The Remarkable Reproduction Rate of Bacteria

One of the world’s fastest-reproducing organisms.

Quite honestly it’s unlikely you’ll ever come across a frilled shark.

Few people do.

You see, they live at great depths in the ocean, and are sometimes referred to as living fossils, although with a mouthful of 300 vicious teeth you might want to avoid calling one that to its face.

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Besides a pretty prehistoric appearance, the frilled shark is also known for having the longest gestation period of any creature on earth, with mothers carrying their young for about 3 1/2 years.

And I thought 9 months felt like a long time!

Compare this rather laid-back reproduction process with a bacterium’s abilities, however, and you’re in for some surprises.

Bacteria are among the fastest reproducing organisms in the world.

Under ideal conditions, for example, one E. coli bacterium becomes two in roughly 30 minutes.

If a human could do that, just one mother could more than populate the whole earth in less than 17 hours.

One saving grace is that bacteria reproduce asexually.

I mean, it’s bad enough knowing you might have all kinds of bacteria slopping around in your gut without also needing to worry about what they might be getting up to down there.

No, fortunately bacteria generally reproduce through a process called binary fission.

In simple terms this means a cell grows to twice its size, then splits into two identical copies.

For a bacterium to remain viable, this division needs to occur at the right time and place, and the process must also ensure that both offspring end up with complete copies of the essential genetic material.

While most bacteria reproduce via binary fission, there are one or two other more unusual propagation methods, one of which is used by the cyanobacterium Stanieria.

It starts out as a tiny spherical cell, then grows to about thirty times its original diameter and “bursts” to release hundreds of little “Mini-Me’s”, each of which then begins the same process all over again.

Twelve years ago, scientists at Cornell University built a device they used to weigh a single cell of E. coli.

Unsurprisingly it was what you might call a featherweight, coming in at 665 femtograms, a femtogram being, well, pretty tiny.

There are ten to the power of fifteen femtograms in one gram – that’s a quadrillion, or 1,000 trillion.

And here’s where it all gets interesting.

As we’ve seen, given the right conditions, a single E. coli bacterium becomes two every 30 minutes, so growth follows a geometric progression, doubling every half hour.

E. coli is facultatively anaerobic, flourishing in places that have no oxygen (such as the lower intestine of warm-blooded animals) and oxygen rich environments, but it does need nutrients to reproduce.

However, if we disregard the fact that its support system would be depleted long before 36 hours were up, what mass of E. coli might be produced from one single bacterium in a day and a half?

Let me tell you.

It would weigh the same as around 600 male African elephants.

I know.

Crazy, right?

We’re talking around 3,000 tonnes of bacteria, all from a single cell.

Fortunately, your lower intestine will run out of nutrients long before it will run out of space, but it’s probably still enough to make you want to reach for the bleach.

Further reading

Bacteria, Growth and Reproduction

Bacterial Reproduction

Binary Fission and other Forms of Reproduction in Bacteria

E. Coli – A Model Organism From Theodor Escherich’s Legacy

Frilled shark

Growth of Bacterial Populations

Is Bleach a Good Disinfectant?

Just How Fast Can Bacteria Grow

Microbial Reproduction

Scientists weigh tiny bacterium

Which animal has the longest pregnancy