Ecology

Hi. In this video will be take a look at ecology, which is the study of organisms, interactions with one another and their environment. Now just Aziz living world can be broken down into various layers of ah hierarchy. The field of ecology can also be subdivided based on these different hierarchies. So, for example, the organism is sort of the fundamental unit of the living world. Adams are to a chemist, as organisms are to an Ecologist. In a sense, now the organism is just an individual living system, and so on. Organism Ecologist is going to be interested in studying that individual living system. And so they're gonna wanna look at things like physical adaptations of on organism, for example, you know, traits that increase in organism's ability to gather or obtain food something like that. Now populations or groups of organisms of the same species that live in the same area. And it's worth noting that it's possible toe have multiple populations of one species in the same area, and that's actually a concept will visit later. Uh, now population Ecologists, they're going to want to look at things like the abundance and distribution of organisms in a population. So for example, uh, you know how many members of the population are there? Something, as seemingly simple is that is an interesting question and especially the population Ecologist. They're going to want to look at changes in this stuff over time. So are the population's increasing? Are they decreasing our populations, merging together our populations, splitting into different populations, that sort of stuff. Now community is a group of populations that cohabit the same area. Now these air populations of different species. But basically it's the sum of all the different populations of species in a particular area. And community Ecologists are going to want to look at the interactions between species. And don't let the seemingly positive term community fool you. Oftentimes this is gonna be one organism eating another organism. Now the ecosystem is basically the community, plus the physical environment. So the community is just the populations, just the organisms, the ecosystems adds the physical terrain that those organisms live in, and ecosystem Ecologists are gonna wanna look at things like the flow of nutrients and energy through ecosystems and through organisms. So looking at are images here you can see here we have a single organism. It's just a frog. Right? And here this is actually a graph of the human population. And hopefully you can see that we're looking at billions on the side here. And we're very close to that eight billion mark at present. And hopefully this chart astounds you as the rate of human population growth has been just, you know, unbelievable. In the past century, I mean, we went from having less than two billion humans on Earth ever. Two now, almost eight billion in under 100 years. Pretty mind boggling stuff. Now here we can see both the community and an ecosystem may actually jump out of the way. Now, uh, in terms of the community, you have thes fish. You have Ah, nice little starfish, their coral all around those air gonna all make up the community. Now the ecosystem here is also going to include things like the rock and the water That's all around these organisms. So you know, uh, community, I just always think of it as basically ecosystem, minus all the terrain and stuff. Now, landscapes are an idea. It's essentially, um, interconnected ecosystems. Sort of like a hierarchy glare above ecosystems. And it's helpful because, you know, ecosystems aren't just discrete units. You know, there's not a border on, you know, like a national border. I mean, on ecosystem, you know, uh, they touch each other. There's sort of transitional zones between them, and so landscapes. Sort of. Take a look at, you know, the greater picture of how ecosystems interact. And also, you know how energy and materials are going to be exchanged across ecosystems. Now, when you get all the ecosystems that exist together, what you have is the biosphere. Earth on Global ecology is going to be again. Just, you know, this study of the bio spheres, everything really often, though, they're going to be looking at the human impact on the biosphere. So they're going to be interested in things like, for example, climate change, which will be talking about at length. Now. Conservation biology is essentially the effort to counter act a lot of this stuff. It's that preserve and manage Earth's biodiversity, and we'll be talking more about that later. Now related to ecology is the study of bio geography, which is essentially the study of the distribution and species. Uh, sorry. Distribution of species and ecosystems over geologic history. So this is going to be a, for example, studying things like, you know why there are certain organisms on some continents and not others, you know, for example, here, you know, we're looking at the sort of super continent that used to exist on Earth. But, you know, of course, due to tectonic activity, you know, the continents broke apart, they went their own directions, and some types of organisms got isolated to particular continents. So, you know, these are all just ideas that bio geography is going to explore. That's that's sort of the interest that those scientists would have. So with that, let's turn the page.

when we look at ecosystems, we're gonna want to examine the biotic factors and a biotic factors. Now, the biotic Factors of living components. This not only includes the organisms, but actually the interactions between organisms as well. Now the non living parts of the environment where the A biotic factors are gonna include things like temperature, moisture, oxygen and sunlight. You can see a bunch of those in this image here just highlighted. Now a biotic factors they're gonna have quite an influence in an organism's distribution and behaviors. They're going to limit where the organism can survive and also in part determine what the organism has to do to survive. Now it's gonna be the interplay between biotic and a biotic factors that determine the distribution of the species. And you can see a nice map of the distribution of a species here. We're actually looking at the distribution of the common juniper. It's a little Conifer plant. It's where juniper Berries come from. If you've ever heard of those now, geologic activity or geologic changes, I should say will have a huge impact on the distribution of species. I mean, you know, we just mentioned how the movement of the continents has played a huge role in determining the history of life on the various continents on Earth. Um, other factors will also play a role inthe e distribution of species like dispersal, which is the movement from the location of birth to breeding site. For some organisms, this isn't gonna be very far. However, there are some organisms that migrate huge distances to get to their breeding sites. And, you know, they could be separated by oceans or vast stretches of land mountains. So the, you know, geologic, uh, factors involved are going to play a big role in this. Now range is the actual geographic distribution of the species. And for example, you know, we just saw the range of the juniper up there. However, thing the you know, uh, the range of an organism can is not necessarily confined toe. One continent is the point I want to make. Now, the Wallace line is an interesting bio geographical division between Asia and Australia. That kind of illustrates this point nicely about how organisms are going to be limited. Maybe not the right word affected. Maybe a better word by geologic changes. So let me jump out of the way here. Hopefully, you look at this map and you recognize that we are looking at Southeast Asia and here's Australia. And you know, all these islands in here. We have, you know, in the, uh, well, parts of Indonesia. And, um, you know, this isn't a geography lesson. So the point I want to make about the Wallace line is that during during the last ice age, they're essentially ah, lot of water waas frozen. So the ocean levels were reduced, and as a result, uh, landmasses looked a little different. Now, here you can actually see what the landmasses, uh, in theory would have looked like by these sort of beige outlines. So, you know, uh, highlighted darker like around and hear those air the actual continent lines today with our, uh, current ocean levels or currency levels. However, you can see that when the ocean levels were lower, there was more land area. Now, the point