Unit 2: 2.1.1: Ecology 101

Plants in the _________ are succulent because they need to hold and store a lot of moisture. A rainforest B) taiga C) savanna D) desert

D) desert

Greater temperature fluctuations occur __________. A) in terrestrial ecosystems B) in marine ecosystems C) in river ecosystems D) in lake ecosystems

A) in terrestrial ecosystems

What distinguishes the savanna and grassland biomes? A) woody plants B) large predators C) seasonal precipitation D) herd of herbivores

A) woody plants

Which of the following is not true about taiga? A) covers former glacial areas B) characterized by mild winters C) is a Russian name D) is a type of coniferous forest

B) characterized by mild winters

Identify the biotic factor of an ecosystem from the following: A) soil composition B) trees C) temperature D) sunlight

B) trees

transcript: section 1

In past lessons, we've spoken about the different levels of organization that we have in this world, the smallest level of which you and I belong, which is an organism. You and I, every smallest microbe, and biggest tree in the world is an organism. The largest group of organization that we talk about is the biosphere, which is the entire Earth and includes all of the biomes in the world. In 1985, an idea was hatched, and a project was started to replicate the biosphere, to create a self-contained building that housed multiple biomes, and they were all self-sufficient. This is called Biosphere 2, and it's located in Arizona. We learned a lot from this project. Most specifically we learned how delicate our ecosystems are and how hard they are to replicate. This is something we're going to talk about in this next section, ecology or the interaction of organisms within an ecosystem. In this section, we'll describe the levels of organization in the biosphere. And looking ahead, we'll identify the ten biomes found on earth and compare and contrast major ecosystems found on Earth. All right, organizational hierarchy of our world. The biggest level of organization, as we talked about, is that of the biosphere. It includes everything, and the smallest of which is an organism. As we mentioned, you and I are both organisms. When you have organisms that can reproduce together and produce fertile offspring, you have a species. When you have a group of organisms out of the same species living in an area, that would be a population. When you have groups of populations of different species living in an area, that would be a community. When you have more than one community, they make an ecosystem. More than one ecosystem creates a biome. And, of course, as we mentioned, all of the biomes are located in the biosphere. So the levels of organization that we'll talk about, organism, species, population, community, ecosystem, biome, and biosphere are all things that we're going to mention today. Species, a group of inter-breeding organisms. You might think that defining species would be easy, right? A dog is a dog. A cat is a cat. A bird is a bird. A fish is a fish. But it's not always so clear cut. Species is defined as group of inter-breeding organisms that do not breed with members of other groups. However, there are a couple of examples that are kind of a grey area. For example, a horse and a donkey, they are definitely different species. But when you put them together, if they do mate, they can produce offspring. And when they do, they produce a mule. So does that mean a horse and a donkey are the same species? Well, not quite, because of the fact that the mule that was produced is sterile. The horse and the donkey could not produce fertile offspring, so because of that they're not considered the same species. Another example is that of a lion and a tiger. In some zoos, when they have them contained in the same area, they will mate. And they will produce something called the liger, which to the contrary of popular belief they do not have any magical powers as Napoleon Dynamite might suggest. But they are sterile, and they cannot reproduce. So a lion and a tiger would still be considered different species even though they can produce some sort of offspring. This angel fish would not be the same species as this clown fish. And this beetle would not be considered the same species as this ant, because they will not inter-breed. Populations are individuals of the same species living in a region. If you look around the room that you're in right now, if there are people in that room with you, that could be considered a population. This bird right here, living in Australia, may live within a certain confined area with a group of its same species. That would be a population. In a different part of Australia there may be another whole population of this bird. They would both be considered populations. This is a Mexican wolf. It lives in the southwestern United States and Mexico. It would be considered a population of the southwestern region. You probably wouldn't want to consider it part of the wolf population, the gray wolf population, up in Canada, because it's a different geographic area. Communities, a group of plants or animals living in a particular area or region. If you have more than one species living in an area, all of those organisms, from smallest microbe to the largest tree or largest mammal, would be considered members of that community. Many different interactions between various species and organisms. So we have all of our interactions, including food chains, food webs, and other actions, that would be seen in a community. Of course, this is one of them. This bird would probably have a great time eating that nice little mouse. And of course the mouse, he eats seeds and other vegetation. Those are all interactions we would see within a community. An ecosystem, a biotic factor is a living component of an ecosystem. An abiotic factor is a non-living component of an ecosystem. So what's the difference? Well, biotic factors are living. That's what the word bio means. It means life. So, a living component of an ecosystem would be you and I, or a plant, or any animal, microbe, bacteria, anything that is alive in that area. An abiotic factor, a non-living component, we would be talking about air, temperature, soil, water, things like that. That would be an abiotic factor. This is the first level that we would consider biotic and abiotic factors, would be in an ecosystem. Here's an example of a lion in the grasslands of Africa. All of those living things including grasses, the trees, the lion, those are all biotic factors. And of course the air temperature, the amount of rainfall, the soil, those would all be considered abiotic factors. A biome is a biotic region characterized by dominant plant life. So, if you look at an area and you see that there are a lot of conifer trees or evergreen trees, that is probably going to be a contained biome. Whereas if you go down further south along the East coast of the United States, you're going to see a lot more broadleaf trees, deciduous trees. That would be different biome. Maybe if you go into the middle of the United States, you're going to see a grassland, like the Great Plains. That would be a different biome. And then, the desert southwest. You're going to have completely different vegetation there, so that would be considered another biome. The prevailing climate of the area is something that would be considered biome. If you live in an area that is hot or cold or dry or really wet, those would all be things to consider when you're figuring out what biome you are in if you're in a certain area. The biosphere, the regions of Earth that are capable of supporting life. The parts of Earth that are capable of supporting life is actually a pretty small amount. It extends from the lower atmosphere, where birds can fly and maybe some sort of bacteria living in dust in the atmosphere to the deep crust of the earth, where once again, certain animals may be in caves or bacteria down in the cracks of the earth might be able to survive. The Biosphere 2, as we mentioned earlier, was a project to help replicate the world, to make a self-contained building that housed multiple biomes. It explored interactions between life systems, the five areas of biomes, and the possibility of space colonization. If we could replicate the biomes on Earth in a self-contained building, and we could be successful, maybe someday we could do the same thing on the Moon or maybe even Mars, and colonize different planets in our solar system. Here's some more pictures of the Biosphere 2. Thinking ahead to the next section, what biome do you live in? Look around, and look at the vegetation that's around you. What climate do you experience from day to day? What the characteristics of your biome? Why are those characteristics important? How might they help you to determine what biome you live in?

