BrainStuff Season 4 Episode 4 What Is The Oldest Living Thing?

What is the oldest living thing? This is an age-old question that has puzzled scientists and the general public alike for centuries. In this episode of BrainStuff, we explore the idea of longevity and what it really means to be the oldest living thing on earth.

To answer this question, we must first clarify what we mean by "living." While the definition of life can be somewhat nebulous, most biologists agree that living things must have a few key characteristics: they must be made up of cells, require energy, respond to stimuli, grow and reproduce.

But even these seemingly straightforward criteria can be tricky to apply. For example, some organisms exist as single cells, while others are multicellular. Some reproduce asexually, while others require sexual reproduction. And some species, like certain types of plants, can clone themselves and technically be considered the same individual over thousands of years.

So when we talk about the oldest living thing, we have to be clear about what we mean by "thing." Do we mean the oldest individual organism, or the oldest species that has persisted over time? Let's start with the former.

One contender for the title of oldest individual organism is a tree in Sweden known as Old Tjikko. This Norway spruce has been estimated to be around 9,550 years old, making it one of the oldest known living things on earth. Old Tjikko was first discovered in the 1950s by a professor of physical geography, who noticed that the tree was growing on a patch of barren land that had recently been exposed by a retreating glacier.

Since then, the tree has been studied extensively, with researchers taking core samples and analyzing the rings to determine its age. While Old Tjikko isn't the tallest or widest tree in the forest, it has survived for millennia by regenerating itself from its roots. In fact, the trunk of the tree may only be a few hundred years old, but the root system beneath it has persisted for millennia, sending up new stems every few hundred years.

But Old Tjikko isn't the only tree vying for the title of oldest living thing. In California, there's a bristlecone pine tree known as Methuselah that has been dated to around 4,849 years old. This tree was discovered in the 1950s by a researcher named Edmund Schulman, who was studying the growth patterns of bristlecone pines in the White Mountains. Methuselah's exact location is kept secret to protect the tree from vandalism, but it is known to be growing in a remote area of the mountains.

While these trees may be impressive in their longevity, they're still just individuals. So what about the oldest species of organism? To answer that question, we have to look at some of the simplest forms of life on earth: bacteria.

One species that has been around for an incredibly long time is cyanobacteria, also known as blue-green algae. This type of bacteria is known for producing oxygen through photosynthesis, and is thought to be responsible for the first photosynthetic activity on earth. Cyanobacteria can be found in almost every ecosystem on the planet, from oceans to soil to fresh water.

While it's difficult to say exactly how long cyanobacteria have been around, fossilized remains of the bacteria have been found in rocks that date back roughly 3.5 billion years. This means that cyanobacteria have been around for almost as long as life itself on earth.

So, what is the oldest living thing on earth? It's difficult to say for sure, as the answer depends on how we define "living" and "thing." But whether it's an individual tree that has been around for thousands of years, or a type of bacteria that has persisted for billions, the natural world never ceases to amaze us with its resilience and adaptability.