Ecosystems and biomes | Ecology and natural systems | High school biology | Khan Academy

Summary

This educational video script delves into the concepts of population, community, and ecosystem in ecology. It explains that a population consists of individuals of the same species within a specific area, while a community comprises multiple populations of different species in the same area. An ecosystem encompasses both biotic (living) and abiotic (non-living) elements within a defined region. The script further explores ecosystem types, including aquatic and terrestrial, and introduces the classification of land ecosystems into biomes based on factors like climate and terrain. Examples such as tide pools, the Amazon rainforest, and various deserts illustrate the diversity within ecosystems.

Takeaways

• 🌿 A population is a group of individuals of the same species living in the same area.
• 🌳 A community is composed of multiple populations of different species living in the same area.
• 🌍 An ecosystem includes both living (biotic) and non-living (abiotic) components within a defined region.
• 🌅 Energy flows through ecosystems, typically entering as sunlight and being transferred among organisms.
• 🔁 Matter is conserved within ecosystems, transforming from one form to another.
• 🌊 Ecosystems can be classified as aquatic or terrestrial, with aquatic further divided into marine and freshwater.
• 🌱 Biomes are large-scale ecosystems categorized by similar climate, flora, and fauna, such as tropical forests, deserts, and tundra.
• 🏞️ The Amazon rainforest and the Sonoran Desert are examples of different biomes with distinct biotic and abiotic characteristics.
• 🌐 The size and boundaries of ecosystems can vary, from a small tide pool to an expansive rainforest.
• 🔬 The study of ecosystems involves understanding the interactions between biotic and abiotic factors and the conservation of matter and flow of energy.
• 🌡️ Climate and terrain are significant factors in determining the types of ecosystems and biomes found in a region.

Q & A

What is the definition of a population in the context of biology?

A population is a group of individuals of the same species living in a particular area.

How does a population differ from a community?

A population consists of members of the same species, while a community includes all living organisms, both biotic and abiotic, within a certain area.

What is meant by the term 'biotic factors'?

Biotic factors refer to the living components of an ecosystem, such as plants, animals, and microorganisms.

Can you explain the concept of 'abiotic factors'?

Abiotic factors are the non-living elements of an ecosystem, including elements like water, air, soil, and sunlight.

What is an ecosystem and how does it differ from a community?

An ecosystem includes both the living (biotic) and non-living (abiotic) components within a certain area, while a community only includes the living components.

How does the size of an ecosystem vary?

The size of an ecosystem can vary greatly, from a small area like a tide pool to a large area like a rainforest or an entire ocean.

What is the difference between an aquatic and a terrestrial ecosystem?

An aquatic ecosystem is one that occurs in water, while a terrestrial ecosystem is found on land.

Why are most aquatic ecosystems considered marine rather than freshwater?

Most aquatic ecosystems are marine because they are found in saltwater environments like oceans, whereas freshwater ecosystems, such as rivers and lakes, are a smaller subset.

What is a biome and how is it related to ecosystems?

A biome is a large community of plants and animals that occupy a distinct region defined by its climate, terrain, and types of minerals, and it represents a major type of ecosystem.

How do the abiotic factors in an ecosystem affect its classification?

Abiotic factors such as climate, terrain, and mineral content are critical in determining the type of ecosystem and its classification into biomes.

Can you give an example of how ecosystems can be classified based on their location?

Ecosystems can be classified as marine, freshwater, terrestrial, and even within the human body, with each classification having distinct abiotic and biotic factors.

Outlines

00:00

🌿 Understanding Populations and Communities

This paragraph introduces the concept of a population as a group of the same species living in the same area. It explains that while there can be multiple populations of different species in the same area, each population is distinct. The paragraph then expands on the idea of a community, which is a collection of all populations in a given area, encompassing both biotic (living) and abiotic (non-living) factors. The narrator emphasizes the importance of understanding ecosystems, which include both biotic and abiotic elements within a defined region. The video aims to explore the types of ecosystems and the interactions between different factors, such as the conservation of matter and the flow of energy. Examples of ecosystems range from tide pools to the Amazon rainforest, illustrating the variability in scale and composition.