transcript: section 2

In this section, we're going to continue talking about the idea of ecology and how organisms interact with one another. But I'd like to draw your attention to the picture in front of you. This is a lemur. In fact, it's not just one lemur. It's two lemurs. Here's one and there's the other one right there. Lemurs are a very unique animal. They're unique, they're endemic, which means they only live in a place called Madagascar. They're similar to monkeys but they have many differences. And the reason they're so unique is because they live in an area that is separated from the rest of the world. Their interactions with their environment has caused them to change and evolve over time. And these interactions are what we're going to discuss further in this section. So Ecology 101, Section Two. We already described the levels of organization in the biosphere. Now we're going to identify the major biomes found on earth. And looking ahead, we're going to compare and contrast major ecosystems found on earth. The major biomes of the earth. We talked about how the biosphere, which is the earth, contains all the major biomes. We have desert, taiga, tundra, savanna, grasslands, temperate forest, and rainforest. Now all of these have very unique qualities, but some of them have some similarities. And since there aren't well defined lines between each biome, you don't just cross a line and all of a sudden you're in grasslands, where you were in a temperate forest a minute ago. There is some transitional areas where they might overlap. So these are the major biomes, but we may see some changing over when you get in between them. The first one we're going to talk about is desert. Desert covers about one fifth of the earth's surface. Now, if you look at a map, and you see the brown areas, those are areas where there's very little vegetation. And the very little vegetation probably means that those areas don't receive a lot of rainfall. If an area receives less than 20 inches of rainfall a year, it is considered a desert. They can occur at low altitudes, and there are some areas with high altitudes. Animals and vegetation have very specialized adaptations. If you ever look at a plant in the desert, they often seem to be very spiny, and sometimes very succulent, which means they hold in a lot of moisture, because they need to save that moisture for when there might be times of less rainfall. Here's an example of a cold desert. Not all deserts are cold. This is Joshua Tree up in California. It can pretty cold up here, well below the freezing mark. However, it is still considered a desert. So just because you go to a desert does not mean that it's going to be hot. In fact, one of the worst deserts in the world that I wouldn't want to be in is that of interior Antarctica. Antarctica is freezing. It's very cold. But they receive less than 20 inches of rainfall every year, so technically, they are still considered a desert. The taiga. The taiga is a place where we have a lot of pine trees, or a lot of conifer trees, evergreen trees. They're extensions of coniferous trees across North America and Eurasia. If you were to take a picture of the earth from the top, you would see a ring of trees wherever there's land, and this would be the taiga. They cover former areas that were covered by glaciers. So if you look where glaciers used to cover, a lot of times these taiga forests have come and moved in those locations. Here's a map that shows the area of the taiga, up on the northern parts of North America and Asia. Taiga is kind of interesting because they have very little vegetation that grows on the undergrowth. The reason for this is because all of those pine needles that fall off the trees create a very acidic environment for all other undergrowth on the ground. So if that soil is too acidic, many plants simply can't grow. So if you were to go into a taiga forest, you'll see a lot of trees, but a lot less undergrowth then you would in other forests around the world. They are present in many areas of Russia, and they have very severe winters. The tundra. The tundra is actually literally the treeless plain. They're found in northern and southern hemispheres. The tundra a location where there are very extreme cold temperatures and very short growing periods. Because of the tilt of the earth, there's a large portion of the year that there just is not sunlight. You'll go 24 hours and you will not see the sun. Likewise, there is also part of the year where the sun will stay out all day long 24 hours a day. However, that section of time of the year is very short, so things have very little time to actually grow. Most plants and vegetation will be small, partly because of that, and partly because there's something called permafrost. There are certain sections of the soil that is always frozen. And because of that, it's very hard for roots of trees and other plants to penetrate down in those areas. So most vegetation grows along the ground, things like lichen and small bushes will grow there. If you look at this map, here's an example. The shows