most abundant elements in the solar system are Hydrogen, Helium, Oxygen, Carbon, and Nitrogen. Four out of these five elements (Oxygen, Carbon, Hydrogen, and Nitrogen) are also among the top five elements in the human body, suggesting a correlation between the elements available in the universe and those utilized by life.

Why is carbon-carbon bond strength significant for the stability of organic molecules?

The strength of carbon-carbon bonds (334 kJ/mol) is crucial for the stability of organic molecules because it allows the molecular backbone to remain intact while functional components can break apart and react chemically with other molecules. Weaker bonds, as found in silicon or nitrogen, would compromise the structural integrity of biological molecules.

Could life exist based on elements other than carbon under different environmental conditions?

It is theoretically possible for life to exist based on elements other than carbon, such as silicon or even heavier elements like germanium or lead, under different environmental conditions that are suitable for those elements. However, carbon is the most plausible due to its abundance, versatility, and the strength of its bonds.

How does the concept of organic chemistry relate to the conditions necessary for life?

Organic chemistry, centered around carbon, is critical for life because it involves the formation and reactions of complex carbon-based molecules. The right conditions, such as those on Earth with liquid water as a solvent, allow for the stable existence and interaction of these organic molecules, which are essential for life's processes.

Outlines

00:00

🌿 The Role of Carbon in Life's Chemistry

The first paragraph introduces the central role of carbon in all living organisms on Earth, highlighting its importance in organic chemistry. Despite not being the most abundant or stable element, carbon is a fundamental component of life due to its ability to form complex molecular structures. The paragraph delves into quantum mechanics to explain carbon's versatility in bonding, its capacity to form up to four covalent bonds, and how this leads to a vast array of possible molecular configurations. The discussion also touches on why other elements, such as oxygen, silicon, and nitrogen, are less suitable for life's chemical requirements, setting the stage for the exploration of carbon's unique properties.

05:01

🌟 Carbon's Abundance and Bond Stability in Life

The second paragraph expands on why carbon is the backbone of life by addressing its abundance in the universe and within the human body. It compares carbon to other elements like oxygen, boron, silicon, and nitrogen, discussing their bonding capabilities and availability. The paragraph emphasizes carbon's bond strength, which is crucial for the stability of organic molecules. It explains that while silicon can also form four bonds and is more abundant on Earth, its bonds are weaker due to its electrons being farther from the nucleus. This makes carbon-carbon bonds more stable and better suited for life's complex chemistry. The paragraph concludes by identifying carbon as the most suitable element for life due to its combination of abundance, complexity, and stability.

10:05

🌌 The Possibility of Non-Carbon Life Forms

The third paragraph entertains the possibility of life forms based on elements other than carbon, suggesting that under different environmental conditions, such as those found on extraterrestrial planets, silicon, germanium, tin, or even lead could potentially support life. It acknowledges the rarity of heavier elements and the importance of Earth-like conditions for carbon-based life. The paragraph also speculates about the potential for silicon-based artificial life forms on Earth and emphasizes the importance of organic chemistry for life. It concludes with a recommendation for further study on the topic through a course on Wondrium and an invitation for viewers to subscribe for more content and ask questions.

Keywords

💡Carbon

Carbon is a chemical element with the symbol C and atomic number 6. It is the basis of all known life on Earth, playing a crucial role in organic chemistry due to its ability to form complex molecular structures. In the video, it is highlighted as the central element for life because of its versatility in forming stable bonds and its abundance in the universe. The script mentions that carbon makes up 20% of our body composition, despite being less than 1% of the Earth's atmosphere, oceans, and crust.

💡Organic Chemistry

Organic chemistry is a branch of chemistry that focuses on carbon-based compounds. The video emphasizes the importance of organic chemistry in understanding the complexity of life. It is defined by the script as the study of chemistry involving carbon compounds, which are essential for life's processes.

💡Quantum Mechanics

Quantum mechanics is a fundamental theory in physics that describes how the physical world works at the scale of atoms and subatomic particles. The video uses quantum mechanics to explain why certain electron configurations are more stable, which influences why carbon is favored in forming the complex structures necessary for life.

💡Noble Gases

Noble gases are a group of chemical elements with similar properties, including helium, neon, and argon. They are characterized by having a full valence electron shell, making them chemically inert and stable. The script uses noble gases as an example of the most stable electron configuration, contrasting with carbon's ability to form complex molecules by sharing electrons.

💡Covalent Bonds

Covalent bonds are a type of chemical bond where two atoms share one or more pairs of electrons. The video explains that carbon can form covalent bonds with up to four other atoms, which allows it to create the complex molecular structures necessary for life. This is a key factor in carbon's role as the backbone of organic chemistry.

