Ecosystem Ecology

Summary

This environmental science video delves into ecosystem ecology, illustrating the interplay between living and nonliving components. It uses the example of kelp forests to explain food chains and the concept of keystone species, emphasizing their crucial role in maintaining balance. The script also covers the organization of life from individuals to the biosphere, introduces major biomes and their characteristics based on temperature and precipitation, and touches on aquatic biomes, food webs, niches, species diversity, and the impact of edge effects on ecosystem health.

Takeaways

• 🌳 Ecosystems consist of both living and nonliving components, with examples like kelp forests where kelp acts as a producer.
• 🐾 The sea otter is considered a keystone species in the kelp forest ecosystem, maintaining balance by controlling sea urchin populations.
• 🔄 The absence of a keystone species can lead to a cascade of changes, such as the formation of urchin barrens, disrupting the ecosystem's structure.
• 🔑 The concept of a keystone species is crucial for understanding the stability and health of an ecosystem, similar to how a keystone holds up an arch.
• 🌿 Life is organized from the individual level to populations, communities, ecosystems, biomes, and ultimately the biosphere.
• 📊 Biomes are classified based on temperature and precipitation, with examples ranging from deserts to rainforests and tundras.
• 🌊 Aquatic biomes are differentiated by salinity, depth, and water flow, with types including wetlands, estuaries, and open oceans.
• 🏞 The Greater Yellowstone Ecosystem exemplifies a large ecosystem, including national parks, forests, and private lands.
• 🔼 Food chains and webs illustrate the flow of energy and the relationships between producers, consumers, and decomposers in an ecosystem.
• 🕊 Species diversity is vital for ecosystem health, as it allows for resilience against environmental changes and disturbances.
• 🏡 The niche of an individual species is influenced by its environment, resources, and the presence of other species, affecting its realized niche versus its fundamental niche.
• 🚫 Edge effects can impact ecosystem health, with natural boundaries supporting more species, whereas human-made edges can damage the ecosystem.

Q & A

What is an ecosystem according to the video script?

An ecosystem is a large area on our planet that contains both living and nonliving material, where organisms interact with each other and their environment.

What role do kelp forests play in the example given in the script?

Kelp forests serve as an example of an ecosystem where kelp acts as producers, converting sunlight into food, which is then consumed by herbivores like sea urchins, and eventually by carnivores like sea otters.

Why are sea otters considered a keystone species in the context of the kelp forest ecosystem?

Sea otters are considered a keystone species because their presence helps control the population of sea urchins, which in turn prevents the overconsumption of kelp and the formation of urchin barrens, thus maintaining the balance of the ecosystem.

What happens to the kelp forest ecosystem if the sea otter population declines?

If the sea otter population declines, the sea urchin population may increase unchecked, leading to overgrazing of kelp and potentially creating urchin barrens, which are areas devoid of kelp and disrupt the ecosystem balance.

What is the difference between a population, a community, and an ecosystem?

A population refers to all individuals of a single species within a certain area. A community is a group of different populations living in the same area. An ecosystem includes all the living organisms (community) and nonliving components of an area, such as climate and soil.

What are biomes and how are they determined?

Biomes are large areas of the world with similar climate, vegetation, and wildlife. They are determined by two main properties: average temperature and average precipitation.

How does the script describe the transition from biome to ecosystem?

The script describes the transition from biome to ecosystem by focusing on a specific area, such as the Greater Yellowstone Ecosystem, which includes not only the national park but also surrounding national forests and private lands, encompassing all living and nonliving components.

What is a food chain and how is energy transferred within it?

A food chain is a linear sequence of organisms through which nutrients and energy flow. Energy is transferred from producers (like plants) to consumers (like herbivores and carnivores) through the act of eating, as indicated by arrows pointing from the food source to the consumer.

What is the significance of species diversity in an ecosystem?

Species diversity is important for the health of an ecosystem because it allows for a greater range of responses to environmental changes, such as temperature fluctuations or resource availability. A diverse ecosystem is more resilient and stable.

What is the concept of a niche in the context of an ecosystem?

A niche refers to the role or function of an individual species within an ecosystem, including its habitat, food sources, and other environmental factors that influence its survival and reproduction.

