Humans and the Environment | Essentials of Environmental Science

Summary

This script explores the multifaceted field of environmental science, emphasizing the intricate relationship between humans and the environment. It delves into the evolution of environmental ethics, the impact of human activities, particularly post-Industrial Revolution, and the importance of an ecocentric approach to understanding Earth's systems. The script introduces key concepts such as ecosystem services, biodiversity, and the challenges posed by human-induced factors like habitat destruction and climate change. It underscores the role of environmental science in identifying solutions to preserve ecosystems for the benefit of all species.

Takeaways

• 🌏 Earth is considered the best planet due to its diverse ecosystems and life forms.
• 🌱 The environment encompasses everything and humans rely on it for survival.
• 🔬 Environmental science is an interdisciplinary field studying Earth's natural systems and human impacts.
• 🌳 Anthropocentrism, biocentrism, and ecocentrism represent different environmental ethics that influence scientific inquiry.
• 🏭 Since the Industrial Revolution, human impact on the environment has been profound and requires an ecocentric approach for understanding.
• 🌿 Scientists use models to represent and understand natural systems and predict the effects of human disturbances.
• 🌊 The hydrologic cycle is an example of a model that shows the interconnectedness of water processes in the environment.
• 🐾 Biodiversity is crucial for ecosystem stability and resilience, with different types including genetic, species, and ecosystem diversity.
• 🌐 Food webs and trophic pyramids illustrate the flow of energy and interactions between species within an ecosystem.
• 🔝 Carrying capacity (K) defines the maximum population size an environment can sustain, affecting species survival and growth.
• 🚫 The acronym HIPPCO summarizes the main human threats to biodiversity: Habitat Destruction, Invasive Species, Population Growth, Pollution, Climate Change, and Overexploitation.

Q & A

What is the definition of environmental science as presented in the script?

Environmental science is an interdisciplinary scientific approach to studying the Earth’s natural systems, human impacts on those systems, and potential solutions to environmental problems.

What are the three terms that describe standards of environmental ethics mentioned in the script?

The three terms are anthropocentrism, biocentrism, and ecocentrism, each representing a different worldview and value system regarding the environment.

How has the scope of environmental science broadened over the last 100 years according to the script?

The scope of environmental science has broadened from anthropocentrism, which is a human-centered worldview, to biocentrism, which ascribes value to both human and non-human life, and finally to ecocentrism, which values the well-being of entire ecosystems including all living and nonliving elements.

What is the significance of the ecocentric ethic in addressing today's environmental problems?

The ecocentric ethic is significant because it requires looking for answers to environmental problems through the broadest lens, considering the well-being of entire ecosystems and not just isolated issues.

How does the script describe the impact of humans on the natural world, especially since the Industrial Revolution?

The script describes the human impact as huge, stating that the earth system now functions in ways unpredictable without understanding how human systems function and interact with and control earth system processes.

What is the purpose of constructing models in environmental science?

The purpose of constructing models in environmental science is to represent natural systems and all of their interconnected factors. Models are powerful scientific tools with the ability to both explain and predict.

What is the hydrologic cycle, and how does the script explain its representation through a model?

The hydrologic cycle is the movement of water on, above, and below the surface of the Earth. The script explains that a model represents this cycle with squiggly lines and rain drops, showing actions like rain falling, running into surface waters or down into the groundwater, or being taken up by plants for photosynthesis.

What are ecosystem services, and why are they important?

Ecosystem services are the benefits that the natural world provides, such as clean air, clean water, fertile soil for crops, and cultural inspiration. They are important because they support human populations and civilizations.

What is biodiversity, and why is it important to protect it?

Biodiversity refers to the variety of life in all its forms and includes genetic diversity, species richness, and ecosystem diversity. It is important to protect because it helps ecosystems be more resistant and resilient in the face of environmental changes.

What is the acronym HIPPCO, and what does it represent in the context of human threats to biodiversity?

HIPPCO stands for Habitat Destruction, Invasive Species, Population Growth, Pollution, Climate Change, and Overexploitation. These are the main anthropogenic threats to biodiversity, impacting the survival and health of ecosystems.

How does the script explain the concept of carrying capacity in relation to population growth?

The script explains carrying capacity as the maximum number of organisms of one species that an area can sustain. It uses the example of a city park where the carrying capacity for squirrels is about 65, illustrating how population growth reaches a limit defined by available resources like food and space.