💡Polymers

Polymers are large molecules composed of repeating structural units. In the context of the video, carbon-based polymers are highlighted for their ability to carry a lot of information, such as in the structure of DNA. The script mentions that carbon can form long, non-repetitive chains of polymers, which are vital for life's complex chemistry.

💡Abundance

Abundance refers to the availability or plentifulness of an element. The video discusses how carbon's abundance in the universe makes it a practical choice for the basis of life. It is mentioned alongside other abundant elements like hydrogen, helium, oxygen, and nitrogen, which are also found in high quantities in the human body.

💡Stability

Stability, in the context of the video, refers to the strength and durability of chemical bonds. Carbon's ability to form strong, stable bonds with other carbon atoms is a key factor in its selection as the backbone of life. The script contrasts carbon's bond strength with that of silicon and nitrogen, which are weaker and thus less suitable for the structural integrity required by biological molecules.

💡Silicon

Silicon is a chemical element with the symbol Si and atomic number 14. It is often compared to carbon due to its ability to form four covalent bonds. However, the video explains that despite silicon's abundance and bond-forming capabilities, its bonds are less stable than carbon's, making it less ideal for the complex and stable molecular structures that life requires.

💡DNA

DNA, or deoxyribonucleic acid, is the molecule that carries the genetic instructions for the development, functioning, and reproduction of all known living organisms. The video uses DNA as an example of a complex carbon-based molecule that carries all the information necessary for life. It highlights the role of carbon in forming the backbone of DNA.

💡Wondrium

Wondrium is an online learning platform that offers a wide range of courses, including one on 'Foundations of Organic Chemistry' mentioned in the video. The platform is endorsed by the video's presenter as a valuable resource for further understanding of the topics discussed, such as why carbon is fundamental to life and the principles of organic chemistry.

Highlights

All life on Earth is based on carbon chemistry, leading to the development of a specific branch of chemistry known as organic chemistry.

Despite carbon not being the most abundant or stable element, it is a fundamental component of life, making up 20% of the human body.

Carbon's ability to form complex molecular structures is crucial for life's chemistry, a concept rooted in quantum mechanics and electron orbital configurations.

Carbon can form a maximum of four bonds with other elements, contributing to its versatility and ability to form stable, complex molecules.

The periodic table's arrangement indicates the maximum number of bonds an element can form, with carbon being in the group that forms the most bonds.

Carbon's capacity to share up to four electrons makes it energetically favorable and stable, unlike noble gases which are already stable due to a complete outer shell.

Life requires elements that can form complex, stable molecules, and carbon, with its multiple bonding capabilities, meets this requirement.

Carbon-based molecules can form various structures like long chains, closed rings, and different types of bonds, offering millions of possible configurations.

DNA, which carries all genetic information, relies on carbon due to its ability to handle the complexity of the four nucleotides that make up its building blocks.

Elements like oxygen, despite its abundance, cannot form complex scaffolds of molecules as effectively as carbon due to its bonding limitations.

Abundance plays a role in why life is carbon-based, as carbon is the fourth most abundant element in the solar system and in the human body.

Silicon, despite its ability to form four bonds and abundance, is not as suitable for life due to its weaker bond strength compared to carbon.

The stability of carbon-carbon bonds (334 kJ/mol) is superior to silicon-silicon bonds (196 kJ/mol), making carbon more ideal for a molecular backbone.

Carbon's combination of abundance, ability to form complex structures, and stable bonds positions it as the best choice for life as we know it.

While carbon is ideal for life on Earth, it does not preclude the possibility of silicon-based life forms under different environmental conditions.

The potential for silicon-based artificial life forms to be created on Earth is suggested, hinting at a future where different elemental bases for life may coexist.

The importance of organic chemistry in the process of life is emphasized, with carbon being central to this process due to its unique properties.

Wondrium offers a course called 'Foundations of Organic Chemistry' that delves into the subject matter covered in the video, providing a deeper understanding of the topic.

Transcripts

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From the tallest Sequoia, to a smartest human, to the most poisonous mushroom, to the tiniest

bacterium…

There is one thing that unites all living things on earth, and that is the fact that

it’s all life is based on carbon chemistry, This element is so important in fact that

it has its own branch of chemistry – organic chemistry.

But carbon is not the most abundant element on earth.

That would be oxygen.

And it is not the most stable, like Helium.

On the surface, it doesn’t appear particularly special.

Yet if we look at our body composition, we find carbon everywhere in our cells.

20% of our body is made up of carbon, but it comprises less than 1% of the mass of the

earth’s atmosphere, oceans and crust.

Why did life go to the trouble of concentrating Carbon 20 fold in our bodies, when other more

abundant elements, like Oxygen and Silicon were available, or even Nitrogen which makes

up 78% of our atmosphere?

The big question is why? We are going to examine that, and we’regoing to trace the logic that nature used

in choosing this all important element - Carbon.

That’s coming up right now…

There are 94 naturally occurring elements on the periodic table.