about this Wallace line is that it's a division between Asia and Australia, and you can see there's other lines in here. You know, I don't want you to worry about that. We're just gonna look at this Wallace line. That kind of goes along here, and he he's basically o r sorry. This line, which is named after this guy, Wallace. The idea is basically that this division existed between these two land masses that prevented a spread of species between them. Right, Uh, you're not gonna find species that are, you know, both somewhere in here and also somewhere in here on. You know, you're not gonna find ancestors of species over here, for example, over in this area. And that's because there was this barrier that separated them. And, you know, even though the landmasses were shaped differently, there was still this actual, you know, water division between them that, uh, you know, separated the diversity of life between these land masses. Uh, in case you're curious, that water division existed because there's actually very deep trench in the ocean there that ensured there was still gonna be a water barrier between those two land masses. Now, exotic species are gonna be non native species to an area, and sometimes these exotic species will actually do really well in this new environment, and they'll spread, and then they'll actually compete with local flora and fauna and they can actually disastrous effects on ecosystems. Here, this looks like a harmless little organism. It's called a zebra mussel. This organism is just wreaking havoc in the Great Lakes, in America and really in freshwater all across the country. Um, you know, these organisms are super invasive, and they totally change ecosystems because they basically they end up eating a lot of their filter feeders. They end up eating a lot of stuff out of the water, which allows for more light to get in and that causes, you know, much greater blooms of algae, for example. So, you know, uh, the point is, they have a major effect on the ecosystems and they throw them out of balance. And so invasive species are usually, ah, bad thing. You don't want invasive species, exotic species. On the other hand, that just means that they're not from the area. So I just want to sort of point out that the invasive has more negative connotation exotic, not necessarily a negative thing. However, exotic species can become invasive. No, with that, let's go ahead and turn the page

When we talk about whether we're talking about the short term atmospheric conditions in an area, he's gonna be things like rainfall or what temperature it is outside. Now. Climate is really looking at long term weather patterns. Oven area. So with weather, we're wondering if it's raining outside. But with climate were wondering how many inches of rain did we receive here in the past year? Something like that. Now climate can actually be viewed from two different lenses. You can look at macro climate, which is climate on the global, regional and landscape scale. And you can also look at micro climate, which is climate of a small area. And this could be really small. I mean, we could be talking about a puddle, and the thing about micro climates is they usually have a climate that differs from the surrounding macro climate, so they kind of stand out for that reason. Now, climate graphs are just representations of climate data, and we actually have a climate graph right here. This is from NASA, and it's showing global temperature averages for the year 2015. No, everything that is in color on this image, as in all The areas that aren't white are different from the average. And hopefully you can see that the Earth was quite a lot and warmer than normal in 2015. And this is pretty alarming. You know, this is, uh this is a new aberration in average temperatures, and it's actually part of a trend that has been ongoing. The global temperature averages increasing now, atmospheric conditions can lead to some pretty amazing phenomena. Uh, you know, we tend to think about physical processes like, uh, you know, things moving due to differences in temperature, for example, on a small scale. But this kind of stuff is happening on a large scale across the planet at all times. So I want to talk about this particular type of atmospheric circulation called Hadley Cell that happens right around the equator. Now the Hadley cell is basically a circulation of air through the atmosphere. That kind of if we're looking at the surface of the earth here and our atmosphere sits on top, the Hadley cell circulates air not on Lee, up and down latitude on the globe, but also up and down through the atmosphere. So the air in the Hadley cell is circulating north south, but it's also circulating vertically. You know it's moving up and down through the atmosphere is well, so hopefully you can gather that from this image these red arrows air trying to represent the movement of air and Hadley cell. Basically, what's gonna happen is at the equator we get the strongest sunlight, so the air there is going to be hot, and it's gonna be hotter than the air that's further away from the equator. Hopefully, follow me so far. Now this warm air allows it, or this warmth in the air allows that air toe hold more moisture and hot things rise up right, so this air is going to rise up in the atmosphere. So basically around the equator, we get this hot, warm air and it rises up in the atmosphere. Now as it rises, as this air rises, it's going to cool, and as it cools, it's going to lose. Moisture is precipitation, so as this hot, moist air rises up, it's going to cause rainfall right. It's going to lose the moisture it's holding now, this cooling air not on Lee so that the air is rising up in the atmosphere is, it cools. But as the air cools, it also gets pushed toward the poles. Right, So it's going to go up and then also start to move either north or south. I'm showing an example. Going north could just as easily be working in this band down here showing the opposite direction. Like you can see here. However, I'm just going to keep working. Uh, in this, uh, northern particular band. Now, the cold air as it's moving towards the pole, it will start to sink right. Cold things sink hot things rise up, thermodynamics. So as it moves towards the pole, it's going to sink down in the atmosphere. So hopefully you can see how these arrows air, showing the movement of that air, right. The hot air rises up, cools moves towards the poles once it gets around this, uh, you know, mid latitude here around 30 degrees and against either be north or South, you'll have them in both both areas. You know, right when it gets around there, it's gonna get cold enough that it's gonna sink back down. Now, what's so cool about the Hadley cell is something we can literally see, right here on this map. Notice how af in the continent of Africa, there's almost like a line right here. It's actually called the Suhel Band case. You're curious, and basically it's going to separate this Junglee area, right this green area from the desert up here. Now why is there such a stark division there? The answer is in part because of Hadley cells, because the rainfall distribution is much higher around the equator and it's quite low in the peripheral areas. So these areas around the equator get all the rainfall and look, this area of desert exists right in essentially the part where the Hadley cell has or rather, the air moving has given off all its moisture. It's going to be dry right, and it's gonna be dry air that's moving over this area this desert. So the point being that these atmospheric circulations and there's more than just the Hadley cell. This is just one to illustrate a point. You know, there's more than just this, but these atmospheric circulations have a major impact on the ecosystems of our planet, and you know you can't really make it any more apparent. Then, right here, this line through the continent. So with that, let's go ahead and flip the page

