WEBVTT 1 00:00:00.000 --> 00:00:02.640 Okay, I think it's time we should start. 2 00:00:03.080 --> 00:00:05.360 So good afternoon, ladies and gentlemen. 3 00:00:05.680 --> 00:00:07.220 I'm Chris Burrell. 4 00:00:07.320 --> 00:00:10.820 I'd like to welcome you to this special session this afternoon 5 00:00:10.820 --> 00:00:14.740 discussing the origins of life, the evolution of life. 6 00:00:15.400 --> 00:00:18.880 These are questions that civilizations have grappled with, 7 00:00:19.060 --> 00:00:20.260 that have pondered. 8 00:00:20.820 --> 00:00:22.260 Where have we come from? 9 00:00:22.980 --> 00:00:24.420 How did it all start? 10 00:00:24.660 --> 00:00:26.140 How did we reach this point? 11 00:00:26.140 --> 00:00:30.320 And each civilization has developed its own account, 12 00:00:30.500 --> 00:00:32.760 its own answers to this. 13 00:00:32.960 --> 00:00:35.000 The ancient Greeks had answers. 14 00:00:35.240 --> 00:00:37.960 The Nordic civilizations had answers. 15 00:00:38.740 --> 00:00:40.180 The dream time of the Aborigines. 16 00:00:41.000 --> 00:00:43.320 And, of course, the main religions of the Middle East 17 00:00:43.320 --> 00:00:45.600 all had their answers to this. 18 00:00:46.480 --> 00:00:48.960 In the past three decades, 19 00:00:49.060 --> 00:00:53.180 we've seen an extraordinary expansion of scientific capacity 20 00:00:53.180 --> 00:00:54.720 to examine this. 21 00:00:54.720 --> 00:00:59.200 In astronomy, organic chemistry, in the biological sciences. 22 00:01:00.740 --> 00:01:02.200 And there's been great progress 23 00:01:02.200 --> 00:01:05.900 to peel away more of the layers of the onion 24 00:01:05.900 --> 00:01:08.880 in the quest for trying to understand 25 00:01:08.880 --> 00:01:12.640 this intriguing and scary sort of question. 26 00:01:14.020 --> 00:01:17.580 Well, I said this is a special session. 27 00:01:18.080 --> 00:01:22.440 The last few days, we've been hearing Antonio Lascano 28 00:01:22.440 --> 00:01:23.880 in many of the sessions. 29 00:01:24.720 --> 00:01:27.440 He tells me now that he's increasingly recognized 30 00:01:27.440 --> 00:01:29.320 when he walks the streets of Adelaide. 31 00:01:29.440 --> 00:01:31.820 Everyone has recognized him. 32 00:01:31.920 --> 00:01:34.680 We've appreciated his scientific breadth, 33 00:01:34.920 --> 00:01:36.280 his wisdom, his humor. 34 00:01:37.560 --> 00:01:39.580 But this afternoon, we're to hear him lecture 35 00:01:39.580 --> 00:01:40.960 on his personal area, 36 00:01:41.180 --> 00:01:44.380 where he's an absolute international leader. 37 00:01:44.860 --> 00:01:47.400 He's a professor 38 00:01:47.400 --> 00:01:50.200 at the National Independent University of Mexico. 39 00:01:50.780 --> 00:01:54.020 He's the president of the International Society 40 00:01:54.020 --> 00:01:54.700 for the State. 41 00:01:54.720 --> 00:01:54.860 He's a professor at the National Institute 42 00:01:54.860 --> 00:01:55.940 for the Study of the Origin of Life. 43 00:01:56.580 --> 00:02:01.520 He's also a researcher into the chemical basis 44 00:02:01.520 --> 00:02:03.180 for the origins of life. 45 00:02:03.360 --> 00:02:09.180 He's an educator, a scientific journalist, and a teacher, 46 00:02:09.760 --> 00:02:14.780 a writer of textbooks for schools and the public, 47 00:02:14.980 --> 00:02:15.800 for the general public. 48 00:02:16.360 --> 00:02:18.700 So, ladies and gentlemen, we're privileged 49 00:02:19.420 --> 00:02:21.940 to hear Antonio Lascano on this topic. 50 00:02:22.360 --> 00:02:23.080 Thank you. 51 00:02:26.200 --> 00:02:28.220 Thank you very much, Chris, for the presentation. 52 00:02:28.440 --> 00:02:30.100 Ladies and gentlemen, thank you very much. 53 00:02:30.300 --> 00:02:33.280 I have to say that for me it's an absolute privilege 54 00:02:33.280 --> 00:02:36.500 to be back in Australia, to be here in this hall, 55 00:02:36.640 --> 00:02:40.840 and to have the chance to share with you some of my ideas 56 00:02:40.840 --> 00:02:44.940 on the origins of life, which I decided was good to put 57 00:02:44.940 --> 00:02:47.140 in the context of evolutionary theory, 58 00:02:47.260 --> 00:02:49.620 because this being a festival of ideas, 59 00:02:49.960 --> 00:02:53.840 one should underline that the idea of evolution is one 60 00:02:53.840 --> 00:02:54.600 of the greatest, 61 00:02:54.720 --> 00:02:56.320 most important intellectual achievements 62 00:02:56.940 --> 00:02:57.900 of Western civilization. 