Why is everything based on carbon and not something else when the choices are so many?

The answer boils down to three things: complexity, abundance and stability.

What do I mean by this?

Let’s start with complexity.

Carbon is able to form the complex molecular structures needed for the complex chemistry

that life requires.

Why is carbon able to do this?

To understand this, we have to look at the foundation of chemistry, which is physics,

particularly quantum mechanics.

Quantum mechanics tells us that some electron orbital configurations are more energetically

favorable than others, making them more stable.

And the most stable configuration of electrons are those of the Noble gases on the far right

side of the periodic table.

These are special elements that have a complete outer shell of electrons.

This is the lowest energy configuration that an atom can have.

This makes them chemically stable because they do not typically need to share, gain,

or lose electrons to form bonds with other atoms to become more stable.

This is also why they are chemically inert, since they do not generally interact with

other atoms to form molecules.

Why are only the Noble gases this way and not other elements?…because they happen

to have the right number of protons to have the right number of electrons to fill their

shell fully.

The driving force behind chemistry is really a hunt to get to the most energetically efficient

state in a system, the state of lowest energy.

And for the most part, this lowest energy state occurs when an atom is able to fill

its outermost shell fully, like the noble elements.

And some atoms can do this by sharing their electrons with other atoms to form what’s

called covalent chemical bonds.

The periodic table of elements is arranged in such a way that we can easily tell by column,

the maximum number of bonds that an element can form with other elements.

Starting from the left column of the table, the first group of atoms can form a maximum

of one bond.

The second column of elements can form 2 bonds.

Third column 3 bonds.

This trend continues up to the fourth column which can form 4 bonds.

After this, the maximum number of bonds decreases, so the fifth column of elements can only form

3 maximum bonds.

Then 2 bonds, one bond, and finally zero bonds for the right most column, which are the noble

elements, which are already the most stable.

What you’ll notice is that Carbon is in the group of elements which can form the maximum

number of bonds.

It has a total of 6 electrons, 4 of which are in its outer shell.

In order fill its outermost shell, it needs 4 more electrons to make 8 like the noble

gas Neon.

So it can share up to 4 additional electrons from other atoms to form covalent bonds, making

it more stable.

This makes Carbon very versatile.

Imagine if Lego bricks could be connected on four sides instead of two, it would make

building things easier.

Each carbon atom can form a strong stable bond with up to 4 other atoms including other

carbon atoms.

This feature of carbon gives it the ability to form complex molecules, which is necessary

for the complex chemical functions that life requires.

Carbon based molecules can form long non-repetitive chains of polymers, they can form closed rings,

and they can form single, double or triple bonds with other elements.

There are millions of possible configurations.

Taken together, this makes Carbon uniquely able to take part in a vast multitude of chemical

processes.

It can easily form long stable polymer chains that can, for example, carry a lot of information.

This is the case for DNA.

DNA after all, carries ALL the information that makes up living things, including us.

And the 4 nucleotides that make up the building blocks of DNA are complex.

Carbon is the backbone partly because it can handle this complexity.

The other elements are not as interesting.

Take for example oxygen with is the most abundant element on earth.

It can form only 2 bonds.

This means that once it bonds with 2 other atoms, it’s done.

It can’t really form interesting scaffolds of complex molecules, like carbon can.

Boron could be interesting because it can form 3 bonds, so it’s molecular structures

could also be fairly complex.

The problem is that it’s extremely rare, so it’s just not very available for life

to have chosen it as its backbone.

This brings us to the second factor that made carbon attractive for life to latch onto,

abundance.

Not only is carbon versatile, it is also abundant.

If we look at the top 5 most abundant elements in our solar system, what we will see is the

following in order of abundance: 1. Hydrogen

2. Helium

3. Oxygen

4. Carvon

5. Nitrogen

Now if we look at the top 5 of elements in

our body, what we will see is the following in order of abundance:

1. Oxygen

2. Carbon 3. Hydrogen 4. Nitrogen

and 5. Calcium - So what we see is that 4 out of the top 5

elements of the solar system are also among the top 5 elements making up the human body.

This give us another clue about why life is based on Carbon.

There is plenty of it in the universe.

It is very abundant.

It’s easier to build something that you have a lot of.

You can’t build a castle if you don’t have enough Lego bricks.

At this point, you might say, if abundance is so important then what about Silicon which

is abundant and can also form 4 bonds, or Nitrogen which forms only 3 bonds, but makes

up 78% of our atmosphere.

This brings us to the third factor in determining the most suitable element that nature chose

for life, stability.

What I mean by this is bond stability.

Let’s look at that.

As I said earlier, the structure of the periodic table is such that as a rule of thumb, all

elements in each column have the same general properties.

Carbon turns out to be the lightest element in group 14 or 4 depending on how you count.