the equator receives more sunlight than anywhere else on Earth, and this is why it's the warmest part of our planet now, toe. Understand why we need to look at how the sun's rays hit the earth, but for our purposes right now, I want you to pretend that the equator is just this red line I'm drawing through. The planet will in a moment get toe Why the image has the earth tilted and what's important about that. But for now, I want you to pretend that the equator is just level with the lines of the sun's rays. So the sun's rays that hit the Earth more or less straight on their coming in, more or less perpendicular to the earth's surface. Those rays air going to spread their energy over a smaller area than, for example, these raise up here that come in at an angle to the earth's surface, right? You sort of have an angle there because of that angle. Thes raise up top are going to spread out over a larger area, whereas these raised by the equator are gonna be concentrated in a smaller area. So let's just assume it's the same amount of energy. In both regions, you have the same amount of energy in a smaller area versus the same amount of energy in a larger area. Well, in the larger area, you're gonna have to spread your energy thinner, right. That means you're gonna have less energy per area. So it's gonna be colder. That's why it's colder up at the polls and warmer at the equator. It's due to how the energy from the sunlight is being spread out. And that's due to the angle at which these rays air hitting the earth. Now let's get to the tilt of the earth in this image. So the Earth experiences seasons, you know, and we refer to them as spring, summer or fall winter. Really? What we're talking about, though, is the tilt of the Earth's axis. So this line is what we know as the Earth's axis. It's the axis around which the earth spins on a daily basis. Right, So here, in this image of the earth revolving around the sun, you can see these little purple circular arrows, those air showing the earth spinning around its axis. Now, this axis, actually, this access the position of this axis relative to the sun changes. So sometimes, like we see in our image, the axis is pointed away from the sun, whereas other times that access is actually gonna be pointed towards the sun. No. When the access is pointed away from the sun, we can see that this upper half of the earth, which we call the Northern Hemisphere that northern Hemisphere is basically leaning away from the sun and notice that, you know, assuming that the raise in this image are, you know, all the rays coming off the sun. Obviously, it's a gross oversimplification, but notice how it's only getting to sun rays, and the Southern Hemisphere is getting all the rest. Well, when the Northern Hemisphere is pointed away from the sun like that, that's what we call winter right? That's when the Northern Hemisphere is colder, because it's getting even less sunlight than usual. Now, when the Northern Hemisphere points towards the sun, notice that now it's going to be getting more sun rays than the Southern Hemisphere. That's what we call summer. So the Earth's axis is changing position relative to the sun as it moves around the sun, and that's what we experience as seasons, and hopefully this little drawing here made it clear that the Northern Hemisphere and the Southern Hemisphere are actually on opposite seasonal schedules, so to speak. You know, we just refer Thio, our Northern Hemispheres, cold months as winter. But that's actually going to be the hottest time of the year for the Southern Hemisphere. And likewise when its warmest in the Northern Hemisphere. It's going to be colder in the Southern Hemisphere. So you know these terms for fall. I'm sorry for seasons. Fall, winter, spring and summer are kind of biased towards the Northern Hemisphere. So sorry, people in Australia. I'm thinking about you now. In addition to the atmosphere circulating, the oceans will also circulate, and this will affect climate patterns, especially those of coastal regions. Now the oceans circulate all over the planet, and we'll talk about that sort of big picture just a second. But before that, I want to talk a little bit about how coastal regions are affected toe. Understand that you need to understand this property of water that we know a specific heat, which is basically the ability of a substance to absorb energy without changing its own temperature. So what does that mean? If you have a high specific heat, you can absorb a lot of energy, and your temperature will only go up a little bit. If you have a low specific heat, your temperature will go up a lot when you absorb just a little bit of energy. Uh, this is a bit of an oversimplification, but for our purposes, that's all you need to understand. So water has a high specific heat, it can absorb large amounts of energy, and it can also store those large amounts of energy. So around coastal regions, oceans, air actually going to be able to warm and cooler coastal areas, depending on the relative temperatures of the air in the water. So I'm gonna give you an example of this, and we're going to get into some details. You don't really need to understand all the details here. I just want to explain how this is happening so you can see how these natural forces work together to produce well, frankly, phenomena that were pretty familiar with that We experience on a regular basis. So So what happens during the day in a coastal area? Well, during the day there's the sun out, and what's gonna happen is the ocean or the water, I should say, is gonna absorb mawr heat, then the land, and that's being represented by these red arrows. So that does not mean the air over the ocean or the air over the land. We're talking about the actual ocean and the actual earth absorbing heat from the sunlight now, because the ocean is absorbing so far, me actually say this another way because the land isn't absorbing as much heat as the ocean. It means the air above the land is actually going to be warmer in the air above the ocean. And that is again because the land is not absorbing as much. Energy is the ocean, the oceans absorbing lots of energy, meaning the air above it is not absorbing or not getting all of that energy, so to speak. So what does this do? Well, if we have hot air, so let's just say hot air, it's gonna rise up when hot air rises, it's gonna leave behind a low pressure pocket. So let's just say low P. It's the hot air rises, and that leaves us with low pressure now because the air is cooler over the ocean and therefore denser. We're gonna have higher pressure over here. Lower pressure over the land so the air is going to move off the ocean up into the land, also known as a sea breeze. Now, at night, we're basically going to have the opposite scenario. Play out the ocean absorbed Mawr energy during the day. So at night, when things air cooled off, it's going to release more energy. Since it's releasing more energy, that means that the air above the ocean is gonna be hotter. So let's say do the same thing. Hot air. It's gonna rise now. The land didn't absorb as much energy during the day, meaning it's gonna release less heat at night. So it's not going to be the air above the land is not gonna be a swarm. It's gonna be cooler, and it's going to be denser. So we're gonna have higher pressure on land because the hot air over the ocean is gonna rise. We're gonna have lower pressure over the ocean, which means we're gonna have a breeze moving from the land out to sea. Now you really don't need to worry about memorizing all the intricacies of these processes. I'm just explaining all the steps so you can see how you know things as simple as energy will cause all of these, you know, patterns in climate and weather that we experience on a daily basis or some of us do. I don't know if you live by the ocean or not. I shouldn't say that I live by the ocean, so I experienced these regularly. Now let's talk about those big picture ocean currents right here. We're looking at really just like a small microcosm of what's going on. But as you can see in this image, I mean, the ocean currents are moving all over the planet, and they carry warm and cool water to various regions. Now notice how, for example, uh, here in the Pacific, we have a warm current that moves up along the coast of Asia here, and it's actually gonna come across the Pacific and move down the coast of California. That's why the Pacific Ocean in California, despite you know, for example, Southern California's warm temperatures always cold. It's always cold, even in the summer. It's always cold now. I grew up on the East Coast, and we have that nice warm water that comes up the coast of the eastern coast of the United States. But notice how across the Atlantic they actually have a cold current moving down the coast of Africa there, and you can see this pattern repeated on other, uh, other currents across the globe. But the point is, you know, thes air, not static systems. They're dynamic there flowing. There's energy moving through them, and that is affecting climate. So with that, let's go ahead and flip the page.

