"Well, welcome to the first lecture of our evolution class." "So today, we're going to try to understand what is evolution and why is it important." "Now, we're going to discuss Darwin's two great ideas." "And then we're going to talk about why the tree of life is important for society and how evolution actually saves lives." "So what is evolution, and why would anybody ask that?" "Well, actually, we ask it because many scientists look at evolution in different ways." "Some think that change must be a heritable change, and some people look at evolution as the origin of new species, new kinds of organisms around the world." "And then finally, people look at evolution in terms of descent with modification." "That is, all about the change in the phenotypes, the appearance of organisms, appearance and DNA." "And so there are many kind of varieties of how people look and study about evolution." "We can think about evolution, evolutionary science being divided into kind of three categories." "First, systematists, ask, what are the units of nature." "systematists go out, they discover new species." "They describe them." "They differentiate them from other organisms." "Population biologists ask, well, is this a population?" "Is this not a population?" "And, how do we look at assemblages of species?" "Then we ask the question." "A big, big question." "Is, what has been the history of life?" "And so systematic biologists are very much involved in trying to piece together the genealogical tree of a life, and we'll talk about that soon." "And then, finally." "And, and it's actually in some ways the most important aspect of studying evolution is how have the properties and why have those properties evolved over time." "And those properties can be behavior, can be physiology, can be the phenotype, can be genetics." "And most evolutionary biologists today, study this third question." "Now, Theodosius Dobzhansky was a world famous population geneticist." "Years ago, in the 30s, he said, nothing in biology makes sense in, except in the light of evolution." "And that's been a kind of a mantra for evolutionary biology ever since." "Now" "Darwin, as all of you well know, took a long, long voyage on the H.M.S. Beagle." "He was out almost five full years." "But the formative time of, of that trip was South America." "So, he came in to the region of Salvador, Brazil today, and that's where he saw his first rain forest." "Then they moved down the coast and out onto the Pampas near Buenos Aires and that's where he saw his first Rheas." "And he saw two different kinds of Rheas, and that became very important." "Then he moved down to the islands down in the south in Tiera De La Fuego and the Falkland Islands, and he moved back and forth there for a number of months, and went through the Beagle channel." "Which was named for the boat, and then up the coast there he saw things like the mocking birds which are very different on some of the different islands." "Actually, the famous Galapagos finches are so difficult to tell out in nature on a particular island, what species you're looking at." "He didn't pay, pay much attention to the, the Galapagos Finches." "But he saw so many new things, and he went inland and did a lot of geology work." "And that also shaped his world view." "And, when he came back, he just, like a lot of us, he set up a home office." "And this home office was in, in the small country village called Down." "And it was there, very soon after the Beagle, that he started hatching all his great ideas." "And two in particular provide this framework of all of biology for comparison and prediction." "And what, it makes what, it makes evolutionary biology extremely important for society." "But he created these notebooks, and these notebooks are phenominal." "So in 1837, he's looking at building phylogenetic trees." "He thinks organisms are related in a geneology that's treelike." "And therefore he said, the affinities of all beings of the same class have sometimes been represented by a great tree." "I believe this simile, largely reflects the truth." "So even in 1837, which is 20 years before the publication of the Origin of Species." "He has, he's starting to map out what that long, long argument for those 20 years is going to be." "And so it's from this tree that we can think about descent with modification." "Then he had another great idea and this came a year or so later in a notebook." "One may say there is a force like a thousan, 100,000 wedges trying to force every kind of adapted structure into the gaps of the oeconomy of nature, or rather forming gaps by thrusting out weaker ones." "And this is his whole argument in a nutshell about adaptation via natural selection, and competition amongst organisms for resources." "Economic resources, i.e. food, nesting places, and so forth." "Now this figure you see on the screen is the only figure in the origin of species, and Darwin put it in there." "Because a tree is very iconic about the history of life." "And it's, it, it's icon of evolution itself, and he was trying to send a message with this tree." "But he got some really cool things in here." "You know, he has things diversifying and then going extinct." "And then some going up to the next level and diversifying still up to the present." "But he was trying to do several things with this." "Show that there's a branching pattern across the history of life and that there's deep time, too." "It's really, really an awesome a diagram to be putting into the Origin of Species." "And no one was thinking in these terms." "Now, phylogenetic trees are very very powerful mechanisms to look at comparison and prediction." "This is a circular tree, and we'll talk about trees in another lecture." "But, on this tree are all