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Video transcript

hi it's mr. Andersen and welcome to biology essentials video 47 this is on ecosystems and we happen to live next to one of the most famous ecosystems on the planet that's the Greater Yellowstone Ecosystem so we live a ride here in Bozeman which is about 60 miles north as a crow flies from Yellowstone National Park and so when we're talking about ecosystems we should figure out where an ecology what level were at so remember Bob Expo is biosphere biome ecosystem community population organism and so basically what is an ecosystem an ecosystem is going to be on all of the biotic and abiotic characteristics in an area and so yellowstone park was founded in 1872 and it was mostly founded to protect these geothermal features and so if we what are what is most famous would probably yell Old Faithful which is about right here but Yellowstone is situated on this giant Yellowstone Caldera which is kind of like that and so when they establish Yellowstone Park they establish it just to protect on the geothermal features so the hot springs the boiling mud and all of that but what they ended up doing luckily is preserving one of the most pristine ecosystems on our planet and so yellowstone part if i look over on this map if i were to trace it it's about right here so this is right on the corner of wyoming and goes into mind montana and idaho toe over here but if you look at around here there's all these national forests and so we eventually have this giant ecosystem which is kind of in this brownish area they didn't really start talking about it as an ecosystem until the 1970s when they were studying grizzly bears and they found that grizzly bears bears were in trouble but this was kind of where they ranged so this was their their range but you can see over here that we're not sure what what an actual ecosystem is how big it is and how big we should make that what's interesting is that this is all a national park and these are national forests around it but once we move out into here we're moving into private land and so there's an interesting kind of conflict that comes up when we move from national land to land that's actually owned by people on the wildlife isn't but the land surely is and so it's a hard thing to maintain but even with all of that Greater Yellowstone Ecosystem is the most pristine ecosystem in the northern latitudes especially in North America that we have so it's pretty cool it's nice to live right next door um so basically in this podcast I'm going to talk about ecosystems and how they're affected by their environment remember they get energy from the Sun but the matter has to be recycled and so the combination of energy coming in and then the matter especially carbon being recycled we come to a new term here that's called primary productivity so depending on where you are on the planet you have either a high level or a low level of primary productivity basically what that is is the producers in an area it's how much biomass they're laying down as a result of that we have these very complex reactions and so those are called food chains basically a feeding chain and if we get more complex that's called a food web but remember every organism that's living in an ecosystem is adapted to that environment and those specific constraints now sometimes there will be impacts on a ecosystem and so those impacts can be biotic or abiotic remember they could be living or nonliving but basically what that does is create competition and so all populations are limited by the amount of availability of these resources that they have and so eventually all populations will undergo logistic growth now if we think let things run naturally they tend to fit a regular balance or find a find an equilibrium but lots of times humans will make changes and those changes can have very quick impacts on an ecosystem and sometimes can lead to extinctions and so let's get started let's first start by defining what primary productivity is primary productivity as I mentioned just a second ago is how much livable mass is being laid down by all the producers in an area remember the producers are going to be those things that do photosynthesis and so they're using energy and then they're weaving matter together to make life and so if we look on our planet we find here in the ocean we're going to have this is measuring the amount of chlorophyll a we're going to have a higher primary productivity here and here then we are right at the equator and that has to do with the currents in the ocean so we need nutrients and we also need availability of light obviously in the Sahara we're not going to have a lot of primary productivity but we're going to have more as we move up into this area the coniferous forests or for sure in the rainforest and so what do we measure primary productivity in well it's grams of carbon per meter squared per year in other words if we were to go out in this Prairie and mark 1 meter so we'll say 1 meter area like that in one year it's the amount of carbon that would be added now how is that carbon being added we're taking in carbon dioxide from the atmosphere we're using light from the Sun and then we're making it into livable material and so it's easy to measure in an area like this just put a quadrant down and measure that sometimes it's harder if you're in a and this would be a terrestrial area or an ecosystem this would be an aquatic area so when you're in water lots of times it's harder to measure the the matter that's being created so sometimes we'll measure the gases that are being produced so we can look at the oxygen that's being produced in an aquatic environment so right here we're going to have higher levels of oxygen being created because the producers are taking that carbon dioxide and making it into a derp so primary productivity is going to be just a measure of how much life can be created in an area on food chains measure where this life goes and so if we start here on the on the right side I've got what are called trophic levels and so we should define what a trophic level is first trophic just means an eating level and so the lowest level trophic level one we call that are going to be producers and so if we're looking at a food chain here in Lake Ontario what are the producers going to be out in this lake it's mostly going to be algae so what they're doing is converting energy from the Sun into livable material and so we would call this trophic level one or sometimes we call these producers okay so if we go to the next level next level trophic level two these are going to be consumers and so consumers remember can't make their own food they have to get their food from somewhere else and so if we were to do a food chain the food chain is going to go like that now that arrow you should get used to the arrow is always going to go from what's eatin to what eats it and the way I remember this is if you look at the head of the arrow it's like the mouth so it's like the mouth of pac-man and so whatever is eating is going to be on this side of the arrow and whatever is eaten is going to be on that side of the earth so now we go to the third level third level is going to be we call these second level consumers but those are going to feed on these organisms so algae is eaten by alpha pods which are a little