mountains can have a really interesting effect on climate because they provide a physical barrier in the atmosphere, which is going to impede or, at the very least, have some effect on air flow. Now one of the really cool phenomena that can arise from a mountain is what's known as a rain shadow, and this is basically a area that doesn't receive a lot of moisture because it's blocked by a mountain. So what's essentially gonna happen is Aziz. Warm, moist air rises over a mountain. It's going to cool and condense, and when it cools, it's going thio lose moisture as precipitation. And so when that air finally gets over the top of the mountain, it's pretty much gonna have lost all its moisture. So as it advances and moves over to the other side of the mountain, it's not going to have any moisture to provide his rain. So we're going to have what's called a rain shadow, this dry area due to a mountain blocking the movement of moist air. Now this can occur on a smaller scale like we see here, but we actually have really amazing example on a massive scale, the Himalayas, that's what we're looking at here. This these air, the Himalayan mountains, uh, sort of on the, uh you could think of it is the northern edge of the Indian subcontinent eyes where you'll find them on a map and you can see there's a line literally a line that goes along here that represents the essentially the boundary of our rain shadow, Right? It's all green on this side because that's the side that has the moist air. Now, when that air rises over these mountains, it loses its moisture. And that's why this landscape, known as the Tibetan Plateau, is particularly dry because all that rain is being blocked. This is a rain shadow. Now. Global air currents will also have a major influence on climate patterns. And you can see that in this figure, we have, um, what are known as the prevailing winds. These air sort of like major wind patterns and you know of note, are these lines in blue which represent what are called westerly winds and because they blow from the west and then we also have in yellow what are called the trade winds, which are northeasterly winds because they blow from the Northeast. Now, you know, there are many other types of global air currents for example, the jet stream that they're gonna have a major influence on, uh, the weather patterns around, rather the climate patterns around the earth. Um, it gets very complicated very quickly. And to be honest, you know, people are still sort of understanding some of the science behind it. So, really, all I want you to know about wind is just that it can have a not only global effect, but in local terms can have a strong effect because wind will actually increase heat loss and water loss. So wind will have a strong effect on local climate. And as we can see in this figure, it also will have a major effect on global climate. So with that, let's go ahead and flip the page.

Okay, everyone in this lesson, we're gonna be talking about bio MEMS. Now what? Our BIOS. You've probably heard this word before, but what's the exact definition? What does it mean? So a bio, um, is gonna be basically a very, very, very, very large community of organisms and their environment. So this is going to be a distinct formation of flora and fauna. Remember, this means biotic things. Living organisms, flora means plants, fauna means animals or other living things, like bacteria or protests or anything like that. So a distinct formation of the flora and the fauna and a biotic factors remember these air non living factors. These were going to be things like rocks and water sources and the atmosphere and types of precipitation and things like that. These air, non living characteristics of an environment, and they're gonna be found across different areas of the planet. So they are very distinct areas of our planet. So very, very large communities off organisms and their environment. It's important to realize that a biodome can contain different ecosystems. A bio is not an ecosystem. An ecosystem is found within a bio. Um, so a bio, um, can hold many ecosystems. For example, a great example of a bio, um, would be a marine bio. Um, so a salty aquatic bio. Um, and this may include many different ecosystems, like a coral reef ecosystem and open ocean ecosystem. Maybe a shoreline ecosystem or a kelp forest ecosystem. Maybe those air all in the same bio. Um, but there are many different ecosystems. Remember that an ecosystem is the interact action between living organisms and their surrounding very specific environment. And those interactions can be found in a much larger bio. Um, so just remember that this is different from ecosystems. Ecosystems can be long to the same bio, but they might be different ecosystems. So bio Miz, bigger than an ecosystem. Okay, Now it's important to understand that the ecosystems and bio MEMS are constantly in a state of disturbance, meaning that they are constantly changing and their temporary changes in the environment that can change the way a particular ecosystem works inside of that bio thes air constantly happening because obviously our planet is never static. It's always dynamic. Something is always changing. And for things like global warming, these air dramatically changing the ecosystems and the bios that they are a part of. So if you look at this really beautiful map that we have off the continents of our planet, you can see that the bios are going to be depicted in different colors so you can have the tundra in this kind of teal color right here the tundra. You can have a grass savannah in this light green. And then there's also, you know, the dry step or the arid desert, these air all different types of bio MEMS, but they may contain different ecosystems within them. Now, whenever you're looking at a bio water scientists trying to understand about that particular bio. So the things we want to discover when we are investigating a bio is we want to understand the bio mass that that bio, um creates or that bio holds what is biomass? So biomass is going to be the total mass off organisms in a given area. So the entire mass, all of the bodies off the living things in a particular bio mawr ecosystem. So if you're looking at the biomass of a ecosystem of an ecosystem, you're looking at the actual mass or all of the bodies of every living thing inside of that ecosystem. Now, granted, this is probably we can't actually determine this, right? We're not going to go through and pick out every single organism and determine their mass, because this is also going to include a lot of microscopic organisms as well, so it's almost impossible to do. Right? So we estimate this and we're going to estimate this via understanding the above ground biomass. So all of the living things that exist above ground that are very easy for us to see because obviously there are organisms that live inside of the dirt, right? Ah, lot of microbes live inside of the dirt. You're gonna have borough ing animals. You're going have things like earthworms and mold, and you're gonna have the roots of trees and plants that air all down there under the earth, which would be incredibly difficult for us to measure. So we used the above ground biomass to kind of estimate the entire biomass. So again, the above above ground biomass is going to be the total mass of living plants and organisms, excluding the roots and excluding the other organisms