



S1: or i believe i'm (uh) participating in the experiment, you may also find yourself in in collateral damage so to speak, so i'd like to introduce Bret and Janine, who just want to, fill you in and tell you about the form you've been handed out. Bret and or Janine.
<MICASE RECORDING ANNOUNCEMENT> 
S1: well while you're filling those in you should know that uh, picking, myself as an example has doomed this to failure because, we uh had to buy a motor from Cedarville Marine up in the eastern upper peninsula this year, and uh i talked to Julie there who's in charge of sales and so on, and she was you know we everything went through and then Michelle and the rest of the crew who've been working up there went through and she said oh, um, your Mr Smith talks funny. and Michelle says yes yes yes yes she's she he he's from England she says well you'd think if he was from England he could speak English without an accent. <SS LAUGH> anyway
R1: so if any of you have any questions, um, you can talk to one of us, either after the class or [R2: we'll be hanging around until Wednesday morning ] we'll just leave our email with professor Smith, you could, direct questions to us through email
S1: i'll give you a couple of minutes because uh i, like you to listen to me as well so_ have you started taping? oh what do you know. <P 0:50> okay, this morning, we're going to continue, with the, discussion of, the factors that determine, where fish can live, their physical properties physiological properties and so on. we've looked so far, at the design of fishes, the way they feed, and those kinds of issues, and we started last time thinking about food, and feeding, and the physiological, capabilities of fishes particularly in terms of the way they process energy. today i'm gonna build on that, and we're going to talk about, how the environment affects the way fish use energy. the topic, this is_ that is, covered, this is often called the <WRITES ON OVERHEAD> Fry, paradigm, after a, physiologist who worked on fish in Canada, recently died, Fred Fry, who not only was great at collecting fish, but he had the most amazing fern collection, the biggest fern collection of anyone in Canada, at the time of his death, i don't know if there was a correlation. now, we've had strange weather, we've had some cold mornings, we've had some hot mornings. um, in the morning, if you're cold, what do you do?
S2: drink coffee
S1: drink coffee...
S3: stay in bed
S1: stay in bed
S4: getting out of here <LAUGH>
S1: get out of here
S5: dress warmer
S1: dress warmer. what about on a hot day what do you do on a hot day?
S5: (get) naked
<SS LAUGH> 
S1: i'm sorry i missed that one
S5: uh take your clothes off i don't know, less clothes yeah.
S1: get naked, okay
S3: take a shower
S1: cold shower is that before or after getting naked? <SS LAUGH> okay. your responses to the environment then, are all behavioral aren't they. you execute behaviors, you do various things, in order to, make yourself feel more comfortable. that's the response to various extremes, um if you're in the boat-well and we're struggling to the get the, uh Whaler going, you know you all start coughing trying to get away from the fumes and those kinds of things, so, your response to a change in the environment is behavioral in order to make yourself more comfortable, and in doing so, you're obviously going to expend energy for example, that you might have been able to use for something else for example swing dancing on Sunday night. however, when we're out in the field, and we're looking at fishes, what do we do? what do we measure?
<P :08> 
S6: in terms of what?
S1: what do you when you_ w- on these sheets, which are describing the habitat, what do you write in there?
SU-F: temperature of the water yeah
SU-F: oh the conditions 
S1: temperature weather, all sorts of things. what do you write about the behavior of the fish?
SU-2: where they are
S1: yeah but not so much in other words, wh- when you're feeling uncomfortable and it's hot, it's the first thing you think is, oh, it's ninety degrees, time to get naked. or, it's uh, you know fifty degrees, oh, time to time to stay in bed, so that your decisions are based on a measured thermometer temperature? no. so we have an interesting dichotomy here, in that as part of science, we measure, the heck out of everything in order to describe the habitat. yet, we know from ourselves, that, organisms don't respond to those things we measure, but rather some, effect of what they measure on the physical condition, and the comfort in the examples eight i gave you those kinds of things. now, we measure, a whole variety of variables, really only for one reason, as a standard for communication with other people. so that if i tell you that the temperature is forty degrees, you because of your superior knowledge of fishes, that's gonna tell you something about, the kinds of fish you might find and those sorts of things, so it's a standard for comparison, but it's not the way that an animal sees and responds to the environment, itself nor the way we ourselves see, and respond, to the environment. so we have a dichotomy in terms of, the way we measure the environment, a product of human technology, versus the way we actually respond to the environment. and um, if you think of human technology and all the devices you can use to describe the technology, there are potentially millions. we've rarely focused on things such as temperature but we could've taken, disso- dissolved oxygen meters out except i can tell you from experience most of the water around here is pretty saturated that we look at, um, we could've measured P-C-Bs and goodness knows what other various poisons that are kicking around, we might have measured we could've measured a host of things to physically describe the environment, but we haven't. you should be grateful. um... there's a technological view though, but the other view is to try and think of the environment the way the animal sees it, and to try and think about, an animal's eye view of the environment, and this is what Fred Fry tried to advocate. he said, how do animals respond to the environment. not what can we measure about the environment, but how do animals respond to the environment. and this led to, the what uh fish biologists call, <WRITING ON OVERHEAD> Fry's paradigm, in which Fry, set up a framework, to think about, common ways, and a common framework, whereby, fish respond to the environment. and it is an energetic based system, because ultimately, any response you make, requires changes in energy use. whether it's staying in bed, cuz obviously then you know you won't shiver, or whether it's, getting naked, so that you reduce sweating perhaps, whatever it may be there is an energetic consequence to everything you do, in responding to the environment, and, Fry, tried to, articulate this... in Fry's paradigm then, what are the guiding principles? what are the axioms of the paradigm? there are considered to be, four axioms, for Fry's paradigm, and a couple of important corollaries, and the corollaries plus some of the axioms link back, to what we talked about on Friday, balanced energy equation. the first axiom, is that the principle of conservation of energy applies<WRITING ON OVERHEAD> and how do we see that expressed in an energetic framework for fish?