63 00:02:58.360 --> 00:03:01.500 And from there it's spread worldwide in a way 64 00:03:01.500 --> 00:03:03.040 that it's absolutely amazing. 65 00:03:03.540 --> 00:03:06.900 One thing that has to be said right ahead is 66 00:03:06.900 --> 00:03:09.620 that whenever we think about evolution, the name, 67 00:03:09.700 --> 00:03:12.340 the great name that comes into mind is that of Charles Darwin. 68 00:03:12.760 --> 00:03:18.180 But one should be very much reminded that, in fact, 69 00:03:18.400 --> 00:03:21.620 the idea of evolution is older than Charles Darwin, 70 00:03:21.740 --> 00:03:23.380 is older than the origin of species. 71 00:03:23.380 --> 00:03:28.140 In fact, there is a lengthy chronology of the idea of change 72 00:03:28.140 --> 00:03:32.440 in nature that started not among biologists, but, in fact, 73 00:03:32.460 --> 00:03:33.920 it started among astronomers. 74 00:03:34.220 --> 00:03:37.760 When Kant in 1786 proposed the idea 75 00:03:38.500 --> 00:03:41.780 that the solar system itself was the outcome of the collapse 76 00:03:41.780 --> 00:03:46.280 of a nebula of interstellar gas that somehow gave rise 77 00:03:46.280 --> 00:03:47.620 to the sun and the earth. 78 00:03:47.800 --> 00:03:50.800 And later on this idea was actually put 79 00:03:50.800 --> 00:03:53.360 in mathematical terms by the Marquis de Laplace, 80 00:03:53.380 --> 00:03:57.020 who made that very famous remark when Napoleon told him, 81 00:03:57.080 --> 00:04:00.200 I don't see the word God mentioned in your book. 82 00:04:00.340 --> 00:04:03.260 And the answer was, sir, this is a hypothesis. 83 00:04:03.320 --> 00:04:06.480 I do not need to explain the origin of the solar system. 84 00:04:06.920 --> 00:04:09.900 But the idea of evolution was already in science. 85 00:04:10.220 --> 00:04:15.660 And then, of course, we know of Darwin and his publication 86 00:04:15.660 --> 00:04:18.160 in 1859 of the origin of species. 87 00:04:18.380 --> 00:04:21.940 But it was preceded, in fact, 50 years by the work 88 00:04:21.940 --> 00:04:23.360 of Jean-Baptiste Delors. 89 00:04:23.360 --> 00:04:25.960 And he was the first to write a book called La philosophie 90 00:04:25.960 --> 00:04:28.800 zoologique, in which also the idea of evolution, 91 00:04:28.980 --> 00:04:30.840 transformation of a species was proposed. 92 00:04:31.360 --> 00:04:35.360 Lyell, who was a professor of Darwin, spoke about the evolution 93 00:04:35.360 --> 00:04:37.640 of the surface of the earth. 94 00:04:38.000 --> 00:04:39.820 Sadiq Karnot and Thomson spoke 95 00:04:39.820 --> 00:04:43.020 about how you can have a system that is isolated 96 00:04:43.020 --> 00:04:47.580 in thermodynamically, not able to exchange matter and energy 97 00:04:47.580 --> 00:04:51.320 with the surroundings, and that goes to increase entropy, 98 00:04:51.540 --> 00:04:52.240 to increase disorder. 99 00:04:52.580 --> 00:04:53.340 So here we have a book called La philosophie zoologique, 100 00:04:53.360 --> 00:04:55.600 and we have the idea of time in thermodynamics, 101 00:04:55.740 --> 00:04:57.600 the idea of evolutionary thermodynamics. 102 00:04:57.820 --> 00:05:00.260 Spencer was writing of language evolution. 103 00:05:00.700 --> 00:05:04.160 And Malthus, which some of my more leftist friends don't 104 00:05:04.160 --> 00:05:07.940 like to very much, was actually speaking about evolution 105 00:05:07.940 --> 00:05:09.200 of human populations. 106 00:05:09.700 --> 00:05:12.740 Renan in France was speaking about the evolution of religions. 107 00:05:13.240 --> 00:05:16.380 Marx and Engels spoke about socio-economical evolution, 108 00:05:16.620 --> 00:05:19.260 the evolution of productive systems. 109 00:05:19.520 --> 00:05:23.340 So what we really see is that the 19th century is the time 110 00:05:23.340 --> 00:05:27.220 in which the idea of change, of evolution, of modifications 111 00:05:27.220 --> 00:05:30.600 in time becomes deeply ingrained in Western culture. 