Therefore, we would expect that the sister elements like silicon and germanium would

have similar chemical capabilities.

Silicon is the next lightest element in the row.

Its position on the periodic table tells us that, like Carbon, it also has four valence

electrons.

This means it can also make four covalent bonds.

For every molecule made out of carbon, there can be an analogous molecule with silicon

in its place.

Silicon also happens to be quite abundant on earth.

In fact, there is more silicon on earth than carbon.

It’s just locked in rocks within the earth’s crust.

Chemically, Silicon has 4 unpaired electrons in its outer orbital, just like carbon.

The main difference is silicon has its unpaired electrons farther away from its nucleus, on

its third shell, whereas carbon’s electrons are on its second shell, closer to the nucleus.

This makes Silicon’s electrons more weakly bound to its nucleus.

The consequence of this is that when silicon bonds with other atoms including itself, the

bonds formed are weaker, and thus less stable.

To give you some numbers, the silicon-silicon bond strength is 196kJ/mol.

In contrast, carbon-carbon bonds are stronger at 334 kJ/mol.

This bond strength factor is also a reason Nitrogen is not well suited to be the backbone

of organic chemistry, as its bond strength is roughly half of carbon.

You can’t make a sky scraper with a foundation built from cardboard.

The structural support has to be strong to hold the walls, windows and doors.

Organic molecules have the same need.

The backbone has to be strong enough to withstand the conditions under which other parts of

the molecule break their bonds and react chemically with other molecules.

So the carbon-carbon scaffold needs to remain intact while its functional components break

apart.

A molecular scaffold made from nitrogen or silicon would more easily break apart.

So if we go back now to the periodic table, and look at the first 3 rows of elements.

If we remove all the chemically inert elements, and then remove elements that can’t from

more than 2 bonds, then we remove all the elements that are exceedingly low in abundance,

we end up with Carbon, Nitrogen and Silicon.

Then if we remove those that cannot form strong single bonds to themselves to create a strong

molecular backbone, this leaves pretty much only Carbon as the best choice.

It is uniquely suited for life because of the best combination of abundance, ability

to form complex structures, and stable bonds with other carbon atoms.

Now, having said all that, there is nothing that would preclude silicon-based life forms

from existing on an extraterrestrial planet, if the conditions are right for it.

By this logic, we can also imagine life based on germanium, tin or even super-dense creatures

made of lead.

But we have to keep in mind that as elements get heavier, they tend to be more rare.

So each of these are less plausible than the last.

For example, Germanium is at least five orders of magnitude less abundant than carbon, and

tin is even rarer.

It so happens that the pressures and temperatures on earth works well for life forms that use

liquid water as the solvent, and carbon based molecules that can form a stable backbone

on which biological chemistry can take place.

If it gets too cold, water turns to ice and we’ll have problems with chemical transport.

If it gets too hot, we will get issues with carbon polymer chains breaking too easily.

We may never know for sure, but it's perfectly possible that carbon trumps everything else

except in extreme environments.

But we can’t rule anything out and we need to be open minded about the conditions in

which life could hypothetically occur.

For example, there are lakes of ethane and methane on Titan.

These liquids, like water on earth, could be used as a solvent by a different type of

lifeform.

So at different temperatures and pressures, it is conceivable that a different element

may be more conducive to life.

One of my patreon supporters pointed out that we Carbon life forms may right now be in the

process of creating Silicon artificial life forms.

And this process is accelerating.

This form of life could very likely to exist in the near future right here on earth.

But there is no evidence for life outside of earth.

It could be quite rare in the universe.

So you can have all the various elements available in abundance, but the interactions or chemistry

of these various elements is the critical process needed for life to happen.

That process is organic chemistry.

And for further study, I’d highly recommend a great course I recently watched on Wondrium,

the sponsor of today’s video, called, “Foundations of Organic Chemistry.”

And just as the title implies, it will help you grasp the details and foundations of the

material I covered in this video.

This is a 36 lecture course that takes you on a learning journey from the basics of atoms,

to the formation of the most important organic chemicals, to the mechanisms behind organic

chemical reactions.

The first courses is even called, “Why Carbon?”

It’s taught by professor Ron Davis of Georgetown University, whose lucid explanations makes

this subject relevant and easily graspable.

You’ll many other wonderful courses like this on Wondrium taught by some of the best

educators in the world like Professor Davis.

That’s why I have been a member of Wondrium for a long time, and you’ll even find my

testimonial at the bottom of their home page.

They are offering a free trial right now, so it’s really easy to sign up.

And you can cancel at anytime, so you have nothing to lose, and a lot to gain.

If you click the link in the description, you’ll get a free trial.

So Be sure to take advantage of their free offer.

That link is Wondrium dot com slash arvin.

That’s wondrium.com/arvin.

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for that.

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I’ll see you in the next video my friend.