The question is why do we need to study ecology or to understand how the way our planet works?
So that’s a question that we are asking here.
This course is majorly aimed at students who are not studying ecology is a stream or they
are not continuing biology, so the mostly aimed at science and engineering students
who may not have studied like us who have graduated in technology without studying ecology.
Why do we need to understand ecology?
So I’ll just like any other course, some motivation to do this ecology.
So I got from Professor David Orr, this was written in 1991, he asked this question in
this lecture, what is education for?
I’m quoting from him if today is the typical day on planet earth, we will lose something
like 116 square miles of rainforest or about an acre a second, we all know the importance
of rainforest in our lives, so and similarly we will lose another 72 square miles of to
encroaching deserts or as a result of human mismanagement and overpopulation, so as we
are growing in number, the desert area is also increasing or desertification is going
on.
We may lose 40 to 100 species and this is we are talking about a typical day on planet
earth, we will lose 40 to 100 species and no one knows whether it is 40 or 100, I asked
this question why we do not know whether it is 40 or 100 because we have not even estimated
how many species are there on earth, so before that itself they are you know vanishing at
a very, very fast pace, so we do not even know whether we are losing 40 or 50 or 100
or how many species on a single day.
And similarly today the human population will increase by 250,000 and today we will add
about 2,700 this number was given in 1991 so you can imagine how much it would have
gone up 2,700 tons of chlorofluorocarbons to the atmosphere and 15 million tons of carbon.
Of course we have removed chlorofluorocarbon elimination into the emitting into the atmosphere,
but we still have lot of carbon being added to the atmosphere.
And tonight the earth will be little hotter that we all know that we are talking about
global warming, and it’s waters more acidic, the reason also we may know because we are
putting more and more carbon-dioxide, nitrous oxide, sulphur oxides into the atmosphere,
this comes back as rain and the water is becoming more and more acidic.
And as it becomes more acidic the fabric of life becoming more threadbare, so this is
a question Professor Orr is asking us, why we need to worry about this and what do we
need to know as engineers and scientist do we need to know how the planet earth works
and whether we need to understand ecology.
So when we come to ecology there are many definitions, before we go into the science
of ecology, I’ll just bring some definitions which are non in literature which is in 1800
itself it was defined by Ernst Haeckel which is one of the best definitions till date,
so it is defined as the scientific study of the processes influencing the distribution
and abundance of organisms.
The interactions among organisms and the interactions between organisms and the transformation and
flux of energy and matter, so this is one of the best definitions or the comprehensive
definition of ecology that we could have, and it emphasizes both living and non-living
components of the natural world.
So there are many many questions that are arising out of this definitions, and that
is what ecology a stream of science that try to address, to understand this processes that
goes on in planet earth or in the universe as such, so it is also can be defined, I mean
various other definitions also came forward in between so it is called the study and distribution
of organisms, so which reinforces the focus on organism as the core of ecology, so there
are various definitions like this in the literature, we are not going into the depth of this definitions
of whether we should focus on organism or whether we should focus on ecosystem or whether
we should look at it as a total system concept.
Similarly I mean one of the best definitions which encompasses all this is given by one
of the best ecologist Evelyn Hutchinson he defined ecology as the science of the universe.
Why is he defined the science of the universes and as I said if it is the science of the
universe it is difficult to comprehensively defined everything that comes under ecology
in our 3 hours of lecture, so that is my job in this course so I will only defined certain
things which are very key and critical to this course and understanding ecology and
why it is important for humans to understand ecology.
So as I said already, ecology is a study of the processes, it is actually, you can define
us you know many of us in different branches of the engineering and science defined different
kinds of processes, it could be chemical process, it could be physical process, so that are
different processes that goes on.
So we are talking about processes that dictate, the distribution and abundance of organisms,
so how do we know that you know how many tigers are there in the forest, how many you know
air exist in the wild, so basically how and where are they distributed?
How many of them are there in the wild?
And for example in a particular habitat how many species are there existing, and why do
they you know exist in a particular way in a particular place, and do they interact,
for example tiger we’ve just not seen in the particular habitat in a particular region
on earth, so is it possible, why are they restricted to certain regions, what are the
other organisms they interact with?
