Skip to content

Are Viruses Necessary?

2019-08-27 · explainer · John · 3:35 · watch on YouTube

Topic: Science & nature · mode: Explainer · tags: self promotion

Sick with a cold, John asks whether viruses are necessary and finds he cannot simply hate them: part of the human genome comes from viruses and placentas evolved from viral proteins; he praises Hank's Journey to the Microcosmos for its sense of awe.

What is said

The parts of the video and what is said in each (★ — how much it matters to the video).

00:00:00 — John's cold prompts the question whether viruses are necessary; how many viruses there are

  • ★★ John has a cold: when he was younger a cold was a slightly annoying background hum, and now it is a borderline catastrophe. (playful) — 00:00:00
  • ★★ John says a teaspoon of water from a healthy river often holds over 400 million viruses. — 00:00:00
  • ★★ John says someone with the flu might have over a hundred trillion flu viruses in their body. (hedged) — 00:00:00

00:00:29 — Humans are part virus: viral DNA in the genome and the viral origin of the placenta; John cannot unambiguously hate viruses

  • ★★ John says there are more viruses on Earth than grains of sand. — 00:00:29 · Earth
  • ★★ John says over 200 viral strains can cause colds, and whichever causes his, there are more of it in his body than stars in the Milky Way. — 00:00:29
  • ★★★ John says that, like all mammals, he is part virus: something like five to eight percent of the human genome comes from viruses. (hedged) — 00:00:29
  • ★★ John explains that viruses cannot replicate on their own, one reason they are often seen as not alive, and rely on the cells they infect to copy themselves. — 00:00:58
  • ★★ John says a virus that infects a sperm or egg puts its DNA into every cell of the resulting organism, which may reuse the viral proteins, as reusing proteins is easier than inventing new ones. — 00:01:27
  • ★★★ John says over a hundred million years ago a small shrew-like creature developed a placenta using proteins from a virus; without it, placentas and humans would not exist as they do. — 00:01:56
  • ★★★ John concludes he cannot unambiguously hate viruses because he is partly a product of them. — 00:01:56
  • ★★ John's second takeaway is that life is weird, really, really weird. — 00:01:56

00:02:26 — Praise for Hank's Journey to the Microcosmos: awe at microscopic life, blurry lines; go watch it; sign-off

  • ★★★ John tells Hank that Journey to the Microcosmos helped him grasp the diversity and ubiquity of life on Earth and is maybe his favorite YouTube channel of all time. (hedged) — 00:02:26 · Journey to the Microcosmos, Hank Green, Earth
  • ★★★ John says not since watching Carl Sagan host Cosmos as a kid has he felt such awe toward the strange universe around us. — 00:02:26 · Journey to the Microcosmos
  • ★★ John says that, zoomed out, we are one solar system among billions in a galaxy among billions of galaxies, while zoomed in a teaspoon of water becomes a universe. — 00:02:26
  • ★★★ John says the microcosmos is especially interesting for defining life or our place in the world because, as Hank said, up close every sharp line turns out to be blurry. — 00:02:55
  • ★★ John notes there are no viruses in Journey to the Microcosmos because viruses are very small even by microscopic standards. — 00:02:55 · Journey to the Microcosmos
  • ★★ John says Hank's show has helped him see the microscopic world as more than a mere threat, which he appreciates. — 00:03:24 · Journey to the Microcosmos, Hank Green
  • ★★ John tells viewers to go watch Journey to the Microcosmos: it's so good. — 00:03:24 · Journey to the Microcosmos

Threads in this video

Where the stories that moved here went next

Mentioned

Central: endogenous retrovirus · Journey to the Microcosmos · placenta · Virus

Also: People: Carl Sagan

Works: Cosmos: A Personal Voyage

Concepts: common cold · DNA · evolution · Influenza · life · microorganism

Places: Earth · Milky Way · Solar System

← Previous: The Amazon isn't "Burning" - It's Being Burned · Next → The Earth Shouldn't Have Oxygen