The first law of ecology is that everything is related to everything else.
- Barry Commoner
Have you ever tried to summarise the logic of studying biology? Well, it can be put in hundreds of thousands of words. Let us try to make it simple. The essence of biological understanding is to know how organisms while remaining an individual, interact with other organisms and physical habitats as a group and hence behave like organized wholes, i.e., population, community, ecosystem or even as the whole biosphere. And guess what, ecology is that branch of science which explains all of this. Now, this might be a question that biology is all about ecology. Well, biology is all about understanding ecology. We study cytology, physiology, morphology, and anatomy of organisms to understand their interaction with the environment. This ultimately leads us to study ecology as the function of biology. Hence, it does make sense that we are now going to study ecology and environment as the last unit of our biology syllabus because we have taken a great ride across all the disciplines of biology, just to understand ecology!
Ecology and environment are not important only because it allows us to understand how living things are interacting with each other but also because it deals with disturbances in these interactions. As far as the current scenario is concerned, ecologists and scientists from various disciplines are focussing more on the ‘disturbed’ part of interactive ecology caused by none other than the invasive human influence. Hence, ecology also deals with the study of anthropogenic environmental degradation and the socio-political issues it has raised. Therefore, it is of utmost importance to realize the principles of ecology in order to maintain the nature in its harmony.
Introduction to Ecology and Environment
Ecology and environment are presented as the tenth unit in the NEET biology syllabus. It is also the tenth unit in the NCERT textbook for class 12, which is going to be your primary and necessary reading material. Although we have established the importance of ecology and environment pragmatically, it is also important to know its weightage for NEET exam. So, the chapter ecology and environment comes with the highest approximate weightage of 13%. Now, you can realize how essential it is to focus on ecology and environment after having read and understood various other aspects of biology.
There are various forms of questions that are asked in the competitive exams from the chapter ecology and environment. There are graphical questions, diagrammatic questions, numerical questions, assertion and reasoning questions, theories related questions, questions based on case studies and practical aspects, etc. Therefore, you will have to do an exhaustive study of this chapter. You will need to relate the theoretical aspects with practical applications and build conceptual understanding so as to solve assertion and reasoning based questions.
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Notes on Ecology and Environment
Let us try to figure out what all topics do we have to focus on in order to approach the chapter ecology and environment in a holistic manner.
1. Organisms and Populations:
Ecology is a subject which studies the interactions among organisms and between the organism and its physical (abiotic) environment. Ecology is basically concerned with four levels of biological organisation – organisms, populations, communities and biomes. We have to focus on the first two levels of biological organisation in this chapter of ecology and environment, that is, organisms and population.
This chapter of ecology and environment tries to explain how and why of a process an organism is performing. For example, when you approach the environment with a scientific frame of mind, you might come up with questions like ‘How does the bird sing?’ Or, ‘Why does the bird sing?’ The ‘how-type’ questions seek the mechanism behind the process while the ‘why type’ questions seek the significance of the process. For the first question in our example, the answer might be in terms of the operation of the voice box and the vibrating bone in the bird, whereas for the second question the answer may lie in the bird’s need to communicate with its mate during the breeding season. Hence, you will get to know of such processes related to organisms and their populations in this chapter as:
- Organisms and environment
- Habitat and niche
- Population and ecological adaptations
- Population interactions-mutualism, competition, predation, parasitism
- Population attributes-growth, birth rate and death rate, age distribution
2. Ecosystem:
An ecosystem can be visualized as a functional unit of nature, where living organisms interact among themselves and also with the surrounding physical environment. Many ecologists regard the entire biosphere as a global ecosystem, as a composite of all local ecosystems on Earth. However, this does not present the functional attribute that can be studied. So, you will approach the ecosystem divided into two basic categories, namely the terrestrial and the aquatic.
In this chapter of ecology and environment, you will first look at the structure of the ecosystem, in order to appreciate the input (productivity), transfer of energy (food chain/web, nutrient cycling) and the output (degradation and energy loss). You will also look at the relationships – cycles, chains, webs – that are created as a result of these energy flows within the system and their interrelationship. Hence, the following topics have to be studied:
- Ecosystem: Patterns, components
- Productivity and decomposition
- Energy flow
- Pyramids of number, biomass, energy
- Nutrient cycling (carbon and phosphorous)
- Ecological succession
- Ecological Services-Carbon fixation, pollination, oxygen release
3. Biodiversity and Conservation:
Have you ever thought what makes our earth the most stable and unique planet? The answer is the availability of water, oxygen, optimum temperature etc. that make it possible for life to exist. These factors are also responsible for the enormous diversity of life. The rich variety
of living organisms on this planet never ceases to astonish and fascinate a layman as well as scientists. You would be baffled to find out that there are more than 20,000 species of ants, 3,00,000 species of beetles, 28,000 species of fishes and nearly 20,000 species of orchids. The ecologists and evolutionary biologists try to find out the reasons and possibilities of having such a vast number of species. However, at the same time, we could lose all that wealth of diversity in less than two centuries if the present rates of species losses continue.
Hence, you will look into these researches in this chapter that offers the following topics:
- Concept of Biodiversity
- Patterns of Biodiversity
- Importance of Biodiversity
- Loss of Biodiversity
- Biodiversity conservation
- Hotspots, endangered organisms, extinction, Red Data Book, biosphere reserves, National parks and sanctuaries.
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4. Environmental Issues:
Human population has seen a boom in the last hundred years. This means an increase in demand for food, water, home, electricity, roads, automobiles and numerous other commodities. This ultimately puts tremendous pressure on our natural resources, and are also contributing to pollution of air, water and soil. The need of the hour is to check the degradation and depletion of our precious natural resources and pollution without halting the process of development.
So, as much as it is essential to study and understand the ecology and environment, we also need to study and understand the various environmental issues and address them for their alleviation. The following topics will be your focus of study in this chapter:
- Air pollution and its control
- Water pollution and its control
- Agrochemicals and their effects
- Solid waste management
- Radioactive waste management
- Greenhouse effect and global warning
- Ozone depletion
- Deforestation
- Any three case studies as success stories addressing environmental issues
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Tips on Ecology and Environment
- Read and understand the concepts from the NCERT textbook for class 12.
- An additional source of reading can be referred to for case studies.
- Keep an update of the recent environmental issues and global efforts to curb them.
- Know about various agencies of UN working for the betterment of the ecosystem.
- Practice the questions.
- Keep revising.
Books for Ecology and Environment
- The NCERT textbook for class 12
- A Textbook of CBSE Biology for Class 12 by Sarita Aggarwal
- Trueman’s Elementary Biology Volume 2
Biology Units-wise Notes for Medical Exams