And also the interactions between organisms, for example tiger interacts with another tiger
or an elephant interacts with another elephant.
Similarly a tiger also interacts with species like maybe deer, it maybe you know it is its
food you know organism, or it could be, the deer could be interacting with another organism
which could be interacting with other deer and it could also be interacting with its
surroundings, plants, various other insects, microorganisms.
The tiger also has other interactions not just interaction with deer alone, it also
has you know interaction with microorganisms maybe this competing with other tigers for
food and other animals also maybe for food.
So there are various kinds of interaction which we call as competition, sometimes you
know coexistence of different organism etcetera.
And in all this events what we see is the transformation and flux of energy and matter
which flows through the system, okay, so the essence of ecology as we can summarize for
the concept of you know science is that it is the flux of energy and matter or materials
through the ecosystem.
So it can be summarized thus the interactions among and between organisms, so the interactions
could be among the same species or it could be between different species which is defined
as biotic interactions, and their environment,
so this environment which is surrounding it is defined as the non or abiotic or nonliving
part of the system.
So as you can see in this picture you have the environment which is, so basically you
have the environment here so which has both living and nonliving part, so this nonliving
and living part interacts through physical and chemical processes, so this is exactly
like physical you know chemical process means it is a chemistry biomass it’s a chemical
reaction or chemical process, it could be an oxidation, it could be reduction, there
are so many processes that goes on in between the biotic and biotic world.
And in the biotic world we have plants, animals, microorganisms which represent the biotic
or the living part, and abiotic means mostly the, I’ll be detailing these two, and this
has, biotic will have nutrients, energy, water, various components that will affect, also
for example the humidity in the atmosphere all this components or temperature this can
externally influence the presence of the biotic or the living part of the system, so the whole
environment is some, is encompassing all this, and they have dictated by energy and matter
flow and also transformation, transformation of energy into material form and vice-versa,
and also matter in one form is getting converted to another.
So the topics of interest that emerges here are what is meant by different species and
how they originate?
What is meant by biodiversity?
What is meant by distribution of different species?
We may not be able to dwell into the details of each of this, but the topics that arise
which is of interest out of this discussion on biotic and abiotic interaction are this
topics.
Similarly biomass, how is it formed?
What is meant by biomass?
Is the living mass of the systems like whether it is a micro or whether it is an animal,
or whether it is a plant, the living mass that you can get is the biomass of the organism,
and the energy that flows in the system from one system to another, for example for food,
we have to take food from the surroundings, and that food is what brings energy to our
system, or any living animal for example gets, there is no directory of taking energy from
the sun and then converting it, the only source that can convert solar energy to useful matter
or energy form is plants on earth.
So the plants convert this energy from the sun and then gets transfer into other organisms
whether it is a herbivore, whether it is a carnivore, it flows through the ecosystem
as we understand and that is, that generates what is known as population of organisms.
How many numbers thrive in a particular community or a particular species, and how they distribute
themselves in different parts of the planet?
The other as I said is the interaction within an between species, it’s again a kind of
you know balancing act for obtaining the energy that is flowing in the system, so how do we
optimize or maximize the energy flow into each of this organism, and each organism is
striving to hardness this energy in some form, this is the essence of ecosystem functioning.
And similarly as humans who are part of this ecosystem or we part of the ecosystem is a
very important question that we have to rise here, and we defined this for our convenience
or understanding to call this as the ecosystem services, okay, the functioning of the earth
or the functioning of different ecosystems and the matter and energy flow on earth can
be you know defined in something called ecosystem services that is the services that are rendered
by the ecosystems that is existing on planet.
Also typical you know ecosystem that all of us understand this is you know carry creature
of a forest ecosystem where you know and the one of the important questions that rise here
is are there boundaries or you know when you define an ecosystem where is its boundary,
for example a tree for example can be defined as an ecosystem in itself when you know there
are different creatures which may depend on it and it could you know for example for a
micro which may be thriving on the plant, it could also be the system with different
interactions possible there, or for example there is a pond which is depicted here which
could or a lake which is depicted here could be an independent entity in itself and it
could form an ecosystem and it is surrounded by let’s say forest, but at the same time
the whole system also can be called an ecosystem which required the water supply to the animals
in the ecosystem and the plants and the other animals who may depend on this system.
