Discovering Darwin

In this, the final episode of Season 2, Darwin does some island hoping, takes a surprising return trip to Brazil, and on October 2, 1836, finishes his 4 year 9 month journey. In this episode of the podcast we are joined by Dr. Belinda Sly, a evolutionary developmental biologist and colleague of ours, to discuss Darwin, his thoughts about the voyage, and if it had an effect on Darwin's mental health. The final two chapters of the Voyage of the Beagle are unusual in that Darwin's writing style oscillates between dry technical accounts on how coral atolls are formed, and how different plants, insects, and animals naturally colonize these isolated islands in the middle of the ocean with very melodic and romantic descriptions of the landscapes and peoples he encountered on these far away islands. Atolls http://geologylearn.blogspot.com/ One can imagine how disorienting sailors must have been when they first encountered the unusual geological structure of an island atoll. http://geologylearn.blogspot.com/ A ring structure of land that either encompasses a calm marine harbor that may or may not also include an island in the middle, as seen in the Bora Bora atoll above. Darwin proposed that these unique structures came about through two natural process occurring at the same rate. The volcano that rose from the deep ocean floor and erupted to originally form the island would go dormant and begin to erode away.  Once the volcano had cooled, marine corals would begin to colonize the new island in the shallow waters to create the coral reef. Slowly the volcano would subside back into the ocean and concurrently the corals would grow upward and outward at the same rate as the island eroded and sank. http://darwin-online.org.uk/ Darwin was the first to actually propose the correct geological model for atoll formation and he spends many pages of Chapter XX explaining his model. Unfortunately Dr. Josh Adkins was unable to join us on the final episode but you can get your Josh fix by listening to his award-winning podcast The CromCast, a podcast dedicated to weird fiction that also has the occasional Bourbons and Barbarians episodes, a series that entertainingly combine bourbon with old school D&D. The opening and closing theme to Discovering Darwin is "May" by Jared C. Balogh. Interlude music is Remember the Way by Mid Air Machine

"At daylight, Tahiti, an island which must for ever remain classical to the voyager in the South Sea, was in view. At a distance the appearance was not attractive. The luxuriant vegetation of the lower part could not yet be seen, and as the clouds rolled past, the wildest and most precipitous peaks showed themselves towards the centre of the island. As soon as we anchored in Matavai Bay, we were surrounded by canoes. This was our Sunday, but the Monday of Tahiti: if the case had been reversed, we should not have received a single visit; for the injunction not to launch a canoe on the sabbath is rigidly obeyed. After dinner we landed to enjoy all the delights produced by the first impressions of a new country, and that country the charming Tahiti. A crowd of men, women, and children, was collected on the memorable Point Venus, ready to receive us with laughing, merry faces." Chapter XVIII-Voyage of the Beagle  After 1.5 year absence, Sarah, Josh and James return to the podcast to finish Voyage of the Beagle. We left Charles out in the Pacific Ocean, sailing the 3,200 miles from the Galapagos to Tahiti. It took the Beagle nearly a month to cover that distance and the sailing was difficult. Tahiti was a welcome sight. A long and brilliantly-white beach is capped by a margin of green vegetation; and the strip, looking either way, rapidly narrows away in the distance, and sinks beneath the horizon. From the mast-head a wide expanse of smooth water can be seen within the ring. These low hollow coral islands bear no proportion to the vast ocean out of which they abruptly rise; and it seems wonderful, that such weak invaders are not overwhelmed, by the all-powerful and never-tiring waves of that great sea, miscalled the Pacific. An Aerial View Of Tahiti...By Sylvain Grandadam  Darwin enjoyed the hospitality of the native Tahitians and the rich abundance of fruits, roasted bananas and pineapples, which he admitted tasted better than any pineapple cultivated in a hothouse in England.  While in Tahiti, Darwin embarked on the last of his difficult and challenging hikes when he went with two native Tahitians to hike into the valley of Tia-auru. When I lived in Kauai I hiked around the north shore and I imagine the landscape there is not much different from the Tahitian landscape, both are volcanic islands with Kauai being older (5 million years old) than Tahiti (1.6 million years old). View of a valley in Kauai that looks like Tahitian landscape In New Zealand Darwin noted the cultural tradition of the native New Zealanders (Maori) tattooing their lips and areas around their face. We discussed how Darwin recognized the role of fashion in a culture and admitted that his bare un-tattooed face was as unsettling to the Maoris as their inked faces were to him. http://servatius.blogspot.com/2015/10/maori-couple-1880s-with-facial-tattoos.html A wonderful description of Maori traditional tattoos can be found here.