that live inside of the dirt. So we're going to estimate the biomass utilizing the above ground biomass. And we're also going to measure something important called the Net Primary productivity, or NPP, off a bio or of an ecosystem. Now, why would we measure this? What are we measuring? Basically, you're measuring the productivity off a bio or an ecosystem. You could do this for ecosystems as well. So what are we looking at? So, in net primary productivity, what we're measuring is the rate that plants in an ecosystem produce energy minus the energy that they consume during cellular respiration. So basically, this is going to be the energy plants make. So what is the energy that plants make? How do they make energy? Remember, they do the process of photosynthesis. They're going to make sugars utilizing sunlight, energy via carbon dioxide and other things. So this is actually measuring photosynthesis. So the energy that plants make minus the energy that plants utilize because, remember, Yeah, plants make their own energy, but they also have to utilize that energy as well. They also do cellular respiration. So this is looking at cellular respiration. Now, how would we measure this? How do you measure the amount of energy that a plant uses and the amount of energy that a plant makes. How do you determine the NPP of an ecosystem? Well, the way that we're going to do this it was is we're going to utilize the above ground biomass estimate and we're going to determine how much co two thes plants take out of the atmosphere for photosynthesis versus how much co two the plants put back into the atmosphere for cellular respiration. Remember photosynthesis, the creation of energy. Take CO two out of the atmosphere and cellular respiration utilizing that energy is going to be putting CO two back into the atmosphere. So this is gonna be the amount of co two taken from the atmosphere minus the amount of CO two put back into the atmosphere. That is gonna be how we estimate the NPP. Normally, this is normally how we're going to estimate this now. Why would we care about the NPP? Well, the NPP is going to tell you how a bio or an ecosystem is functioning. Obviously, if the net primary productivity is very high, there's a lot of photosynthesis going on. Maybe there's a high amount of plants in this area. Maybe we're looking at the tropical Amazon rainforest. The NPP of that forest very, very, very high, right? It's a very productive environment. While you could be looking at the I don't know, maybe a certain particular um, forest in winter that productivity's not going to be very high, especially a forest in North America. In winter, when all the leaves air gone, there's not going to be very high productivity because there's not a lot of photosynthesis happening. So MPP is definitely tied to the season and the location off that particular ecosystem, and it's going to tell you the health of that ecosystem as well and how productive the plants or the primary producers of that ecosystem or bio, are functioning. So this is very important for the health off the bio and the ecosystems within it. Okay, everyone, let's go on to our next topic

when we look at terrestrial bios, we're gonna want to consider both the biotic and a biotic factors. And we'll notice that what constitutes of bio is going to be a similarity in those biotic and a biotic factors. Even if bios might be separated by oceans, I mean, for example, Tiger, which you find across North America and across Eurasia, is separated by an ocean, Yet it's still considered all part of one bio. Now, the A biotic factors, we're going to really wanna look at our temperature and moisture. But we're also gonna want to consider sunlight and wind as well. And the reason we're really gonna want to focus on temperature and moisture is that bio moms tend to be adapted to very specific moisture and temperature ranges. Likewise, the average temperature and precipitation, as well as the annual variation in temperature and precipitation, is gonna have a major effect on what life forms we find their You know what species air present when talking about bio MEMS. You also might here, uh, two terms come up that I wanna kind of throw out real quick. One is ecotone, which is basically a transition between bios like a transitional area. And remember, we said bio MEMS, you know, they don't have national boundaries. They they're not just, like, completely isolated areas, they bleed into each other. And so you have transitional zones between bio MEMS. Also, when we talk about the plant community in some bios, we're gonna we might refer to the canopy. The canopy is just the above ground portion of the plant community. I remember there's a lot of action going on under the dirt's where all the roots are. That's where all the fungus is helping those plants survived. When we talk about the canopy, we're talking about just the above ground portion and really, you're mostly gonna hear that when talking about bios that have a lot of vertical growth. Now, here you can see a nice, really nice figure that shows the, uh, you know, the difference basically, in pris annual precipitation and annual average temperature in various vie OEMs. And it gives you a really nice idea, sort of how these bios might transition between each other so you can see, uh, you know, very cold with low rainfall. Here is tundra and kind of on the opposite end with a lot of year round warmth and rainfall. We have tropical rainforests and we're gonna talk about both of these by OEMs. Actually, we're gonna talk about tropical rainforest right now. Spoiler alert. So tropical rainforest is going to be located in the equatorial region, sometimes called the tropics. Wonder why you can see that band cross here? Oh, jeez. I cut off Madagascar. I can't cut off Madagascar. There we go. So this band is right around the equator. And in these tropical rainforests, we're going Thio have lots of moisture and warm temperatures year round. There's gonna be really, like, very little seasonal variation in temperature in these regions with some variation precipitation, but they're still going to be receiving precipitation year round. Regardless, Now the plants in these communities are going to be vertically layered. Hence, theater term canopy. They're going thio, you know, have a a variety of strategies to fight for light. Let's let's say, because the plant growth is so vertically stacked, you know, everyone is trying to use every little bit of light they possibly can, so there's very intense competition for light. Now the trees in these forests are going to be what we call broadleaf. And, uh, that basically just means they're angiosperms that have broad, flat leaves, and they're also going to produce seeds surrounded by fruit. Now we also call these evergreen forests because, well, since there's little to no seasonal variation there green all year round. And what you really need to know about the tropical rain forests of the world is that they are so rich in species diversity. They're also incredibly productive areas. I mean, they don't cover, you know, a ton of the earth's surface, but they hold, you know, it's estimated to be like nearly half the species on the planet. Additionally, uh, they're going to be responsible for large, uh, large amounts of productivity, which means drawing a lot of carbon dioxide out of the air. Now with that, let's go ahead and flip the page.