112 00:05:30.820 --> 00:05:36.020 In this sense, Charles Darwin should be seen not as the starter 113 00:05:36.020 --> 00:05:39.300 of the idea of evolution, but rather as the culmination 114 00:05:39.300 --> 00:05:41.900 of 19th century thoughts on evolution. 115 00:05:42.560 --> 00:05:46.280 Now, by one of those extraordinary things 116 00:05:46.280 --> 00:05:49.240 that happened in history, as I already mentioned, 117 00:05:49.460 --> 00:05:53.320 Jean-Baptiste de Lamarck published in 1809 his book, 118 00:05:52.740 --> 00:05:52.800 The! 119 00:05:53.320 --> 00:05:55.080 La philosophie zoologique. 120 00:05:55.160 --> 00:05:57.940 And in a way, this book became the birth certificate 121 00:05:57.940 --> 00:06:01.520 of Charles Darwin, who was born precisely on 1809, 122 00:06:01.680 --> 00:06:07.280 and who was a self, liked to self-describe himself as, 123 00:06:07.300 --> 00:06:09.260 in fact, a follower of Lamarck. 124 00:06:09.380 --> 00:06:11.420 Now, whenever we think about Darwin, 125 00:06:11.540 --> 00:06:14.640 we think about this very venerable English gentleman, 126 00:06:15.040 --> 00:06:18.060 a member of the rural gentry that came 127 00:06:18.060 --> 00:06:21.220 from a very distinguished family and changed forever the way we 128 00:06:21.220 --> 00:06:23.000 look at life, the way we look at ourselves. 129 00:06:23.320 --> 00:06:27.880 But the fact is that we shouldn't forget that Darwin once was a very young fellow. 130 00:06:28.060 --> 00:06:30.780 And when he was a young fellow, he didn't happen 131 00:06:30.780 --> 00:06:35.340 to be a very distinguished student, so much, in fact, that his family, 132 00:06:35.480 --> 00:06:39.100 his father especially, had very deep concerns about the family reputation 133 00:06:39.640 --> 00:06:41.680 because of his very poor achievements in school. 134 00:06:42.000 --> 00:06:46.920 Now, Darwin came from a family that, on the father's side, 135 00:06:47.080 --> 00:06:52.760 had very, very distinguished physicians, especially his grandfather, Erasmus Darwin, 136 00:06:52.760 --> 00:06:54.960 who was a larger-than-life figure. 137 00:06:56.220 --> 00:07:00.460 He developed a number of very interesting ideas on therapeutics, 138 00:07:00.480 --> 00:07:05.920 on the use of electrical discharges to cure a number of ailments, so much to the point 139 00:07:05.920 --> 00:07:11.020 that if you read the dedication of Frankenstein by Mary Watson Crapshailey, 140 00:07:11.200 --> 00:07:16.060 you will find out that it is dedicated precisely to Dr. Darwin, 141 00:07:16.580 --> 00:07:20.880 whose researchers have demonstrated the truth of what is described in this book. 142 00:07:21.000 --> 00:07:22.740 He made a tremendous impact. 143 00:07:22.760 --> 00:07:23.980 He made a tremendous impact in English society. 144 00:07:24.520 --> 00:07:28.900 His son, Robert Darwin, who was a very stern gentleman, 145 00:07:29.880 --> 00:07:33.340 he was an Englishman, he was very fond of gardening, of course, 146 00:07:33.480 --> 00:07:36.180 but he was very stern with his children. 147 00:07:36.440 --> 00:07:41.680 And he finally decided that both Charles Darwin and Erasmus, his brother, 148 00:07:41.820 --> 00:07:45.560 should be sent to the best possible medical school in the United Kingdom. 149 00:07:45.760 --> 00:07:48.580 So they were sent to the Edinburgh School of Medicine, 150 00:07:48.840 --> 00:07:52.600 where one of the things that was, for me, very natural, 151 00:07:52.760 --> 00:07:54.260 not for my American colleagues, 152 00:07:54.540 --> 00:07:58.420 is that you didn't have to be ordained to be a teacher in that university. 153 00:07:59.100 --> 00:08:01.140 Charles Darwin went there with his brother. 154 00:08:01.360 --> 00:08:03.540 He was there only for six months or so, 155 00:08:03.680 --> 00:08:06.500 and we know exactly why he left medical school. 156 00:08:06.780 --> 00:08:10.380 First of all, he could not tolerate the idea of blood. 157 00:08:10.600 --> 00:08:16.020 The idea of smelling blood, of looking blood, made him absolutely ill. 158 00:08:16.520 --> 00:08:20.960 Secondly, he could not cope with the weather in Edinburgh. 159 00:08:21.300 --> 00:08:22.740 Lovely people, but horrible. 