<P :06> 
SS: (energy) 
S6: energy they get from their feed equals the energy that they have to work with?
S1: <USES OVERHEAD THROUGHOUT> correct the energy they get in the food is equal to the energy for metabolism and growth, which is the balanced energy equation... this is just the, higher order organization of which things are fitted and that is, essentially, you can't have any bits and pieces hanging out, you have to have everything accounted for, in terms of, the energy budget of the the fish. the second axiom is very important, because it says that, metabolic requirements, are met first <P :09> if there is a change in the environment, there is a metabolic, energetic, consequence. in other words, if you choose to run from the motor because you're suffocating in the boat-well from the fumes in the motor, there is energy required, for you to not even even not only make a decision which is a small amount of energy, but to run from the boat-well, for example. if you choose to lie around in bed on that cold morning, it means that uh there is an energetic consequence in that you're remaining in a microhabitat, where your energy expenditure actually is going to be lower. but if you decide to go out on a brisk walk, instead, then to to maintain your temperature, then, obviously energy is expended there. after, four or five hours in waders, energy has been expended in significant quantities, to fill your waders with sweat. and energy is delightfully expended, when you then go for a swim in the cool water at the end. okay so Fred Fry reckoned, um and i think he's probably right that in general, metabolic requirements are met first. you respond to the environment in a metabolic framework, and, they are met first. these metabolic requirements to think of some corollaries now are going to be met from, the physiologically useful energy <P :05> which is the energy, that is left over, after paying those taxes the fecal loss, the nitrogenous loss, and the apparent heat increment, all the procedures that precede, the assimilation and, um, making available the various substrates from food. a critical corollary here though, is that given the balanced energy equation <P :05> where P is the proportion of energy that's lost in the various taxes, R is the uh the ration, it must equal metabolism and growth, for a given amount of food input, meta- all the me- metabolic requirements are met first, therefore, the surplus, is available for growth, including reproductive products. mentioned this on Friday, the surplus is available. so for those ecologically critical factors, for the evolutionarily important factors, it's the surplus only that is available after all the living costs are paid. okay? so an important corollary here is that if metabolic requirements are met first then, growth, and material for metabolism, is based on, a surplus. the third axiom which essentially i've already described to you, is that all animal responses to the environment, are ultimately met at the metabolic level. <P 0:15> all responses to the environment are ultimately met at the metabolic level. a change in the environment, then has a metabolic consequence. change in the environment ultimately met- met- uh the metabolic level. this also has an important corollary, which follows directly from here, and that is, the growth responses, the surplus is going to be inversely related to the metabolic response, for a given amount of food available and remember, food is typically, limiting. in other words, if the metabolic rate increases, there will be a smaller surplus. conversely, if the animal behaves in such a way as to lower its metabolic rates by choosing an appropriate habitat for example, the surplus can increase. but there's inverse relationship between, growth and metabolism. the fourth, axiom, is that there are a limited, set, of, responses <P :05> in terms of animal, function, there are only a few ways that animals actually respond to the environment. and this is quite in contrast, to the technological ways, that anima- that we may measure the environment, when it comes to, how animals respond to the environment, then, there is a relatively, limited, set, of, ways in which animals respond to the environment. there are actually, five of these. and, let me introduce these to you and i'm gonna develop, a, flow diagram here so i strongly recommend, you leave a piece of area in your notes so that we can fill this in, as i develop the pieces. okay. first of all, there are two major categories, of ways in which animals, can respond to the environment. these are, lethal, and sublethal. um, you could quickly deduce, there are there are some factors in the environment, that kill, and the response of the animal is to turn over with its little fins in the air and say goodbye cruel world. alternatively there are whole other things, that can affect animals, that, do not, kill them. now the, lethal factors virtually anything can be a lethal factor. um, too high a temperature can kill, too low a temperature can kill, too little oxygen can kill actually too much oxygen can kill, carbon dioxide all the things we can measure, can be at high enough levels, that they can kill organisms. however, death does not occur instantly. at least for most things, um, unlike uh say in Terminator when the uh bomb goes off and everyone's fried within seconds, uh usually the environment doesn't kill quite as fast. it kills relatively slowly, so what (if) animals can enter situations, that would if they stayed there would eventually kill them, and they can wander in there for a while. turns out that there is a, um a resistance zone. if we think of, some environmental variable, such as temperature which we can measure, there is some point out here where if the animal stayed, it would die... and there is another level out here, where it is totally sublethal. let's think of a trout. what temperatures are likely to kill a trout if a trout's stream goes up and stays at those sorts of temperatures Dana?
