Humans and the Environment | Essentials of Environmental Science
Summary
TLDRThis 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
- đ Earth is considered the best planet due to its diverse ecosystems and life forms.
- đ± The environment encompasses everything and humans rely on it for survival.
- đŹ Environmental science is an interdisciplinary field studying Earth's natural systems and human impacts.
- đł Anthropocentrism, biocentrism, and ecocentrism represent different environmental ethics that influence scientific inquiry.
- đ Since the Industrial Revolution, human impact on the environment has been profound and requires an ecocentric approach for understanding.
- đż Scientists use models to represent and understand natural systems and predict the effects of human disturbances.
- đ The hydrologic cycle is an example of a model that shows the interconnectedness of water processes in the environment.
- đŸ Biodiversity is crucial for ecosystem stability and resilience, with different types including genetic, species, and ecosystem diversity.
- đ Food webs and trophic pyramids illustrate the flow of energy and interactions between species within an ecosystem.
- đ Carrying capacity (K) defines the maximum population size an environment can sustain, affecting species survival and growth.
- đ« 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 Earthâs 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
đ 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.
đż 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.
đ 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.
đ 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.
Mindmap
Keywords
đĄEnvironment
đĄEnvironmental Science
đĄAnthropocentrism
đĄBiocentrism
đĄEcocentricism
đĄEcosystem Services
đĄBiodiversity
đĄCarrying Capacity
đĄEndangered Species
đĄHIPPCO
đĄFood Web
đĄSymbiosis
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.
Weâve 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 thatâs
because of the environment.
What is the environment?
Well, itâs everything.
And we humans depend on it for our literal existence.
So donât 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 Earthâs
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 cultureâs - or a scientistâs - worldview, the environmental ethic will
influence what questions are asked and what value we put on the answers.
Todayâs 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: âfor 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.â
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 approachâlooking 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 earthâs climate,
but it can also be a chart or graphic that represents the carbon cycle.
Hereâs a model of the planetâs 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, itâs 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 canât 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 donât 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.
Letâs 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 isnât alone in an empty void.
Theyâre hanging out, at the same time and the same place, with lots of other populations
â 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 youâve got an ecosystem.
When studying a single species, like a white-tailed deer or an African elephant, nothing works
in isolation; therefore, we canât 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, youâre 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.
Whittakerâs graph works because terrestrial biomes are mainly defined by their temperature
and precipitation patterns, however, this doesnât 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 earthâs 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.
Hereâs 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 isnât the only service the ocean provides, it absorbs lots of carbon dioxide
from the atmosphere, helping to regulate the entire planetâs 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 theyâre natural hazards or human impacts.
An ecosystem with high biodiversity is like a giant, well-spun spiderâs 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:
Whoâs 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 â from producers all the way up to apex predators â and emphasizes why there
are proportionally fewer species as you move up the pyramid.
In other words, why thereâs 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 dogâs intestine.
Two, mutualism.
In a mutualistic relationship both species benefit, like bees pollinating flowers.
And three, commensalism, where one species benefits and the other isnât necessarily
affected.
Whales donât really care about the barnacles on their skin, but the barnacles rely on the
whales for a lot.
All these types of interactionsâpredator/prey, competition, symbiosisâinfluence how a population
grows.
Hereâs 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 populationâs carrying capacity.
And because squirrels and earthworms require different resources - thatâs 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, theyâre 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 Iâve 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.
Letâs 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.
Thereâs still some patches of our snake friendâs natural habitat, but theyâre
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 âpetâ that escaped gardens, are all invasive species.
Because they usually donât 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 isnât 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 itâll 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 donât 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 weâll see you in the next one.
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