160 00:08:22.760 --> 00:08:23.160 Horrible weather. 161 00:08:23.400 --> 00:08:26.160 And thirdly, he said, 162 00:08:26.260 --> 00:08:30.900 I cannot accept the idea of getting up at five in the morning, 163 00:08:31.120 --> 00:08:34.400 have a Scottish breakfast, and then go to lectures. 164 00:08:34.620 --> 00:08:37.260 So he left school, and the family decided, 165 00:08:37.500 --> 00:08:41.020 well, if you're not good as a physician, you might as well be good as a minister. 166 00:08:41.280 --> 00:08:43.540 So he was sent to Cambridge to study divinity. 167 00:08:43.840 --> 00:08:47.000 He was not exactly what you would call an outstanding scientist. 168 00:08:47.300 --> 00:08:50.060 And then, thanks to family connection and family money, 169 00:08:50.220 --> 00:08:51.980 he got a position as a, 170 00:08:52.620 --> 00:08:53.940 naturalist in the Beagle, 171 00:08:54.020 --> 00:08:56.520 under the leadership of Captain Fitzroy. 172 00:08:56.860 --> 00:09:02.180 Now, we know exactly what Darwin's feelings were when he boarded the Beagle, 173 00:09:02.300 --> 00:09:06.240 because he wrote on the very first day in his diary, 174 00:09:07.120 --> 00:09:12.400 this place is crowded, it's very smelly, it moves a lot, it's very noisy. 175 00:09:12.420 --> 00:09:16.420 I cannot see how I can tolerate being in this boat for five years. 176 00:09:16.600 --> 00:09:19.760 And the boat was still tied up to the piers of Plymouth. 177 00:09:20.780 --> 00:09:21.740 He had... 178 00:09:21.980 --> 00:09:24.040 All the elements to be a failure, 179 00:09:24.220 --> 00:09:27.760 but then, with his extraordinary powers of observation, 180 00:09:28.080 --> 00:09:33.680 with an extraordinary boiling brain in which everything was being sucked in, 181 00:09:33.780 --> 00:09:35.320 connected, and so on, 182 00:09:35.360 --> 00:09:38.160 he finally came back to England, went back to England, 183 00:09:38.320 --> 00:09:41.460 decided that London was not the place for him to be, 184 00:09:41.600 --> 00:09:44.260 moved into Down, he married his cousin, 185 00:09:44.380 --> 00:09:48.200 which is something that always is prone to jokes in Mexico, I have to say. 186 00:09:48.340 --> 00:09:50.820 He married his cousin and settled there, 187 00:09:50.900 --> 00:09:51.560 and became... 188 00:09:51.980 --> 00:09:53.700 In many ways, the reluctant revolutionary. 189 00:09:54.700 --> 00:09:59.020 Darwin, for me, is the best example of how we should not ever have a prejudice 190 00:09:59.680 --> 00:10:03.780 about the men and women that can change life, that can change society. 191 00:10:04.260 --> 00:10:07.360 He was the less outstanding revolutionary, 192 00:10:07.760 --> 00:10:10.800 and nevertheless, he changed forever the way we see ourselves 193 00:10:10.800 --> 00:10:12.860 and the way we see life on Earth. 194 00:10:13.180 --> 00:10:17.920 And of course, all of you know that after much pressure from his friends, 195 00:10:18.060 --> 00:10:20.580 after receiving the letter from Wallace, 196 00:10:20.800 --> 00:10:21.920 who came out with the similar... 197 00:10:21.980 --> 00:10:23.400 idea on natural selection, 198 00:10:23.680 --> 00:10:27.980 he published in 1859 the famous Origin of Species, 199 00:10:28.140 --> 00:10:31.540 and as one of his peers remarked, 200 00:10:31.540 --> 00:10:33.980 you might have as well published a book on pigeons, 201 00:10:34.120 --> 00:10:39.580 because the book is full of examples taken from how you can raise pigeons, 202 00:10:39.680 --> 00:10:41.880 or horses, or sheep, or cows, 203 00:10:41.980 --> 00:10:45.880 and select features that you find interesting for different purposes. 204 00:10:46.200 --> 00:10:51.640 The basic idea, however, behind the Origin of Species is a very simple one. 205 00:10:51.980 --> 00:10:56.420 It's the fact that you can understand the unity and diversity of life 206 00:10:56.420 --> 00:11:00.420 thanks to a common origin and to the mechanism of natural selection. 207 00:11:00.720 --> 00:11:03.380 It's a very simple but a very powerful idea. 208 00:11:03.680 --> 00:11:09.120 So simple, so powerful that Huxley, one of his best friends, once said, 209 00:11:09.700 --> 00:11:12.740 it's a pity that idea didn't occur to me. 210 00:11:12.820 --> 00:11:16.440 I think it's the best praise one can have for a colleague, for a friend. 