Well in the previous lecture we have begin with discussing some of the issues and problems which have been encountered and which in essence necessitate for us to look at why environment is one of the most growing concerns of this present era and today in this lecture we are going to look at some of the principles of ecology and also to look at some of the various trends or the waves of environmentalism with beginning from the1960s, so that we have an idea how these environmental movements have evolved over a period of time and what are the kind of issues which are being raised regionally and globally and what are the initiatives they have taken. And also in this we will try to have much more of an idea before beginning with the real the content of the course and to begin with we will just try to look at some of the principles of some basic principles of ecology. And yesterday in the previous class we had given an overview if not a brief conceptual analysis of what ecology is? What environment is?
Today in this lecture will be looking more into some of the basic principles of ecology. Now I just list down some of the points and we will just look at one by one. The first one says: All levels of organizations overlap and interact. Now in this the whole ecosystems some way or the other interact in different levels and that overlaps. Any kind of actions of one species has an arching impact on the other that is the level of how different organizations of species interact at different levels. And within these ecological systems virtually everything is related to everything else which means we cannot afford to see things in isolation but in a more interrelated manner. And thirdly if you look at this the abundance and distributions of living organisms on earth are affected by the aspects of the physical biotic and the social environment. Now when we say social environment it is not this the human even animals have their own social organizations and they do also reflect some kind of how their physical aspects does have an influence on the social organizations.
Now in the fourth point of these biotic communities differ in numbers and kinds of species the diversity of species. And the roles of ecological needs in the community. The geographical locations or habitations or environment does have some kind of influences on the species that is a that that particular ecological needs where the biotic inhabits. And in the fifth point this species in biotic communities form some kind of a network of relationships or symbiosis which may be either favorable or unfavorable for its species. For instance if you classify and look at the animal kingdom, there are the herbivores and carnivores. Herbivores are more dependent on plants for the means of livelihood. Whereas carnivorous are more or less dependent on the other species of animals. Now carnivores in some sense are more you know, unfavorable for the other species and similarly even humans whatever we consume if consuming access or maybe we are not able to meet the carrying capacity of that ecological needs which we have discussed earlier will eventually pose a threat to the ecology and will lead to ecological imbalances.
Now these different ecological communities have analogous components and may be similar in basic organizations even though their constituent species are very different. No matter how different they are they have some bit of a similar similarities in the basic organization. Now the human populations if you look at, are typically subject to certain ecological principles although we artificially dissociate ourselves from other living systems. All of our activities whatever we do how we try to leave some kind of imprint on the environment and even our the use of this advanced technologies are ultimately dependent on nature.
Now in the upcoming courses will also try to engage more in looking at the
nature culture debate and how is nature evolving, the kind of perceptions, the kind of attitudes knowledge societies have will engage more in-depth in the debate between nature and culture. Now the biological interactions which are usually a multiple and cumulative and rarely if ever do, interactions occur singly or in isolation. As I had discussed a species cannot be understood in isolation but some form of interactions do occur among different species.
I will just try to categorize into four. How these ecosystems are being divided into different components which will, to some extent provide a central theoretical premise in looking at ecology in a more general sense. Now if you look at the first one that is the abiotic substances. It includes water, oxygen, nitrogen, and etcetera. Which are supposedly outside the living organism but we cannot survive and live without all this which of course is also a basic art of our existence. And the second thing is the producers that is, the green plants and bacteria which is commonly known as autotrophic and these producers are on which we the living species rely on for the supply of our food chain systems, and thirdly if you look at that is the consumers which is more or less the organism the living species which utilize organic materials which again is manufactured by the producers that is the heterotrophic and finally it is the decomposers that is bacteria and fungi which is known as saprophytic.
Now there is this constant interrelation between the producers the consumers and decomposers. Now if any of this is missing or there is inadequate or inefficiency on the part these whole basic components of our ecosystems will become imbalance. Now the fact remains that these ecosystems are in a sense self-regulating and that is not mean that they are simple or stable. Or in a sense inexhaustible or which cannot be in a sense destroyed but this the increase in these producers in a sense is said to create a positive feedback on consumers that is the living organism whereas the increase in consumer creates negative feedback on producers.
Now over here we can try to look at or contextualize by looking at the relationship which are normally applied in economic system that is the demand and supply now for instance if there is too much of a demand and like in supply there will be some kind of a negative if not imbalances. So there has to be a mutual or balance between the demand and supply and maybe if the supply is much more in higher position then it can have a positive feedback on the consumers.
Now perhaps these pictures can best explain which is of course our diagrammatic representation of how the terrestrial ecosystems which shows the producers, consumers and decomposers, how there is this linkages or interconnectedness among these basic components of our ecosystem.
Now if you look at this statistic or chart this gesture j-shaped curve of human population growth and over here the years are given. Now over the span of 2,000 years human have encountered different kinds of disasters like some of them to mention a few of the black death plague which was more or less between 1200 to 1400 AD and again the world war 2 which was in the late 1940s again now all this to some extent have impacted on the human population but yet the human population has increased and raised and on the in the light of this we can perhaps talk about how the Malthus tries to explain the rise of population. And he in fact in a very critical manner sees the occurrence of war as a check or a measure to control this rise of this population and he infers is population, the rise of population as extract to the existence of mankind itself because the resources which we have might not be sufficient enough to meet the increasing demands of this rising population. Now no doubt Malthus does have many critics as well. And there are many who do not really subscribe and agree to the kind of theory he posed in that population theory.
Now this ecosystem homeostasis refers also to a relative balance of Newton
cycles energy flows and species and compositions in the ecosystem which of course we have seen in that diagram how the provider consumer and a composer all these inter relationships are being seen now moving on to the other the second part that is by looking at what are the trends if not environmental movements which have been witnessed in the second half of the 20th century, And which of course begins in the West.