Outlines

00:00

🌏 Earth's Environmental Science Overview

This paragraph introduces the concept of environmental science, emphasizing the interdependence of humans and the environment. It explains that environmental science is an interdisciplinary field that studies natural systems, human impacts, and seeks solutions to environmental issues. The paragraph outlines the evolution of environmental ethics from anthropocentrism to ecocentrism, highlighting the importance of an ecocentric approach to address current environmental challenges. It also introduces the idea of scientific models as tools for understanding and predicting environmental changes, using the hydrologic cycle as an example.

05:02

🐿 Ecosystem Dynamics and Biodiversity

The second paragraph delves into the definitions of species, populations, ecological communities, and ecosystems, illustrating how they interact within the natural world. It discusses the concept of biomes, determined by rainfall and temperature patterns, and the importance of biodiversity at genetic, species, and ecosystem levels. The paragraph further explains the ecosystem services provided by nature, such as clean air, water, and fertile soil, and the aesthetic and cultural values humans derive from the environment. It concludes by emphasizing the need for biodiversity protection due to its role in maintaining ecosystem stability and resilience.

10:02

🍃 Ecological Relationships and Population Growth

This paragraph explores the intricate relationships within ecosystems, including food webs, trophic pyramids, competition, and symbiosis. It explains how these interactions influence population growth and carrying capacity, which is the maximum number of individuals an area can sustain. The paragraph also discusses the factors that make certain species more vulnerable to endangerment, such as size, specialization, and reproduction rates. It highlights the importance of protecting species and their habitats, as well as the role of laws like the Endangered Species Act in conservation efforts.

15:04

🏞 Threats to Biodiversity and Environmental Science's Role

The final paragraph identifies the main human threats to biodiversity, summarized by the acronym HIPPCO: Habitat Destruction, Invasive Species, Population Growth, Pollution, Climate Change, and Overexploitation. It discusses the consequences of habitat loss and fragmentation, the impact of invasive species, and the effects of pollution and climate change on ecosystems. The paragraph also addresses the issue of overexploitation and how environmental science can help identify and mitigate these threats through laws, policies, and international treaties. It concludes by emphasizing the importance of environmental science in understanding and preserving ecosystems for the benefit of all species.

Keywords

💡Environment

Environment refers to all the physical, chemical, and biological factors that influence the life of an organism, including the natural systems of the Earth. It is central to the video's theme as it underpins the discussion on how humans interact with and rely on the environment. The script mentions the environment as the source of everything a person could need, highlighting its importance for human existence.

💡Environmental Science

Environmental Science is an interdisciplinary field that studies the Earth's natural systems, human impacts on these systems, and seeks solutions to environmental problems. It is integral to the video's message as it represents the scientific approach to understanding and addressing the complex relationships between humans and the environment. The script describes it as drawing on various disciplines to study the natural world.

💡Anthropocentrism

Anthropocentrism is a worldview centered on human beings and their interests. In the context of the video, it is one of the three environmental ethics discussed, starting from a human-centered perspective and evolving towards ecocentric ethics. The script uses this term to illustrate the historical shift in how humans have valued and interacted with the environment.

💡Biocentrism

Biocentrism is an environmental ethic that ascribes value to both human and non-human life. It represents a shift from anthropocentrism, acknowledging the intrinsic value of all living beings. The video script uses biocentrism to discuss the broadening scope of environmental science and the recognition of the value of life beyond human interests.

💡Ecocentricism

Ecocentricism is an environmental ethic that values the well-being of entire ecosystems, including all living and nonliving elements. The video emphasizes ecocentricism as the current ethical stance needed to address today's environmental problems, advocating for a holistic approach to understanding and protecting the environment.

💡Ecosystem Services

Ecosystem services are the benefits that humans obtain from ecosystems, such as clean air, water, and fertile soil. The video script highlights the importance of these services to human life and how they are provided by the natural world. This concept is crucial to understanding the interdependence between humans and the environment.

💡Biodiversity

Biodiversity refers to the variety of life in all its forms, including genetic, species, and ecosystem diversity. The script discusses biodiversity as a critical aspect of environmental health that needs protection, emphasizing its role in ecosystem stability and resilience.