211 00:11:16.520 --> 00:11:21.440 Such a simple idea, and he was brewing it in his mind for a number of years. 212 00:11:21.980 --> 00:11:24.360 Now, if you read the Origin of Species, 213 00:11:24.480 --> 00:11:28.160 you will find that at some parts it's very dense, it's full of detail, 214 00:11:28.640 --> 00:11:31.100 it can be a little bit complicated to enjoy, 215 00:11:31.340 --> 00:11:36.040 but one part of his writings that I enjoy enormously is reading his notebooks. 216 00:11:36.360 --> 00:11:41.200 And I like them because there you can see the way his mind was actually working. 217 00:11:41.480 --> 00:11:43.900 This particular page, I'm very fond of, 218 00:11:44.020 --> 00:11:46.700 for a very simple reason, it says, I think. 219 00:11:46.980 --> 00:11:51.300 And this I think summarizes in a very simple phrase, 220 00:11:51.440 --> 00:11:51.960 I think. 221 00:11:51.980 --> 00:11:56.020 The doubts, the certainties, the question that he was undergoing, 222 00:11:56.340 --> 00:12:01.000 and then he draws this hypothetical phylogenetic tree 223 00:12:01.000 --> 00:12:06.180 in which he explains how you could have divergence of different species from a common ancestor. 224 00:12:06.700 --> 00:12:10.220 And then there is this other page from one of his notebooks 225 00:12:10.220 --> 00:12:13.320 that I'm particularly fond of, Thinking of the Origins of Life, 226 00:12:13.460 --> 00:12:18.940 because here you have three hypothetical species drawn in bold lines, 227 00:12:19.060 --> 00:12:21.000 and just looking at the similarities, 228 00:12:21.200 --> 00:12:21.960 Darwin found, 229 00:12:21.980 --> 00:12:25.540 and he proposes, okay, so these two must have diverged later on 230 00:12:25.540 --> 00:12:28.060 from the ancestor of these other species. 231 00:12:28.420 --> 00:12:32.080 And he has in broken line a hypothetical phylogeny. 232 00:12:32.260 --> 00:12:37.960 And I like the idea of a broken line as a hypothesis of evolutionary relationship, 233 00:12:38.380 --> 00:12:40.940 because that's exactly what our phylogenies are. 234 00:12:41.160 --> 00:12:44.060 Whenever we construct a phylogenetic tree, 235 00:12:44.220 --> 00:12:47.940 what we are proposing is a hypothesis of evolutionary relationship 236 00:12:47.940 --> 00:12:49.820 that may be correct or may be wrong. 237 00:12:49.820 --> 00:12:52.920 And we have to be, in biology, extremely eclectic 238 00:12:53.460 --> 00:12:57.860 in the sense that we take all possible data on behavior, on molecules, 239 00:12:58.100 --> 00:13:01.620 on biogeographical distribution, on morphology, 240 00:13:01.720 --> 00:13:05.760 in order to complete, to assert or not our hypothesis. 241 00:13:06.220 --> 00:13:09.580 Now, the other thing that you can see from these two pages 242 00:13:09.580 --> 00:13:14.520 is that, from Darwin's notebooks, is that although he failed medical studies, 243 00:13:14.820 --> 00:13:18.680 he did keep physicians' hand writings until the very end of his life. 244 00:13:18.680 --> 00:13:24.080 It's quite an ordeal to go through his notebooks and try to understand them, 245 00:13:24.160 --> 00:13:26.880 to the point that there are some words and phrases 246 00:13:26.880 --> 00:13:29.140 that have always been left with a question mark, 247 00:13:29.200 --> 00:13:31.500 because we really don't know what he wanted to mean. 248 00:13:32.100 --> 00:13:38.360 Nevertheless, I want you to please compare this phylogenetic tree 249 00:13:38.360 --> 00:13:42.880 with the one that is drawn on the basis of the comparison of a molecule 250 00:13:43.540 --> 00:13:47.120 that is involved in the replication of retroviruses, 251 00:13:47.180 --> 00:13:48.660 specifically the antigen. 252 00:13:48.680 --> 00:13:49.600 So, what is the relationship between the antigen and the HIV virus? 253 00:13:49.740 --> 00:13:55.460 We can construct using exactly the same basic principles that Darwin developed. 