What is an edge effect and how can it impact an ecosystem?

An edge effect is the phenomenon that occurs at the boundary between two ecosystems, such as a forest and a grassland. It can impact the ecosystem by creating a unique habitat that supports a variety of species. However, artificial edges created by human activities can disrupt the natural balance and negatively affect the ecosystem's health.

Outlines

00:00

🌿 Ecosystem Ecology and Keystone Species

This paragraph introduces the concept of ecosystems as large areas containing both living and nonliving elements, using the example of kelp forests. It explains the role of producers, consumers, and the impact of keystone species like sea otters on the ecosystem's balance. The loss of a keystone species can lead to a cascade of negative effects, as seen with the sea urchins and kelp. The paragraph also covers the organization of life from individuals to populations, communities, ecosystems, biomes, and the biosphere. It sets the stage for a deeper dive into biomes and the importance of understanding the interactions within ecosystems.

05:01

🌳 Terrestrial and Aquatic Biomes and Ecosystem Dynamics

This section delves into the major biomes, both terrestrial and aquatic, and their defining characteristics, primarily temperature and precipitation for terrestrial biomes, and salinity, depth, and water flow for aquatic ones. It discusses how these factors determine the type of biome, from tropical rainforests to deserts and from freshwater wetlands to open oceans. The paragraph also transitions from the concept of biomes to ecosystems, emphasizing the importance of producers, consumers, and decomposers. It introduces the food chain and food web, the roles of herbivores, carnivores, and omnivores, and the significance of keystone species and species diversity in maintaining ecosystem health. The impact of human-made edges on ecosystems and the importance of preserving large, healthy areas are also highlighted.

10:04

🏞️ Ecosystem Protection and the Role of Diversity

The final paragraph focuses on the importance of ecosystem protection, emphasizing the need for maintaining large, contiguous areas to ensure healthy edges. It discusses the concept of the 'edge effect,' which can be beneficial if it's a natural boundary but detrimental if it's a human-made abrupt edge. The paragraph illustrates the impact of shrinking protected areas on the proportion of the edge effect, which can harm the ecosystem. It concludes by reviewing the hierarchy of ecological organization from individual to biome and touches on the roles of producers, consumers, keystone species, diversity, and the niche, which is likened to the 'job' of an individual within an ecosystem.

Keywords

💡Ecosystem

An ecosystem is a community of living organisms, such as plants, animals, and microbes, interacting with each other and their nonliving physical environment, which includes air, water, and soil. In the video, ecosystems are discussed as large areas on the planet that contain both living and nonliving material, with examples like the kelp forests and the Greater Yellowstone Ecosystem, illustrating the interconnectedness of life and environment.

💡Producers

Producers, also known as autotrophs, are organisms that can produce their own food from inorganic substances using light or chemical energy. In the video, kelp is given as an example of a producer, as it uses sunlight to convert carbon dioxide and water into glucose, which serves as a food source for other organisms in the ecosystem.

💡Herbivores

Herbivores are animals that eat only plants and are primary consumers in a food chain. The script mentions sea urchins as herbivores that feed on kelp, demonstrating the flow of energy from producers to primary consumers in an ecosystem.

💡Carnivores

Carnivores are animals that eat other animals, classifying them as secondary or higher-level consumers in a food chain. The sea otter is highlighted in the video as a carnivore that preys on herbivores like sea urchins, thus playing a significant role in controlling sea urchin populations.

💡Keystone Species

A keystone species is a species that has a disproportionately large effect on its environment relative to its abundance. The sea otter is referred to as a keystone species in the video because its presence helps maintain the balance of the kelp forest ecosystem by controlling sea urchin populations, preventing them from overgrazing on kelp.

💡Urchin Barrens

Urchin barrens are areas in the ocean where sea urchins have grazed kelp to such an extent that no kelp remains. The video describes this phenomenon as a result of unchecked sea urchin populations, which can occur if their natural predator, the sea otter, is removed from the ecosystem.

💡Biome

A biome is a large community of plants and animals that occupies a distinct region defined by its climate, geography, and the types of organisms that live there. The video script discusses various terrestrial and aquatic biomes, such as deserts, boreal forests, and open oceans, which are determined by factors like temperature and precipitation.