💡Carrying Capacity

Carrying capacity is the maximum number of individuals of a species that an environment can sustain. The video uses the concept of carrying capacity to explain the limits of population growth in a given area, such as the example of squirrels in a city park, illustrating the balance between population size and available resources.

💡Endangered Species

Endangered species are those that are at risk of extinction due to various threats. The script discusses the vulnerability of certain species, such as elephants and blue whales, to becoming endangered due to factors like slow reproduction rates and specialized habitat needs.

💡HIPPCO

HIPPCO is an acronym for the main human threats to biodiversity: Habitat Destruction, Invasive Species, Population Growth, Pollution, Climate Change, and Overexploitation. The video script uses HIPPCO to summarize the various ways in which human activities negatively impact the environment and biodiversity.

💡Food Web

A food web is a scientific model that represents the complex interactions between predators and their prey within an ecosystem. The video script explains how food webs map the flow of energy and nutrients, illustrating the interconnectedness of species and the transfer of energy through different trophic levels.

💡Symbiosis

Symbiosis refers to a close and long-term biological interaction between two different species. The script discusses three types of symbiosis: parasitism, mutualism, and commensalism, providing examples like bees pollinating flowers and barnacles on whales, to illustrate the various ways species can interact within an ecosystem.

Highlights

Earth is described as the best planet with diverse ecosystems and species.

The environment is everything around us, and humans depend on it for survival.

Environmental science is an interdisciplinary approach to studying Earth's systems and human impacts.

Anthropocentrism, biocentrism, and ecocentrism are standards of environmental ethics.

Ecocentric ethic is crucial for addressing today's environmental problems.

Human impact on the natural world has been significant, especially since the Industrial Revolution.

Environmental systems should be studied from an ecocentric approach to understand disruptions.

Models in environmental science help explain and predict the behavior of natural systems.

The hydrologic cycle is a model representing the movement of water on Earth.

Ecosystem services are the benefits humans derive from the natural world.

Biodiversity encompasses genetic, species, and ecosystem diversity, contributing to ecosystem resilience.

Food webs and trophic pyramids represent predator-prey relationships and energy flow in ecosystems.

Competition and symbiosis are key interactions that influence population growth and evolution.

Carrying capacity defines the maximum number of organisms an area can sustain.

Endangered species are at risk of extinction due to factors like size, specialization, and reproduction rates.

The Endangered Species Act in the U.S. protects species and their habitats.

Human activities, summarized by HIPPCO, pose significant threats to biodiversity.

Environmental science is a diverse field of study that impacts our understanding and preservation of ecosystems.

Transcripts

Earth is objectively speaking, the best planet.

We’ve got oceans filled with things that look like this, and this, and also this, towering

forests full of things that literally eat light and air, clouds, rainbows, clouds that

look like rainbows, adorable sloths, funky looking caterpillars, and a universe of invisible

tiny things that can do everything from make food to power the cycle of nitrogen on this

here hunk of rock.

This beautiful, weird, corner of the universe has everything a person could need - and that’s

because of the environment.

What is the environment?

Well, it’s everything.

And we humans depend on it for our literal existence.

So don’t you think you should learn a little more about it?

In this series of lessons on environmental science Miriam and I are going to explore

all the ways humans interact with and rely on the environment.

Welcome to the Essentials of Environmental Science!

Environmental science is an interdisciplinary scientific approach to studying the Earth’s

natural systems, human impacts on those systems, and potential solutions to environmental problems.

People who work in the field of environmental science draw on aspects of biology, chemistry,

economics, politics, human geography, urban planning, the list goes on, in their study

of the natural world.

The scope of environmental science has steadily broadened over the last 100 years: starting

from anthopocentrism - a human-centered worldview which has its roots in the European societies

from which most modern scientific practices descend.

Then into biocentrism - which ascribes value to human and non-human life, and finally into

ecocentrism - which values the well-being of entire ecosystems including all the living

and nonliving elements.

These three terms: anthropocentrism, biocentrism, and ecocentrism, describe standards of environmental

ethics.

Depending on a culture’s - or a scientist’s - worldview, the environmental ethic will

influence what questions are asked and what value we put on the answers.

Today’s environmental problems, from water pollution to endangered species to climate

change, require us to look for answers through the broadest lens: the ecocentric ethic.