05:02

🌍 Classifying Land Ecosystems into Biomes

The second paragraph delves into the classification of land ecosystems, known as biomes, which are determined by factors like temperature, moisture, climate, and terrain. It showcases a diagram of the major types of land biomes found across the planet, such as tropical forests, boreal forests, savannas, deserts, tundra, chaparral, and polar ice. The paragraph highlights the Amazon rainforest as an example of a tropical forest biome and discusses how the climate and mineral composition of an area can influence its biome. It also points out the variability within biomes, using the Sonoran Desert and the Rock Desert as examples to demonstrate that even within the same biome category, ecosystems can have distinct characteristics and levels of biodiversity.

Keywords

💡Population

A population refers to all the organisms of the same species that live in a particular area. In the video, the concept is introduced as a fundamental unit of ecological study, emphasizing that while populations are composed of individuals of the same species, they are confined to specific geographic regions. The script uses the example of organisms sharing the same area to illustrate how a population is defined and how it differs from other members of the same species that are not in that area.

💡Community

A community, as mentioned in the script, is a collection of all populations of different species that live in a particular area. It is a broader concept than a population, as it encompasses all living organisms, not just one species. The video script explains that a community is made up of biotic factors, which are all the living organisms within a certain area, highlighting the interdependence and interactions among different species.

💡Ecosystem

An ecosystem, according to the video, includes not only all the living organisms (biotic factors) in a given area but also the non-living components (abiotic factors) such as water, air, and soil. The script explains that ecosystems can vary greatly in size, from a small tide pool to a vast rainforest, and they are defined by the interactions between living and non-living elements. The concept is central to the video's theme, as it sets the stage for discussing the types of ecosystems and their functions.

💡Biotic Factors

Biotic factors represent the living components of an ecosystem, including plants, animals, and microorganisms. The video script emphasizes that these factors are crucial for understanding how ecosystems function, as they interact with each other and with their environment. The script provides examples such as starfish and sea anemones in a tide pool, illustrating how biotic factors contribute to the ecosystem's dynamics.

💡Abiotic Factors

Abiotic factors are the non-living physical and chemical components of an ecosystem, such as temperature, light, water, and minerals. The video script explains that these factors influence the types of organisms that can survive in an ecosystem and how they interact. The concept is used to contrast with biotic factors, showing that ecosystems are shaped by both living and non-living elements, as exemplified by the water and rock in a tide pool.

💡Marine Ecosystems

Marine ecosystems are those that occur in saltwater environments, primarily the oceans. The video script discusses marine ecosystems as a type of aquatic ecosystem, highlighting their importance due to the vast majority of aquatic ecosystems being marine. The script contrasts marine ecosystems with freshwater ecosystems, emphasizing the differences in salinity and the types of organisms that inhabit these environments.

💡Freshwater Ecosystems

Freshwater ecosystems are those that consist of non-salty water, such as rivers, lakes, and streams. The video script points out that despite the importance of freshwater for human life, freshwater ecosystems make up a small subset of all aquatic ecosystems. The script uses the example of the upper Amazon River to illustrate the concept of a freshwater ecosystem.

💡Biomes

Biomes are large-scale ecosystems characterized by similar climate, flora, and fauna. The video script introduces biomes as a way to classify land ecosystems based on their dominant features, such as tropical forests, boreal forests, and deserts. The script explains that biomes are determined by factors like temperature, moisture, and terrain, and provides examples of different biomes found across the globe.

💡Tropical Rainforests

Tropical rainforests are a type of biome characterized by high rainfall, stable temperatures, and dense vegetation. The video script describes the Amazon rainforest as an example of a tropical rainforest biome, emphasizing its biodiversity and the complex interactions among its organisms. The script uses this example to illustrate the rich and varied life found in such ecosystems.

