Why do humans have a third eyelid? - Dorsa Amir

Discover how evolution and natural selection influence why the human body has vestigial organs— body parts that no longer serve their original purpose. -- You know that little pink thing nestled in the corner of your eye? It’s actually the remnant of a third eyelid. In humans, it’s vestigial, meaning it no longer serves its original purpose. There are several other vestigial structures in the human body, quietly riding along from one of our ancestor species to the next. But why have they stuck around for so long? Dorsa Amir investigates. Lesson by Dorsa Amir, directed by Avi Ofer. Animator's website: https://www.aviofer.com Sign up for our newsletter: http://bit.ly/TEDEdNewsletter Support us on Patreon: http://bit.ly/TEDEdPatreon Follow us on Facebook: http://bit.ly/TEDEdFacebook Find us on Twitter: http://bit.ly/TEDEdTwitter Peep us on Instagram: http://bit.ly/TEDEdInstagram View full lesson: https://ed.ted.com/lessons/why-do-hum... Thank you so much to our patrons for your support! Without you this video would not be possible! Mark Morris, Catherine Sverko, Misaki Sato, Tan YH, Ph.D., Rodrigo Carballo, SookKwan Loong, Bev Millar, Merit Gamertsfelder, Lex Azevedo, Noa Shore, Taylor Hunter, Kyle Nguyen, MJ Tan Mingjie, Cristóbal Moenne, Goh Xiang Ting Diana, Kevin Wong, Dawn Jordan, Yanira Santamaria, Prasanth Mathialagan, Savannah Scheelings, Susan Herder, Samuel Doerle, David Rosario, Dominik Kugelmann, Siamak H, Tracey Tobkin, Dwight Tevuk, Anthony Kudolo, Mrinalini , Yanuar Ashari, Ivan Todorović, Alex Schenkman, Brittiny Elman, Ryohky Araya, Paul Coupe, David Douglass, Ricardo Paredes, Bill Feaver, Eduardo Briceño, Arturo De Leon, Christophe Dessalles, Janie Jackson, Dr Luca Carpinelli, Heather Slater, Yuh Saito, Quentin Le Menez, Mattia Veltri, Fabian Amels, Sandra Tersluisen and PnDAA.