This podcast episode is dedicated to Chapter III from Charles Darwin's Origin of Species. The title of the chapter is Struggle for Existence.  We discussed Thomas Malthus and how his ideas of population growth influenced Charles Darwin. In particular, Malthus noted that human population growth is geometric which is clearly represented by the graph below that shows global human population growth in the last 300+ years.  Human population on earth is currently over 7 billion with the estimates that in the next 50 years we may level off somewhere between 7-16 billion people, which is a large margin of error. The thought is that cultural norms and female education will decrease individual female fertility which will ultimately dampen global population growth. If true and human population stabilizes it will be unusual since humans would be exhibiting self-regulation of their population instead of having external mortality factors (disease or predation) determining population size. Graph summarizing human population growth. Although Malthus was correct in his view of human population growth, his prediction about the rate of food availability being linear was wrong because modern agriculture has also shown a geometric increase in yield/acre by utilizing evolution (artificial selection in breeding newer varieties of crops) and fossil fuels to operate machinery, irrigate crops and manufacture fertilizers, pesticides and herbicides to increase crop yield. This phenomenon has been named the Green Revolution and it began in western cultures at the end of World War II. The graphs below show how increases in yield/acre for two food crops (corn and wheat) and two other crops (cotton and tobacco) have mirrored the geometric increase of human population growth. Increase productivity in selected crops One of the exciting ideas that Darwin introduces in this chapter is the idea of trophic cascades, the interaction between the various organisms in an ecosystem. We discussed Darwin's beautiful example of the complex indirect relationship between cats in a village and the population of clover in the fields. Recently a complex example has come to light when wolves were reintroduced to Yellowstone national park. The reintroduced wolves altered the foraging behavior of elk thereby reducing the elk negative impact on young tree recruitment which increased forest and understory growth. Increase in tree growth along the river banks stabilized the soil and reduced erosion which resulted in improved water quality and river flow.Ultimately the reintroduction of wolves influenced fish communities, beaver abundance and other indirect effects which are documented in detail in a variety of scientific papers which can be found at the Global Trophic Cascades research program website from Oregon State University. The researchers have linked a large number of their original research papers for free download. From Ripple et al. (2014) Science 343 If you do not feel like reading, then we recommend you watch the short but wonderful TED talk by George Monbiot as he describes some of the complex trophic cascades uncovered in different ecosystems. Josh and Sarah brought up the idea of how invasive species can illustrate the importance of predators and disease in controlling population size since many invasive species can dramatically increase their population size when compared to their native population sizes in the land of origin. We mentioned Josh's favorite study species the Hemlock Wooly adelgid (Adelges tsugae),  kudzu (Pueraria montana var. lobata)  and winter creeper, all of which are invasive in the eastern US. Wooly adelgid image from http://www2.ca.uky.edu/ Kudzu image from http://www.forestryimages.org Winter creeper image from http://www.local12.com URL: http://freemusicarchive.org/music/Kevin_MacLeod/Best_of_2014_1461/Broken_Reality Comments: http://freemusicarchive.org/ Curator:

"In the morning (17th) we landed on Chatham Island, which, like the others, rises with a tame and rounded outline, broken here and there by scattered hillocks, the remains of former craters. Nothing could be less inviting than the first appearance. A broken field of black basaltic lava, thrown into the most rugged waves, and crossed by great fissures, is everywhere covered by stunted, sunburnt brushwood, which shows little signs of life. The dry and parched surface, being heated by the noonday sun, gave to the air a close and sultry feeling, like that from a stove: we fancied even that the bushes smelt unpleasantly." Chapter XVII - Voyage of the Beagle From Darwin and the Beagle, A. Moorehead 1969In this podcast Josh, Sarah and James talk about Darwin's visit to the Galapagos Island and how that experience ultimately contributed to Darwin rejecting the notion of the fixity of species and developing his theory of the evolution and the process to create new species.  The Galapagos islands are a chain of volcanic islands that poke out of the Pacific ocean over 500 miles off the coast of Ecuador.  