uh hi everyone welcome to biology 1105 my name is Ros I'm your professor for this course and I'm really excited to see you on September 9th although right now as I'm recording this lecture I have a pretty brutal cold that's just set in um so this is recorded lecture one in the course outline it corresponds to the week starting Monday September 9th there's two recorded lectures for that week of class on September 9th if you're watching this after after Monday September 9 you're all good that's kind of what you're meant to do if you're watching it before Monday September 9 you're awesome you're ahead of things as the uh term goes on I'm going to try to post the lectures a little bit ahead of time throughout the term um so the topic of this lecture This Record lecture is the scientific method and questions hypotheses and predictions at the beginning of every recorded lecture I'm going to show you a little a blur like this that um summarizes what you should learn in the lecture and you can also find the same information in the PDF titled study guide for 1105 that's available on our bright space the material in this lecture should be familiar to you from previous experience that you've had in high school but what I hope to do in this lecture is show you some pretty neat examples that will get you excited about this topic and about the term okay so to start off um I'm going to play a 30- second video clip and I've removed the audio so there's no sound and I want you to just imagine that you're on the saan in Kenya and you're observing animals doing this uh strange thing and I want you to think about what are you observing and what questions do you have about it so here's that clip to transport you to to uh the African Savannah e okay so what did you see and what questions do you have based on what you saw also what assumptions did you make based on your prior knowledge what assumptions might you have been making about what you were seeing in this scene all right so another 30 second clip now I want you to imagine you're in the foot hills of the Himalayas and you're hiking along um with these characters that are shown in the clip and again again there's no audio in this this clip and you're seeing these massive colonies of bees attached to the rocky walls of the cliffs around you and the bees are doing something really strange each of these colonies can have thousands of giant bees all right so again what questions do you have about what you saw there what you saw the bees doing can you write down at least two possible hypotheses that could provide different answers to one of your questions so hopefully um I can hear from you guys in our one of our inperson meetings what you thought okay so science is all about asking questions when you watch these videos when you watch animals and Wildlife outside in real life you're doing science science can be regarded as an open-ended quest for understanding and the directions of your questions the directions of inquiry are Limitless there are no wrong questions in science but some questions are better than others for guiding our scientific investigations and so science is about asking lots of questions and always refining and improving them over time to be able to ask questions we need background knowledge and that knowledge can come from various sources including textbooks including um peer-reviewed scientific papers that are published in journals including Knowledge from other experts including Knowledge from your own previous observations and Explorations good question are also questions that are new they're questions that haven't been asked and answered before in these background sources and so answering one of these new questions would add to our knowledge what makes relevant background information will depend on what you're studying so we could ask ourselves what kinds of things might we need to know for the video clip where we were observing that weird Behavior done by that ostrich um maybe we need to know are these adult animals are they juveniles are the individuals in the video male are they female what season is it what usually happens during that season do these two individuals know each other already and is the act of somebody observing them in the environment somehow influencing their behavior as just a few examples I'm sure you can think of others so where do our scientific questions come from um well in no particular order they come from our own curiosity and exploration which includes lucky accidents they come from a need to solve a practical problem and they can come from previous scientific studies reading and discussing what other people are working on can really highlight Unsolved Mysteries and so I really encourage you throughout your degree to read scientific articles uh as you get into upper year courses you'll be doing this more and more and also to go to seminars here on campus often there's like really fascinating visiting speakers giving talks about their research to to uh people the community at the University and here in the biology Department we have seminars um most Fridays at 2:30 p.m and if you go to the biology Department website you can um see a schedule and often our questions come from more than one of these um sources okay so here's a neat example of where scientific questions can come from and and how uh that can guide the process of science and so this is an example of an accident that raised an important scientific question and so Alexander Fleming um wrote about um his September in 1928 he wrote when I woke up just after Dawn um in September 1928 I certainly didn't plan to revolutionize all of medicine but I suppose that's exactly what I did and so what happened well in September he had just come back to his lab from summer vacation vacation and before he left for vacation he had stacked a bunch of Petri dishes a bunch of cultures of stao caucus bacteria on a bench in the corner of the lab not having a chance to clean them before leaving and when he came back from vacation he took the dirty dishes and he saw something that looked like this one of the cultures on this petri dish was contaminated with a fungus and the colonies of the staf caucus bacteria immediately surrounding the fungus had been destroyed whereas other staky colonies further away were perfectly normal and in that moment he famously said that's funny so he later identified the mold you can see it as the large white patch at the top of the dish he identified it as penicilium and for a while he called the substance that it was producing that killed bacteria for a while he called it mold juice but he eventually named it penicillin and that Discovery alone that lucky accident isn't science it was an accident but it spurred Fleming to begin a whole series of Investigations on the antibacterial effects of the