Biologist Answers Biology Questions From Twitter | Tech Support | WIRED

This video explores biology's most fascinating open questions, showing that even basic concepts like "what is life?" remain unsettled—viruses fail the standard definition yet clearly affect living systems. It highlights how evolution is messy and branching, not a linear march toward humans, as illustrated by transitional fossils like Archaeopteryx and the metabolic demands of our large brains. The program also covers astonishing biological contrasts, such as orchid seeds the size of dust motes versus a 40-pound double coconut, and explains practical mysteries like why grasses grow from their base and how penguin feathers repel water. It touches on real-world applications, including using CRISPR to save clonal Cavendish bananas from disease, while noting that mutations are often misunderstood. Ultimately, the video underscores that biology is full of unanswered questions and that bioethics asks not just whether we can alter DNA, but whether we should.

• ▶ 0:17 Tor reframes the Twitter question "Are viruses alive?" into the deeper question, "What does it mean to be alive?"
• ▶ 0:30 He explains most biologists define life by three criteria: being made of cells, responding to the environment, and reproducing—then shows viruses fail the cell and independent reproduction tests.
• ▶ 0:48 Despite failing that definition, viruses clearly impact living systems, so Tor concludes the definition of life itself remains an open question.
• ▶ 1:04 Succulents are finicky houseplants because they are adapted to extremely dry wild conditions, storing water in their leaves—conditions that are hard to replicate indoors.
• ▶ 1:37 Orchid seeds, like those of the spotted coral root, are as tiny as dust motes, with a single vial containing about one million seeds.
• ▶ 2:01 In contrast, the world's largest seed, the double coconut from the Seychelles, can weigh 40 pounds—about 11 orders of magnitude larger than an orchid seed.
• ▶ 2:35 Darwin's theory of evolution applies to plants just as much as animals.
• ▶ 2:50 Archaeopteryx is a key transitional fossil with both reptile and bird traits—and would have made a messy, biting pet.
• ▶ 5:14 Dogs and foxes belong to different genera and cannot interbreed, unlike dogs and wolves, which can hybridize.

• ▶ 6:25 Biologist Thor Hanson calls the linear evolution cartoon “the most destructive cartoon in the history of science,” emphasizing evolution is messy, complex, and branching rather than a simple progression to humans.

• ▶ 7:38 Human evolution is largely driven by brain size, but brain tissue is metabolically expensive—about 20% of daily calories fuel a brain that is only 2% of body weight—so bigger brains required new behaviors and food sources.

• ▶ 8:32 Regarding mutant double-sized corn kernels, Hanson warns it may not be a mutation at all; plants can respond strangely to disease, bacteria, or fungi, so the cause cannot be determined with certainty.

• ▶ 8:51 CRISPR could help save Cavendish bananas from fungal disease because these bananas are all clones, making them equally vulnerable; CRISPR might reactivate a gene for disease resistance.
• ▶ 10:17 Most plants grow from the tips of their shoots, but grasses grow from the bottom—an adaptation to grazing and lawn mowing.
• ▶ 10:59 Climate change affects wildlife in three ways: move, adapt, or die; it can also disrupt species relationships, as seen in chimpanzees attacking gorillas in Gabon.
• ▶ 12:19 Mutations arise from DNA copying mistakes; most are useless and vanish, but occasional beneficial traits persist and drive evolution, as with blue eyes.
• ▶ 12:18 Extinct species do not naturally come back, but scientists are attempting to recreate some, like the woolly mammoth, using ancient DNA — though it remains far off.
• ▶ 12:05 The number of genetically unique humans is not running out: with 20,000–30,000 genes, billions of DNA base pairs, and variable gene expression, every individual remains distinct.
• ▶ 15:00 Penguin feathers are structurally waterproof rather than simply ice-proof; they trap air pockets and push against water’s surface tension, though biologists still aren’t certain exactly how it works.
• ▶ 15:45 Top unsolved mysteries include the human genome—where the DNA sequence alone isn’t a recipe book—and everyday puzzles like why we yawn.
• ▶ 17:46 Bioethics means asking not just whether we can alter DNA or combine species, but whether we should.

• ▶ 0:00 Introduction and Are Viruses Alive? (0:00 - 1:04) - Tor opens with a joke and tackles whether viruses count as living things.
• ▶ 1:04 Succulents and Seeds (1:04 - 2:35) - Why succulents are fussy, and how seeds range from orchid dust to giant double coconuts.
• ▶ 2:35 Evolution in Animals and Plants (2:35 - 5:43) - Darwin’s theory applies to plants, Archaeopteryx as a pet, identifying deer bones, and dog–fox crossbreeding.
• ▶ 5:43 From Fish to Humans: Evolution and Mutant Corn (5:43 - 8:51) - How fish could walk on land, where human evolution may head, and what makes mutant corn kernels larger.
• ▶ 8:51 Banana CRISPR, Plant Growth, and Climate Change (8:51 - 12:19) - Can CRISPR save bananas, plus how plants grow and how climate change affects wildlife.
• ▶ 12:19 Genetics, Extinction, and Human Diversity (12:19 - 14:57) - Blue-eye mutations, de-extinction, why monkeys still exist, and the finite pool of unique human genomes.
• ▶ 14:57 Penguin Feathers, Unsolved Mysteries, and Bioethics (14:57 - 18:24) - Penguin feather waterproofing, favorite unsolved biology mysteries, Darwin’s discovery process, and bioethics.