QUIZ TIME! The Dreaded E-word... So where were we? 2/18/11. Dr. Ben Waggoner BIOL 1400

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1 QUIZ TIME! The Dreaded E-word... Dr. Ben Waggoner BIOL Plants that can conduct water from the soil to all parts of the plant are called. 2. Write down two examples of connective tissue in your own body. 3. An organism that has a mycelium would probably belong to the Kingdom. 4. An organism that contains collagen would probably belong to the Kingdom. 5. So where were we? Fossils have been shown to be the remains of once-living organisms. Some fossils in fact, almost all of them represent life forms that are extinct, no longer existing on Earth. Fossils show that various life forms have appeared and disappeared over the history of the Earth, in some sort of order. In 1831, Capt. Robert FitzRoy of the British Navy was preparing for a threeyear surveying voyage to South America. He was looking for a naturalist for the voyage, and asked around here and there... 1

2 FitzRoy was captain of the ship HMS Beagle, a small ship (about 100 feet long) assigned to chart the treacherous coasts of South America and Tierra del Fuego. A professor at Cambridge University, John Henslow by name, told Capt. FitzRoy about a student of his. This student had just graduated with a bachelor's degree, and he was interested and knowledgeable about biology and geology. He was preparing for a career as a minister in the Anglican Church, but he leaped at the chance to sail around the world... Despite some trouble getting his father s approval, our young hero Charles Darwin was finally allowed to go. HMS Beagle left England on December 27, The Beagle reached South America early in 1832, and spent the next three years traveling up and down the Atlantic and Antarctic coasts. 2

3 Darwin s Voyage... Darwin had the time and resources to take long trips inland (which was just as well, since he was usually seasick aboard ship) He was able to ship specimens and send letters and writings back to England which made him famous before he even returned He later (1845) published a journal of his travels, now known as Voyage of the Beagle. Still a great read. Among many other things, Darwin collected South American fossils including bones of this beast, the extinct glyptodon. Though unusually large, the glyptodon was clearly very similar to a uniquely South American group of mammals: the armadillos. I m not kidding about the pink fairy armadillo (Chlamyphorus truncatus), by the way... but let us move on. This picture shows three of the twenty South American species. (Incidentally, the nine-banded armadillo, which you re familiar with, is a relatively recent migrant into North America it didn t cross the Rio Grande until about 1850, and didn t enter Arkansas until about 1920.) 3

4 2/18/11 And this kept happening! Unique fossil vertebrates of South America turned out to be very similar to living vertebrates that were also unique to South America. For example, this giant skeleton, Mylodon, turned out to be very much like that of the living tree sloths. Skipping over a lot of stuff... After three years of exploring South America, on the way home, the Beagle stopped for food and water at some small islands, named for the Spanish word for tortoises : This wonderful relationship in the same continent between the dead and the living, will, I do not doubt, throw more light on the appearance of organic beings on our earth, and their disappearance from it, than any other class of facts. Voyage of the Beagle, chapter 8 The Galápagos Islands are 600 miles from the nearest land, the South American mainland. They re located right on the equator in the Pacific Ocean. Galápagos. 4

5 The Galápagos Islands are volcanic eruptions still happen to this day, most recently in April 2009 and are, relatively speaking, quite young. Much younger than South America. Congealed lava flow on the Galápagos Islands Galápagos wildlife includes many distinctive and unique forms... including Sula nebouxii, the bluefooted booby. Sula nebouxii isn t unique to the Galápagos it's found on the coasts of mainland South and Central America but many species are unique to the Galápagos... Most Galápagos animals and plants are similar to South American ones, but NOT identical... and found nowhere else in the world. Most Galápagos animals and plants are similar to South American ones, but NOT identical... and found nowhere else in the world. Larus fuliginosus, the Galápagos gull Amblyrhynchus cristatus, the Galápagos marine iguana 5

6 Most Galápagos animals and plants are similar to South American ones, but NOT identical... and found nowhere else in the world. Another unique species Geochelone elephantopus, the Galápagos tortoise gave the islands their name. Opuntia echiops, the Galápagos prickly pear cactus Darwin found that each island and sometimes each mountain peak on the same island has tortoises with different, distinguishable shell shapes. (The map shows Albemarle Island, now called Isabela, in the Galápagos... ) Probably the most famous Galápagos life forms are the finches, a group of seed-eating birds. There are fourteen different species of finch in the islands... Small ground finch, Geospiza fuliginosa 6

7 Not only are different species found on different islands (although they often overlap), but each species has a distinctive way of life (sometimes a very un-finchlike way of life) and each shows adaptations to that way of life. Woodpecker finch Cactospiza pallida Vampire finch Geospiza difficilis Cactus finch Geospiza scandens Large ground finch, Geospiza magnirostris Seeing this gradation and diversity of structure in one small, intimately related group of birds, one might really fancy that from an original paucity of birds in this archipelago, one species had been taken and modified for different ends. Voyage of the Beagle, ch. 17 And back sailed the Beagle... to Australia, across the Indian Ocean to South Africa, and back through the Atlantic, returning to England on October 2, Darwin had his hands full, writing up his discoveries and collaborating with various scientific experts... but he still found time to think about a strange possibility. Maybe, just maybe, biological species weren't fixed they could somehow change over time, over many generations. Down House, near London, where Darwin lived from 1842 until his death in