desserts tend to be around 30 degrees latitude north and south, basically just outside of that tropical region, and they're usually found in the interior of continents. Now most people tend to think of desserts is just being really hot all the time, when in fact the temperature and deserts is highly variable, both seasonally and daily. In fact, temperatures can vary by as much as 40 F in a given day. Could you imagine going from 80 degrees during the day to 40 degrees at night? I can't even imagine temperature changes like that on a daily basis. Now we also know hopefully from our discussion of the Hadley cell why rainfall is so low in deserts, right? Because of those atmospheric circulations that air, causing all the precipitation to get sucked up by the tropics of it. None is left for those poor desserts, but they're surviving right? In fact, there is lots of life in the desert. Now there's not a ton of vegetation. It tends to be mostly scattered with lots of bare patches of earth. However, there is some doesn't all look like this sea of dunes you see here in this image and most organisms that live in deserts tend to have water conservation adaptations. So, for example, reptiles, which are common to deserts, have scales made of keratin, which creates an impermeable barrier for water and helps prevent water loss from the body, maybe even more famously, or cacti, which have adaptations that allow them to store fluids in their body. And additionally, it should be noted that animals have learned to exploit those storage abilities of Capt. I. So life is ever evolving. Now here we have. This nice global map lets us see the major desserts distributed across the globe. And really, all I want to point out is just you know how you can see that you have that tropical band in the middle and then desert on either side of that, you know, show you over here. So this is tropical region, and then we have desert and more desert up here. Of course, there are exceptions. There's always exceptions, but Justus, a general trend, something to bear in mind. Now Savannah is a bio, Um, that usually occurs around the equator, and it's cool. It's kind of Ah, found is a transition zone between forest and desert or forest and grassland, and that's why it tends to be mostly made up of grasses with some small woody plants. However, it does have some scattered trees, as you can see in this picture here. Of course, you wouldn't call that a forest by any means, but there are some trees now. The savannah well, rather, Savannah's will usually be found around the equator, and their rainfall will be highly seasonal. They have. In fact, they can have dry seasons that can last most of the year, almost the whole year. Because of that, the plants of the Savannah have to be drought tolerant, as it could be really long time before they're going to see any rainfall. Also, because the dry season can last so long. Wildfires air fairly common, which is why most Savannah plants are also fire tolerant. I mean, if you can't regrow from, uh, you know, your average regular run of the mill wildfire, you're not gonna last long here, kid. So with that, let's go ahead and flip the page

Chapel Eliza Bio primarily found in California and Baja California. This is basically just scrubland. So little shrubby plants like you see in this image here where rainfall is going to be highly seasonal and you're also gonna have regular fires, which is gonna mean you're not gonna have a lot of tall trees right now. It is usually found at mid latitude coastal regions. Hence California and Baja California. However, you will find it in other parts of the world. It's just most common to there now. Temperate grasslands are kind of like oceans of grass is basically, uh there these big planes of grasses and they have dry winters, meaning not a lot of precipitation in the winter and lots of precipitation in the summer. And temperate grasslands include the Eurasian steppe, which is a massive, massive grassland that spans both. Well, it's kind of expands a large part of the Eurasian continent. I was gonna say it spans Europe in Asia, but I don't like making those distinctions because it is just one landmass, and also you'll find it in the North American prairie. Now we call it temperate because it falls into the temperate zone, which is basically the zone that lies between the tropics and the polar regions, and it's characterized by moderate temperature fluctuations. So not a lot of extremes here. Now, broadly forests or rather temperate broadly forests are gonna be found mainly in the Northern Hemisphere. And they're going to be dominated by disingenuous trees. And, you know, the temperatures. They can vary moderately. You will see, you know, snow in the winter and hot summers. Uh, but these aren't super extreme, uh, seasonal variations in temperature, and you'll also see moderate precipitation year round in these environments. Now here we're actually looking at what's called a temperate mixed forest, meaning that it is part broadleaf, as we see here. But hopefully you can identify. There are actually a couple Conifers in there. I only point this out just in case. There's a stickler out there going. I see some Conifers in that image that's not totally broadly forest. You're right. You caught me. I just happen to think this is a really beautiful picture, which is why I chose it. Now with that, let's flip the page

Tiger is the largest terrestrial bio on earth. It covers North America and Eurasia. It's absolutely mind boggling how much land area is taken up by tiger. Sometimes this bio is called northern coniferous forest, or perhaps boreal forest, and really, it's dominated by Conifers. And the reason for that is because Conifers are both cold tolerant and water loss resistant. And hopefully you can see by how far north this bio Miz. It's going to get very cold there. Additionally, drought is common, which is why the waxy needle like leaves of Conifers are well suited to this bio. Now the Arctic Tundra is the northernmost terrestrial bio. It basically runs along the northern edge of the the northern edge of land masses in the Northern Hemisphere and year round. It is cold, it's super cold. In fact, it's so cold year round that it has what's called permafrost, which is basically soil that remains frozen all year round. It also has very low precipitation, so this is clearly not an easy place to live. Yet life finds a way. As you can see from this image behind me. Um, it actually can be kind of beautiful in a way. Now I don't want Thio Harp about global warming, but I do want to say that the area, the amount of permafrost that is the area that is considered permafrost, has been shrinking at a pretty alarming rate due to global warming. Now with that, let's go ahead and flip the page.