exactly where the tundra would be. It's north of the taiga, which we just spoke about. There's often frost in the ground and as we mentioned, there's permafrost. So there's certain layers of the soil that are always frozen. They have extreme low temperatures, very little precipitation, poor nutrients in the soil, and short growing seasons. The savanna. The savanna covers 20% of the earth. It has grasses and scattered trees. It is a transitional biome, which means that it's kind of in between two biomes. It's not quite a grassland because it does have trees, but it's not a forest because it has a lot of grass in between those trees. So it's going to have more scattered trees, very sparsely spaced around, and combined with a lot of grass. It has very seasonal precipitation and droughts. And for many of the savannas in Africa, this causes big fire seasons. These fire seasons, though, are very healthy for the environment. And the fire actually replenishes the soil by replacing all of those nutrients that were taken out of it. It's the largest portion found in Africa. That's the largest savanna that we have in the world. One of the biggest events that happens in the savanna takes place in the Serengeti, which is in Africa. And it's the migration of the wildebeest, where millions and millions of wildebeest travel across a part of Africa to follow the food and get away from the dry land caused by drought. It happens year after year. And even though many wildebeest die in this process, it helps to feed predators along the way, and it helps for the overall health of that ecosystem. Grasslands. Grasslands are where grasses are the dominant form of vegetation. So if you look at a grassland, pretty much the majority of what you're going to see is grass. The best use that we have for grasslands is-- you guessed it-- agriculture. If you drive into the Great Plains, which is a grassland in the United States, you're going to see that there's a lot of farmland there. It's because it has great soil, very fertile soil, and it's usually semi-flat, so it's very easy to cultivate. It occurs on all continents except for Antarctica, and it's usually contained on the interior portions of the continents. They receive 20 to 35 inches of rain per year, and the temperatures range from zero to 85 degrees. Temperate grasslands have cold winters and warm summers. Here's an example of an organism that lives in temperate grasslands. This is a fox, and he would have a great time feeding off of all the field mice, squirrels, and things that would live in the grass areas of that part of the country and the world. Temperate forests. Temperate forests are found in the Eastern US, Canada, Mexico, America, Europe, China, Japan, North Korea, and Russia. Pretty much all over the world. Well, what does temperate mean? Temperate means that the temperature changes. We have extremes. We have a winter, we have a summer. And what happens when we have these winter and summer, a lot of times these temperate forests, they change throughout the year along with the seasons. They receive 28 to 60 inches per year. And in these distinct seasons that they have, they may drop their leaves. These deciduous trees that you see some pictures of some beautiful red and orange forests, that is in the fall, could be back East, of all the trees as they are getting ready to go dormant for the winter season. That is a temperate forest. Rainforests. Rainforests are found near the equator in South America, Central America, Central Asia, Australia, and Africa. If you look at this map, here is the part of the world where rainforests occur. If you look at this map, you'd notice that they all exist right along the equator. Well, the real reason for that is because the way the earth is set up, we get very large amounts of precipitation in that part of the world. And all that precipitation leads to massive vegetation growth along with their wonderful temperatures year round. Temperatures remain constant about 75 degrees year round because they live right along that equator. The average rainfall is about 80 inches per year. Of course, there is also a huge species diversity in the rainforest. We have some of the largest species diversity of anywhere in the world that is contained in the rainforest. The largest diversity of plants and animals on the planet. Get real with science. As we mentioned, the lemur that exists in Madagascar, that only lives in Madagascar. They are a group of primates but they are endemic to Madagascar, which means that they don't exist anywhere else. They currently are all endangered species. There's several species of these guys. So these guys are one of the reasons that we would want to make sure that we protect our ecosystems, such as places like Madagascar, which is in danger from logging, human development, human expansion, and loss of habitat. So thinking ahead to the next section. What types of biomes can we see, and what types of ecosystems might we see in our area? If you look around, what types of vegetation exist around you? What temperatures do you experience on a daily basis?