So on a human point of view there are two ways in which ecology becomes useful for human
sustenance on earth and we need to look at it in two ways one is how we, how ecosystems
are affecting our lives, and the other is how we are affecting the existence of the
ecosystems and how it can internal affect the existence of other species also on earth,
so there in that context there are two things that we bring forward that is one is what
are the services provided by ecosystems for existence of life on earth, so and the other
is the how this ecology can be used in various applications, so ecosystem service is an important
concept here to understand and appreciate ecology and to appreciate the conservation
of ecosystems.
So the brief introduction in ecosystem services is I’ll detail this in the next few lectures,
one is importance is that sustain life supporting functions and produce natural capital like
biomass production, so what we mean by sustain life supporting functions as we know that
the earth has its you know for all living systems that we have oxygen, and air, water,
and food are the most important criteria that required for supporting life functions or
sustain life on earth.
So the food, fuel, fiber and medicine etcetera are secondary things that we require for sustaining
human life on earth, so in other words ecosystems provide the fundamental services for existence
of life on earth.
So second thing that is written in gist year as regulation of climate, how the micro I
mean the climate on earth is dictated by ecosystems, for example oxygen I mean just which was not
there in the beginning of the planets evolution if you look at, and there are many theories
on how oxygen came into the atmosphere and then eventually how life started getting supported
on oxygen and how a living system started using oxygen, or similarly how carbon-dioxide
is taken up by plants and oxygen is liberated into the atmosphere, all these processes basically
is an, what is known as an oxidation process that happens on earth where in the primitive
periods of the earth’s evolution if you look at the processes that we are going on
where mostly reductive in nature and the hypothesis say that when the water molecule started breaking
down to hydrogen and oxygen in the presence of either the ionosphere where ionization
could happen and hydrogen and oxygen started separating, oxygen started staying back in
the atmosphere and hydrogen being liberated outside, or similarly plants contribution
to through photosynthesis how oxygen started coming into the atmosphere and the other living
systems started evolving based on this.
So and from then onwards we know that the climate is regulated very, on a very fine
basis for sustenance of life on earth, for example temperature on earth surface we talk
about global warming because the temperature if it goes from the current average temperature
to some about 2 degree Celsius, the catastrophic effects that it can bring due to various other
processes which are regulated by this temperature, so this temperature is linked again to the
amount of carbon-dioxide in the atmosphere or other greenhouse gases as we know like
water vapor and methane present in the atmosphere, so all this regulate the climate and enter
the temperature on the earth and that can affect the life itself on earth.
Similarly ecosystems are also serving global biogeochemical cycles so which all of us know
what is meant by biogeochemical cycles, you would have studied it in school, this is with
reference to the various cycles that we study, one is carbon-dioxide cycle, water cycle,
nitrogen cycle, phosphorous cycle there are many cycles which are regulated by living
and nonliving systems together or the general what are known as ecosystem services again,
so if you take each of this cycle that dictates the micro and macro climate on earth it is
very important to see how there are all of different ecosystems or living organisms and
other interactions with its surroundings affect the global biogeochemical cycles which is
in intern contributing to the regulation of the climate as well.
Similarly when we drink water for example we do not realize how we get those water in
those systems, for example today when I say water filtration, an example is can we all
drink water from our wells today, many times it is very difficult to drink directly the
water that is coming in a tap in public places today because we do not trust the quality
of water and we believe that it may be contaminated with it, it’s all possibility because of
various kinds of pollution that we are causing and how this water can get filtered, so in
a natural system maybe 50 years ago you could go and drink water from anywhere, from a stream
or a well or pond.
How did we trust this water?
Most of the time this water would have been clean and this is one of the biggest services
that ecosystems provide cleaning or the filtration of water and that happens through various
systems that is beautifully placed on earth.