aquatic bios include both freshwater and marine bio MEMS and will be characterized by solidity and light penetration. Unlike terrestrial bios, where we were mostly looking at temperature and precipitation now solemnity, you can just think of as saltiness of the water. However, technically, salinity is a measure of dissolved salutes in a solution. And really, what you need to know is that this is gonna have a profound effect on us. Moses and water balance in organisms. Now the water depth is going to affect the availability of light. It's also gonna have an effect on pressure and temperature. But we're going to focus on light right now, so the upper regions of a body of water are considered part of the photo zone. This is basically the depth of water that receives enough light to carry out photosynthesis. As you can see in this chart right here, the photo zone is not very deep at all. It's our rather compared to the other zones. It's pretty shallow. The a photo zone is going to be the portion of water below the photo zone, and it's going to receive little or no sunlight and the deep, deep depths of the A photo zone are called the abyssal zone, which is basically the deep depths of the ocean that don't ever see the light of day. There's no light there ever. They're in perpetual darkness, and this actually will have a really interesting effect on the organisms that live there now. In addition to depth affecting the penetration of light, the cloudiness of a fluid can also have an effect. Now we call this CLOUDINESS in a technical sense. Turbidity. It's basically just a fluid being cloudy. Do do suspended particles. Now I'm gonna jump out of the way here. You can see two, two bodies of water converging, and there's a line between them, right? So here's one body right here and here's body number two. Over here, you can see the literal line of convergence because of how turbid this water is right. It's just a ton of suspended particles in there, giving it that color. But turbidity is also going to diminish the ability of light to penetrate. Now, Cem, or definitions about you know, regions in thes aquatic biomass will sometimes use the term littoral zone, which is basically the area of a body of water that still close enough to the short that sunlight will penetrate through to the bottom. So, you know, in our image here, for all intents and purposes, let's just call this region the littoral zone. Since these plants right here still getting enough light for photosynthesis. So you know it's the light is gonna make it all the way to the bottom to these plants right here. Now the Palese GIC zone is basically water that's not close to the shore, not close to the bottom, and is going to actually comprise parts of or, well, the photo zone and parts of the A photo zone as well. So the police GIC zone you can see is, you know, kind of just like this region e drew my line too far down. It's not the bottom. It's like this region here. It's just the, you know, just water. Open open water. Let's let's say now, underneath this you have the benthic zone. It's like the lowest level of body of water. Uh, sometimes you might hear it called the seabed, and this is going to both include the sediment and some subsurface regions. So the benthic zone is kind of all this biz in here and organisms that live in the benthic zone are called bent those and there. Well, the benthic zone is going to be particularly rich in what's called detritus or detritus. It's just debris or waste. It's usually dead organic matter, and it's particularly abundant in the benthic zone because anything that dies above the benthic zone is gonna sink down in the water and find its way to the benthic zone. They're gonna be a lot of organisms living in the benthic zone that actually eat and recycle this dead organic matter. So with that, let's actually go ahead and flip the page.

the movement of water can have a dramatic effect on the organisms that live in it. In fact, take, for example, the river dolphins that have evolved to sleep in one hemisphere of their brain at a time, totally bizarre phenomenon that allows them to live in these waters with currents. So, you know, if they were to sleep in both hemispheres simultaneously, they probably get smashed around by the water currents. You know, could end up dying for example. So this is an adaptation based on the movement of water. Now the movement of water is also going to affect nutrient availability and we're going to take a look at that in just a second. I do want to quickly mention plankton, which are these small floating organisms in water mainly made up of diatoms, which you can see here and proto zones as well as crustaceans and these guys are gonna be a very important food source in aquatic bio MEMS. Now, speaking of that nutrient availability, the deeper waters tend to be richer in nutrients because all of that dead organic matter is gonna sink to the benthic zone and so that water is going to have more nutrients. So, ocean upwelling is this interesting phenomenon where nutrient rich, that nutrient rich water from the depths will rise up and replace surface water that's moving away from coasts in this way, adding more nutrients into the system. Now, thermo clines are pretty, I guess you could say bizarre phenomenon, they kind of go against our common experience. You know, if if we're looking at a body of water, we kind of would expect that the temperature would just go down with depth. However, you can sometimes have these distinct layers called Thermo clines, that will actually separate deeper, colder waters from warmer surface waters. And in the thermal Kline, you're gonna have this really abrupt temperature change. So, notice here that our Y axis on this chart is depth and our X axis is going to be temperature. Notice that in these deeper depths, for example, as we go down, there's very little variation in temperature, right? It's just like from there to there, you know, very small variation in temperature. However, up here, you have this rapid drop in temperature, right, barely go down in depth at all. And yet we're experiencing a massive temperature change, that is a thermo client. So, this horizontal line that I've drawn across here is representing our thermal Kline. It's that that band were in abrupt temperature change happens and it's gonna separate these warmer surface waters up here from these colder waters of the depths. Now, water temperature can actually also lead to nutrient rich water from the bottom coming up and enriching the water closer to the surface. This is actually something that's going to happen in lakes. It's an event known as lake turnover and it's going to be due to seasonal temperature changes. So, in the winter will, you know, assuming, let's just say, this is like a, you know, smaller body of water, like a smaller lake will have ice covering the top and surprisingly, that's actually going to be colder. Then the water below the water below will actually be a little warmer than that surface water. Now during the spring we'll have our first turnover event because as the ice melts and as the ice melts into the water, it's going to cool it and that cold water is going to sink, that warmer water that was at the bottom, that nutrient rich water is gonna rise up and move towards the surface. So we're going to have some mixing of nutrients now in the summer, you're going to have much more dramatic temperature gradient through your lake. You know, it's going to be fairly warm at the top and you know, roughly unchanged at the bottom. But what's going to happen during the fall is as that surface water cools, it's going to sink, move down and cause some of that nutrient rich water from the bottom to come up. So this seasonal turnover will actually happen both in fall and spring. And it's going to cause um you know, some mixing of the more nutrient rich water from the bottom with the surface waters of the top. And we're getting this um cycling of water due to these temperature changes. So with that, let's go ahead and flip the paint

