Cacti are famous for their spine-shaped leaves, their water-retaining tissues, their green stems, and especially for being among the most well-adapted organisms on Earth for dry environments. This episode, we’re joined by Dr. Aly Baumgartner to discuss the diversity of cacti, their unique adaptations for an unusual lifestyle, and their mysterious evolutionary past. In the news: Stone Age jewelry, kelp fossils, long-jawed fish, and early trees. Time markers:Intro & Announcements: 00:00:00News: 00:06:00Main discussion, Part 1: 00:38:25Main discussion, Part 2: 01:25:00Patron question: 02:04:00 Check out our website for this episode’s blog post and more: http://commondescentpodcast.com/ Join us on Patreon to support the podcast and enjoy bonus content: https://www.patreon.com/commondescentpodcast Got a topic you want to hear about? Submit your episode request here: https://commondescentpodcast.com/request-a-topic/ We’re an Audible Affiliate Partner! Use this link for a 30-day free trial to Audible: https://www.audibletrial.com/CommonDescent Lots more ways to connect with us: https://linktr.ee/common_descent The Intro and Outro music is “On the Origin of Species” by Protodome. More music like this at http://ocremix.org. Musical Interludes are "Professor Umlaut" by Kevin MacLeod (incompetech.com). Licensed under Creative Commons: By Attribution 3.0 http://creativecommons.org/licenses/by/3.0/