Humans have had a huge impact on our natural world, especially since the Industrial Revolution.

One 2011 article put it this way: “for better or for worse, the earth system now functions

in ways unpredictable without understanding how human systems function and how they interact

with and control earth system processes.”

To truly understand environmental systems and human impact, it is important to not simply

study an organism, like an endangered species, or a pollution source, like an oil spill,

in isolation.

Instead, we should try to understand natural or human-caused disruptions to the environment

from an ecocentric approach–looking at the bigger systems at play.

If you learn one thing from watching our series on environmental science, make it this: We

humans benefit from the environment, but we are also part of it.

That means our actions can and do affect Earth systems, so a lot of environmental science

focuses on how to protect, preserve, and restore the systems human activity degrades.

One way scientists do this is by constructing models to represent natural systems and all

of their interconnected factors.

Models are powerful scientific tools with the ability to both explain and predict.

A model could be code on a computer that recreates the physical processes of the earth’s climate,

but it can also be a chart or graphic that represents the carbon cycle.

Here’s a model of the planet’s hydrologic cycle.

Environmental science helps us to understand how all the living and nonliving components

are interrelated.

Rain falls, runs into surface waters or down into the groundwater.

Or, the water can be taken up by plants for photosynthesis.

This model represents all these actions with squiggly lines and rain drops.

However, like any scientific model, it’s not perfect.

It cannot possibly represent everything going on at any one time.

The only thing that can do that is the earth itself.

But even though we can’t run global-scale experiments, a model does allow us to predict

what would happen if something in the system changed.

For example, if humans clear-cut a forest, this model would predict that there will be

less evapotranspiration from the trees into the atmosphere.

We could then expect to measure less water vapor in the atmosphere around that location.

So, models help us to understand, one, a system, two, how natural and human disturbances occur,

and three how, where, or when to measure those changes.

It is through this process that environmental science can analyze and address environmental

problems.

Now - I know I just said that you don’t want to look at a single organism exclusively,

but it is probably easier to start thinking about how biotic, or living, and abiotic,

or non-living, components fit into a system, by beginning with one example.

Let’s use a single white-tailed deer, a member of the species Odocoileus virginianus

to define some terms and look at how an ecosystem works.

Biologists define species in a number of ways, but one common definition of species is a

group of organisms that can successfully reproduce with each other.

A group of individuals of that species of deer living in a particular area is called

a population.

But this population of deer isn’t alone in an empty void.

They’re hanging out, at the same time and the same place, with lots of other populations

– like pine trees, fungi, squirrels, or bats.

Together, an ecological community is a group of populations living in one area at a particular

time, interacting with one another.

If you add in all the abiotic components, like the air, rocks, water, and even something

like the temperature, then you’ve got an ecosystem.

When studying a single species, like a white-tailed deer or an African elephant, nothing works

in isolation; therefore, we can’t study anything in isolation, so researchers need

to consider all the abiotic and biotic components of that species and its ecosystem together.

Think about it: Organisms in a tropical rainforest have adapted to different conditions than

those in a savannah, or a tundra, a desert, or in temperate grasslands.

We call these different broad regions of the planet, defined by their patterns of rainfall

and temperature, biomes.

Latitude - the distance north or south from the equator - can be a useful tool in determining

where certain biomes exist.

It is no surprise that the hot, humid conditions all along the equator created tropical rainforest

biomes around the world.

At higher latitudes, the cooler parts of the world, you’re more likely to find biomes

like tundra or the boreal forest.

This graph, created by ecologist Robert Whittaker, represents the different major terrestrial

biomes.

The y-axis is average precipitation and the x-axis is average temperature.

Whittaker’s graph works because terrestrial biomes are mainly defined by their temperature

and precipitation patterns, however, this doesn’t tell us much about the wide variety

of aquatic ecosystems that exist in oceans, rivers, lakes, swamps, coral reefs, and marshes.

Aquatic ecosystems are defined by things like salinity, water flow, and depth.

This all kind of feels like a bunch of definitions, but they are important to understand, because

everything from prehistoric to modern life as we know it was constructed in and around

these natural systems.

We humans benefit immensely from all aspects of the natural world.

We depend on earth’s systems for clean air to breathe, clean water to drink, and fertile

soil in which to grow crops.