Similarly another important services soil formation bio-microbes from various decaying
matter and other minerals, the decomposition generate healthy living soil which is important
for sustenance of life on earth again because we plant, we grow plants and then our food
is coming from you know good soil formation.
Erosion control this is also very important for flood control and other processes as well,
and many other natural features of scientific, historic and economic and intrinsic value
are supplied by an ecosystems services which can be, so the question is because we are
calling it service, is it possible to assign an economic value to it, that is a big question
that we need to address and so what is known as ecological economics, so the applications
of ecology comes up in terms of you know, if you are an ecologist who is trained in
ecology or you are interested in ecology you can help within the conservation of species,
for example this comes when globally we know that many species are threatened us I said
in the first slide 40 to 100 species are vanishing from earth everyday so due to increasing human
population and conversation of natural habitats to agriculture lands or industries or other
human occupied areas where other species are finding it difficult to exist.
So the conservation of species ecosystems and biodiversity are very, very important
as you can see from the left hand side for the services that they providing and it is
one of the important application that arising out of ecology, learning ecology.
Similarly how one should manage, I mean the word should not be used here, earth knows
it’s on management but at the same time since human beings are an overarching phenomenon
on earth currently, natural resource management has become a big you know area in itself,
for example agriculture, agroecology, forestry, agroforestry, fisheries, all these are what
are known as natural resources in some way or other, so this how do we you know how humans
are managing this, humans are part of the system but at the same time managing this
system.
Similarly city planning, how urban ecology whether how for example most of the cities
around the world are becoming you know almost unlivable because of the pollution intensity
there, the noise, the light, everything that is not very favorable for existence of life
is happening and how do we plan cities in future for example or currently to favor a
better and better living condition, how do we control for example floods in cities, almost
every city in India has faced a severe flood when there is a huge rain happening because
again urban planning where ecology is not considered is one of the reasons why this
happens periodically, for example lakes are vanishing from urban environment, so this
is an important thing for planning for cities, so we need to look at the ecosystems which
are supporting for example flood control in the city, so where did they vanish?
Can we bring them back?
How do we incorporate you know ecology for naturally existing systems in this cities?
Similarly community help, it is an very important criteria and important factor as we all know
that in urban areas or in semi-urban areas as human population has increasing and various
other organisms are also able to thrive, an example is mosquitos, so this is many times
it is correlated to the destruction of forest habitats, and many of this, some of the disease
germs for example existing in forest can come in contact with human communities as more
and more forests are getting destroyed and that is a possibility.
And similarly health as such is you know if you have clear air with no need to tell or
emphasize anything more, held this something that comes from clean air or clean food and
clean water, so all this are naturally provided by ecosystems and there is no need to emphasize
more on health on any other accounts, so as we pollute more our health is in danger and
earth services are reducing, so naturally services should be promoted here and the ecosystem
services have to be given a role there for taking care of the health as well, so human
health is at jeopardy because of we are destroying the ecosystem.
Similarly as I said economics, so if you put all the services which are listed on the left
hand side of this panel and look at it, and if you could assign some values to it we know
the economics that is generated which is now, which is not visible to us many times, so
we can do some calculation to show that for example purification of water using and natural
ecosystem in a lake and if I could drink the water directly from the lake instead of artificially
creating cleaning systems or desalination systems etcetera to drink that water again,
estimate the cost to see how much is the what is lost in terms of converting a natural system
by polluting it and then you going back and then again doing a cleaning to get that water
in the form that we could consume or for example if I could eat the food which is clean, the
after effects of it being not good food is much more in terms of health benefits or in
terms of the you know human wellbeing, all this are cannot be put into in economic terms,
current economic terms and that is one of the reasons why we are not able to you know
appreciate what ecosystems are providing us, so which is very important to you know consider
the left hand panel very of this slide, to understand that how this ecosystem services
are related to economics.
And of course this is also an understanding and facing and applied science and human social
interaction and what is known as human ecology.
So basically as I said we are not out of this system, we are just part of the system and
we have existence which are related to only this how well the system is performing, so
it is very important to appreciate the services provided by the ecosystems and how human beings
are interacting and how we are affecting the ecosystems, and how ecosystems are affecting
us.