254 00:13:55.760 --> 00:13:58.980 We can come up with a history of the HIV virus, 255 00:13:59.240 --> 00:14:04.760 which is, of course, a major pathogen, which has caused a tremendous change, 256 00:14:05.660 --> 00:14:08.380 has tremendous socio-economical consequences, 257 00:14:08.800 --> 00:14:12.740 has led to the isolation of people in a terrible way, and so on. 258 00:14:12.880 --> 00:14:17.060 And here, what you have is how we can actually reconstruct the different, 259 00:14:18.680 --> 00:14:22.840 the relationships of different strains of the HIV virus. 260 00:14:23.180 --> 00:14:28.800 We can actually put the place of what is probably one of the oldest HIV virus 261 00:14:28.800 --> 00:14:36.100 that we can recognize from a blood sample that was kept by Shenz in Belgium from 1959 until today. 262 00:14:36.340 --> 00:14:40.700 We can relate the HIV virus to other retroviruses. 263 00:14:40.940 --> 00:14:48.000 We can deduce without any problem that, in fact, the two epidemics that we are witnessing 264 00:14:48.680 --> 00:14:54.820 comes from two different jumps that retroviruses made from different primates into our own species. 265 00:14:55.300 --> 00:15:00.460 And this is showing, in fact, how using the methodology developed by Darwin first, 266 00:15:00.620 --> 00:15:05.680 that retroviruses evolve, diversify, and can overcome the species barrier. 267 00:15:06.040 --> 00:15:09.580 It's very complicated to get a visa to visit Australia. 268 00:15:10.020 --> 00:15:13.820 Viruses don't need a visa to jump from one species into the other. 269 00:15:13.980 --> 00:15:18.540 Viruses are the perfect way to actually go through frontiers, 270 00:15:18.540 --> 00:15:18.660 to get to the border of the world. 271 00:15:18.680 --> 00:15:22.300 They are undetected in many ways through the taxonomical frontiers 272 00:15:22.300 --> 00:15:24.360 that separate different living entities. 273 00:15:24.780 --> 00:15:29.500 And this particular tree shows very clearly that evolutionary theory 274 00:15:30.080 --> 00:15:33.520 is not something that is related only to the disappearance of dinosaurs 275 00:15:33.520 --> 00:15:35.900 or to the emergence of land plants. 276 00:15:36.260 --> 00:15:39.540 Evolution is something that has to do with our everyday life 277 00:15:40.080 --> 00:15:46.060 because it's true that we can reconstruct the evolution of a retrovirus like the HIV-1, 278 00:15:46.280 --> 00:15:48.480 but it's also true that using evolution, 279 00:15:48.560 --> 00:15:48.660 evolution is not the only way to get to the border of the world. 280 00:15:48.680 --> 00:15:48.980 And so, in order to get to the border of the world, 281 00:15:49.580 --> 00:15:54.580 We can actually develop therapies to control the development of the disease 282 00:15:54.580 --> 00:15:55.940 in people that are infected. 283 00:15:56.300 --> 00:15:59.780 So, quite clearly, evolution is not something only for textbooks. 284 00:16:00.020 --> 00:16:02.460 It has to do with our everyday life. 285 00:16:02.660 --> 00:16:04.700 And there's another wonderful example of this, 286 00:16:04.840 --> 00:16:08.240 which has to do with bacterial resistance to antibiotics. 287 00:16:09.280 --> 00:16:13.780 I made the experiment today in a pharmacy, 288 00:16:14.060 --> 00:16:17.580 in a chemist's office nearby. 289 00:16:18.360 --> 00:16:18.660 And I found that the bacteria were not as strong as the antibiotics. 290 00:16:18.680 --> 00:16:20.000 I went and asked him, 291 00:16:20.040 --> 00:16:24.900 Can I have an antibiotic because I have some diarrhea? 292 00:16:25.340 --> 00:16:27.140 I have no diarrhea, I have to say. 293 00:16:27.300 --> 00:16:30.720 But I wanted to test how it works in Australia. 294 00:16:30.980 --> 00:16:34.000 And the question immediately came from the chemist, 295 00:16:34.100 --> 00:16:35.620 Can I see your prescription? 296 00:16:36.180 --> 00:16:37.460 And I said, I have none. 297 00:16:37.860 --> 00:16:42.400 And he said, well, I'm sorry, then I cannot give you any antibiotic. 298 00:16:42.500 --> 00:16:47.900 If you do the same experiment in Latin America or in a number of Asiatic countries, 299 00:16:47.900 --> 00:16:51.900 you will immediately get the antibiotic you need without any prescription. 