substance that penicilium was producing what kinds of bacteria would this mold juice kill how does it kill the bacteria could it kill bacteria that caused diseases in farm animals could it kill bacteria that caused diseases in humans and so this is an example of an accident leading to questions that spurred a major advance in science okay so questions are used to formulate hypotheses and predictions well what's a hypothesis well I have a daughter she's uh turning 8 years old and uh as I've taught this course over the last uh six years I ask her every fall what's a hypothesis and in the first couple years when she was 3 years old she really had no idea she thought it was something to do with like size or more and then she started to realize um okay and I've heard that but I don't know what it means and then last year she said she didn't know what it meant and then she realized oh it means a guess so she's starting to get the definition I haven't asked her yet this year what it means but she formulated a legit hypothesis on the whiteboard in my office one day when she was in there sick so um I'm pretty curious to see what she says if I ask her this year what the definition is okay so for the purpose of our course a hypothesis is an exper explation that answers a research question and the formal definition is a clear statement that provides a plausible explanation for a phenomenon a hypothesis needs to be testable that is we need to be able to formulate a prediction based on that hypothesis and we need to be able to gather data that would either refute or support that particular explanation so science is this iterative process of observing things asking questions speculating forming hypothesis making careful predictions and then collecting the data to test those predictions it can be difficult to articulate predictions that are specific enough and that can be tested against available data and often we have to figure out how we can distinguish between multiple competing hypotheses so I have a couple of neat examples of historic hypotheses to show you next um okay so the first one uh arises from this like fundamental question in biology and that question is where do living things come from for thousands of years people observed that maggots which are we now know our larval flies and other insects eventually arise from dead meat or cooked meat that you leave out for a long time so where do those living things come from what's going on well one hypothesis called spontaneous generation is that living things can arise spontaneously from non-living matter and this idea goes back to Aristotle in ancient Greece around 350 years before the year zero so that's about 2,000 years ago another hypothesis is that living things must come from other living things by means of reproduction and that's called biogenesis the amazing thing is Aristotle's spontaneous generation hypothesis held strong for almost 2,000 years that's incredible we now know that H2 is true but it wasn't H1 wasn't disproven until the 1800s when the uh microbiologist Louie Pastor did a series of really elegant experiments on bacterial growth along with other microbiologists at the time so um the little uh video clip in the bottom of the slide illustrates what he did he had these ingenious experiments with this Swan necked flask where the swan neck uh prevents um contamination from the air and he added a rich nutrient broth to two flasks sterilize them both so that there'd be nothing living in there and so they're identical and then if you break the swan neck off of one of them and allow air currents to enter the flask and to contaminate it um you get bacterial growth you get microbes growing in there and so that experiment allowed us to reject the spontaneous generation hypothesis so again the lesson here is that it often takes time in this case thousands of years for people to develop the right methods for a hypothesis to even be testable okay here's another example that's similar um and a really good research question that people have wondered about for a long time is like where do birds go in the winter people would observe that as the seasons changed um in the fall many many species of bird disappear birds that you saw in the summer you're no longer seeing in the fall and winter there's a few other species that you might only see in the winter and then they're gone like the following spring and summer so what's going on well historically there have been a couple of different competing hypotheses so Aristotle founding biologist one of the P first people to write a lot about biology had a couple of ideas he thought that red starts in the fall were probably transforming themselves into Robins where he thought that other species like swallows burrowed underground and this is why we don't see swallows in the winter so those were a couple of um candidate hypotheses that Aristotle had to explain The Disappearance of birds in the winter um okay and then again nearly 2,000 years later another guy Charles Morton reasoned okay that doesn't make sense the burrowing thing doesn't make sense they wouldn't have any air and birds need air and he also noticed he observed that birds disappeared when the weather was changing and when food resources were changing and becoming a lot less common so he reasoned that birds are probably going somewhere better and where did he conclude they must be going the moon so his hypothesis in the 1600s was that the birds that disappear in the winter are flying to the moon for the winter and then coming back in the spring and he even calculated that it should take them about 60 days to get there so we now know that that's like ridiculous but it was actually based on very a lot of logic at the time um and then something incredible happened to just prove hypothesis number three here this stor was captured in Germany in the 1800s so the stor was captured alive with an arrow piercing its neck and the arrow was from Africa so the stor had been attacked by a hunter in Africa and by some amazing Stroke of Luck the the injury wasn't enough to kill it and it showed up in Germany and so the file stor or Aeros stor in English was the first evidence that birds can fly from one continent to another and so this led to a new hypothesis again like more than a thousand years after Aristotle that many birds fly to other parts of the world often on completely different continents and so we now know that there are a whole series of different migratory flyways that different species of birds use around the world that of migratory Birds um and again the amazing thing is that it can take a really long time for people to be able to artic calate and test the right hypothesis and it often requires methods or observations that we just don't have at first the other lesson here is that it's really good to have