💡Food Chain

A food chain is a linear sequence of organisms in which the species at one trophic level feeds on the species at the level below it. The video explains food chains as a way to represent the flow of energy from producers to consumers, with arrows indicating the direction of energy transfer, as seen in the example of plants being eaten by insects and fish.

💡Food Web

A food web is a complex network of food chains that intertwine to show the multiple feeding relationships among organisms within an ecosystem. The video mentions food webs as a way to study the interactions between producers and consumers in an ecosystem, illustrating the complexity of energy flow and species interdependence.

💡Niche

A niche refers to the specific role or function of a species within an ecosystem, including its habitat, food sources, and activities. The video describes the niche as the 'job' of an individual organism, using the squirrel and dung beetle as examples to show how organisms exploit their environment and resources to survive and reproduce.

💡Species Diversity

Species diversity refers to the variety of species within an ecosystem and is an important factor in maintaining ecosystem health. The video script explains that a diverse ecosystem is more resilient to environmental changes, using the example of how different species respond to temperature variations to emphasize the importance of diversity.

💡Edge Effect

Edge effect refers to the changes in environmental conditions and species composition that occur at the boundary between two different ecosystems or habitats. The video discusses how edge effects can be both positive and negative, depending on the nature of the boundary and its impact on the species living there. It warns against human-caused edges, such as roads, which can disrupt the natural transition and harm ecosystem health.

Highlights

Ecosystems are large areas containing both living and nonliving material, like the example of kelp forests.

Kelp are producers, converting solar energy into food for herbivores and indirectly for carnivores.

Sea otters, as a keystone species, help maintain the balance of the kelp forest ecosystem.

The absence of sea otters can lead to overpopulation of sea urchins and the destruction of kelp forests.

Biomes are larger areas than ecosystems, determined by temperature and precipitation.

Aquatic biomes are differentiated by salinity, depth, and water flow, unlike terrestrial biomes.

The Greater Yellowstone Ecosystem is an example of a large ecosystem including various land types and nonliving factors.

Producers form the base of ecosystems, with consumers organized in food chains and webs.

Herbivores, carnivores, and omnivores are categorized by their diet within the ecosystem.

Decomposers and detritivores play a crucial role in recycling dead organic material.

A niche is the role or job of an individual within an ecosystem, influenced by the environment and resources.

Species diversity contributes to the health and resilience of an ecosystem.

Niche generalists, like raccoons, are more adaptable to environmental changes than specialists like koalas.

Edge effects occur at the boundary of ecosystems and can impact the health of the ecosystem.

Protecting large areas with healthy edges is important for maintaining ecosystem health.

The concept of the biosphere as the largest ecological unit, encompassing all life on Earth.

The importance of understanding the hierarchical organization of life from individuals to the biosphere.

The practical implications of ecological knowledge for environmental conservation and management.

Transcripts

Hi. It’s Mr. Andersen and this is environmental science video 7. It is on ecosystem ecology.

Ecosystems are large areas on our planet that contain both living and nonliving material.

A great example could be these giant kelp forests. The kelp are producers. So they are

taking energy from the sun and converting that into food, which is eaten by herbivores

like this sea urchin, which in turn are eaten by carnivores like this sea otter. Now the

problem with the sea otter is if it dies due to hunting or predation, then the sea urchin

populations will take off. Sea urchins feed on kelp by trimming the bottom and sometimes

the kelp will simply float away. And so if you have too many sea urchins you get what

are called urchin barrens where there are no kelp. And therefore the whole ecosystem

kind of folds in on itself. And so we like to think of the otter as a keystone species.

Just like on this arch, this keystone at the top holds everything else in place. You can

think of each of these stones now as a different species. If we remove that keystone species

then the whole things folds in on itself. In other words some species are actually more

important than others. Before we get to ecosystems we should understand how life is organized

from the very small, one individual for example, sea urchin. It is in part of what is called

a population, or all of the sea urchins in an area. We then take all of the populations

together. That is a community. We then add the non living material. That is an ecosystem.