💡Conservation of Matter

Conservation of matter, as touched upon in the video script, refers to the principle that matter cannot be created or destroyed, only transformed from one form to another within an ecosystem. The script suggests that understanding this principle is crucial for studying ecosystems, as it helps explain how materials cycle through different organisms and environmental components.

💡Energy Flow

Energy flow in ecosystems is the process by which energy enters an ecosystem (typically as sunlight) and is transferred through the food chain, eventually being lost as heat. The video script discusses energy flow as a key aspect of ecosystem function, explaining how energy moves from producers to consumers and decomposers, highlighting the importance of this process for the survival and interaction of organisms within an ecosystem.

Highlights

A population is defined as a group of the same species sharing the same area.

Other members of the same species not in the same area are not part of that population.

An area typically contains multiple species, each forming its own population.

A community is a collection of all populations within a certain area, including different species.

Biotic factors refer to living components within a community.

Abiotic factors include non-living elements like climate and soil.

An ecosystem encompasses both biotic and abiotic factors within a defined region.

Ecosystems can vary greatly in size, from a small tide pool to a vast rainforest.

Matter and energy flow within ecosystems, with energy typically entering as sunlight.

Ecosystems can be classified by their aquatic or terrestrial nature.

Aquatic ecosystems are further divided into marine and freshwater types.

Most aquatic ecosystems are marine, with freshwater ecosystems being less common.

The human body can also be viewed as an ecosystem, with its own biotic and abiotic interactions.

Land ecosystems are categorized into biomes based on factors like climate and terrain.

Biomes include tropical forests, boreal forests, savannas, deserts, and more.

Even within the same biome, ecosystems can differ significantly due to local variations.

Desert ecosystems, such as the Sonoran and Rock Desert, demonstrate the diversity within a biome.

Transcripts

- [Voiceover] So, just as a bit of review.

If we take the members of a certain species

that share the same area,

we call that a population.

Population.

All of the organisms in this particular population

will be members of the same species.

There could be other members of that species

that aren't in that same area,

and they wouldn't be a member of this particular population.

And a certain area won't have just one,

or it doesn't tend to have just one species in it.

So, we could call this population one.

You might have other populations there

of a different species.

So, this is another species right over here.

All of them combined in the same area,

we could call this population,

population two.

And if you take...

And we could, obviously have many more populations there.

And if you take all of the populations

in a given area,

there's flexibility on how you define that area

or define that region,

you take those together,

so you're really taking all of the living things

in a certain area, we call that a community.

A community of populations.

Now, the community only consists of living things,

the biotic factors.

So, let me write that down.

Biotic referring to the living things in a certain area.

But if we want to think about not just the living things,

but also the non-living things in that region.

So, I'll write abiotic.

Let me do that in another color.

So, let's take the abiotic factors,

or the abiotic environment.

And, once again, we're sharing the same region,

and that is flexible on how you define that region.

You put all of these things together,

and then you get your ecosystem.

Your ecosystem, once again,

it could be a very small region,

it could be a very large region,

but it's made up of all living things,

the biotic factors, and the non-living things,

the abiotic factors.

Now, what we're gonna think about in this video

is just the types of ecosystems that you might have.

Think a little bit about it,

and also begin to think about how the different factors

interact with each other.

How there's conservation of matter

where, within an ecosystem, matter tends to go

from one form to another.

You also have a flow of energy.

Energy tends to enter an ecosystem

in form of light, and that energy gets transferred

from one organism to another,

and, sometimes, even involving the non-living things,

eventually, getting turned

into actual heat.

Now, in terms of the types of ecosystems.

I already mentioned there's a lot of variety there.

This, right here, is a picture of a tide pool

at Half Moon Bay, not too far from where I live.

I've actually been to the tide pools at Half Moon Bay.

And you could consider one particular tide pool,

both the abiotic factors, the water,

and the rock there,

as well as the biotic factors,

the starfish, the sea anemones,

and whatever else might be living there.

