Why Don't We All Have Cancer?

Summary

The script explores the natural and inevitable process of cell death and renewal in the human body, highlighting the millions of cells that die and are replaced daily. It delves into DNA replication, the potential for mutations leading to cancer, and the body's autocorrect mechanisms that catch most errors. The video also discusses environmental factors contributing to DNA damage and the surprising rarity of cancer given the numerous daily mistakes. Advances in science and technology are presented as our接力 to natural selection in the ongoing battle against diseases like cancer, with a focus on prevention, detection, and treatment improvements.

Takeaways

• 💀 The human body constantly sheds dead cells, with about 5.5 grams of dead skin lost weekly.
• 🌪️ Indoors, a significant portion of the material seen dancing in sunlight is actually dead human skin.
• 🔥 Humans are biological furnaces, converting food energy into movement, breath, thought, and warmth.
• 🤲 The heat from a resting hand is sufficient to power a Stirling engine, demonstrating the body's active cellular processes.
• 🧬 Human DNA replication involves copying three billion nucleotides, a process prone to errors, some of which can be harmful.
• 🧬 DNA mutations can be random, inherited, or environmentally induced, such as by UV radiation.
• 🦒 Giraffes have black tongues due to dark pigmentation that protects against solar radiation.
• 🛡️ The body has biological mechanisms like proofreading and mismatch repair that correct most DNA errors.
• 💊 Despite these mechanisms, cancers still develop due to the accumulation of mutations over time.
• 🧬 Cancer is not a single disease but a collection of 200 different diseases, each with unique characteristics.
• 🌱 Natural selection has less influence on diseases that affect us later in life, as it is more concerned with reproductive success.
• 📈 Modern advancements in science and technology are improving our ability to prevent and control cancer beyond our body's natural defenses.
• 🌐 The Large Hadron Collider's technology has contributed to medical advancements, such as reducing the need for special shields during eye tumor removal.
• 🛑 The fight against cancer is not just a battle but a mutiny, where we are now in control of the direction our 'boats' take.

Q & A

How many cells die in a human body since the beginning of the video?

More than a million cells have died in the human body since the beginning of the video.

What percentage of the material seen indoors, dancing across sunbeams, is dead human skin according to Ohio State University?

According to Ohio State University, 80% of the material seen indoors, dancing across sunbeams, is dead human skin.

How much dead skin does an average person shed off their body every week?

An average person sheds about 5.5 grams of dead skin off their body every week.

What is the biological process that allows the heat from a person's hand to run a Stirling engine?

The biological process that allows the heat from a person's hand to run a Stirling engine is the body acting as a biological furnace, burning food energy to move, breathe, think, and stay warm.

How many mistakes are made during the synthesis of DNA for each daughter cell during cell division?

During the synthesis of DNA for each daughter cell during cell division, enzymes make 120,000 mistakes.

What is the term used to describe a cell that behaves abnormally, stimulates its own growth, and can potentially multiply forever?

A cell that behaves abnormally, stimulates its own growth, and can potentially multiply forever is referred to as cancer.

What are some of the causes of DNA mutations in the human body?

DNA mutations in the human body can occur randomly, be inherited, or be caused by the environment, such as exposure to ultraviolet radiation from the Sun.

Why do giraffes have black tongues?

Giraffes have black tongues because the dark pigmentation protects their tongues from solar radiation while they are hanging out all day.

What is the term used to describe the phenomenon where natural selection has less influence on diseases that affect us later in life?

The term used to describe the phenomenon where natural selection has less influence on diseases that affect us later in life is the 'selection shadow'.

How has modern science, technology, engineering, and mathematics contributed to the fight against cancer?

Modern science, technology, engineering, and mathematics have contributed to the fight against cancer by making progress against late-acting diseases, improving prevention, detection, and treatment methods, and increasing survival rates.

What has been the historical improvement in the survival rate of people diagnosed with cancer over the past 40 years, according to Cancer Research UK?

According to Cancer Research UK, 40 years ago, only one in four people lived ten years or longer after being diagnosed with cancer. Today that number is 2 in 4, and they believe that in twenty years, the statistic could be as high as 3 in 4.