And then we even have larger areas which are called the biomes. What is larger than the

biomes? That is going to be the biosphere. That is going to be our planet. And so before

we get to ecosystems we will start by studying the major biomes, both terrestrial or land

based and aquatic. We will then move on to the interactions at the ecosystem level. So

that is going to be all of the producers and consumers interacting. A good way to study

that is going to be with their food webs. We are also going to add abiotic or non living

material. We will then jump to individuals and the role of a niche. That is going to

be the job that an individual has. We will then move to the importance of keystone species,

diversity. And then finally edge effects in keeping that ecosystem healthy. And so let’s

start with terrestrial biomes. A desert could be an example. A boreal forest could be an

example. Now there is really only two properties that determine what biome we are going to

have. That is going to be the temperature, average temperature and the average precipitation.

So you could be given a map and just told what is the average temperature and precipitation.

You could make a pretty good guess as to what the biome is going to look like. And so if

we graph those on a graph where we have precipitation on the y, so that is going to be the amount

of annual precipitation from 0 to 400 centimeters per year. And then we look at temperature

from the very cold on the left, -10 degrees celsius as an average up to 30 plus degrees

celsius. You could kind of guess as to what biome are we going to find where it is really,

really hot and where it is really, really moist. You could even point to it on a biome

map. It is going to be the tropical rainforest. And so what you can do on this map is just

read precipitation, temperature. That tells you the biome. If we were to go in Africa

right here and then move to an area where it is still hot but we have less precipitation,

that is going to be a tropical forest or savannah. You are probably familiar with that. If we

keep moving up, so we have even less precipitation then we are going to get into a subtropical

desert. And you can see those at this latitude and at this latitude right here. If we keep

going across from Africa though, lets go up here, we are then going to have temperate

grasslands. Sometimes we have temperate deserts. You can see we have a lot of those in the

midwest of the United States. If we keep going then we are going to get to temperate seasonal

forests. If we keep going then we go to the boreal or northern forests. And then we eventually

get to the tundra. So these are the major biomes. We could fill in a couple of other

ones. So right here in the mediterranean we are going to have woodland shrub lands. We

would have that over in California as well. And then if we go up here we will have these

temperate rainforests where it is cooler but they receive tons and tons of precipitation

throughout the year. And so you can see those are those the major biomes. If we start looking

at aquatic biomes it is not temperature and precipitation, because water exists. And so

it is going to be salinity, the amount of salt, the depth within that water and then

the flow of the water. And so the first way to divide the aquatic biomes is to those that

are freshwater and those that are going to be saltwater. If we look at those that are

freshwater you are probably familiar with almost all of these. Wetlands are areas where

we are going to have water for a large portion of the year but we still have vegetation in

that area. We could move from there to areas that are kind of the boundary between fresh

and salt water. So a salt marsh is going to be an area where we have water flowing in.

So we could have a mix of freshwater and saltwater. Estuaries are like this. Or we could have

mangroves. Those are areas, mangrove is kind of based on a tree that can grow in salt water

and those are important as a border between marine and terrestrial systems. And then as

we move out to the ocean itself we have intertidal zones. So that is going to be when the tide

comes in and out. That thin area along the coast. Coral reefs you are probably familiar

with. And open oceans. Open oceans are really not a super productive ecosystem out in the

middle of the ocean. Only near the top where we get a certain amount of light. So now we

are going to go from biome to ecosystems. So this is going to be a smaller area but

it is still really big. One of the most famous ones in the world is the Greater Yellowstone

Ecosystem. It is really just south of me. I live right here. And so it is bordered by

Montana, Idaho, Wyoming and Wyoming. But it is not just Yellowstone National Park that

makes up the ecosystem, it is going to be this whole area around it, which is going

to contain the national park. But also national forest and private land as well. It is a really

large area. Also includes all of the abiotic or nonliving material. So for example the

temperature, the pH of this water, the flow of the water are all considered when we are

thinking about the ecosystem. Now let’s go to the parts of the ecosystem. So everything

is built on these producers. And so those things that do photosynthesis. If we look

at a terrestrial versus an aquatic we are going to find the same kind of transition.