Those combined, that could be an ecosystem.

You might say that the entire beach is an ecosystem.

You might say that the entire region is an ecosystem.

Once again, it depends on how much you want

to zoom in or how much you want to zoom out,

and you can zoom out a good bit.

This rain forest, right over here,

this is the Amazon rain forest.

You can consider the whole rain forest an ecosystem,

or maybe you just want to study,

maybe you just want to study

what's happening in this exact region, right over there.

You can also consider that an ecosystem.

You can consider what's happening in the river, itself,

an ecosystem, or, maybe, one part of that river.

And, as you notice, I'm talking about some ecosystems

that are on land, and some that are in water,

and that is a general way, one way of classifying them.

So an ecosystem, you could have it on land.

You could have it on, near, in the water.

So, you could say it's aquatic.

And then, if within aquatic,

you could have ones that...

You have salt water, or partially salty water,

and these are called marine,

and the main marine ecosystem,

we're thinking about the oceans and things like that.

And then, you have freshwater ecosystems.

Like if you are in the upper-Amazon,

that is freshwater that is flowing.

So we could say fresh, freshwater,

non-salty water.

And even though it looks like rivers are big

and there's a lot of freshwater around us.

Obviously we need freshwater to live,

most of the aquatic ecosystems are marine,

are not involved freshwater.

Freshwater is a very small subset.

Now, this is just a few examples.

Even your body, you could view your body

as a whole ecosystem.

You could view parts of your body as an ecosystem.

You could look at just...

You could look at just a fraction of...

If this is my hand right over here,

you could take just a little square, there,

and you could consider that an ecosystem.

You can think about the different bacteria

that are there, other types of microorganisms

that are there, and how they're interacting

with the non-living things, the air.

How they're interacting with the oil on your skin,

with the dead skin cells, and also,

how they're interacting with the living skin cells,

and you, yourself.

Now, since we're in the, since we're focused

on how we can classify ecosystems,

one thing that's often done

is classifying land ecosystems into various categories.

And, right over here, we have depicted

the major types of land ecosystems

on our planet

and where you might find them.

And these different types of land ecosystems,

these are called biomes.

Biomes.

And as you can see from this diagram,

tropical forests, you can find it right over here.

This is the Amazon rain forest.

You can find it in Africa.

You can find it in Southeast Asia.

You can find it in Central and even Southern

or North America.

You have boreal forests which you'll find

in more northern latitudes.

Savanna, desert, tundra, chaparral, polar ice,

temperate forest, temperate grasslands,

and these are just helpful

for thinking about roughly the types of ecosystem,

or ecosystems we would find in those regions.

And it's typically most determined by

temperature, moisture, the climate.

Actually, the climate and the terrain

and the types of minerals that you would find there,

that tends to be a pretty good indicator

for what it will be like, what the life would be like.

But even with that said, there could

still be a lot of variety.

For example, the Sonoran Desert, that is right over here

in the southwest United States,

in the northwest Mexico.

This is a desert, and there's deserts

all over the rest of the planet,

but they won't have...

They might be similar in a lot of ways,

but they won't have the exact same climate,

or the exact same abiotic factors,

or the exact same biotic factors.

So, for example, right now I'm gonna show you a picture,

pictures of the Sonoran Desert and the Rock Desert

that's on the island of Boa Vista.

Boa Vista is right over there.

You really can't see it.

It's a very small island off the coast of Africa.

And, as we see in these diagrams, or in this picture,

you don't have to be an expert to recognize that,

okay, these are both deserts.

They both look dry.

There's not a lot of water here,

but they are also very different.

The Sonoran Desert looks to have

at least a lot more life,

than the Rock Desert have here.

It's appropriately named the Rock Desert

because it seems, at least to the naked eye,

it looks like all you can see is rock.

So biomes, once again, it's a very rough,

high-level way to classifying land ecosystems.

But even the same biome can be very, very...

Two things that are categorizing in the same biome

could be very different.