hey everybody it's mr smeeds and today we'll be covering topic 2.4 which is ecological range of tolerance our objective for the day is to be able to describe what ecological tolerance refers to and we'll be practicing a new skill at the end of today's video which is reading a passage and identifying the claim of the author so ecological range of tolerance refers to the range of conditions so these could be conditions like temperature salinity ph or sunlight that an organism can endure before injury or death so it's important to note that both species as a whole but also individual organisms have a range of tolerance for all of the different conditions in their environment let's look at an example salmon have a basic temperature tolerance range of about 6 to 22 degrees celsius but some individual salmon are going to have different adaptations that allow them to live slightly outside of those ranges so again the basic tolerance range for salmon is going to be about 6 to 22 degrees but then we'll also have individual salmon themselves which have slightly different ranges another way that we can think about this is how temperature tolerance changes from species to species so even within the group of fish that are referred to as salmon we have different subspecies and so we have six subspecies here and we can see that if we look at this graph which is going to show us the different temperatures on the x-axis and the aerobic scope on the y's this is a measure of how well they're using oxygen we're going to see that different species of salmon have slightly different temperature tolerance ranges what we have to remember is that the reason that salmon have different temperature tolerances is due to genetic diversity so we have genetic diversity within a species of salmon so that individual members themselves will have slightly different tolerances this is going to make the population as a whole more resistant to changes such as global warming that may warm up the body of water they live in so remember this connection back to genetic biodiversity it's beneficial to a population because some individual salmon will have temperature tolerance ranges slightly outside of that 6 to 22 degrees so they may survive in these warmer waters that come with global warming now we'll talk about three different zones that can occur within the range of tolerance for a given species so first we have the optimal zone the optimal zone is the range where the organism is able to survive grow and reproduce think of this as where they thrive or where they would like to be so if we look at the graph here what we can see is that we have this optimum range here and that's where the number of organisms is going to be the highest so when the ph or temperature for a given species in their habitat is right within this optimum range we're going to have the largest population size we're going to have the highest number of individuals surviving because it's in their ideal range they can survive but they can also reproduce and grow so the population should thrive however we also have a range that we call the range of physiological stress so this is going to be the zone or the range where the organism can survive but they're going to experience some sort of physiological stress now this may be something as extreme as infertility or lack of growth or just decreased activity and so if we look at the graph again here what we'll see is that as we move further outside of their optimum zone we have a lot fewer organisms so there are fewer organisms because the population may not be able to reproduce the individuals may not be able to develop and eventually if the condition again such as ph or temperature shifts so far that we're outside the range of physiological stress we eventually get to something that we would refer to as the zone of intolerance so this is the range where the organism will actually die now an important point here is that we don't want to just say that the organism dies or the species can't live here we should actually cite a specific cause for the die-off so that could be something like thermal shock it could be lack of access to food water or oxygen so whenever possible if we're writing an frq or discussing a concept related to ecological tolerance we want to actually try to name the stressor we'll talk more about this in a minute now we'll talk about some writing tips that are related to using ecological range of tolerance in an frq answer so when you have an frq that's about a human activity or a natural event that causes a disturbance it's a really good idea to try to connect your answer to ecological range of tolerance and if possible your case would be even stronger in your answer if you're able to connect the human activity to climate change and therefore global warming so let's look at a few examples here electricity generation transportation agriculture all of these release carbon dioxide into the atmosphere which drives climate change and therefore warms the earth or global warming when we have global warming we have a temperature increase that could be outside the range of tolerance for many species this could cause a population decline in those species another example could be connecting it to the ocean so if we have global warming we're going to see a rise in ocean temperatures as well that's going to move the temperature in the ocean outside the range of tolerance for many different fish species and that's going to result in die-offs because they have moved into this zone of physiological stress and then eventually into the zone of intolerance now another frq writing tip to make your answers even stronger is connecting this shift in range of tolerance to a specific physiological stress so we don't want to just say that the organisms died or the species went extinct or the population collapsed our answer will be much stronger if we can actually cite a specific physiological stress so here are a bunch of examples of physiological stress we could say that the organism suffocated so it didn't get enough oxygen in order to survive we could say that it experienced thermal shock so the temperature in the water changed so fast that the organism died we could say that it had a lack of access to water or food or nutrients if we're talking about a plant or oxygen so all of these different physiological stressors are good things to cite your answer instead of just saying the organism died or the population crashed let's look at a few examples if we're talking about global warming we could connect that to a rise in ocean temperature then we could say that that's going to shift the temperature outside the range of tolerance for a fish species and since global warming increases water temperature and warm water holds less oxygen fish may end up suffocating due to lack of oxygen so notice how in red there at the end of the answer we've actually specifically given a physiological stressor so instead of just saying it got too warm for the fish we're connecting it to less dissolved oxygen and therefore the fish are going to suffocate we have another example here where we can connect global warming to droughts so that's going to shift rainfall patterns outside the range of tolerance for different plant species that's going to result in less soil moisture and the physiological stress here is that the plant's roots may not be able to take in enough water and so the plants may die again instead of just saying it got too dry for the plants we've actually connected it to a more specific physiological stressor which is lack of water so the roots are not able to bring the water into the plant that it needs to survive so again the big point of emphasis here on frqs in general but especially when we're talking about range of tolerance is be as specific as you can we don't just want to say it gets too hot for an organism so it dies we want to try to connect that to a specific physiological stressor today's practice skill for frq 2.4 is a little bit different than the ones we've tried in the past we've never done this one before but i want you to give it a shot it's going to be identifying the claim of the author so i want you to read this passage which is about thermal tolerance in salmon and then identify the claim of the author by writing one sentence that gives a claim in this case it should be an actually testable hypothesis so try to identify a claim that the author makes that could actually be tested with an experiment all right everybody thanks for tuning in today don't forget to like this video if it was helpful subscribe for future apes video updates and check out other notes over here to the side and as always think like a mountain write like a scholar