The Hazy Evolution of Cannabis

Summary

This video explores the long and complex history of cannabis, from its earliest known use in funeral rituals 2,500 years ago in China, to its domestication around 12,000 years ago on the Tibetan Plateau. It traces the plant’s evolution, its spread across Eurasia, and its dual purposes for hemp and psychoactive properties. The video delves into how cannabis produces THC and other molecules that interact with the human endocannabinoid system, explaining the science behind why cannabis gets people high and how humans have shaped its evolution for millennia.

Takeaways

• 🌄 Cannabis was first used in a funeral ritual 2,500 years ago in western China, where people burned cannabis leaves and inhaled the smoke.
• 🌿 The earliest known domestication of cannabis occurred around 12,000 years ago in China, making it one of the oldest cultivated plants.
• 📜 Cannabis originated about 28 million years ago on the Tibetan Plateau, evolving in steppe environments after the collision of India and Asia.
• 🧬 Cannabis sativa is now considered the only species of cannabis, although it includes multiple lineages, such as those bred for hemp or psychoactive properties.
• 🔬 Genetic analysis has shown that drug-type and hemp-type cannabis diverged around 4,000 years ago, as humans began selectively breeding for different uses.
• 📅 Cannabis spread from its origin across Eurasia, appearing in Europe 6 million years ago and in China 1.2 million years ago.
• 🧪 THC, the primary psychoactive molecule in cannabis, mimics naturally occurring endocannabinoids in animals, influencing mood, appetite, and memory.
• 🦠 Cannabis chemicals have antifungal, antimicrobial, and UV protection properties, which originally helped the plant survive in harsh environments.
• 🌍 Cannabis has a long history with humans, used for both its psychoactive effects and for hemp fibers, reaching Africa by the 13th century and Latin America by the 16th century.
• 🧩 The exact reason why cannabis produces THC and why it gets humans high remains mysterious, possibly a side effect of evolutionary defense mechanisms.

Q & A

What ancient funeral ritual involving cannabis is described in the script?

The script describes a funeral ritual that took place around 2,500 years ago in the mountains of western China. People placed hot stones in wooden containers, covered them with leaves, and burned them, filling the space with smoke. By inhaling the smoke, the attendees altered their mental states, marking the earliest known use of cannabis.

Where and when did the genus Cannabis originate according to recent studies?

Recent studies suggest that the Cannabis genus originated around 28 million years ago during the mid-Oligocene epoch on the Tibetan Plateau. It diverged from its sister genus Humulus, which contains hops, a key ingredient in beer.

How did plate tectonics play a role in the evolution of cannabis?

The formation of the Tibetan Plateau, caused by India colliding with Asia around 35 million years ago, led to the development of open, arid steppe environments where cannabis thrives. This geological shift set the stage for the emergence and spread of cannabis.

When and where did the first fossil traces of cannabis appear?

The first fossil traces of cannabis appeared in Europe around 6 million years ago and in eastern China around 1.2 million years ago. By the time humans arrived, cannabis was already present across many parts of Eurasia.

Why is it difficult to trace the domestication history of cannabis?

The domestication history of cannabis is difficult to trace because its wild ancestor may no longer exist, the plant frequently grows feral, cannabis breeding has often been done in secret due to legal restrictions, and samples are hard to legally collect. Additionally, cannabis has been bred for multiple purposes, like hemp fibers and psychoactive properties, complicating the analysis.

When and where was cannabis domesticated according to genome sequencing studies?

Genome sequencing studies published in 2021 revealed that cannabis was domesticated around 12,000 years ago in what is now China. This makes it one of the earliest known domesticated plants, earlier than crops like wheat and corn.

What genetic divergence occurred around 4,000 years ago in cannabis lineages?

Around 4,000 years ago, cannabis began to be deliberately bred for two different purposes: hemp for fibers and oils, and drug-type cannabis for its psychoactive effects. This resulted in genetic divergence between the two types.

How does cannabis produce its psychoactive effects in humans?

Cannabis produces a molecule called THC (tetrahydrocannabinol), which binds to receptors in the human endocannabinoid system. This system regulates functions like appetite, mood, and memory. THC mimics the body's natural cannabinoids, causing the psychoactive effects of cannabis.

What ecological roles do the chemical compounds produced by cannabis serve?

The chemical compounds produced by cannabis, including THC, serve various ecological roles such as defending the plant against disease with antimicrobial properties, protecting it from UV radiation, and deterring pests with their off-putting taste and disorienting effects.

Why is the effect of cannabis on humans described as an 'accidental quirk of biochemistry'?

The psychoactive effects of cannabis on humans may be an accidental quirk because the plant originally evolved THC and other compounds for ecological defenses, not to interact with human biology. The fact that THC can mimic human cannabinoids is a coincidence in biochemistry.