S2: twenty-five?
S1: say twenty-five so the ultimate lethal la- lethal level for something we can measure, for a trout might be twenty-five C. um, what sort of temperatures might be important if uh the thing's just sort of not feeling too great, maybe down here at twenty-four twenty-two say, they can remain at twenty-two though that's pushing it a bit, well trout can still move into this zone, because in this zone they will resist death, and therefore export a zone of, resistance, they can resist death for a while even though if they stay there they could die. this is quite important because say in a lake such as Douglas Lake that stratifies and you have a thermocline, we have warm water above and cool water below. now the water above might be well what's the temperature at the surface of Dougla- Douglas Lake just at the moment? 
S4: twenty-four
S1: twenty-four? oh darn there goes that example. what was the temperature at Kleiber dam? was it twenty-seven? something like that? okay, um, but in the bottom of Kleiber dam, the temperature was probably pretty low, probably down maybe as low as fifteen sixteen, so there's nothing to stop a trout, coming up into this twenty-seven degree water, for just long enough to snatch off some im- poor innocent, unsuspecting minnow. so, fish in lakes such as these, such as the cold water fish, may come inshore, to the, warm water, potentially lethal water, say to feed. those, perch we caught in the gill net, i'm sorry to remind you of that, they had come from the cooler waters, moving onshore, to feed. now Clay and John are picking up some of these mosh- movements of the fishes in the- in their project to see just how much they are, and the larger fish typically are down in the cooler waters and they move in upshore and, you are finding probably not today in view of the weather, but certainly on the first run you found the inshore offshore movements of some of those fish. and what they're doing is, in spite of the fact that the surface temperatures if they stayed there, would be lethal, they can still go in there for a while, to exploit the resources and then run off, run back home to the, the cool water. so, in this uh, lethal, in terms of lethal factors, there is an ultimate lethal level, for anything we can measure, that will eventually have a, well biological response, a sort of behavioral response, in that the animals will die, okay? but, it always takes time to die, and fish can exploit the resistance zone, between the completely sublethal level of a factor, and the ultimately lethal level, they can go in there for a while come out and so on. so in the boat-well, while we're getting the engine going in spite of the fact that the smoke becomes blue with fumes and bad language, we can still tolerate that carbon monoxide, for a short period of time, if, we're stupid enough to but we can still tolerate it for a while right? how many of you have seen The Full Monty? not many of you have seen The Full Monty yeah, you know that guy was able to be pulled out of the car where he was trying to commit suicide, um because it does take a while and thereby it saved his life. um and if you haven't seen The Full Monty have you seen The Full Monty you should see The Full Monty, um, in your spare time. okay, so these are lethal factors. one thing to mention about lethal factors, is that they, uh it's a very common method, used in monitoring the environment. and it's used in, bioassays. there are many forms of bioassays, but a very common form, is this lethal bioassay, where they will spo- expose organisms such as fish, to a wide range of say, temperatures P-C-B levels and so on, and construct a curve to try and find the relationship between, dose, and death, um, drug companies do this kind of thing although they are trying to find the relationship between dea- uh dose and life of course those kinds of things, but the bioassay is a very standard method for pollution control and these kinds of things. it's a very easy technique to use because, it's very easy to tell when a fish is belly up and therefore dead. but, i hope you realize, that as a technique for monitoring the environment, it's really pity(sic) s- pretty stupid. after all, if you're in monitoring the environment, you actually want, living organisms, not dead organisms, so why do you measure death in order to, provide something that is safe? there's a logical disconnect there. the problem is it's easy, and there are other and better ways but very much more expensive ways, if you're interested in, life. okay. well those are the, uh the lethal levels. so there's the lethal level. now let me think about the, uh and this causes death... or, it destroys the functional integrity of the organism, which i always thought meant death, and these do not, cause, death. now there are two, major categories amongst the s- the sublethal this sublethal group. the first is a set that the that affects, the amount of energy, that can be made available <P :08> so it determines the amount of energy for metabolism, there're another set of factors, that determine the distribution of energy, in other words, how it is used... because, i- in thinking of the way animals respond, they, they're going to use energy for various things, and those things are gonna be changed by the environment, but before the environment uh can d- can cause a change in the use, the environment also is gonna affect, how much is going to be available, how much is gonna be available. and let's look at the this set first because there are two groups, in here, that determine, how much is available. one are environmental factors called controlling factors, and another is a set called, limiting factors. these together, determine, how much metabolic energy, an animal has, in order to interact with, the, environment. let's look at these, uh in t- in uh sequence. controlling factors first of all, are fundamentally, going back to, the chemistry that you thought you'd left behind you, the physics that you thought you would never see again. um, well as we've seen already these things keep rearing their ugly heads. um, does anyone remember anything about enzyme substrate affinities? yeah i see some heads nodding. well, um, you'll recall, that, a certain amount of energy is required, for an enzyme to bind with its substrate and thereby, participate in an enzyme catalyzed reaction. and uh the amount of energy that's available, depends on the kinetic energy and of course we can, quantify the kinetic energy, in terms of our measurements of temperature. okay, so you need a certain amount of energy. what happens, if the amount of energy in uh that is available in the substrates and so on increases? metabolic rates, enzyme cataly- catalyzed reactions, start going faster don't they? therefore any environmental factor, that affects the kinetic energy, of the reactants, is gonna cause chemical reactions to go faster. so these controlling factors, are factors that actually affect, the rates of biochemical reactions. now you'll alwa- also remember from the laws of mass action, that the rates of a metabolic reaction, depends on the concentration of the products and the physical condition of the products. we also know then that anything that influences say, um volume changes and so on will also affect rates of reaction. for example, suppose an enzyme and a substrate combine, and in doing so, there's a volume increase. anything that prevents such a volume increase is gonna inhibit that reaction. so things that also affect spatial, factors about che- uh reactions, also, can alter_ things in the environment that can ho- uh chan- things in the environment that can affect, the spatial changes during reactions for example, can influence them. now in terms, of human technology and measurement, what are the two, factors in the environment that we could measure, that will influence this fund- the fundamental, biochemical properties, of metabolism...?