300 00:16:52.280 --> 00:16:54.740 In other words, there are a number of societies 301 00:16:54.740 --> 00:16:58.500 in which the people can administer themselves an antibiotic, 302 00:16:58.700 --> 00:17:02.460 which is normally used in a very unprofessional way, 303 00:17:02.600 --> 00:17:04.320 without any medical control, 304 00:17:04.620 --> 00:17:08.800 not for the time that's necessary to actually complete the scheme. 305 00:17:09.080 --> 00:17:13.760 And the result is that we are developing resistance to antibiotics. 306 00:17:14.320 --> 00:17:15.440 How does that happen? 307 00:17:15.580 --> 00:17:17.640 Well, assume that we have a bacteria, 308 00:17:17.640 --> 00:17:17.880 and we have a bacteria that is not a bacteria, 309 00:17:17.880 --> 00:17:19.980 that begins reproducing, 310 00:17:20.060 --> 00:17:23.260 and all of a sudden you have a mutant, just by chance, 311 00:17:23.360 --> 00:17:26.920 or because it acquires a virus that carries on the gene 312 00:17:26.920 --> 00:17:29.280 that can decompose, given an antibiotic, 313 00:17:29.640 --> 00:17:34.760 and it will not prevail among the population of other bacteria, 314 00:17:35.040 --> 00:17:37.100 among other things, because it has no advantage. 315 00:17:37.500 --> 00:17:41.480 But the moment we apply to this colony of bacteria, 316 00:17:41.760 --> 00:17:45.900 whether in our guts or whether under laboratory conditions, 317 00:17:46.280 --> 00:17:47.860 then what immediately happens 318 00:17:47.860 --> 00:17:51.020 is that the bacterial strains that are resistant to an antibiotic 319 00:17:51.020 --> 00:17:51.980 will be selected. 320 00:17:52.320 --> 00:17:54.200 It's a very simple mechanism, 321 00:17:54.420 --> 00:17:58.780 and the basic point to underline here is that natural selection 322 00:17:58.780 --> 00:18:01.700 has no foresight, no goals, it only produces results. 323 00:18:02.220 --> 00:18:06.280 That is the basic idea behind natural selection. 324 00:18:06.720 --> 00:18:08.300 And of course, in this case, 325 00:18:08.360 --> 00:18:12.760 we can reconstruct the genealogy of these different strains of bacteria, 326 00:18:13.080 --> 00:18:17.460 but in biology, in historical times, in a historical perspective, 327 00:18:17.860 --> 00:18:19.820 genealogy means phylogeny, 328 00:18:19.940 --> 00:18:23.280 and that means reconstructing the history of life on Earth. 329 00:18:23.460 --> 00:18:25.820 And we actually can do so very easily, 330 00:18:26.040 --> 00:18:28.160 and by comparing, for instance, 331 00:18:28.420 --> 00:18:32.480 the molecules involved in the synthesis of proteins, 332 00:18:32.740 --> 00:18:36.680 we have come up to recognize that at a cellular level, 333 00:18:37.880 --> 00:18:41.380 life on Earth is not divided in plants or animals, 334 00:18:41.620 --> 00:18:47.760 it's not divided in, let us say, in prokaryotes or eukaryotes, 335 00:18:47.760 --> 00:18:51.160 but it's actually divided into three major groups 336 00:18:51.160 --> 00:18:52.320 that are called the bacteria, 337 00:18:52.980 --> 00:18:56.300 like the ones that produce the yogurt that you had for breakfast, 338 00:18:56.540 --> 00:19:00.160 the archaea, which are basically fastidious prokaryotes 339 00:19:00.160 --> 00:19:02.820 that like to leave most of them under extreme conditions, 340 00:19:03.080 --> 00:19:06.520 and eukaryotes, which is, of course, the branch of the tree 341 00:19:06.520 --> 00:19:10.220 in which ourselves and most of our relatives and best friends are located. 342 00:19:10.720 --> 00:19:16.240 I have to say that I have said here that these are major groups. 343 00:19:16.280 --> 00:19:17.520 There is a word 344 00:19:17.520 --> 00:19:17.740 that I have to say, 345 00:19:17.740 --> 00:19:22.300 a word that is used by a very distinguished microbiologist, Karl Woese, 346 00:19:22.420 --> 00:19:26.380 which is domains, the domain archaea, the domain bacteria, 347 00:19:26.540 --> 00:19:27.640 and the domain eukarya. 348 00:19:27.920 --> 00:19:29.280 But as a Latin American, 349 00:19:29.640 --> 00:19:32.940 I always feel a little bit uneasy when Americans use the word domains. 350 00:19:33.300 --> 00:19:38.260 So let me just refer to them as lineages, three basic lineages. 