1 00:00:05.770 --> 00:00:07.390 How does science work? 2 00:00:07.390 --> 00:00:09.170 How do scientists like myself and the people 3 00:00:09.170 --> 00:00:11.660 we're going to be learning about come to conclusions. 4 00:00:11.660 --> 00:00:15.790 Now I want to differentiate between, here, between facts and the process. 5 00:00:16.920 --> 00:00:19.320 Scientific facts can change. 6 00:00:19.320 --> 00:00:22.210 Unfortunately, you're going to be tested upon facts, but you need 7 00:00:22.210 --> 00:00:25.220 to know that some of these facts, may not really be facts. 8 00:00:25.220 --> 00:00:26.780 We saw that, for example, with Barbara 9 00:00:26.780 --> 00:00:30.680 McClintock, who discovered, against what people had thought, 10 00:00:30.680 --> 00:00:34.930 against popular idea, that the DNA can change. 11 00:00:34.930 --> 00:00:37.490 Originally, her facts were not believed. 12 00:00:37.490 --> 00:00:40.490 But now we know that that really is a scientific fact, that DNA can change. 13 00:00:40.490 --> 00:00:47.210 So what is the process of biology? Well, there's two general processes. 14 00:00:47.210 --> 00:00:51.260 Two general approaches to science. One I'll call discovery science. 15 00:00:51.260 --> 00:00:52.950 This uses induction. 16 00:00:52.950 --> 00:00:55.220 This is what Darwin did when he went out on the Beagle. 17 00:00:55.220 --> 00:00:55.740 He didn't have any 18 00:00:55.740 --> 00:00:57.100 grand hypothesis. 19 00:00:57.100 --> 00:01:02.220 He started collecting data and based on this data, through induction, he 20 00:01:02.220 --> 00:01:06.950 developed new theories and new hypotheses which then could lead to experiments. 21 00:01:06.950 --> 00:01:09.530 This is the same type of approach that used in the modern 22 00:01:09.530 --> 00:01:14.560 genome project, where they're developing huge or gathering huge amounts of data. 23 00:01:14.560 --> 00:01:19.130 Huge collections of gene sequences. Without any real hypothesis. 24 00:01:19.130 --> 00:01:21.020 The hypothesis comes from 25 00:01:21.020 --> 00:01:21.930 analyzing the data. 26 00:01:23.170 --> 00:01:26.630 But the approach used by most scientists 27 00:01:26.630 --> 00:01:28.300 is what I would call the deductive approach. 28 00:01:28.300 --> 00:01:30.890 Where we're using hypoth, hypotheses. 29 00:01:30.890 --> 00:01:32.030 Hypothesis driven science. 30 00:01:32.030 --> 00:01:34.760 And I want to just give a very simple example. 31 00:01:34.760 --> 00:01:37.400 Let's say, that you're sitting, watching this and let's just 32 00:01:37.400 --> 00:01:39.970 say it's 9 o'clock at night, wherever you are sitting. 33 00:01:39.970 --> 00:01:42.780 And as you're watching me speak, you're yawning. 34 00:01:42.780 --> 00:01:47.210 You're getting very tired. Now, I want your thesis, 35 00:01:47.210 --> 00:01:50.980 your master's thesis, to be about why are you tired at 9 36 00:01:50.980 --> 00:01:56.220 o'clock at night while you're watching Daniel Shamovitz teach what a plant knows? 37 00:01:56.220 --> 00:01:58.790 Now to develop your thesis, you're going to need to 38 00:01:58.790 --> 00:02:02.430 develop first hypotheses, and we could think of several hypotheses. 39 00:02:02.430 --> 00:02:06.070 Maybe the first hypothesis is that Shamovitz is a rather boring teacher. 40 00:02:07.200 --> 00:02:10.060 Well I'd, I'd rather think of a second hypothesis. 41 00:02:10.060 --> 00:02:12.370 The second hypothesis could be that you woke up too 42 00:02:12.370 --> 00:02:14.590 early in the morning and that's why you're tired. 43 00:02:14.590 --> 00:02:21.180 So now what experiments can you design to test these hypotheses? 44 00:02:22.220 --> 00:02:24.360 Let's go to the first one that I'm a boring lecturer. 45 00:02:25.430 --> 00:02:29.290 So the obvious experiment would be to do is to switch the lecturer. 46 00:02:29.290 --> 00:02:30.740 So you'll go back to the Coursera 47 00:02:30.740 --> 00:02:33.310 homepage, choose another course, and start watching it. 48 00:02:34.840 --> 00:02:35.980 You're still yawning. 49 00:02:35.980 --> 00:02:36.720 You're still tired. 50 00:02:37.810 --> 00:02:41.308 Now does that finding prove that I'm not boring? 51 00:02:41.308 --> 00:02:43.300 No, unfortunately not. 52 00:02:43.300 --> 00:02:45.220 because he could also be boring in the next lecture. 53 00:02:45.220 --> 00:02:49.600 So you do a third lecture. And that lecture also causes you to yawn. 54 00:02:49.600 --> 00:02:54.120 So, does that mean that I'm not boring? No, it could be that she was also boring. 55 00:02:54.120 --> 00:02:57.870 But if you do this enough times, and each time, you're still tired. 56 00:02:57.870 --> 00:03:02.310 You've realized that you don't have enough proof to actually support that hypothesis. 57 00:03:02.310 --> 00:03:02.880 So now, let's go 58 00:03:02.880 --> 00:03:05.960 to the second hypothesis. That you woke up too early in the morning. 59 00:03:07.100 --> 00:03:08.790 What would the experiment be? 60 00:03:08.790 --> 00:03:10.080 Again, it's pretty obvious. 61 00:03:10.080 --> 00:03:14.240 Let's say you don't wake up until noon the next time you watch my lecture. 62 00:03:14.240 --> 00:03:15.960 And now you come to the lecture of Shamowitz g/ and 63 00:03:15.960 --> 00:03:19.070 what a plant knows and lo and behold, you're full of energy. 64 00:03:20.370 --> 00:03:22.430 So what's the result of your experiment? 65 00:03:22.430 --> 00:03:25.280 The result is that you were tired because you're not getting enough sleep. 66 00:03:26.800 --> 00:03:28.050 So that's on 67 00:03:28.050 --> 00:03:29.500 a very simple level. 68 00:03:29.500 --> 00:03:32.130 And what we want to see now through plant biology, are what are 69 00:03:32.130 --> 00:03:35.510 the hypotheses that lead to the findings that we're going to be talking about.