Outlines

00:00

🧬 The Human Body: A Dance of Life and Death

This paragraph delves into the natural process of cellular death and renewal in the human body. It highlights how our bodies are constantly shedding dead skin cells, contributing to the dust in our environment. The video also touches on the living aspect of our bodies, emphasizing the role of cellular activity and division, which is crucial for our survival. The process of DNA replication is discussed, noting the potential for errors that can lead to mutations, some of which may result in cancer. The paragraph introduces the concept of diseases like cancer, which are characterized by abnormal cell growth, and how environmental factors like UV radiation can contribute to genetic damage.

05:01

🦇 The Evolutionary Puzzle of Aging and Cancer

The second paragraph explores the evolutionary concept of the 'selection shadow' and its implications for the prevalence of diseases like cancer in humans. It contrasts the lifespans of mice and bats to illustrate how different environmental pressures can influence the development of age-related diseases. The paragraph also discusses historical life expectancies and how advances in modern medicine and technology have increased human lifespans. It emphasizes the progress made in cancer research and prevention, highlighting the importance of continued efforts to understand and combat this complex group of diseases. The video concludes with a metaphorical reflection on the battle against cancer, suggesting that it is less of a war and more of a collective effort to overcome a mutiny within our own bodies.

Keywords

💡Cell Division

Cell division is the process by which a parent cell divides into two or more daughter cells. It is fundamental to growth, development, and the maintenance of living organisms. In the video, cell division is highlighted as a mind-blowing process that requires copying an exact sequence of three billion nucleotides for each new cell, illustrating the complexity and precision required for life to function.

💡DNA

DNA, or deoxyribonucleic acid, is the hereditary material in humans and almost all other organisms. It contains the genetic instructions used in the development and functioning of all known living organisms. The script discusses how DNA replication during cell division is not perfect, leading to potential mistakes or mutations that can have various outcomes, including the development of cancer.

💡Mutation

A mutation refers to a change in the DNA sequence. Mutations can be caused by DNA copying errors during cell division, environmental factors, or inherited from parents. The video script explains that mutations can lead to abnormal cell behavior, potentially resulting in cancer if they stimulate uncontrolled cell growth and other harmful effects.

💡Cancer

Cancer is a group of diseases characterized by the uncontrolled growth and spread of abnormal cells. The video emphasizes that there are over 200 different types of cancer, each with unique origins and characteristics. It also discusses how environmental factors and genetic mutations can contribute to the development of cancer.

💡Autocorrect

In the context of the video, 'autocorrect' refers to the body's biological mechanisms that function like a proofreading tool, catching and correcting most errors during DNA replication. The script highlights that while these mechanisms are effective, they are not perfect, which is why cancers can still develop.

💡Natural Selection

Natural selection is the process by which certain heritable traits become more common in a population because they confer a selective advantage. The video script suggests that natural selection has limited influence on diseases that affect us later in life, as these diseases do not impact our ability to reproduce and pass on our genes.

💡Selection Shadow

The term 'selection shadow' is used in the script to describe the concept where natural selection has less influence on traits or diseases that manifest later in life, after an organism's role in reproduction has passed. This concept helps explain why age-related diseases, such as many types of cancer, persist in the population.

💡Life Expectancy

Life expectancy is a statistical measure of the average number of years that a person is expected to live, based on the year of their birth. The video script uses life expectancy to discuss historical changes in human lifespans and how improvements in healthcare and living conditions have increased the average lifespan.

💡Environmental Damage

Environmental damage refers to harm caused by external factors, such as exposure to harmful substances or radiation. The video script mentions how exposure to ultraviolet radiation from the sun can cause genetic damage, which may contribute to the development of skin cancer.

💡Genetic Variation

Genetic variation is the presence of different forms or types of a gene in a population. The script discusses how genetic variations can influence an individual's susceptibility to certain diseases, such as cancer, and how these variations can become more common in a population through natural selection.