Although many of the islands are relatively close to each other, Darwin was struck by how the plants, insects, birds and reptiles on each of the islands were distinctly different from the other islands. Bartolome Island, Galapagos Islands, Travel ChannelAlthough most people associate Darwin and his experience with the Galapagos finches in developing his theory of evolution, we make the argument that it was the Galapagos tortoises that first intrigued and befuddled Chuck and stimulated him to begin pondering "...that mystery of mysteries—the first appearance of new beings on this earth." In the Voyage Darwin writes- "I have not as yet noticed by far the most remarkable feature in the natural history of this archipelago; it is, that the different islands to a considerable extent are inhabited by a different set of beings. My attention was first called to this fact by the Vice-Governor, Mr. Lawson, declaring that the tortoises differed from the different islands, and that he could with certainty tell from which island any one was brought. I did not for some time pay sufficient attention to this statement, and I had already partially mingled together the collections from two of the islands. I never dreamed that islands, about fifty or sixty miles apart, and most of them in sight of each other, formed of precisely the same rocks, placed under a quite similar climate, rising to a nearly equal height, would have been differently tenanted; but we shall soon see that this is the case." DARWIN RIDING TORTOISE, HEROES SCULPTURE GARDEN, by MARJAN WOUDA www.marjanwouda.co.uk Josh talks about Darwin's experiences with these cyclopean creatures, drinking from their bladder and riding them like a horse, and about recent efforts to determine how many different species of tortoises actually exist and the current conservation efforts to protect them. The image of Darwin riding a tortoise reminded us of the old sketch a friend of Darwin's made showing Charles Darwin riding a beetle. Sarah talked about the marine and terrestrial iguanas found on the islands and how Darwin would throw the marine iguana into the ocean for it to rapidly return to shore wherein Darwin picked it back up by the tail to fling it back in the ocean. Darwin repeated this "experiment" until he was convinced that although the marine iguanas were perfectly adapted to swimming in the oceans they preferred to stay on shore, where it was safe. Looking out to sea - https://www.flickr.com/photos/45325473@N04/page2 We finished the conversation about the role of the Mockingbirds and Finches found on the Galapagos islands in convincing Darwin that different species of the same type of animal could be found on different islands, although the islands themselves were not remarkably different from each other in habitat and geology. In addition, these islands were not significantly different from volcanic islands of Cape Verde Darwin visited 3.5 years earlier off the coast of Africa, and yet the species found in each of these archipelagos were more closely related to their neighboring continents than they were to each other. Sarah told us about her recent guest appearance on  The Common Descent which is an excellent podcast that discusses the diversity of life, past and present. Check it out! The opening and closing theme to Discovering Darwin is "May" by Jared C. Balogh. Interlude music Big Beats Alternative by Sunserarcher http://freemusicarchive.org/music/Sunsearcher/

To celebrate the 186th Anniversary of Charles Darwin setting sail on the HMS Beagle we post a Bonus podcast discussion with Dr. Geoffrey Williams, an economics professor, on the expenses and wealth of Charles Darwin.  Hope you enjoy the conversation! image from Darwin Online

"I climbed up on foot to very near the crest; from the Puna I experienced, I cannot suppose the elevation is less than 8000 to 10000 ft; There was a good deal of snow, which however only remains here in the winter months. The winds in these districts obey very regular laws; every day a fresh breeze blows up the valley & at night, an hour or two after sunset, the air from the cold regions above descends as through a funnel. — This night it blew a gale of wind, & the temperature must have been considerably below the freezing point, for water in a short time became a block of ice. No clothes seemed to oppose any obstacle to the air; I suffered much from the cold, so that I could not sleep, & in the morning rose with my body quite dull & benumbed."  [Voyage of the Beagle, Chapter XVI]In this episode we discuss the various expeditions Charles Darwin organized to explore the Andes mountain range in South America. These adventures are recounted in chapters IX, XII, XV, and XVI in The Voyage of the Beagle. Image from Darwin OnlineWe started our discussion with the Santa Cruz expedition that Darwin and Fitzroy engaged with while the HMS Beagle was grounded for repairs at the mouth of the Santa Cruz river. This 17 day journey occurred from April 18-May 8, 1834 and involved the men dragging three whale-boats upriver hoping to find the source of the river at the base of the Andes mountains. In our discussion James erroneously said the trip was 185 miles but further reading in Fitzroy's account we find the following- "Late on the 4th we returned to our tents, thoroughly tired by a daily succession of hard work, and long walks. At this bivouac we were about one hundred and forty miles, in a straight line, from the estuary of Santa Cruz, or from Weddell Bluff; and about two hundred and forty-five miles distant by the course of the river." [Fitzroy, Narrative pg 356].The men dragged the boats upriver for 14 days until Fitzroy decided it was time to turn back and then it only took them 3 days to return to the HMS Beagle. Sarah discussed the complex geology of the region and the ships artist had come along to make amazing drawings of the scenery.  C. Martens. T. Landseer. BASALT GLEN – RIVER SANTA CRUZ.We scanned the wonderful map that Nora Barlow includes in her edited edition of the Diary of the Voyage of the H.M.S. Beagle and have highlighted the 4 different trips we discussed in this podcast. The Santa Cruz journey is indicated by the red line, Andes 1 trip is the pink loop, the Andes 2 expedition is indicated by the green loop over the Andes and the Andes 3 trip is indicated by the purple line. We discussed on our reliance of the wonderful website called About Darwin which maps in detail the various journey Darwin has during the 5 year voyage. Highly recommend the site, great information. Josh discussed the earthquake Darwin experienced and the state of destruction he observed in Concepcion. This reminded James about plate tectonics and how the west coast of South America resides on the suture line between two major tectonic plates - the Nazca and South American Plates. map from https://www.thoughtco.com/map-of-tectonic-plates-and-their-boundaries-1441098 As Sarah remarked, Darwin did some amazing geologizing while engaged in those 1,000 mile + expeditions through the Andes and valleys of South America.  He created a beautiful cross sectional map that can be found here- Darwin's map.  The opening and closing theme to Discovering Darwin is "May" by Jared C. Balogh. Interlude music is Little glass men - Moon Shadow

"Whilst going on shore, we pulled alongside a canoe with 6 Fuegians. I never saw more miserable creatures; stunted in their growth, their hideous faces bedaubed with white paint & quite naked.— One full aged woman absolutely so, the rain & spray were dripping from her body; their red skins filthy & greasy, their hair entangled, their voices discordant, their gesticulation violent & without any dignity. Viewing such men, one can hardly make oneself believe that they are fellow creatures placed in the same world. [Beagle Diary, February 25, 1834] In this episode we are joined by our esteemed colleague Dr. Jeremy Paden to discuss Darwin, Fitzroy, and other early explorers views of the native peoples of Tierra del Fuego.  As we outlined in episode 1 of this season, Fitzroy had kidnapped four native Tierra del Fuegians with the hopes of converting them to Christianity and ultimately returning them back to their native lands to nucleate the conversion of the "savages" to a live a civilized agrarian life of tubers, legumes, and bible verses. Unfortunately, Boat Memory, one of the natives that Fitzroy had gang pressed into missionary service died from small pox in England but the other three - "Fuegia Basket", "Jemmy Button", and "York Minister" survived their journey to England,  their education therein, and their ultimate return to tip of South America to rejoin their family and friends. Sketches by Fitzroy of his kidnapped victims. Image from Darwin Online. On January 23rd, 1833 the HMS Beagle stopped by Wollya bay (later spelled Woolliah and then Wulaia] to build a outpost for Jemmy, Fuegia and York. Fitzroy and his crew, along with the help of Mr. Matthews, a missionary Englishman, planted crops, built a cabin, and transferred the useless accouterments of "civilization". In Keith Thomson’s book HMS Beagle: The story of Darwin’s Ship he vividly describes the scene and foreshadows the failure of the settlement: “Over the next week the party from the Beagle built a small outpost and finally unloaded all the incredible paraphernalia that had been sent from England by well-wishers, all the Victorian knickknackery that seemed so splendid in London but appeared ridiculously out of place at this remotest end of the world. A seemingly unending pile of soup tureens, chamber pots, wineglasses, and beaver hats was transferred from the boats, while more practical souls set about planting potatoes, beans, root vegetables, lettuce, and cabbage in the gardens”. [pg. 172][Correction] During our retelling the story of the return of the three Fuegians we mixed up the time scale of events. We stated that Mr. Matthwes survived a year at the outpost before he was picked up by Fitzroy but in actuality he only lasted about 2 weeks before he abandoned the missionary effort and left the HMS Beagle to join his brother in New Zealand.  At then end of the podcast we enjoyed a lively discussion on how negatively did Darwin view the natives of Tierra del Fuego? The opening and closing theme to Discovering Darwin is "May" by Jared C. Balogh.  Interlude song - Missionary Man by the Eurythmics