multiple alternative hypotheses and the reason why is that nature is complicated we want to avoid getting stuck on uh our own like personal favorite ideas if you have one hypothesis that you think is the right explanation for some phenomenon that's great but if you only focus on that hypothesis you're probably going to miss other things that are going on so to try to avoid our own biases it's important to consider multiple alternative hypotheses try try to think of all the possible ways that something could be going on also if we're going to be able to distinguish multiple competing hypotheses they need to have distinct predictions so this is a beautiful quote from Nobel prize winning scientist franois yakob who you'll learn about in biology 1103 if you're in it now maybe you've already taken it he used bacteria and viruses to figure out how DNA is transcribed from um from The genome into enzyme products in cells and so in his quote he says that contrary to what he once thought the scientific process wasn't just observing it wasn't just accumulating experimental facts and drawing up a theory from them he says it begins with the invention of a possible world or fragment thereof which was then compared by experimentation to the real world and it was this constant dialogue between imagination and experiment that allowed one to form an increasingly fine grained view of reality so I think that's really beautiful um that science is this dance between creative thinking and critical thinking creative thinking on the left side of the slide here crital critical thinking on the right um and franois yakob referred to the creative things as like night scientists the things that scientists think about at night and the critical stuff is like your day job the kind of rigorous um rot tasks that you have to do during the day this leads to another really important theme in this course science is done by people and it's a highly social system and it works best when people collaborate across different perspectives because any one person or group of people will have certain knowledge but they won't know everything they won't have all the answers and so collaboration working across groups will um enhance what we're able to do also people are not perfect no single study is perfect any given scientific study will have mistakes sometimes a few sometimes major mistakes and we're going to look at that a lot throughout this course the Hallmark of science is that we update our beliefs based on evidence and data so we're always willing to refine what we think about things and this is also the reason for your first homework assignment in this course which is due on uh September 12 um thinking about the social part of Science and why diversity in science is so important as an aside this is completely optional not required if you like podcasts there's a really beautiful podcast episode on the topic IC of curiosity and the process of discovery it's the Radio Lab podcast and the episode is called Golden Goose I really recommend it it starts with a boy who's just really into collecting shells and it leads to a whole lifetime of of questions and potentially uh revolutionary discoveries in medicine so it's it's I really recommend it okay so a few common misconceptions first one it's hard to come up with questions questions have to somehow be like the good enough well actually asking questions is like brainstorming you should just let your questions all hang out let them FL flow freely great scientists ask many more questions than they ever answer and just the act of like talking to someone about something of just saying those questions out loud will often stimulate more ideas and help you find the best ones this is true in science it's also true in your coursework if you really want to um improve your learning improve your understanding of a topic like talking about the coursework with somebody else will help you think through it better okay another myth is if your hypothesis is not supported if you end up ruling it out you've made a mistake like you're bad at what you're doing well actually doing great science means that you're refuting things you're knocking hypotheses down all the time the important thing is that your hypotheses have to be based on a sound background ground they have to be testable and that your predictions have to allow you to distinguish between multiple explanations and the data you collect needs to be relevant to testing a particular prediction okay so this slide has kind of a brief uh review about questions and hypotheses and it has a reminder that scientific questions are often descriptive like how many of this are there in the world or how often does this happen where does this happen when does this happen those are descriptive types of questions scientific questions can also be causal uh for example why does this happen what causes this to happen does condition X affect outcome y a really common challenge for students but also for like scientists writing scientific papers is keeping clear the difference between hypotheses and predictions and so this slide just has a reminder a hypothesis is an explanation a hypothesis answers a question okay so let's get into predictions what's a prediction predictions are derived from your hypothesis and they're more specific your prediction is the outcome you expect to observe under a set of specific conditions if your hypothesis is true predictions can sometimes be written as if then statements for example if we observe X then we expect y will increase or decrease or if we change X then we expect y will increase or decrease they can be written in many different ways though they can also be written as measurement X will you know go up or go down with an increase in measurement y so these are not the only ways predictions can be written so don't get hung up on the exact wording this is just meant to be a conceptual framework to help you understand what a prediction is okay what's a good prediction good prediction should follow logically from the hypothesis we wish to test and not from other alternative hypotheses good predictions should have a specific Direction so they should state that something will increase or decrease or state how two groups will differ and good predictions lead us to obvious measurements that allow the prediction to be tested so what do I mean by the direction part of those criteria well if we go back to the examples on the slide before um those like increased decrease up and down those kinds of words are telling us about the direction of that prediction okay so um a little case study here of going from a question to a hypothesis to prediction and data so let's walk through an example so imagine that you're walking along a rocky Shore in Nova Scotia in Canada and you notice that the the sea snails are