💡Cancer Research

Cancer research involves the study of all aspects of cancer, from its causes and development to potential treatments and prevention strategies. The video script acknowledges the contributions of organizations like Cancer Research UK in advancing our understanding of cancer and developing new ways to prevent, detect, and treat the disease.

Highlights

Every week, about 5.5 grams of dead skin sheds off of your body.

80% of the material seen indoors, like dancing dust, is dead human skin.

The human body is a biological furnace, converting food into energy for various functions.

The heat from a resting hand can power a Stirling engine, as demonstrated on Grand-Illusions[.com].

Cells divide millions of times a day, with DNA replication requiring the copying of three billion nucleotides.

During cell division, enzymes make 120,000 mistakes, some of which can be harmful or beneficial.

DNA mutations can lead to abnormal cell behavior, potentially resulting in cancer.

Cancer is a term for 200 diseases with various origins and natures but similar abnormal cell growth characteristics.

DNA mutations occur randomly but can also be influenced by environmental factors like UV radiation.

Giraffes have black tongues due to dark pigmentation that protects against solar radiation.

Our bodies have biological mechanisms that correct over 99% of DNA errors, similar to autocorrect on a phone.

Cancer development is influenced by the accumulation of mistakes and mutations over time.

Cancer Research UK has contributed significantly to understanding and combating cancer.

Evidence of the selection shadow suggests that diseases affecting complex multicellular organisms late in life persist.

Humans are living longer today due to advancements in science, technology, and medicine.

40 years ago, only 1 in 4 people lived ten years or longer after a cancer diagnosis; today it's 2 in 4.

Modern advancements like proton beam control from the Large Hadron Collider have improved cancer treatment.

Cancer is not one disease but 200 different types, requiring various cures and prevention methods.

The fight against cancer is a relay race where natural selection has done some work, and now it's humanity's turn.

Transcripts

Hey, Vsauce. Michael here.

Since this video began

more than a million of your cells have

died. It's natural, don't worry.

But you are literally covered with death

Dead stuff. Fingernails, your hair,

the outermost layer of your skin - all made out of dead things.

And you are losing this dead stuff constantly. Every week

about 5.5 grams of dead skin sheds off of your body.

Ohio State University found that 80%

of that material you see indoors, beautifully dancing across sunbeams,

is dead human skin.

But for the most part, you are made out of

living stuff. You are a biological

furnace, burning food energy to move and breathe and

think and stay warm. As you can see on Grand-Illusions[.com], the heat from your own

hand while you sit still

is enough to run a Stirling engine.

Your cells are busy and active and dividing

millions and millions of times every day. In fact, because of that, you shouldn't even

really be called a person.

You should be called a persON

and on and on and on and on and on and on and on... But here's the really

mind-blowing

thing about the mind sustaining process of cell division,

the replication of instructions. DNA for each daughter cell

requires copying an exact sequence

of three billion nucleotides. That's a lot.

Luckily, our bodies are perfect-ly happy to do it but they're not perfect.

Every time a single cell in your body divides, the enzymes that synthesize

your DNA

make 120,000 mistakes.

Some of these mistakes

wind up being beneficial. Some of these mistakes wind up being harmful and

some are just neutral,

they don't make a difference. But if a mistake,

a mutation in a cell's DNA, causes the cell to behave abnormally

and stimulate its own growth, ignore signals to stop,

stimulate the body to give it its own blood supply, potentially

multiply forever and unstick from where it began to spread throughout the body,

it becomes a special type of cell.

We have found 200 diseases with various origins and natures that

fit this description. Despite being different, they often go by the same name:

cancer.

DNA mutations occur randomly in your body

but they can also be inherited or caused by the environment.

For example, exposure to ultraviolet radiation from the Sun

can cause all kinds of damage, including genetic damage.

If little or no skin protection is used, the accumulation of all these types of damage

can be quite dramatic. This man drove a truck

for years, exposing one side of his face to more sunlight

than the other.

And for 15 years this woman worked in a room

that had the same window. A window to her left.

Environmental damage to the body,

whether cancer-causing or not, is serious business.

In fact, giraffes have black tongues because the dark pigmentation protects

their tongues

from solar radiation while they're hanging out all day.

