From something as small and complex as a chromosome to something as seemingly simple as the weather, sex determination systems vary significantly across the animal kingdom. Biologist and teacher Aaron Reedy shows us the amazing differences between species when it comes to determination of gender. A quiz, thought provoking question, and links for further study are provided to create a lesson around the 6-minute video. Educators may use the platform to easily "Flip" or create their own lesson for use with their students of any age or level.

From something as small and complex as a chromosome to something as seemingly simple as the weather, sex determination systems vary significantly across the animal kingdom. Biologist and teacher Aaron Reedy shows us the amazing differences between species when it comes to determination of gender.

Sheena Iyengar studies how we make choices -- and how we feel about the choices we make. At TEDGlobal, she talks about both trivial choices (Coke v. Pepsi) and profound ones, and shares her groundbreaking research that has uncovered some surprising attitudes about our decisions. Sheena Iyengar studies how people choose (and what makes us think we're good at it). A quiz, thought provoking question, and links for further study are provided to create a lesson around the 24-minute video. Educators may use the platform to easily "Flip" or create their own lesson for use with their students of any age or level.

TED Video: Leaps and bounds separate that which is ironic and that which many people simply say is ironic. Christopher Warner wants to set the record straight: Something is ironic if and only if it is the exact opposite of what you would expect.

Storyteller and educator Awele Makeba combines performing arts and history to tell a powerful story from the American civil rights movement. A quiz, thought provoking question, and links for further study are provided to create a lesson around the 9-minute video. Educators may use the platform to easily "Flip" or create their own lesson for use with their students of any age or level.

Legendary ocean researcher Sylvia Earle shares astonishing images of the ocean -- and shocking stats about its rapid decline -- as she makes her TED Prize wish: that we will join her in protecting the vital blue heart of the planet. Sylvia Earle has been at the frontier of deep ocean exploration for four decades. She's led more than 50 undersea expeditions, and she's been an equally tireless advocate for our oceans and the creatures who live in them. A quiz, thought provoking question, and links for further study are provided to create a lesson around the 18-minute video. Educators may use the platform to easily "Flip" or create their own lesson for use with their students of any age or level.

Different species often depend on one another. David Gonzales describes the remarkable relationship of the Clark's nutcracker and the whitebark pine, to illustrate the interdependency known as symbiosis. A quiz, thought provoking question, and links for further study are provided to create a lesson around the 2-minute video. Educators may use the platform to easily "Flip" or create their own lesson for use with their students of any age or level.

The world turns on symmetry -- from the spin of subatomic particles to the dizzying beauty of an arabesque. But there's more to it than meets the eye. Here, Oxford mathematician Marcus du Sautoy offers a glimpse of the invisible numbers that marry all symmetrical objects. Oxford's newest science ambassador Marcus du Sautoy is also author of The Times' Sexy Maths column. He'll take you footballing with prime numbers, whopping symmetry groups, higher dimensions and other brow-furrowers. A quiz, thought provoking question, and links for further study are provided to create a lesson around the 18-minute video. Educators may use the platform to easily "Flip" or create their own lesson for use with their students of any age or level.

Photographer James Balog shares new image sequences from the Extreme Ice Survey, a network of time-lapse cameras recording glaciers receding at an alarming rate, some of the most vivid evidence yet of climate change. A quiz, thought provoking question, and links for further study are provided to create a lesson around the 22-minute video. Educators may use the platform to easily "Flip" or create their own lesson for use with their students of any age or level.

At face value, the lines between verbal irony, sarcasm, and compliments can be blurry. After all, the phrase 'That looks nice' could be all three depending on the circumstances. In the final of a three part series on irony, Christopher Warner gets into the irony you may use most often and most casually: verbal irony.

In the developing world, access to incubators is limited by cost and distance, and millions of premature babies die each year. TED Fellow Jane Chen shows an invention that could keep millions of these infants warm -- a design that's safe, portable, low-cost and life-saving. A quiz, thought provoking question, and links for further study are provided to create a lesson around the 5-minute video. Educators may use the platform to easily "Flip" or create their own lesson for use with their students of any age or level.

Will it rain tomorrow? How likely is your favorite team to win the Super Bowl? Questions like these are answered through the mathematics of probability. Watch this artistic visualization of your odds of passing a test if you don't know any of the answers.

Stand by for an animated exploration of the famous Fermi Paradox. Given the vast number of planets in the universe, many much older than Earth, why haven't we yet seen obvious signs of alien life? The potential answers to this question are numerous and intriguing, alarming and hopeful. A quiz, thought provoking question, and links for further study are provided to create a lesson around the 6-minute video. Educators may use the platform to easily "Flip" or create their own lesson for use with their students of any age or level.

Since 1845, Americans have been voting on Tuesdays -- but why? In this humorous talk, Jacob Soboroff shares the history of Election Day and shows how voting on a Tuesday affects voter turnout. A quiz, thought provoking question, and links for further study are provided to create a lesson around the 3-minute video. Educators may use the platform to easily "Flip" or create their own lesson for use with their students of any age or level.

India is fast becoming a superpower, says Shashi Tharoor -- not just through trade and politics, but through "soft" power, its ability to share its culture with the world through food, music, technology, Bollywood. He argues that in the long run it's not the size of the army that matters as much as a country's ability to influence the world's hearts and minds. After a long career at the UN, and a parallel life as a novelist, Shashi Tharoor became a member of India's Parliament. He spent 10 months as India's Minister for External Affairs, building connections between India and the world. A quiz, thought provoking question, and links for further study are provided to create a lesson around the 18-minute video. Educators may use the platform to easily "Flip" or create their own lesson for use with their students of any age or level.

Kevin Allocca is YouTube's trends manager, and he has deep thoughts about silly web video. In this talk from TEDYouth, he shares the 4 reasons a video goes viral. A quiz, thought provoking question, and links for further study are provided to create a lesson around the 7-minute video. Educators may use the platform to easily "Flip" or create their own lesson for use with their students of any age or level.