In this episode of we are joined by the historian Dr. Gregg Bocketti (Transylvania University) in a discussion on the cultural and political conditions of South America when Charles Darwin set shore in Brazil and surrounding territories in the 1830's. In 1831, a year before Darwin was to arrive in Rio de Janerio, the emperor Don Pedro I decided to return to Portugal  to help his daughter reclaim the throne of Portugal and left behind his 5 year old son Don Pedro II to be regent of the Kingdom of Brazil.  Because of his weak regency and lacking of ruling control, local strongmen rose in power and resolved their disputes through local civil wars. Pedro II at around 11 years of age. Wikipedia Gregg vividly described the diverse social and cultural life Darwin would have encountered in in Rio de Janerio. At the time that Darwin visited Brazil it was still a country based upon a slave economy, which is clearly evident in the painting below that was created around the time Darwin was visiting the city. John Steinmann, a Swiss artist, lived in Rio de Janeiro between 1825 and 1833. Gregg spoke about the horrific conditions that the slaves had to endure and the various roles slaves played in the Brazilian economy. One of the interesting aspects of slavery in Brazil was that some slaves took on trades and technical trade positions and were able to work on the side to make extra money for themselves which could be used to purchase their freedom. Painting by French painter Jean-Baptiste Debret Follow this link to a story on NPR that gives a vivid account of slavery in Brazil and how they were one of the last countries in the Americas to abolish slavery. http://www.npr.org/sections/parallels/2013/11/12/244563532/photos-reveal-harsh-detail-of-brazils-history-with-slavery Darwin spent a time exploring the countryside of Brazil, Argentina and Chile and on some of those expeditions he would be guided by the local cowboys known as gauchos. Darwin was impressed with the gauchos riding ability and skill in capturing animals with the bolas, a set of heavy balls affixed to the end of ropes and twirled and thrown to entangle the legs of rheas, guanacos or any other small prey they were hunting.

In this episode we discuss the extensive library on the HMS Beagle that was created by Charles Darwin and Robert Fitzroy.  Over 400 books were in the ship's library and the catalog had a heavy emphasis on travel accounts (travelogues), natural history and geology.  We discussed Humboldt and his influence on Darwin and Jeremy told the story about the dragon tree and Darwin's wish to travel the lands of Humboldt to see the same sights as Humboldt. Dragon trees in the canary islands (picture from http://pixdaus.com/canary-islands-dragon-tree-or-drago-tree/items/view/267293/)Here is Humboldt's description of the dragon tree- Although we were acquainted, from the narratives of so many travellers, with the dragon-tree of the garden of Mr. Franqui, we were not the less struck with it's enormous magnitude. We were told, that the trunk of this tree, which is mentioned in several very ancient documents as marking the boundaries of a field, was as gigantic in the fifteenth century, as it is at the present moment. It's height appeared to us to be about 50 or 60 feet; it's circumference near the roots is 45 feet. We could not measure higher, but Sir George Staunton found, that, 10 feet from the ground, the diameter of the trunk is still 12 English feet; which corresponds perfectly with the assertion of Borda, who found it's mean circumference 33 feet 8 inches, French measure. The trunk is divided into a great number of branches, which rise in the form of a candelabrum, and are terminated by tufts of leaves, like the yucca which adorns the valley of Mexico. It is this division, which gives it a very different appearance from that of the palm-tree*. [Humboldt, Alexander von. 1814-1829. Personal narrative of travels to the equinoctial regions of the New Continent, during the years 1799-1804. pgs 144-145] Since 36% of the books in the Beagle library were travelogues, and Darwin's own Voyage of the Beagle is a travelogue, we invited Dr. Jeremy Paden, professor of Spanish Literature at Transylvania University, to discuss with us the role of travelogues in the 16th-19th century as a literature form. During our discussion Jeremy highlighted Thomas Falkner as an influential travelogue writer who wrote  A description of Patagonia, and the adjoining parts of South America (1774).  