Go back far enough, beyond where sunshine hits, and their tongues are pink.

Given the sheer number of environmental dangers to our DNA

and the sheer number of mistakes our own bodies make with our DNA every day,

it is incredible that we all aren't developing cancers constantly

and immediately after being born. One of the things we have to thank

is our body's own version of autocorrect.

Biological mechanisms, like proofreading and mismatch repair,

catch and correct or stop more than 99% of errors.

We grow old and pass away for many,

many reasons. But when it comes to cancers, our bodies'

own internal autocorrect is like the autocorrect

on your phone. It's pretty good, but it's not perfect. Cancers

still develop, especially after the accumulation of mistakes and mutations

over time. I'm incredibly grateful to Cancer Research UK.

They helped me a lot with this episode, and thanks to work by groups like them,

we are at an accelerating rate finding ways to prevent and control cancer

beyond what our bodies can do alone. I mean, after all, natural selection can

only see so much

because of the selection shadow.

We aren't all the same and if your genetic variations make you and your children

more successful at reproducing,

well, what do you know, your characteristics become more common.

But this phenomenon has a weak influence

here. Later in life, after your role in reproduction and raising offspring to

independence

has passed.

We have found evidence of the selection shadow

at work with mice and bats.

Raised under perfect conditions, with veterinary medicine and safe lives,

mice only live about two to three years.

Whereas bats, with similar sizes and metabolisms, can live for

thirty years or more. The significant difference here is that

unlike mice, bats have had in the wild for millions of years

fewer predators - a smaller chance of dying early

due to extrinsic mortality. They've, on average, had more days for natural selection

to influence. This could be a very good explanation for why diseases that affect

our complex multicellular selves

late in life are still with us.

But wait, why are humans living so long today?

I mean, in the past, but genetically recently, weren't

teenagers considered middle aged?

Not really. Well, it's true that in the past life expectancies were quite

a bit lower, a life expectancy is merely an

average number of years a person was expected to live as soon as they were born.

And in the past, infant mortality was so high

the average was brought down significantly. It's true that in the

early 1600s, here

in England, life expectancy was only 35 years.

But if you made the age of 21... Well,

you could easily expect to live well into your 60s.

Lifespans that go beyond the age of reproduction have

always made sense for humans, because we are intelligent

and social, useful to one another and our children

take a lot of time and guidance to gain independence.

But that just moves the selection shadow ahead. It's still there,

suggesting that, in the end, our bodies might just be

tools our sex cells use to reproduce

and grow up to do it again. Nature and time haven't helped our bodies battle

late acting diseases because a chicken

is just an egg's way of making another egg.

But maybe not for long. Our minds and modern science technology engineering

and mathematics are making progress

against late acting diseases. And when it comes to cancers,

Cancer Research UK points out that 40 years ago

only one in four people lived ten years or longer

after being diagnosed. Today that number is 2 in 4.

And they believe that in only twenty years that statistic could be as high as 3 in 4.

Refrigeration and sanitation are tackling stomach cancers caused by infection,

vaccines are preventing cervical cancer, anti-smoking campaigns and reductions

of obesity and diabetes and the elimination

of cancer-causing chemicals from our everyday lives are giving us an edge.

We learn more every single day. The process

is slow, but steady. Because cancer is not just

one thing. It's unlikely there will ever be a single cure for cancer because

there are two hundred different types

of cancers. But there will be cures and better methods of prevention

and detection. Advances are coming from all over.

For example, what we have learned about controlling proton beams because of the

Large Hadron Collider

has reduced the need for special shields during the removal of eye tumours.

The statistical surprise that cancers aren't more common in our bodies

is a sign that we're involved in a relay race.

Natural selection already did some of the work, now it's our turn.

When we talk about cancer we often use the language of war:

it's a battle, it's a fight. But the challenge

isn't so much a war with winners and losers and surrender

as it is a mutiny. We can't help the fact that we are all at sea.

Natural selection at least gave us boats

but now we are making where those boats go

our decision.

And as always,

thanks for watching.