lakes and ponds, air standing bodies of water that will have variable salinity, oxygen concentrations and nutrient availability. On one end, you'll have a Liga trophic lakes, which have low primary productivity, meaning not a lot of photosynthesis going on because they have poor nutrient content. However, these lakes tend to have high oxygen concentrations. On the other end, you'll see you trophic lakes, which have high primary productivity because they have high nutrient concentrations. However, these usually have low oxygen levels, and I'll explain why now? Not all you trophic lakes start out. You trophic lakes, some lakes under goat eutrophication, as it's called, where nutrient rich stuff gets into the lake. Often you'll see, you know, nutrient rich fertilizers on agricultural lands or something, getting into the runoff water and finding their way into a lake. And they'll just inject a bunch of nutrients into the lake, which will lead to an explosion in primary productivity. So, you know, like a big algae bloom or something to that effect, all of this new plant matter or I should say photosynthetic organisms, you know it's gonna be a lot of algae. All of these, uh, new photosynthetic organisms are going to eventually die, which is going to feed the decompose er populations. Now all of those d composers are going to eat all the dead algae and whatever and they're going to consume oxygen in the process. So basically, you know the high primary productivity leads to high amounts of decomposition which are going to lead thio low oxygen levels. Now, most of the plants that you'll find in lakes and ponds are gonna be in the littoral zone. And that's because this is going to be the area that gets the best light. Remember, light will penetrate all the way to the bottom of the littoral zone. And bordering the littoral zone is what's known as the limb net IQ zone. This is basically like this surface waters away from shore of a lake now lakes and ponds. Also, I should mention have a benthic zone just like all aquatic biomass. And this benthic zone is going Thio have lots of sediment and dead organic matter and be fairly, uh, nutrient rich. If it has lots of dead stuff in it now, wetlands are amazing. Bio Uhh! You know, we often over overlook them or kind of write them off because we're just like they're just Boggs or swamps or marshes. Gross, right? Well, actually, they're really important because they have this amazing ability to filter pollutants from water. They're kind of like nature is Britta. They basically I mean, really like they, you know, they clean water, making it potable. Uh, now, wetlands are basically just land that's been saturated with water, and it doesn't have to be permanent. You know, they could be seasonal, like they get inundated with water on a, you know, some sort of regular seasonal basis. And what you'll see with wetlands is they'll, you know, they'll they'll often have a lot of what's called emergent vegetation. So here, you know, I'm kind of just like encircling the more watery part, right, and you'll see, got some lily pads here and here on the sides, right. Those were all like, floating plants, this stuff all around. That's what we call emergent vegetation. It's gonna, you know, shoot its roots are rather it's shoots up out of the water and, um, you know, have a portion of its, uh, body be above the water surface. So, you know, you often see things like cat tails and grasses and that sort of stuff, Uh, that sort of emergent vegetation in wetlands. Now, streams and rivers are going to be flowing bodies of our flowing water, and usually they're gonna be headed toward an ocean or a lake or some other river. So you know, they'll join together, and eventually that river will go to some lake or ocean or something like that. Now, what characterizes these by OEMs is the volume of water flow. How much water is flowing, right? Do you have just, you know, a little trick Lee Stream? Or is this a rushing torrent of a river? And you know, one interesting thing to note about water flow is it will actually affect the oxygen content. So faster flowing water has lower oxygen levels in general. Now, when a river meets the sea, it conform an estuary. This is a semi enclosed body of brackish water, brackish water, meaning a mix of freshwater and saltwater. And it's basically a transition between rivers and the ocean. And here you can see a new estuary that's part of the Amazon. So this is the Amazon or, you know, the estuary of, uh, part of the Amazon River coming in and meeting the Atlantic Ocean here, and with that, let's go ahead and flip the page.

oceans are massive bodies of salt water that cover the majority of Earth's surface and ocean bios have some special terminology. We should go over now. The littoral zone of oceans is a little different. You see the waterline where oceans meet. The land is not fixed. Oceans have a tide, so the water level will actually flow from the high tide point to the low tide point. And this area, this literal zone is called the intertidal zone. And here we're looking at it, you know, as a beachhead. But sometimes thes intertidal zones will actually be rocky and can have verticality to them. And they can also have depressions that water gets trapped in That we call tide pools and type pools could be incredibly rich and diverse ecosystems. Now, the area that extends out from the littoral zone or the intertidal zone, is called the Neurotic zone, and this is basically just shallow ocean that covers the continental shelf. Now the Continental shelf is the extension of land that comes off of contents, rather continents that goes under water. So, uh, you know, imagine, uh, if you were to pull the continent out of the ocean, a little bit. You know, this would just look like a continuation of the landmass. Now at the edge of the Continental Shelf, you'll have a sharp drop off, and there is where you get the open ocean. Scary stuff. The open ocean where the zone of open ocean is called the Oceanic pally GIC zone. And it's just what's beyond the continental shelf. Now. The benthic zone in oceans is going to be markedly different from the benthic zone of a lake, for example, because oceans air so much deeper and more vast now, the marine benthic zonas it's called or sea floor, if you prefer, is basically in darkness. Always now, coastal areas will receive light. If you know they're the benthic zone is shallow enough. However, the majority of the marine benthic zone is going to be in total darkness Now. Coral reefs are you know, it's hard to over sell them. They're just incredible ecosystems. And, you know, they're such a rich bio in terms of species and in terms of you know, the sort of services they provide to the areas around them. And here's a map. You can see the location of coral reefs all over the world. They're going to be built by coral, which are these little animals that secrete these structures made of calcium carbonate. That's probably what you picture when you think of coral and those calcium carbonate structures are, you know, you probably look at them and think of them as rock or something. It's actually not rock, but you know, you can see these structures here in this this massive coral. Now the reason I bring up calcium carbonate is because coral reefs are super threatened by ocean acidification. Calcium carbonate will readily react with acids because carbonate is a base. So even a small increase in acidity can result in great damage to coral reefs. And you can see it from satellite photos. You know, looking at the Great Barrier Reef, see just how much of that has been eroded. Now, the last bio I want to talk about are these deep sea hydrothermal vents. These air fissures in the earth that release geo thermally heated water really, really hot water. And there are two reasons I want to bring these up. One is because they're potentially the source of life on Earth. Here you can see what's called the Lost City. Thes are a special group of hydrothermal vents that form these carbon stacks. And it is It has been proposed that life may have started inthe e little nano tubes in thes carbon stacks. I'm not gonna get too much into the details, but, you know, it's cool stuff. It's a very interesting theory, whether or not you believe it. Now, this is the other reason I wanted to bring up thes hydrothermal vents because they have some really interesting ecosystems, uh, or rather say communities of organisms that have developed there, you see, pretty much everywhere we've been talking about. Up to this point, uh, has been a community that's more or less supported on photosynthetic organisms. But these communities are not supported by photo autotrophs, but by chemo autotrophs they're supported by bacteria and archaea that can uhh, you know, essentially fixed carbon from the uhh you know, from performing various chemical reactions with the inorganic, uh, compounds available or sorry, not inorganic compounds. Theknot compounds available to them from these hydrothermal vents. Basically, they're just very cool ecosystems because they're so different from like everything else we see. You know, it's, uh, they're super unique in that there's like a very rich, diverse community built on top entirely on top of chemo autotrophs, you know, we're so deep down there's no photosynthesis is happening here. So very cool stuff. Now that's all I have for this lesson. I'll see you guys next time.