sorts of organisms called model organisms." "And they are used extensively." "In medical science and in, in basic biology, molecular biology, developmental biology." "So they include things like the mustard plant, fungus saccharomyces, senor abditus, the roundworm, the famous famous fruit fly drosophila, various arthopods and insects, invertebrates and then bacteria." "And here we are, right here." "This tiny little sprig on the tree of life." "Now, why is this kind of thing important?" "Well, we study all these organisms because we think they help human health." "The systems, the biochemical systems, the developmental systems share similarities with those of us." "Now, if that's the case, it can only be the case because of shared descent with modification." "So we study roundworms and we study Arabidopsis and bacteria because they tell us something about ourselves, and they also help us design drugs, and find ways to thwart disease." "So Descent with Modification is an incredibly important idea." "He didn't devlop it in all the grand things that we have today, but it's the basis for all comparative biology." "It enables us to reconstruct pycogentic trees and talk about similarity across those trees." "And if you can do that, then you have the ability to make predictions." "So something that happens in a fruit fly may be very very important for human health." "And we can, we can make those predictions and we can test them." "But then a tree of life, as I will show you in just a few slides, can help us discover new life forms that have major, major importance for for all of us." "Now, I'm going to give you just some examples of why this is really important for for all of us." "in the late 2000s, 2007, a, a series of Yale graduate, undergraduate students took a trip to Peru for field work." "And they were collecting endophytes." "These are small microorganisms inside plants." "And, they were taking these endophytes and culturing them, when they got back to the lab up in Yale, to find out, what are the biochemical properties of these endophytes." "And they found out that 74% of those endophytes were bioactive." "And here's an example of what they found." "So there's a fungus, tiny tiny little fungus that lives inside a inside plants, and it's called a gliocladium." "And gliocladium is really cool because it also can be nicknamed a myco-diesel." "Myco for fungus, diesel, for diesel fuel." "Because, that little tiny fungus, generates chemicals that are found in our normal diesel fuel." "And they also yield antibiotics, anti cancer drugs, and a host of other bi-products of all of their metabolism, another really good example, here's how the tree of life helps us save lives." "And this is one of the very first trees ever used to show where disease organisms come from, and what they're related to." "So, West Nile Virus erupted in New York City." "It killed a number of people who were who were older and their immune systems were compromised." "And it broke out in birds." "And it killed a ton of birds at our zoos and elsewhere." "And no one knew what this was." "This was an emerging disease, but what they did is they sequenced some of its DNA, and then they built a phylogenetic tree, and they found out that the New York version, a variation of this virus was related to things in Israel," "in Africa, in Italy, and down in East Africa." "Then they began to understand it's etiology and where it came from." "And that had, had broken out in Europe and elsewhere." "And so they were able to identify it, and then we followed this." "It's all across the country now." "And its, its, its pathway all the way across the country has been a tract by phylogenetic trees and using DNA analysis." "Okay, so here's a really cool example." "In Yellowstone National Park are these very large hot springs." "And in these hot springs are, are lots and lots of different kinds of bacteria." "And actually the color, the yellow color around it, are microbial mattes of one kind or another." "And these hot springs have been explored by microbiologists that want to discover new kinds of bacteria." "And in order to do that, they, they take samples and they build phylogenetic trees." "And that way they can identify the kinds of bacteria, and whether they're new." "So on this illustration on the right, all those in red are new bacteria." "Now, this important because in this hot springs was found some years ago a bacterium that is involved in what we call the polymerase chain reaction." "So, it's, it's the way we amplify and duplicate DNA for analysis." "Science basic science analysis." "And lots and lots of clinical analysis." "And that is important because that polymerase inside that bacterium operates at very, very high temperature." "So, we can repu-, replicate the DNA of any organisms using this bacterial nucleus time and time and time again, millions and millions of times." "So, that one little bacterium found in, in Yellowstone National" "Park has generated billions of dollars of economic activity over tons and tons of different kinds of biotech companies." "So, there's take home messages." "First, Darwin had these two really great ideas;" "descent with modification and adaptation via natural selection." "We've talked a little bit about descent with modification and we'll look at that more in upcoming lecture on phylogenetic trees." "And, then we['ll also explore more adaptation via natural selection." "But, a good take home point here is, that all of this work is very important in saving peoples lives." "Evolution saves peoples lives." "That it is not just an arcane science." "We use evolution in our daily lives, in many many ways." "I've given you some examples already." "And we'll see many more examples, in subsequent lectures."