We have the plants at the bottom. The herbivores. Then we have carnivores and carnivores on

top. So we have these different levels of consumers as we move up. They are organized

in what is called a food chain. And the arrow is going to show where the energy is going

or where the food is going. So food goes from the plant to the insect itself. Students sometimes

confuse which way the arrows go. And here is an easy way to remember that. So just think

of the arrow as the mouth of what is eating it. So this is a mouth of a fish. We know

that the arrow always goes from the food to what is eating it. Or the organism to what

eats that organism. If we organize all the food chains in an area then we have a food

web. And so it is going to have producers on the bottom and then it is going to have

the consumers above that. Different levels of consumers. If you look we have aquatic

and terrestrial all mixing in. Some terms that you may be familiar with are herbivore.

Herbivore is going to be something that just eats plants. We have carnivore, something

that just eats other living things. But we also have an omnivore. That is going to be

something that eats plants and other living things. Keystone species remember is going

to be a species that keeps everything kind of in check in that ecosystem. And I am really

leaving off a bunch, which is going to be all the decomposers. So as material dies we

have to recycle that. So that is going to be decomposers. An example are detritivores

that can eat large bulk amounts of dead material. What is the niche? Now we are at the level

of an individual. So a niche you can think of as like the job of an individual. So if

we take this squirrel and say how does the squirrel preform over different temperatures,

well we are going to get a distribution like that. There are going to be areas where it

can survive. Outside that would be areas where it dies. If it is too cold or if it is too

hot. As we move closer to the middle we get areas where it can survive and grow. And finally

where it can survive, grow and reproduce. And so the environment has a lot to do with

a niche. But also what we are using as a food source. So this dung beetle for example exploits

a niche by taking dung, rolling it up and using that as an eventual food source. What

else determines it then? Not only the environment but the resources, the food that you need.

Or the space you need to live in. And so we can represent that on this graph as here is

the two resources I need and that is going to be my fundamental niche. That is where

this squirrel could live. Now what you will find is that it actually does not fit that

way. You have what is called a realized niche where it could live in all of those areas

but it only lives in the small area. And the reason why, you are probably guessing is that

there are other niches outside that. There is competition going on. Species diversity

is actually good. It is good to have all of these different species. So let me use this

model to show you how that works. Imagine we have species that are just cold tolerant.

They love the cold. Warm tolerant, they love the heat. Or a nice diverse mix of the two.

And so let’s say we apply some cold weather. What happens? All those that are not cold

tolerant die. You can see the warm tolerant are going to be most affected. You are going

to see the diverse species in the middle. And the cold ones are doing fine. But let’s

say we change it up now and it is really hot. Then we are going to have this impact. And

so right here by having a diverse population, this does not have to deal with just temperature,

but it can be resources you are feeding on, the more species we have the healthier that

ecosystem is going to be. That even applies at the individual level. So a raccoon is what

is called a niche generalist. It can eat lots of different food resources. It can live in

lots of different areas. Where as a koala can only eat Eucalyptus leaves. Which of these

do you think is more susceptible to change in that environment? Definitely is going to

be the koala since it is only feeding on one thing. If that resource is impacted it is

going to be impacted as well. The edge effect also affects the health of an ecosystem. Edge

effect is going to be a boundary between two ecosystems. It actually can be a healthy area.

So if it develops over a long period of time what you will get is this transition from

here into the forest. And so that is an area where we can actually support more species.

The problem is that humans lots of times will just create an edge, so we make a trail or

we make a road. And now what happens is there is not this natural boundary and that can

damage the health of the ecosystem. The size of the edge is always going to be the same.

And so watch what happens when I take this shape. Think of this as a protected area.

So the edge will always remain the same. But watch what happens when I shrink the protected

area. The edge becomes a larger proportion. Let me even shrink it up even more. And so

that edge becomes the largest thing. And so if we are trying to protect an ecosystem,

protect an area, it is important that we have the largest area with the healthiest edge

that we possibly can. And so did you learn the following? Can you pause the video now

and fill in the blanks? Well I hope so, but I could work through it. It goes from individual

to population to community to ecosystem to biome. Major examples are terrestrial and

aquatic. Could you list some of those? We have interactions between producers and consumers.

Keystones species, diversity and then the edge effect can affect the health of the ecosystem.

And then remember the niche is the role of an individual. It is kind of like its job.

I hope you learned that. And I hope that was helpful.