S3: temperature?
SU-M: temperature? 
S1: temperature, temperature is our, indirect measure, of heat energy and kinetic energy and so on. and what about, volume changes?
SU-M: pressure 
S1: pressure. fish, as species and or as individuals, are exposed to a huge range of temperatures, and potentially a huge range of pressures. these can affect rates of reactions and therefore, the amount of energy that is available. if we were to, plot a relationship say, between temperature, and metabolic rate, we would find then as temperature increases, that, the active metabolic rate increases, and so does the standard metabolic rate... okay? the active metabolic rate and the standard metabolic rate. these two shaped curves, are not a slip of the pen. the sta- the active metabolic rate does tend to increase more linearly with temperature, whereas the active_ the the standard metabolic rate, tends to increase curvilinearly, essentially, doubling, for every ten degree r- change in temperature. in fact, we measure, the effect of metabolic rate, on temperature uh temper- we we- measure, quantify the effect of temperature on metabolic rate by a quantity that we call, Q-ten, which is the rate at any temperature... at uh ten degrees higher, than that at a, lower temperature. should be familiar from with Q-ten from uh, basic biology. is anyone not familiar with Q-ten? <SEVERAL STUDENTS RAISE HANDS> okay then obviously basic biology failed let me, <SS LAUGH> digress a little here. um, there is no fundamental physical set of principles to describe, the precise effect, of temperature on enzyme catalyzed reactions in real organisms. organisms are way too complicated, for some simple physics to describe exactly, what is happening. but because, temperature has such a huge rate on metabolic rates because of its fundamental biochemical, um effects, biologists, do need a way to communicate with each other about the effects of temperature, so they invented this Q-ten, and Q-ten is just a descriptor, so if i take the rate of metabolism at this temperature, and say it's ten milligrams of oxygen per hour, and i look ten degrees higher and i measure it again, then maybe it's twenty milligrams of oxygen per hour, so at the the higher temperature it was twenty, um at the uh lower rate it was ten, that gives you a value of Q-ten, of two, and typically, um metabolic reactions increase by a factor of two, for every ten degree increase in temperature. that's quite a steep geometric function and you can realize that over a forty or fifty degree temperature range that is typical of, fishes over the globe, that's a huge change in temperature. um, that is accounted for by adaptations in the enzymes as you might expect. um, if we look at metabolic scope, which you will recall is sta- active, minus standard, you wind up, with a curve sort of relationship, because of the shape of the standard metabolism, the scope for metabolism is relatively, lower, at, higher pressures, and it is also low at very low pressures or at very high_ uh very low temperatures or at high temperatures.
S6: X axis is wha- is that temperature or pressure? 
S1: uh the X axis is still temperature thanks Mary... you'll notice that there's a hump in the middle. at that hump in the middle, the metabolic scope, is largest. this means, that where the metabolic scope is largest, the, fish have the largest amount of energy that they can make available, a surplus energy, no i shouldn't use surplus cuz i use that for growth but the largest amount of energy in which they can deal with environmental change. where the metabolic scope is highest, they can change the metabolic rate, by the largest amount, in order to deal with the unexpected. running for the bus for example when you suddenly need a big increase in energy. um well, that is the, um, place where metabolic scope is highest. and for this reason, this is sometimes defined as, an optimum temperature. recall when i told pe- when i told you, that people say talk about an optimum this or an optimum that, always ask what the criteria are. this optimum temperature is defined as that, that maximizes, the metabolic scope and we can do the same thing with pressure, or any other factor, that directly affects, the biochemical properties, at a fundamental level. s- and temperature and pressure are the things we measure, that can do that. now some interesting experiments have been done at various times, where for example, fish have been put, in a metal trough in which you heat one end, and cool the other, so it sets up a temperature gradient. and you then look in this trough, and you see, where do fish prefer to be? do they have a, preferred temperature, and what is it? well fish do have, preferred temperatures. and they would choose those temperatures, whenever you put them in a trough in a temperature gradient. it just so happens, that the preferred te- well i don't think it just so happens, but it so happens, that the preferred temperature of a fish, is that at which the metabolic scope, is maximized. so this optimum, as determined by, physiologists, proves also to be the, preferred temperature, for fishes. it is believed and uh, this is, at least confirming evidence, that fish will tend uh it was believed before this was shown that fish should, choose temperatures that maximize their metabolic scope, that maximized their capability of responding, to, changes in the environment. that makes sense doesn't it? if things are gonna change and you don't know quite how, give yourself, as much pillow as much cushion, as possible. okay? this applies metabolically, as well as, putting you guys through college or whatever it may be, uh in my case looking at retirement and goofing off, um and so on you know, have as much slack as you can it applies metabolically, as well.
