🧠 A Quick Reminder

In the last lesson, we learned something strange:

Even though genes live inside the same body, they don’t always get along.

Sometimes, they fight.

They try to:

• Win

• Copy themselves more

• Beat other genes

But when they fight too much, something bad can happen…

The body gets hurt.

This lesson is all about how that happens.

⏳ What Is Aging?

Let’s start with a big question:

Why do people grow old?

Why don’t we just stay young forever?

Well, one big reason is… gene conflict.

🔧 Genes That Help… Then Hurt

Some genes are like builders. They fix the body when it’s young.

But as we grow older, those same genes might start:

• Overworking

• Breaking things

• Making tiny mistakes

It’s like a tool that works great at first — but later goes too far.

Genes want to stay copied, not to make you live forever.

So once you’ve had children…

Your genes might care less about keeping you young and healthy.

That’s one reason aging happens.

🧪 The Gene Fight Behind Cancer

Now, let’s look at something scarier: cancer.

Cancer is when cells start growing too fast.

But why do cells do that?

Because sometimes, a selfish gene inside the cell says:

“Grow more! Copy me more!”

That gene:

• Ignores rules

• Keeps making copies

• Never stops

This creates a lump — a tumor — that can grow and hurt the body.

So cancer can be seen as:

A gene trying too hard to win the game.

🪞 Strange Changes: Why Bodies Sometimes Look Weird

Gene fights can also make bodies look or work strangely.

For example:

• A baby is born with extra fingers

• A child’s eye doesn’t grow the same as the other

• A brain develops differently

These are not anyone’s “fault.”

They often happen because:

Some genes gave too many instructions,
Or fought with other genes,
Or made changes that didn’t match.

🧬 Selfish Genes Don’t Think Long-Term

Here’s something very important to understand:

Genes don’t “think.”
They don’t care about:

• The future

• The whole body

• Long, healthy lives

They only “care” about getting copied, again and again.

So if doing something helps a gene copy itself now, it may do that…

Even if it hurts the body later.

🧠 Can Gene Conflict Be Good Too?

Yes, sometimes!

A little competition can:

• Keep bad genes quiet

• Let better genes shine

• Make bodies try harder to stay strong

But when the fight gets too big…

The body becomes the loser.

🧠 Recap

✅ Genes can cause problems when they fight
✅ Aging may happen because genes stop helping after a while
✅ Cancer happens when a gene tells cells to grow too much
✅ Some birth changes happen from gene instructions fighting
✅ Genes don’t plan ahead — they just try to copy themselves now