uh present in some places but not others and that when you see sea snails they're often like cluster together in these dense groups there's an example of that on in the photo there so that's your observation and so you wonder why do the snails occur in groups that's our question okay we could come up with a bunch of different hypotheses maybe snails group together to shelter themselves from the action of the Waves so maybe there's some kind of Sheltering advantage to being in a group maybe grouping provides snails with protection from predators like crabs that eat snail so those are just two hypotheses you could think of more I know um they could both be true or maybe only one of them is true or maybe neither of these are true maybe both of these are that I've thought of so far are incorrect let's come up with some predictions deriving from these two hypotheses we've thought up so far so a prediction for hypothesis one could be that snails would be less likely to be found in groups on beaches that don't have a lot of wave action and a prediction for hypothesis 2 could be snails snail groups will be more likely to be found if predators are present like crabs okay so let's say we want to design an experiment to test these two hypotheses that we've got so far and we need to think about what are we actually measuring here um let's say it's like whether the number of groups of snails versus snails on their own or something like that and let's say in our experiment we're going out and we're going to manipulate the uh environment in some sections of the beach we're going to have some areas that are like the top left that we allow to just be as they are they um there's waves hitting this beach and there's crbs Predator crabs present and let's say we're going to put up barriers in some other um places on the beach this is shown on the top right and um and bottom right so we're going to prevent waves from accessing those parts of the beach so we're going to prevent wave action with some kind of barrier and then let's say that we're also going to remove crabs from some areas of the beach so we'll have some patches of the beach that uh where waves are happening but we remove the crabs and we'll have some patches of the beach where we've put up a barrier to remove waves and we also remove the crabs Okay so we've got four different conditions in our experiment and we're going to measure the like count the number of groups of snails or something as OS to solitary snails okay so where would you predict snail groups would occur most often if the shelter hypothesis is true hopefully this is easy right which of these four conditions should have high levels of grouping snails if our shelter hypothesis is true so the answer should be the places where waves are allowed to happen normally but not we expect to not see snails in the other two conditions if if this hypothesis was true what if our Predator hypothesis is true where would we expect to see snail groups hopefully this is easy for you and the answer is the um conditions where the Predators are present we'd expect to see the snails occurring in groups okay so just coming back to our ideas so far these aren't the only kind of outcomes we could get from this experiment because it's possible that one of our hypotheses is true but the other one is false but it's also possible that both of them are true maybe snails group to protect themselves from waves and to protect themselves from crabs and it's also possible that neither of them are true so if both of them are true where do we expect to see um groups of snails in in our experiment if snails group because of wave action and because of crabs where would we expect to see snail groups take a moment to think about the answer here and hopefully again it was clear we'd expect to see groups of snails in all three of these conditions but not in the condition where we remove waves we remove crabs what if you ran this experiment and you saw something like this what if you found that snails were forming groups in all four of these experimental conditions in other words the experimental conditions um had equal numbers of snail groups regardless of the changes you made in the environment what would that tell you it should tell you that neither of those hypothesis are true that um snail grouping has nothing to do with whether or not there's waves and whether or not there's crabs okay so just um a little terminology that we'll repeat later in the course a null hypothesis is a negation of one or more hypotheses okay so let's say that happened and we ruled out hypothesis one and hypothesis 2 and let's say we come up with a third hypothesis snails are found in groups where their food plants occur like there's something about like you know places where there's like the plants that snails eat they all come and gather around those places so maybe that's why they group well now we've got three possibilities and if hypothesis one and hypothesis 2 are still on the table the possibilities that how the world could be quickly become more and more complicated and so that's why it's so important to have really specific predictions that distinguish the different possibilities okay uh a practice question here what if you ran the earlier experiment we looked at and you had these four conditions and you only observed snails grouping in the top left condition so you only saw them in groups if there were waves and crabs present what would you conclude there so think about this on your own we'll talk about this in class um uh on September 16th and one more short practice question to finish this video um let's say you're part of a running club and you notice that some weeks you perform much better you're faster than others you might have a question why like what determines whether you're like performing at a fast level of sprinting or a slow level and let's say you have some potential hypotheses well here we're just going to focus on maybe it has something to do with the amount of sleep you got the night before so maybe your running speed is determined by the amount of sleep and then let's say you have a null hypothesis that goes along with that first hypothesis and the null here is sleep does not influence your running speed okay so on this slide at the bottom are kind of three candidate predictions Illustrated as data so you've got three Scatter Plots illustrating hours of sleep that you got on the x axis and then your running speed on the y axis and I just want you to think about which um which of these three predictions at the bottom could potentially go with uh hypothesis one and hypothesis 2 at the top top of the slide um okay so uh that's it for this first pre-recorded lecture um there'll be another lecture lecture two that goes with the week of um September 9 UM and I'll see you in class soon