S6: so Fry made that prediction before the (xx)
S1: Fry did indeed. and uh some guy wanted to pad his publication record you've all heard of padding publication records, spent years doing this experiment and publishing one fish's preferred temperature and then another and then another and then another, until he was the laughing stock. he had a huge long publication thing, absolute laughing stock, a warning for those who believe in um, the least publishable unit. okay, these are, controlling factors. they control the rate of metabolism, by the fundamental effect on the state of activation of matter, and the way in which biochemical reactions take place. it doesn't matter, what you necessarily measure, this is a common, biological response, for a suite of factors that technology can measure and we can call, temperature and pressure. but the principle in terms of animal responses, occurs in a- i- in terms of biochemical reactions, the fundamental, biochemical reactions that underlie metabolism. now it's all very well, having a metabolic capability, that is set by, these, controlling factors. but you can only realize that potential, if there is nothing in the way. you can only realize that potential if there is nothing in the way. for example you have tremendous potential up here, to learn all sorts of things. however, if you have to eat in the cafeteria for eight solid weeks, then you're likely to go crazy and you won't realize the full potential, right? you have to get out of camp occasionally, um, that's a, a somewhat arcane limiting factor but but it illustrates the point. other, in terms of the um re- responses to the environment, any factor in the environment, that prevents an organism from realizing its metabolic, capability, that is defined as, a limiting, factor. now, continuing with our metabolic framework, let's think of say metabolism C-six-H-twelve-O-six equals six C-O-two plus six H-two-O plus energy, okay this is what we're doing this is the overall equation for the metabolism of carbohydrates with oxygen, oh we've missed out the oxygen. the overall, metabolism of carbohy- by by burning it with oxygen. what happens if there's not enough oxygen?
<P :05> 
SU-5: they're not gonna have enough energy
S1: gonna slow the rate of metabolism isn't it? in other words, the uh things like temperature and pressure, controlling factors will determine, the potential rate for this reaction. but, if oxygen is limiting, you won't realize the potential. if carbon d- if uh carbon dioxide, is not removed, then you know from the laws of mass action that you'll slow this reaction, and the potential won't be realized. if we were looking at the metabolism of an amino acid, if, the nitrogen, was not being removed fast enough, then that would limit the reaction. limiting factors then typically, interfere with, the supply of metabolites, and or, the removal of waste products. so factors that limit metabolism, that prevent the metabolism from realizing the potential, set by the controlling factors, those factors preventing that potential being realized, are considered, limiting factors. they limit the potential from being realized and they are typically the metabolites the substrates or the products of metabolism, that have to be supplied at adequate rates, or have to be removed at adequate rates. Jenny did you have a question?
S5: yeah i just_ you said that the supply of metabolites and
S1: okay i repeated it. okay. um, i think this is pretty obvious and it doesn't matter what we measure. okay? anything, that interrupts metabolism in this way has the same metabolic consequence for the organism, and that is, it limits the metabolism. it doesn't matter whether it's high levels of say zinc in the environment which damages the gills, it doesn't matter if it's low oxygen, it doesn't matter if it's high carbon dioxide, it doesn't matter if it's an accumulation of waste products, it just simply doesn't matter, the metabolic response of the animal is identical, in all of those situations, and if you know that something is a limiting factor, you know what it's going to do. and if you measure something new or you could, you know what suites of chemicals do, you know what the animal response is you don't have to study every single individual, jot and tittle and so on in the environment, because, you can often deduce the category of responses it's likely to be and therefore, know what the animal is going to do. or, let us think what happens with a a limiting factor because, we get s- some interesting kinds of results here. let's look at metabolism again, and we'll look at uh we'll look at uh the controlling factor as a function of temperature, and here's the active metabolic rate and here's the standard metabolic rate. a limiting factor, something that interrupts metabolism, is likely to have its greatest effect, when the energy demand is highest. for example, if you're just going for a walk, in the middle of Ann Arbor where the carbon monoxide levels are substantially higher than up here, you know that's fine. but if on, you know Saturday night when the traffic's crawling down Main Street, and you're sitting having your coffee <COUGHS FOR EFFECT> you know, and then you have to run somewhere, it's when you have to run somewhere that suddenly the uh, pollution effects are likely to be realized, so that um, limiting factors have their largest effects, when animals are pushed towards their, their limits. they tend to depress then, the, maximum potential, you can realize. now, if you, look at the metabolic scope now, as the same function of temperature, and we have this relationship normally, when you subtract off this maximum, find an interesting thing happens. first of all, the range of habitats in which an animal can live, has been restricted, as a result of this limiting factor. it can no longer live, in the full range of environmental possibilities, that might be possible, with just thinking of temperature or pressure alone. this additional environmental factor, has limited, the range of environments in which the animal will now, choose to live. adding this second factor then, has restricted, the set of habitats in which the animal can live... this part of the course we're talking about, what factors determine, where animals may live. and you can begin to see that this physiological approach that Fry is putting