transcript: section 3

What you're looking at in front of you is a kelp forest. A kelp forest is much different than any other forest you might be familiar with because it's in the ocean. Kelp is a type of seaweed that anchors itself to the ground, grows up through the water and lays across the surface to catch as much sunlight as possible. This is a type of aquatic ecosystem. We're going to learn about a few types of aquatic ecosystems in this section, and some terrestrial ecosystems. Ecology 101, Section Three. As you might recall, in the past sections we've described the levels of organization in the biosphere, we've identified the major biomes found on earth, and now we're going to compare and contrast the major ecosystems found on earth. So we'll start off with aquatic ecosystems. Aquatic ecosystems are any ecosystem that is contained within a body of water. There are two different types of aquatic ecosystems that we're going to talk about. The first one is a marine ecosystem. Here's an example of a marine ecosystem. Marine ecosystems are present in some sort of body of water that contains a large amount or a certain concentration of salinity, or salt. Freshwater ecosystems, on the other hand, might be exactly what you think. They are ecosystems contained in a body of water with much less dissolved salt in that water concentration. Then we have terrestrial ecosystems. Terrestrial ecosystems are ecosystems that are present outside of a body of water. So if you look at the picture below, you might notice that that is a terrestrial ecosystem. However, within it is contained an aquatic ecosystem. So although they are separate, they still do interact with one another. Aquatic ecosystems refer to communities found within bodies of water. So as we mentioned, any ecosystem that is contained within a body of water is considered an aquatic ecosystem. So that can be something from as big as an ocean to something as small as a pond or a puddle in certain areas of the desert. Freshwater ecosystems and marine ecosystems are the two types of aquatic ecosystems that we're going to talk about in this section. This is an example of two different types of aquatic ecosystems. If you look at the picture, this is an ocean. As you might know from swimming in the ocean, you get a mouthful of water, you would know that that has a large amount of salt in it. That would make this a marine ecosystem. However, looking at this nice little river that's flowing into that ocean, you would then also know that fresh water, which is present in rivers, would also be an aquatic ecosystem. But this would be a freshwater ecosystem. So as we mentioned before, even though these are considered two types of ecosystems, they do at some point mix a little bit and interact with one another. Here's another example of a marine ecosystem. Here we have the ocean, and it comes in very close contact with a terrestrial ecosystem right here. Marine ecosystems cover about three quarters of the earth's surface. Now, that's pretty easy to understand if you've ever looked at a map of the earth or a globe. You'll notice that most of it is blue. It's because most of it is covered by water. However, even though these oceans are very huge, there's a large area of these oceans that are pretty much unproductive. The reason they are unproductive, they don't produce a lot of food, they don't produce a lot of organisms, because out in the middle of those deep oceans, there just isn't much to survive on. There's not a lot of nutrients, there's not a lot of things for organisms to eat. So the areas where most of these organisms survive that are in the ocean are along the coastal areas. So we would look around the coast of any large body mass, and you're going to find a much larger concentration of organisms and species there. The marine ecosystems compose 97% of the planet's water. So as we mentioned before, if you've ever been swimming in the ocean and got a mouthful of water, you would know that it's very salty. Saltwater is not drinkable for people. So if you think about that, that means that 97% of the water on this planet is not drinkable. They generate 32% of the world's primary producers. Now if you remember from the past sections, producers are something that use sunlight to create there own food. They are also something that feeds the rest of us. Whether you eat producers or whether you eat other consumers that eat producers, those producers supply the rest of the world with food. Marine ecosystems contain dissolved sodium chloride, which is the same as table salt that you might put on your steak. The average concentration of salt in the oceans is 35 parts per thousand. That means that for every 1,000 water molecules, there are 35 salt molecules. However, even though that is an average, there are certain areas of the ocean that have more salt that, and certain areas that have less salt concentration than that. And that's really important when it comes to maintaining our tides and our different currents within the ocean. Some of those currents rely on differences in salinity or water, and if we didn't