Falkner described the region of Patagonia, a rugged area at the tip of of South America that also encompassed the Streights of Magellan. Straits of MagellanUnlike the map above which show the Straits of Magellan as a simple channel, the real Straits of Magellan are quite complex and convoluted as seen in the Google map below. Notice the large number of cul-de-sac inlets and waterways that can easy lead you astray. We noted that the tip of South America looks more like a spongiform brain that has mad cow disease as shown in the image below, left image is a brain with Creutzfeldt-Jakob disease and brain on the right is normal brain. James highlighted an unusual book in the collection - Werner's Colours, a small book that includes colour swatches that Darwin used as reference when he was taking notes of specimens. Excerpt from Werner's Colours You can peruse the entire Beagle library at the Darwin Online website. At the end of the podcast we spoke with Dr. Paden about his own research and interest in poetry. James mentioned his appreciation of Jeremy's poem on the liver fluke parasite and we reprint it here- Compulsion Falling from the masticating jaws of ungulatesthat clip the tips of grass blades, the black antescapes this evening’s immolationand the circuitous route of cud-balls,from stomach to teeth, stomach to teeth. Ignorant of why it leaves the sweet feastof slime balls secreted by common land snails,come dusk, the ant climbs again the broad greenleaf to spend the night in sirshasana​,​pinschers clamped ​to the end of a grass blade. Larval lancet liver flukes, encystedin snail-trail droppings, once eaten,​ move to​the ganglion be

In this episode Sarah, Josh and James discuss the opening chapters of Voyage of the Beagle where Darwin recounts the initial months of his voyage that includes an aborted stop at the Canary Islands, a visit to Cape Verde and then his first overland trip in Brazil. James discussed how Darwin spent as much time off the Beagle traveling overland than he did sailing in the Beagle. By Jules de Caudin - Relation complète du naufrage de la frégate La Méduse faisant partie de l'expédition du Sénégal en 1816, by A. Correard, H. Savigny, D'Anglas de Praviel and Paul C.L. Alexandre Rand des Adrets (dit Sander Rang). Reprint 1968 by Jean de Bonnot éditeur., Public Domain, https://commons.wikimedia.org/w/index.php?curid=19330900James talked about the work of the scholar John van Wyhe who scoured through Darwin and Fitzroy’s diaries and journals to reconstruct the day-to-day itinerary for the HMS Beagle during the 5 year voyage and lists location, latitude/longitude coordinates and where Darwin was located – either on ship or on land. When you break down of the 1,740 day voyage you realize Darwin made great efforts to spend time away from the ship. From Darwin’s perspective he almost equally split his time between being at sea, at anchor or traveling on land. Based on the itinerary of the Beagle Darwin spent 580 days at Sea, 566 days at anchor and 594 days away from the Beagle on overland excursions.  Interesting, even when anchored or exploring on land, Darwin would return to sleep on the Beagle which he found to be very comforting.  Darwin spent 1,144 nights on the beagle (65.8% of the trip) whereas he spent 596 nights off ship which is only 34.2% of the trip. Over half (55%) of that time was spent in South America alone.  James discussed how Darwin's diary and notebooks in the first 2 months of the journey included interesting details that were absent in the Voyage. In particular, Josh talked about the ritualized hazing that sailors would inflict on the new crew members when they crossed the equator, a ritual called the line-crossing ceremony. Josh referenced this nice article from the Atlas Obscura website that discusses the odd ritual of hazing as one crosses an imaginary line on the earth's surface. Sarah also talked about the Tropic of Cancer and the Tropic of Capricorn and how the wind patterns associated with those imaginary lines on the earth drove trans-Atlantic slave trade and the conquest of the New World. We focused on the first overland trip that Darwin took when he landed in Brazil. This was the first of many trips that Darwin took while Captain Fitzroy fastidiously checked his charts and maps by reiterately sailing up and down the coast of South America. http://www.mun.ca/biology/scarr/Voyage_of_the_Beagle.jpg As Darwin traveled overland he mentioed many interesting animals and plants he encountered in the jungles of Brazil. One group of animals Darwin became enamored with was planaria (Plathyhelminthes). Interesting, even to this day new species of flatworms are being discovered in Brazil. James pointed out that this group of animals also exhibit great species diversity in the marine habitat where they show a beautiful diversity in colors. Here are just few examples of the amazing color diversity of marine flatworms one can find with a simple google image search. Sarah became obsessed, like Darwin, with bioluminescence. Sarah discussed the amazing evolution of bioluminescence and how it has evolved independently across a number of disparate phyla and kingdoms. Darwin was particularly enamored by a large click beetle that incorporates bioluminescence in mating display. One of our students took a wonderful picture of the same beetle during our Tropical Ecology class to Belize. photo by Kali Mattingly The opening and closing theme to Discovering Darwin is "May" by Jared C. Balogh.  Interlude music http://freemusicarchive.org/music/DubRaJah/Reprise/7_Chitwan