together, is beginning to contour the space if you like, in which an animal, may, live. and maybe it's doing it in a way that's fully quantifiable. something that we can measure and put in our computers as, wonderful three-dimensional displays and so on, we can contour, the space, where animals, may, live. which is after all, the goal, of, this first part of the course. something else is interesting. note, that here, it's the optimal temperature because metabolic scope, has increased. but now with this factor, the, m- ma- the scope is maximized, at a somewhat, lower, temperature. this means then, that... if the preferred temperature, for a fish, where a fish chooses to live, is determined, where the metabolic scope is maximized, the interaction of these factors, is going to make this fish now, choose a different environment. in terms of in this case temperature. and that's what happens. in experiments that are done, where fish are given choices in habitats, when you begin to add on, these factors that are now limiting metabolism, instead of choosing, the habitat, that in the absence of limiting factors maximize scope, they choose a new habitat, that still maximizes the metabolic scope, but it's a different habitat. so, this approach, in thinking about how animals respond, how you described your response to the environments, fish are doing the same kinds of things. the environment, is not, measured by a fish in terms of temperature, or radiation levels or U-V-B and those kinds of things. but in terms of its behavior, in ways that affect its metabolism, exactly the way you described your behavior, with respect to heat and cold. and just as we could c- cou- we could define your, preferred habitat and where you lived and so on in terms of those behaviors, so you can by fish and there's just these limited number of factors, categories, that do so. okay? so these two sets of factors, determine the amount of energy that's available for metabolism, and therefore, the amount, of scope if you like, available to respond to changes in the environment. it max- the animals, choose, factors that maximize the cushion, environments that maximize the cushion, in terms of these controlling and limiting factors. and again it doesn't matter what you measure, this is a demonstrable, metabolic, uh res- response, and the animal's behavior is such, as to achieve, these, metabolic, maxima, in terms of, scope. you all with me? it's a pretty dry subject i know. stop smiling, um, okey doke. distribution of energy. there are two sets of factors now, that determine, how the energy, is actually, used let me see if i can get it all on here. one of these is, regulatory, and the other is, directive... let me take these two, one by one. animals are made up, of a whole complex of systems, right the way from their biochemistry, through to the whole organism and so on, and the purpose of all those, is to provide some sort of, environment in the cells, for the metabolism, so it continuing functioning op- functioning optimally these kinds of things. in other words we are a mass of regulated systems, and those regulated systems are designed to provide a buffer, between, desirable conditions inside the animal for the biochemical aspects of metabolism, and the all too variable environment, which can, vary in ways that are not always predictable how many people were expecting a storm this morning? i wasn't i hung my washing on the line last night. [S2: oh no ] yeah it wasn't much i'm a clean guy... so, there are a whole of bunch of, c- uh situations regulated situations. if there is a change in the environment, temperature, P-C-Bs carbon monoxide mother-in-laws you don't know about that yet, or whatever it may be, change in the environment, a- and that affects a regulated system, then something is gonna happen, to push that system back to wherever its set point is or, or whatever. that requires a change in energy use, in other words, from the energy that was a- made available from from the environ- for- the energy that was_ is made available as a result of the interaction of controlling and limiting factors, now if there is a change in a regulated system, some energy is going to be shunted, somewhere, in order to deal with that regulated system. if you're stressed, and you have a high energy use, and things sort of get easy, in four weeks time, um your energy, your energy consumption may go down. now it doesn't matter what you can measure. it doesn't matter whether we're talking about heavy metals P-C-Bs, um levels of carbon monoxide that make you uncomfortable changes in carbo- in the global carbon dioxide level, um all these kinds of things it doesn't matter, the fish respond energetically in the same kind of way, they shunt energy into this regulated system, to correct, a perturbation. just as you turn on the heat, turn on the air conditioning to regulate temperature, animals are doing exactly, the same kinds of things. and uh, l- let's think about what happens here, and again i will continue to, set up, in terms of, a controlling factor, and the metabolic rate, and here we have the active metabolic rate, here we have the standard metabolic rate, and here we have the scope... now, we define standard metabolic rate as something that keeps body and soul together and all those kinds of things. but if a regulated system, is changed or has to work differently, then you see this as an increase, in the, standard metabolism. opposite to the limiting effect that we saw earlier. however the effect, is quite the same kind of thing, for the... uh regulating factor, as it is that we saw for the limiting factor. the optimum temperature, is shifted, there's a new optimum temperature, and the range of habitats that can be occupied, is also shifted. the principle, wow, becomes the same, a common principle, now. that factors then that begin to interfere with each other all have the same thing they interact in ways, that limits the range, of, something in which the animal can live the range of environments in which the lif(sic) can uh fish can live, or any other organism for that matter, and it also shifts the optimum environment the one that is that the fish will choose, to maximize, its uh, cushion its scope for activity. Mary did you have a question?
S6: so you're saying that, the need to use a regulatory system, increases your standard metabolism?