have those differences and that saltiness, then those currents would not continue to function properly. Freshwater ecosystems. These freshwater ecosystems include lakes, ponds, rivers, streams, springs, and wetlands. Now not all lakes are going to be freshwater, such as the Great Salt Lake in Utah. But for the majority, our lakes, rivers, and streams, are going to be freshwater. That doesn't mean that they don't have any salt. They contain lower salt concentrations. Salt is really important for every organism in the world to survive. So we all need a little bit of salt. So all water in the world, unless it has been distilled or something has been done to it, it will contain some sort of salt or other things dissolved within it. They are classified depending on temperature, light penetration, and vegetation. So we would consider these freshwater ecosystems different types by looking at the temperature of the water in the surrounding area, the amount of light that can penetrate that water into the ecosystem, and the type of vegetation that grows in that ecosystem. Terrestrial ecosystems include dry land ecoregions. They're classified by biome type. So you might remember the different biomes that we talked about, the desert, the grasslands, the tundra. Those are all different types of biomes that help us classify our terrestrial ecosystems. Terrestrial ecosystems occupy 28% of the earth's surface. They have much greater temperature fluctuations than aquatic ecosystems. The reason for this is because it takes a much more energy to change the temperature of a drop of water than it does to change the temperature of a section of air. It takes much more energy to change that temperature. So because of that, sunlight warms aquatic ecosystems much slower than it does the terrestrial ecosystems out in the air. Light is also more readily available in terrestrial ecosystems. If you can imagine swimming down 30 or 40 feet into the water, you would notice that it gets much darker down there. So then imagine being a plant and trying to survive on the bottom of a lake or pond or seabed that is 30 or 40 feet below the surface. You're going to receive much less sunlight there than you would out on the ground. So they receive much less light in aquatic ecosystems, and it is much more readily available in terrestrial ecosystems. So getting real with science. I'd like to talk about these kelp forests again. That first picture I showed you of kelp forests-- and as I mentioned, they are a type of seaweed that anchor themselves into the ground, grow up, and then lay across the top of the ocean, or the surface of the ocean. They do this because they want to collect as much light as possible to help them grow. Now kelp forests are some of the most productive and dynamic ecosystems in the world. They produce a lot of food that can feed a lot of organisms. And they're very dynamic. Some of these kelp have been recorded growing 10 inches a day. So if you were to break that down per hour, that's just a little less than half an inch per hour. That is really fast growth. They're a specialized habitat for certain organisms. Otters love kelp forests because there are sea urchins in that kelp forest which they love to eat. Sea urchins eat the kelp, the otters eat the sea urchins, they're all happy unless they're getting eaten. A resource for understanding marine ecosystems. So if we look at these, we can really understand ecosystems. There's a really good example of how we can interfere with ecosystems when a number of years ago, the sea otters in the area off of the coast of California were hunted to near extinction. In fact, many people thought that sea otters were extinct in that area. What happened to that ecosystem were that the sea urchins that otters normally eat their population grew exponentially and the kelp forest begin to disappear. Well luckily, the sea otters were not completely extinct. And as they became protected and their population made a comeback, the sea urchins once again were brought under control and the kelp forests were able to make a comeback. So looking back, because of our over hunting of sea otters in that area, we almost lost an entire ecosystem. It was pretty close. Here's a picture of a guy enjoying swimming, scuba diving within those kelp forests. So I'd say looking back at this section, we've once again accomplished our mission. We talked about the levels of organization, and they are the organism which is the smallest, such as you and I, species, population, communities, ecosystems, biomes, all the way up to the largest level of organization which is the biosphere or the earth. The major biomes found on earth, we've talked about those, the different ones like desert, taiga, tundra, grasslands, savanna, temperate forest, and the rainforest, and all their differences and similarities. And we've talked about two main ecosystems found on earth, such as terrestrial and aquatic, and that aquatic ecosystems can be broken down into two separate sections, marine, which has salt water, and freshwater, which has much less salt dissolved in that water.

