Cell Division (Mitosis and Meiosis)

Have you ever scraped your knee and watched, day by day, as brand new pink skin slowly covered the spot? Or have you ever tried on a pair of pants from last year, only to find they are way too short? It seems like magic, doesn't it. How does your body know how to fix itself. How do you get taller while you sleep. Think about a tiny, hard acorn that can grow into a giant, towering oak tree over many years. What is the secret force that makes all of this happen. It’s me. I am the invisible worker inside every living thing, always busy building, repairing, and creating. I am the reason a cut heals, a plant grows toward the sun, and you become a little bit bigger every single day. I work without you even knowing it, making sure everything is running smoothly. I am the reason you are you, and I am happening inside you right this very second, making sure you are healthy and strong. Can you guess who I am.

Hello. I am Cell Division. For thousands of years, nobody knew I existed. People saw life happening all around them, but how it all worked was a great mystery. Then, one day in the year 1665, a very curious man in England named Robert Hooke decided to look at the world in a new way. He built a microscope, which was a new invention at the time, and he looked at a very thin slice of cork from a tree. What he saw amazed him. The cork was made of thousands of tiny, empty boxes, like a honeycomb. They reminded him of the small rooms, or “cells,” where monks lived, so that’s what he called them. He was the first person to see the building blocks of life. But it wasn't until the 1850s that scientists like Robert Remak in Germany watched me in action. He saw living cells actually splitting in two to make new ones. He realized that every new cell had to come from an old one. I wasn’t magic, I was a process.

I have two very special jobs, and for each one, I do a different kind of dance. My first and most common dance is called Mitosis. You can think of it as my “copy-paste” dance. I perform this dance billions of times a day inside your body to help you grow and heal. When a cell gets old or you need more cells to get bigger, I begin. I carefully make a perfect copy of everything inside that cell, especially the important genetic instructions. Then, like a magician, I split the cell perfectly into two identical twins. A scientist named Walther Flemming was the first person to watch this whole dance from beginning to end in 1882. He was amazed at how organized I was. My other dance is even more special. it’s called Meiosis, and it’s my “mix-it-up” dance. This is how new life is made. Instead of making an exact copy, I take the genetic instructions from two parents and shuffle them all up. This was first described by a scientist named Edouard Van Beneden in 1883. My Meiosis dance is the reason you are a unique mix of your parents, and why you don't look exactly like your brother or sister.

So why does all my dancing matter. I am the reason that life on Earth can continue. I am the engine of growth and the secret to healing. Every living thing, from the biggest blue whale in the ocean to the smallest ant on the sidewalk, depends on me to live. Understanding my two dances, Mitosis and Meiosis, is incredibly important. It helps doctors understand how to heal people when I’m not working correctly, and it helps scientists understand the great, beautiful web of life that connects us all. I am the quiet, constant, and incredible rhythm that keeps the world alive. I am happening in your bones as they grow, in your skin as it mends, and in every leaf of every tree. I am the dance of life itself, and I am so proud to be a part of you.