S1: um, typically a change in the environment from the preferred environment, can be thought of as an addition to standard metabolism. it increases the energy required just to keep body and soul together. a_ for you, in winter, with inadequate s- s- central heating, you will, make up for the inadequate central heating, as so often happens in campus housing i understand, uh will be maki- make up for that, by increasing your metabolism, if it really gets cold you'll start shivering, but you'll still crank up your metabolism a little. on the other hand in um uh, in in the summer, when you'll be sweating like a pig all the energy will be required for that, um, if you don't have air conditioning. and these can be seen as an increase in the minimum energy the standard metabolic rate, in order to keep body and soul together. um, stresses of all sorts will do the same thing. all the chemical stresses uh uh and so on, that are in the environment will tend to do the same, kinds of things. the, response of the organism to this category is always the same. the consequences are entirely predictable, in terms of energy supply, and therefore in terms of the range of habitats where the animal may be able to live, and indeed in terms of the, preferred habitats for the animal<P :07> did you leave lots of space? the, last category is, directive responses. and there are two types in here, and these are things that affect, the animal's use of energy in space, and in time, and that figure is now, complete. let's think of uh, the use of energy in space. we're in the boat-well, we pull the engine uh the the starting cord, on the, on the Whaler, nothing happens blue smoke comes in. you know you're starting to cough and choke, um because i forgot to put the Whaler outside before doing this knowing the consequences. what do you do you run out. in this case, you are using energy, in space. to redistri- to i- in space. you are changing your location, and the metabolic consequence is that driving locomotion so, this th- in this case the blue smoke from the engine, is directing you in space. and that direction in space, involves the expenditure of energy. and it would appear in the same kind of ways, of um if it was a sustained energy requirement, that uh, y- tha- tha- that was- distri- directing you in space, then that would have the effect obviously on environmental choices but, i- it's pretty obvious that if you move from one place to another, these directing factors, are affecting, the distribution of the organism, into different environments. um something else we can measure such as oxygen. if oxygen levels are low, fish will move to, different habitats. the low oxygen the environmental condition, that the animal wants to avoid, will direct it in space. things that attract animals such as, dog food in uh minnow traps, um uh an olfactory cue in the environment can direct an a fish in space. okay? and as a result it's gonna change the habitat, in which the animal lives. now we've got some fisher people here, um, out in Lake Erie do you fish in Lake Erie? do you eat the fish in Lake Erie? uh okay. um if you have a choice between the thermal plume, from the Cook Power plant to the rest of Lake Erie where are you likely to find the biggest fish?
S2: the bottom
SU-F: the bottom?
S1: in the plume or the open lake. the bottom's so close to the surface in Lake Erie. okay well you haven't experienced this then but fishermen say you catch the biggest fish, by thermal plumes power plants are good for us, they provide big fish, um, this is a case where, um a lot of the predators, will accumulate near these productive areas, to feed, um and they have been attracted, they've been redirected in space by in this case the thermal environment, in such a way that they can increase their energy uh, consumption. so these are factors that direct animals in space. they can also, you can also, see, um that animals are directed in time... February this year. it was still grey in Ann Arbor wasn't it. how did you feel in April when the sun came out...? good? great? terrific? you know they say when spring comes a young man's fancy turns now why is that? things are happening in time. um, the environment is variable, but there are certain clues in the environment. things like photoperiod, temperature period, are major factors. they corollate with major events in the environment and many of them, happen to do with good times to reproduce and those kinds of things, and tend to be associated with sex, but there's also getting ready for winter. when winter comes, fish, um go and hide those kinds of places. so, factors in the environment can also influence the way fishes respond in time, particularly seasonally, for reproduction, for parental care, for migration, and those kinds of things. these again involve energy expenditures. um, i'm told that uh, sex requires a lot of energy perhaps you could advise me sometime, <SS LAUGH> um... that energy sort of has to come from somewhere. hence the preseduction meal perhaps, that we were talking about the other day, <SS LAUGH> um, but anyway, uh uh i- as you can see there there are energetic consequences though in preparing animals in time, for various events that are happening in the environment in their life, and again, this energy is entirely the ener- the energy use is entirely predictable, and in term- in in the same way as we talked about with limiting and um regulating f- um, factors, so that fish are choosing environments to maximize their available energy, in space and time, um as well. now, i focused on, metabolism, but for every single one of these, any factor, that has an effect that increases metabolism, is going to tend to decrease, growth... i'm not gonna go into that with any detail, but i'm sure you can realize that we could run through all of these factors, and look at the growth implications. so that we could think about how, a controlling factor influences um use of energy, um the acquisition of energy and those kinds of things, i'm not gonna do that, um, because, it all essentially follows, from the balanced energy equation and given a, a certain amount of food, you know what are going to be the growth consequences, um you know what are going to be the growth consequences, uh for a change in metabolism and food tends to be, limited. therefore, anything in the environment, that increases the metabolic needs, tends to reduce ne- growth, it tends to reduce the surplus available for, growth and reproductive products. now, a lot of animals are already walk- working or uh hm, <SMACKS LIPS> a lot of animals are already walking a tightrope, in terms of the surplus energy available, for growth reproduction, and for survival. so a factor in the environment that reduces the surplus available, it's obviously going to have an impact on the persistence of an animal, in its environment. so again we can see how this framework, can begin to contour, where animals can live, and where they, do not live. now, for that reason, looking at metabolic responses, is a very very good way, of bioassaying and monitoring. this traditional bioassay that kills animals as