Explain why the marine ecosystem generates a significant fraction of the oxygen in the atmosphere. A) The marine ecosystem generates 32% of the world's primary producers. B) The organisms in the marine ecosystem converts carbon dioxide to oxygen faster than organisms in other ecosystems. C) Sunlight can easily penetrate the marine ecosystem. D) Evaporation is higher in the marine ecosystem than any other ecosystem.

A) The marine ecosystem generates 32% of the world's primary producers.

What are Earth's ten biomes? A) tundra, taiga, grasslands, deciduous forest, chaparral, desert, desert-scrub, savanna, rainforest, and alpine B) alpine, arctic, savanna, chaparral, desert, dry scrub, deciduous forest, taiga, tundra, and grasslands C) grasslands, desert, desert-scrub, savanna, chaparral, tundra, arctic, alpine, evergreen forest, and deciduous forest D) sahara, alpine, tundra, taiga, desert, desert-scrub, rainforest, deciduous forest, chaparral, and grasslands

A) tundra, taiga, grasslands, deciduous forest, chaparral, desert, desert-scrub, savanna, rainforest, and alpine

Environments are covered with manmade structures like roads, buildings, and sewers. Green spaces such as parks, backyards, and undeveloped lots are scattered among the developed areas instead of all connected together. Plants and animals have to deal with exposure to toxins from vehicles and loss of habitat and food sources. These are all ways that __________. A) humans have intervened to both manage and manipulate the environment to ensure species survival B) nonhuman life in an urban ecosystem differs from that in an undeveloped forest ecosystem C) cities have been developed to keep wildlife out of public areas D) humans have impacted the environment and caused wildlife species to become domesticated E) nonhuman life adjusts to its new habitat

B) nonhuman life in an urban ecosystem differs from that in an undeveloped forest ecosystem

Savanna is considered a transitional biome because it is intermediate between two ________. A) climates B) regions C) biomes D) ecosystems

C) biomes

Deserts are defined by __________. A) coniferous forests B) mild summers C) high temperature D) low rainfall

D) low rainfall