‘Modern man has never witnessed the eruption of a super volcano, but we know of their devastation. This is Lake Toba, located in North Sumatra, Indonesia. The lake was formed by a super volcano that erupted 74,000 years ago. Keep in mind Lake Toba’s caldera is smaller in comparison to Yellowstone’s magma pocket, but evidence from its last explosion should give you an idea of the kind of devastation we’re talking about.’

The lake shot is replaced by a slide of microscopic organisms.

‘To understand how the history of Lake Toba affected humanity, we turn to Homo sapiens DNA. While most of our species’ DNA is stored in the nuclei of our cells, a small portion can also be found in the mitochondria—the rod-shaped cells responsible for energy production. What’s unique about the mitochondria is that its DNA is passed only from mother to child. This feature allows geneticists to trace the natural lineage and diversity of our population by focusing on mutations present in our genome. By analyzing the rate and distributions of these mutations, scientists are able to detect patterns in the history of humanity’s population growth.

‘With 7 billion people on the planet, scientists expected to find a wide range of genetic diversity. Instead, what they found was something totally unexpected—a bottleneck, or sudden drop in population.’

The African-American Chair of the Physics Department raises a hand. ‘You’re referring to a major catastrophe?’

‘Yes, sir. Something in the history of Homo sapiens decimated our entire species, reducing the number of human beings left on our entire planet to, incredible as it seems, a mere few thousand. The simple and frightening fact is, the DNA of every man, woman, and child living today can be traced back to these few thousand survivors. Now, because mutations in human DNA take place with clock-like regularity, scientists were able to approximate a date when this sudden change occurred.’ She pauses for effect. ‘The bottleneck occurred 74,000 years ago, right after the explosion that formed Lake Toba.’

The representative of English Literature looks pale. ‘Are you saying this … this super volcano wiped out nearly every human being on the planet?’

‘Yes, ma’am. And keep in mind, Lake Toba’s caldera was nowhere near as large as Yellowstone’s monster.’

‘Is Yellowstone dormant? Has it ever erupted before?’

Lauren clicks over to the next image—a fossil embedded in soil and ash.

‘The geological record shows that Yellowstone’s hot spot has been responsible for three major eruptions. The first happened 2.1 million years ago, the second 1.3 million years ago, the most recent 630,000 years ago. Scientists agree that this periodicity of eruptions is likely to continue, meaning the next explosion could occur 100,000 years from now … or, as some geologists fear’—she ignores Professor Laubin’s roll of the eyes—‘very soon.’