i pointed out is looking at the wrong thing. we're not interested in killing organisms, we're interested in the conditions whereby, they can persist in a healthy way. and i would suggest to you, that um, a metabolic, a metabolic response is_ that you can measure relatively easily and now with computers and so on, you can do them in bulk, is a much more sensible way of thinking about, and monitoring the environment. and with a framework such as the one that Fry advocates, you know the choices in which you can fit things i- are relatively small. you know what's gonna happen. and you then know for different chemical species you don't have to measure all the chemical species if you know, a little bit about the periodic table, then you know that certain metals are all gonna have the same effect you don't need to study all of them. so you ha- a- set up also a predictive framework, that can obviously be more economical in terms of animals sacrificed, time space money and uh, and those kinds of things. the only caveat i do want to add that is primarily, uh important it's i- w- well mainly important in production situations, is that, um, in terms of the total intake, as i said energy is typically limiting so therefore a change in metabolism, will have an effect on growth. but in culture situations you can regulate that. and as you increase the temperature or, since we don't usually modify pressure in culture situations, you can begin to, um, manipulate the growth rates. because the rates of metabolism go up with a controlling factor effect, fish can also eat more and grow faster, if the food is available and the temperature is higher. of course this is why fish are born early in the spring, when all the food is popping out to take advantage of that. but ultimately food is limiting in the in most environments, um, but this does become important in culture situations... okay i want to, oh, finish this by, looking at some of the, um, strengths and weaknesses that are involved here, because some of Fred Fry's students uh about, twenty years ago actually it was but it was kind of fun at the time, um and some people still, um, believe this is all you need in order to describe where fish live. and that you can quantify exactly where a fish will, and should live. you can describe the environment in terms of measurable parameters, you can actually contour, that N-dimensional hyperspace that is the niche does anybody know what an N-dimensional hyperspace is like? i can't even conceive of it but anyway, here is a way, to contour the environment to actually put numbers on, the N-dimensional, hyperspace, that is this arcane, definition, of the niche, that, was handed down to us i guess by Hutchinson and co right? we can do it, we can actually define, where, the fish can live, and that was a great argument which involved Jim Cobb, and um, Darrel Watson, who's a ecologist at um, Wisconsin, because, Jim Cobb, uh j- uh Watson essentially said to Jim Cobb, in print, this is the biggest load of carp i've ever seen... now why is that? here we have a device where you really can measure everything, and you can contour this N-dimensional hyperspace, in measurable quantities, and all these kinds of things. surely then we can say where the fish lives. well yes we can, we can use this kind of approach, plus the biomechanical approaches on locomotion and feeding mechanisms and so on, to define, where a fish, may live, and that is its fundamental niche. fundamental niche is where a fish, may live. the problem is, it doesn't tell you where a fish does live or any other organism. and Darrel Watson really absolutely, socked this poor guy, in the chops, just knocked him flat, cuz he said, your approach, cannot predict, what happens, when you add, a competitor to the situation, or a, predator, to the environment... okay? there is no way that you can predict, what will happen, when those, biological, factors, change <P :04> sure if you add a predator to s- t- a predator to the system, you_ we can say yes, the metabolism may increase as the fish flees from the predator more often, um and we can talk about how the a- presence of a competitor, might reduce the amount of food that's available and reduce the surplus for growth, and therefore a- a- and so on. yes we could talk about that, but, we can't really predict what's gonna happen to the metabol- well we can actually predict what's gonna happen to the metab- metabolism of the fish, that is caught. but we can't predict, the population dynamics. you can't predict the community structure. you cannot in other words predict, the realized, niche. you can't predict the realized niche, which includes, both the, bot- biotic factors, and, the abiotic factors, plus the third element which is chance that i'll be talking about later. so why go through all this stuff? in terms of understanding, fish capabilities, in order to, understand, how fish, respond to a changing environment, certainly in understanding how fish, respond, to a human modified environment, in terms of the physical chemical composition of that environment, this is a very strong and useful framework. it is extremely useful the things we have been talking about so far, in understanding, where a fish may live. it's an extremely powerful approach for predicting, where fish may live, in ways that are, testable. science advances by formulating testable questions, and in theory, falsifying those hypotheses. this is an ideal way of saying, hey, this is where a fish should be, and if it isn't, what is going on it helps also articulate, the questions about the realized niche and things that are important. for many fish, the fundamental niche is the ones that they they they they do in fact occupy as well it also happens, to, uh coincide with the realized niche, but it is, incomplete. since you cannot predict, what's gonna happen at the population the community levels, what happens if you add a competitor, what happens if you add a, a a a predator, or what happens if a chance event such as this morning's storm comes by. you can't handle any of those, and those are the factors that are, added on top of, these fundamental niche ideas, to affect the ultimate, distribution, of, fishes... and there i will stop for a short break any questions? there's a a lot of material in here, and, it does require a mindset which is a little different, from the one you're used to. e- the mindset you're used to in science classes is, measurable quantities using human technology. this is a mindset, that tries to take an animal eye response-related view, of the world. so it's a little different, and my experience has been, that you probably need to think a little about this. and of course we'll have a review session later. okay? any questions...? terrific. well um, can we reconvene, i've got a few pieces of business and odds and ends i have to deal with, and i want to say a little bit about how things are going with the projects, so i'd like to reconvene if we could at half past nine. remember there is good coffee in the store. okay?
SU-M: there was good coffee
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