We also place aesthetic and cultural value onto our natural resources through poetry,

songs, and paintings dedicated to and inspired by nature.

All together, this practically endless list of benefits that the natural world provides

are called ecosystem services.

Here’s an example to get your head around ecosystem services: the oceans are full of

fish, which is a huge benefit for millions of people around the world.

But, that isn’t the only service the ocean provides, it absorbs lots of carbon dioxide

from the atmosphere, helping to regulate the entire planet’s climate.

And a huge portion of the oxygen we breathe comes from photosynthetic marine plankton.

The ocean also serves as a highway system for transporting goods from country to country

on cargo ships, and we even harness the energy of waves and tides to generate electricity.

Biodiversity, in all its forms, is an area that especially demands protection.

There are three main types of biodiversity: 1) genetic diversity

within a population, 2) species richness - species diversity within an ecosystem, and 3) ecosystem

diversity in an area.

A population with large genetic diversity has greater potential to adapt to environmental

changes.

High species richness makes an ecosystem more stable, and better able to recover from disturbances.

And an area with a rich diversity of habitats and ecosystems can support a more robust and

stable community of organisms.

So biodiversity overall helps an ecosystem be more resistant and resilient in the face

of environmental changes, whether they’re natural hazards or human impacts.

An ecosystem with high biodiversity is like a giant, well-spun spider’s web: lots and

lots of interconnected points.

If the web has a little rip in one area, it can probably still function, because it is

supported and held together by hundreds of other strands woven together.

But if the web is only made of two or three strands, then the same small rip could collapse

the entire web.

Within that ecosystem web, species constantly interact with each other and those relationships

have shaped those species evolution.

And some of the most important evolutionary relationships are predator/prey relationships:

Who’s eating who.

Food webs and trophic pyramids are both scientific models which represent how predators and their

prey interact within an ecosystem, but they emphasize different things.

The arrows in a food web map the flow of energy and nutrients within the system, which in

general goes from plants, to primary consumers, to secondary consumers.

On the other hand, the pyramid helps to quantify how energy moves between different trophic

levels – from producers all the way up to apex predators – and emphasizes why there

are proportionally fewer species as you move up the pyramid.

In other words, why there’s always more mice than eagles, and why it takes so much

grass to make a cow.

Another important ecosystem relationship is competition.

Limited resources, like food or nesting sites, can cause competition.

This can be within species - intraspecific competition - or between different species

- interspecific competition.

Elephants and giraffes may experience interspecific competition for water in an arid climate.

Two trees of the same species can experience intraspecific competition for sunlight needed

for photosynthesis.

These competitive pressures for limited resources are strong driving forces for natural selection,

and individuals with the adaptations to get more resources tend to survive better.

A final major way in which different species interact is symbiosis.

Generally symbiosis is broken into three categories: one, parasitism in which one species benefits

and the other is harmed, like a tapeworm in a dog’s intestine.

Two, mutualism.

In a mutualistic relationship both species benefit, like bees pollinating flowers.

And three, commensalism, where one species benefits and the other isn’t necessarily

affected.

Whales don’t really care about the barnacles on their skin, but the barnacles rely on the

whales for a lot.

All these types of interactions–predator/prey, competition, symbiosis–influence how a population

grows.

Here’s a model representing the growth of a population of squirrels in a city park.

If we look at how that population changes over time, we see that it experiences lots

of growth early on, when a pair of squirrels first discover this amazing new park, but

then eventually the population reaches its carrying capacity.

Carrying capacity, which is normally written as an uppercase K, is the maximum number of

organisms (of one species) that an area can sustain.

In our city park here, the carrying capacity is about 65 squirrels, but if we head underground,

the carrying capacity for earthworms is probably in the millions.

Food, space, and the threat of predation help to define a population’s carrying capacity.

And because squirrels and earthworms require different resources - that’s why they have

such different carrying capacities.

On the flipside from population growth or upper limits, when the numbers of a particular

species are low enough that it might become extinct, we consider that species endangered.

Some qualities make certain species more at risk than others of becoming endangered or

extinct.

Like size: large organisms with big home ranges and habitat needs like elephants or grizzly

bears are at greater risk; or specialization: super specialized organisms with specific

dietary needs or habitat requirements like pandas and koalas are also at greater risk.

And reproduction rates: organisms who reproduce slowly and require many years of parental

care, like blue whales or a mountain gorilla, they’re at greater risk too.