351 00:19:38.520 --> 00:19:41.220 One of the things that has emerged very quickly 352 00:19:41.220 --> 00:19:43.620 from this overall picture of the biosphere 353 00:19:43.620 --> 00:19:47.660 is that most of the diversity that we see of life on Earth 354 00:19:47.660 --> 00:19:47.720 is that most of the diversity that we see of life on Earth 355 00:19:47.740 --> 00:19:49.340 is dominated by microbes. 356 00:19:49.800 --> 00:19:53.980 And since microbes have been the dominant form of life on Earth 357 00:19:53.980 --> 00:19:59.520 since it started more than 3.8 to the 9 years ago until today, 358 00:20:00.320 --> 00:20:04.980 prokaryotes, bacteria, and archaea, and many eukaryotic microbes 359 00:20:04.980 --> 00:20:09.000 are in fact where we find the greatest diversity on life. 360 00:20:09.140 --> 00:20:10.780 And without them, we would not be here. 361 00:20:10.940 --> 00:20:14.120 You can take away the fungi, you can take away humans, 362 00:20:14.280 --> 00:20:16.980 you can take away other animals, and the biosphere 363 00:20:16.980 --> 00:20:18.980 will thrive on without any problem 364 00:20:18.980 --> 00:20:22.540 because prokaryotes have all the metabolic abilities to go on. 365 00:20:22.680 --> 00:20:27.040 If you take away the prokaryotes, life on Earth will not go on 366 00:20:27.040 --> 00:20:31.620 for more than a few thousand years or a million years at the most. 367 00:20:31.780 --> 00:20:36.300 So clearly this is the most resistant, the oldest forms of life 368 00:20:36.300 --> 00:20:38.500 that we actually have to study. 369 00:20:38.500 --> 00:20:41.420 We want to understand how did life appear on Earth 370 00:20:41.420 --> 00:20:44.800 and how was it maintained during several millions or billions of years. 371 00:20:45.140 --> 00:20:46.960 Now, here we immediately see 372 00:20:46.980 --> 00:20:47.140 that the Earth is in a very turbulent state. 373 00:20:47.140 --> 00:20:47.840 We immediately face a problem. 374 00:20:47.980 --> 00:20:52.500 If we draw a timeline with the origin of the solar system 375 00:20:52.500 --> 00:20:55.560 and of the Earth at 4.610 to the 9 years ago 376 00:20:55.560 --> 00:20:57.380 and the present here to the right, 377 00:20:57.560 --> 00:21:00.200 one of the problems that we immediately recognize 378 00:21:00.200 --> 00:21:04.140 is that at the very beginning, the Earth was probably very hot. 379 00:21:04.280 --> 00:21:09.760 It was a very turbulent place with comets and meteorites falling all the time, 380 00:21:09.800 --> 00:21:13.420 with very unstable continents, 381 00:21:13.680 --> 00:21:16.960 very likely too hot to have a very high temperature, 382 00:21:16.960 --> 00:21:18.720 very likely to have water, liquid water on the surface. 383 00:21:18.980 --> 00:21:21.600 So if we have no water, it's very difficult to imagine 384 00:21:21.600 --> 00:21:23.320 how we could have life appearing. 385 00:21:24.040 --> 00:21:26.700 On the other hand, if we go back in time, 386 00:21:26.820 --> 00:21:30.220 and I have to say the Australians are extraordinarily privileged 387 00:21:30.220 --> 00:21:34.700 because some of the oldest evidence of microbial life comes from here 388 00:21:34.700 --> 00:21:37.680 and from the work of extremely distinguished scientists 389 00:21:37.680 --> 00:21:40.540 like my friend Malcolm Walter and so on, 390 00:21:40.640 --> 00:21:45.280 we can be quite sure that 3.5 to the 9 years ago, 391 00:21:45.280 --> 00:21:50.040 there was already a thriving biosphere composed mostly of prokaryotes. 392 00:21:50.160 --> 00:21:55.300 We have very good evidence that life was very dominant on the Earth 393 00:21:55.300 --> 00:21:57.460 since 3.5 years to today. 394 00:21:57.720 --> 00:22:02.000 The problem that we have is that clearly life must have evolved 395 00:22:02.000 --> 00:22:06.800 after these turbulent times about 4 billion years ago 396 00:22:06.800 --> 00:22:09.920 and older than 3.5 billion years ago, 397 00:22:10.040 --> 00:22:13.180 but we don't have any sedimentary rocks from this period. 398 00:22:13.180 --> 00:22:15.340 And if we don't have any sedimentary rocks, 399 00:22:15.400 --> 00:22:18.860 we are faced with a problem because we therefore cannot know the pH 400 00:22:18.860 --> 00:22:20.960 or how acidic the primitive ocean was. 401 00:22:21.160 --> 00:22:24.140