crustacean those are fed on on by rainbow smelt and then if we were to go one more level then we get to the level of chinook salmon so this would be the fourth trophic level or we call this a first second third level consumer now this is a food chain food chains are linear they go from what's eatin to what eats it to what eats that to what eats that so it just goes in one direction but you can imagine that there's a lot more food chains in Lake Ontario than the one that I've just drawn here and so if we were to add the other food chains now we get what's called a food web a food web is going to show all the connections not only this one two amphipods to rainbow smell to chinook salmon which i think we're actually introduced into Lake Ontario but it's also going to show the flow of perch to wawa it's going to show all these interactions and in any ecosystem this is a fairly simple food web is just showing the major ones obviously if we were to include all the different types of algae this would be a massive food web and so in an ecosystem there's all these connections between the organisms and and and it's pretty pretty detailed now each of those have adaptations that will allow them to live where they are in other words the green algae are adapted to this kind of an environment same with the diatoms okay next thing I need to talk about is growth and we've mentioned this when we talked about communities and how populations grow in general all growth is going to be exponential so if we were to go with handful pods they're going to create more info pods and eventually we get exponential growth I could do a color that you could actually see so we get exponential growth like that but the problem is as you start to grow their start to be limiting factors pretty soon you're too crowded there's not enough food there's competition there's also going to just be drought there's going to be meteorological geological changes that can limit that growth and so all growth will eventually become logistic in other words it's eventually going to reach what we call a limit in science we call that k or k stands for carrying capacity so capacity Aaron capacity is going to be the maximum level that in ecosystems can support of a specific population now it's not going to be linear like this this is just using a mathematical representation obviously populations are going to bounce up and down and they're going to bounce up and down on this carrying capacity but in general all populations will undergo to that let's look at some real populations so wolves were reintroduced into Yellowstone Park in 1995 so they put some packs there this is actually a picture of one of the first wolves coming out of the enclosure they brought them from Canada and they left them in an enclosure for months if I remember because they didn't want them just to run back to Canada so they eventually release them and let's look at what their population has grown so blue is all the wolves in Yellowstone Park and then the other two bars are just in different areas but if we look at the population growth population growth as varied a little bit but it's gone up and down and up and down and up and so what's it doing well you can see that this part was more exponential growth and now it's approaching what's called logistic growth in other words there are so there's just a certain number of wolves that you can actually support yellowstone part if we were to draw in what the k value is i would say k value and so far it looks like right about here maybe around 140 hundred and fifty wolves at Yellowstone Park can support now those wolves are moving outside of the park as well yeah there's competition that happens then so this is the same thing here is that growth of wolves so the wolves are going to be on this side so their population went up they've gone down up down it'll probably go up so it's just going like that so on this side we've graphed the wolves but let's look at what has happened at the El population so the elk population is going to be listed on the other side something like eighty-seven percent of what wolves eat our elk so these are two are linked together they eat bison the moves they eat a lot of different things but in general they're mostly eating elk and so if we look at what's happened to the elk population during this time the elk population started at around this is in the northern area of Yellowstone Park started around 16,000 but it's steadily dropped off ok so now it's down to who knows 5,000 elk maybe in 2011 so what's what pressure is that going to put on wolves well now there's not a lot of food to eat and so the wolf population is going to drop off as the wolf population drops off they're going to feed on less elk and so there's probably going to be this predator-prey relationship between the two where the elk population will start to make a comeback it'll drop off like that and then if we look at the wolf population wolf population is going to follow that as well and so we reach what's called a equilibrium now this is great for wolves not great if you're in elk hunter in Montana because the population has gone from 16,000 down to like 5,000 so as they move out of Yellowstone Park as wolves move into that area that's private like I mentioned at the beginning and they're there get to be real human issues and impacts with that last thing that I want to talk about relates to humans then so humans can have huge impacts on an ecosystem and not knowingly we can make big changes so let me tell you the story of the white Park pine whitebark pine is going to be found in Yellowstone Park if we look at where it is here's here's present-day whitebark pine so it's usually going to be found in higher areas but basically it's a sturdy kind of a pine it can you can deal with lots of snow and really cold temperatures but they'll produce a pine nuts during the year and those pine nuts are gathered up by squirrels so the squirrels love to grab the pine nuts they dig and create these mittens are which are just like a stash of a bunch of these pine nuts they'll feed on those during the winter but sometimes they forget where they are and a lot of the time those mittens our mittens I think midd ENS are rated by grizzly bears so grizzly bears will move up into these areas and they'll raid these mittens and so it's a big part of their food supply before they start to hide in the winter and so what's happening well global warming so changes to the global climate or climate change is creating warming conditions in Yellowstone Park and this is progresses projections of what will happen to the whitebark pine population if we just get a moderate increase in temperature they can't deal with that and so the whitebark pine is going to drop off as a result of that squirrels aren't going to have any nuts that they can actually stash Grizzlies aren't going to have that and so you can see that this food chain um is tied to the environment tie it into the in this case it's going to be the overall temperature and so human impacts are so fast so global climate change is so fast that it forces pressure on all the species within that ecosystem in all those connections a lot of the ones we don't even know and so that's ecosystems they're really delicate they also have feedback loops that kind of maintain that equilibrium but I hope that's helpful