Contrast those species with something like a… cockroach, which reproduces early and

prolifically and are more generalists than specialists when it comes to diet and habitat.

Being able to quickly reproduce is an evolutionary advantage that maximizes the chance that a

random genetic mutation will help an individual survive a disturbance.

An African Elephant, with its much slower reproduction rate and specialized habitat,

does not have that evolutionary capacity for change on a rapid scale.

So some species need more protection than others - how do we do that?

In the United States, we have the Endangered Species Act, which protects not only the species,

but also its habitat.

This is crucial because without its habitat, that species cannot exist in nature.

Hopefully, by now I’ve done my job and showed why it is so important to protect species,

habitats, and biodiversity.

But - what are we protecting biodiversity from?

[beat] Us.

The main anthropogenic, or human, threats to biodiversity can be summarized by the acronym

HIPPCO: Habitat Destruction, Invasive Species, Population Growth, Pollution, Climate Change,

and Overexploitation.

Starting with Habitat loss: Simply put, if an organism loses its habitat, it cannot survive.

Related to habitat loss is the concept of habitat fragmentation.

Let’s say that this snake requires this much area for its habitat.

But then people show up and build a road here, a few houses there, a mall over here.

There’s still some patches of our snake friend’s natural habitat, but they’re

separated from each other.

This separation reduces the ability of individual organisms to reach each other and will reduce

the genetic diversity of the population.

When considering habitat loss and fragmentation, we also need to think about scale.

Human land use affects different organisms in different ways.

Consider the differences in home ranges between a small anole lizard - maybe no more

than 100 square meters - and a grizzly bear, which requires up to 1600 square kilometers

of territory.

Next: Invasive species - species that are not native to an area but end up there nonetheless

-often because of people - are another huge threat to biodiversity.

Burmese Pythons in the Everglades, lionfish in coral reefs (both of which are a result

of humans releasing their pets), or even kudzu vines in the southeastern US, an imported

plant “pet” that escaped gardens, are all invasive species.

Because they usually don’t have natural predators in their new environments, populations

of invasive species can explode and outcompete native species.

The presence of lionfish can reduce the number of smaller fish on a coral reef by almost

80%.

On to Pollution, which is both a visible and invisible threat to biodiversity.

You can see an oil spill actively harming wildlife and damaging habitats.

But a lot of pollution isn’t quite as obvious: like, sulfur or lead in the air or pharmaceuticals

or other toxins in the water.

One of the greatest sources of pollution right now is the use of fossil fuels; when burned,

oil, gas, and coal release tons of air pollutants AND dangerous greenhouse gases that lead to

climate change.

Climate change is the focus of this entire channel - and it’ll get its own episode

in this series.

But, I want to point out right now that global warming and climate change are affecting more

than human lives.

Rising temperatures, more acidic oceans, and the many other impacts of climate are also

affecting wildlife biodiversity in a big way.

Coral reefs are bleaching at an increasing rate as warmer ocean temperatures cause tiny

coral animals to expel the symbiotic algae that provide them with a majority of their

food.

And after a bleaching event - if the algae don’t come back, the coral will die.

Finally, using living natural resources at a faster rate than they can reproduce is overexploitation.

Catching fish quicker than they can make baby fish collapses fisheries - and the related

fishing industry that relies on them.

Killing elephants for their ivory will decimate a population quicker than it can repopulate.

When environmental science can identify overexploitation, laws, policies, and international treaties

can come in to help regulate our consumption of these resources and protect biodiversity.

So as you can see environmental science is a large and diverse field of study that encompasses

many different scientific disciplines at various scales from the microscopic to the macroscopic.

Which is pretty fitting, because the environment itself is this thing that is everywhere.

And while one of the main lessons you should take from these videos is that humans are

not separate from these natural systems, we are in a unique position to study them for

two main reasons: one, we rely on ecosystems and the numerous types of services they provide

in order to support our own populations and civilizations.

And two, as the species with the most influence, and as far as we know the most intelligence

on Earth, we are also in a unique position to study and preserve these ecosystems for

the benefit of all species.

The rest of this playlist will be a tour through various ecosystems, looking at the services

they provide, and how human and other living populations interact with all of this.

Thanks for watching, and we’ll see you in the next one.