Introduction to Ecology

The word ‘ecology’ has been derived from the Greek words: ‘oikos’ means home and ‘logos’ means study. Ecology simply is the branch of biology which deals with the scientific study of interactions between the organisms and their environment. In a broad sense, ecology can be defined as the scientific study of the distribution and abundance of the organisms and the interactions that determine the distribution and abundance. The distribution and abundance of organism show where they occur, what is the number occurring there and how they occur there? Interactions determining the distribution and abundance are with the factors which are physical and chemical (abiotic) or other living organisms (biotic).

In the primitive society, the people had a practical interest in ecology as they had to depend mostly upon the natural resources, plants and animals around them, and also had to understand the natural processes. In the modern society, due to the advancement by modern technologies, people seem to depend less upon the environment in comparison to the primitive people. As a result, people hardly realize that they depend on nature for air, water, food and for other purposes like waste assimilations, ecological processes, recreation and other ecological services. It seems that human have been taking nature and it’s services for granted unless there is a crisis, as they assume that there are unlimited resources and they can be fulfilled by technology. But, the truth is that life necessities like air and water are recyclable but not replaceable.

Credit: Thomas Fuhrmann, CC BY-SA 4.0 https://creativecommons.org/licenses/by-sa/4.0, via Wikimedia Commons

Origin of the subject ‘Ecology.’

The writings of Hippocrates, Aristotle, and other philosophers of ancient Greece contain references to topics related to ecology. The word ‘ecology’ (oekology) was first proposed, coined, and described by the German biologist Ernst Haeckel in 1869, but Reiter made its first authentic use in 1885. Before this, many scholars had contributed to this subject during the 18th and 19th centuries but hadn’t used the word ‘ecology’. For example, Antony Van Leeuwenhoek, known as the ‘father of microscopy,’ started the study of food chains and population regulations in the early 1700s. During the same period, the English Botanist Richard Bradley studied biological productivity. The basic theory for a unified field of general ecology was established after different contributions made by the scientists, for example, the biotic community concept given by Frederick E. Clements and Victor E. Shelford, the food chain and material cycling concepts presented by Raymond Lindeman and G. Evelyn Hutchinson, and the whole lake studies done by Edward A. Birge and Chauncy Juday. During 1968-1970, the astronauts took the first photographs of Earth as seen from outer space for the first time in human history. This revealed how alone and fragile Earth revolves around space. This burst upon as a worldwide environmental awareness movement. Since the 1970s, the whole world has become concerned about pollution, population growth, food, and energy consumption, natural areas, and biotic diversity as the popular press has done a wide media coverage. The first ‘Earth Day’ was initiated on 22 April 1970. Thus, the 1970s is also regarded as the ‘decade of the environment’.
As we are in the 21st century, environmental concerns are increasing at an alarming rate due to the burning issues of climate change, over greenhouse effect, and global warming. In the past, ecology was taken as a sub-discipline of biology, while, in the present era, ecology has emerged as a new integrative discipline that links the physical, biological, social, and natural
sciences together.

Branches of Ecology

The two main branches of ecology are Autecology and Synecology. 

Other branches of ecology are as follows: 

• Gynecology (Ecological Genetics): It deals with the study of genetic composition and variability about the origin of ecads, ecotypes, new species, etc. 
• Paleoecology is the study of the relationship between the organism and the environment in the past. In this, palynology, paleontology, and radioactive dating methods have significant importance. 
• The word ‘ecology’ has been derived from the Greek words: ‘oikos’ means home and ‘logos’ means study. Ecology simply is the branch of biology which deals with the scientific study of interactions between the organisms and their environment. In a broad sense, ecology can be defined as the scientific study of the distribution and abundance of the organisms and the interactions that determine the distribution and abundance. The distribution and abundance of organism show where they occur, what is the number occurring there and how they occur there? Interactions determining the distribution and abundance are with the factors which are physical and chemical (abiotic) or other living organisms (biotic).
• In the primitive society, the people had a practical interest in ecology as they had to depend mostly upon the natural resources, plants and animals around them, and also had to understand the natural processes. In the modern society, due to the advancement by modern technologies, people seem to depend less upon the environment in comparison to the primitive people. As a result, people hardly realize that they depend on nature for air, water, food and for other purposes like waste assimilations, ecological processes, recreation and other ecological services. It seems that human have been taking nature and it’s services for granted unless there is a crisis, as they assume that there are unlimited resources and they can be fulfilled by technology. But, the truth is that life necessities like air and water are recyclable but not replaceable.
• It deals with the study of the specialized field of ecologies like agronomy agriculture, aquaculture, horticulture, animal husbandry, forestry, wildlife management, conservation ecology, and pollution ecology. These all are concerned with the conservation and economic uses of organisms.
• Systems Ecology: It is the study of the interpretation of ecological concepts and processes in terms of mathematical models and formulae. 
• Terrestrial Ecology: It deals with studying the organisms living on land, their interaction with the environment, and their adaptation to their environment. 
• Aquatic Ecology: It is the study of the ecosystems and their components found in the water bodies like marine, freshwater, or estuarine. Thus its types are marine ecology (oceanography), freshwater ecology, and estuarine ecology.
• Microbial Ecology: It studies the interaction of the microorganism communities in their microhabitat containing abiotic substrates. 
• Taxonomic Ecology: It deals with the study of the identification and classification of organisms present in an area.
• Evolutionary Ecology: The combined scientific study of evolution and ecology focuses on the physical and genetic changes occurring among organisms being affected by ecological factors over time. It also helps study the effect of environmental interactions like competition, predation, parasitism, and mutualism in the evolution of individual species in a population or the entire community. 
• Population Ecology (Demecology): It deals with the study of the population structures and dynamics and various factors that affect the population size, density, dispersion modes, growth rate, and mortality rate. 
• Behavioral Ecology: It is the study of the relationship between the animal’s behavior to its environmental adaptation and reproductive success. It examines the interaction between the survival value and the behavior of organisms and their offspring. 
• Physiological Ecology (Ecophysiology): It deals with the study of the survival of populations as a result of the functional adjustment of organisms with different ecological conditions like temperature, sunlight, soil condition, wind, humidity, precipitation, water availability, topographic factors, biotic factors, etc. 
• Chemical Ecology is the study of adaptations of animals with a preference for particular chemical substances. 
• Geographic Ecology (Ecogeography): It focuses on the study of the geographical distribution of animals (zoogeography) and plants (phytogeography). 
• Conservation Ecology: It deals with the study of the management of biodiversity through means of conservation and restoration. The need for this branch of ecology has arisen due to the decreasing biodiversity, overexploitation of natural resources, degradation of the environment, and extinction threats to wildlife.

Levels of Organization

We know ecology is the interconnection between the abiotic (non-living) and biotic (living) components. The systems consisting of the living and non-living components comprise the ‘biosystems,’ ranging from genetic systems to ecological systems. The environmental levels of the organization hierarchy include the eleven integrative levels of the organization, according to Barrett et al. 1997 as depicted below:

1. The ‘cell’ is the foremost and exceptional level in the ecological organization as it is the lowest level at which the properties of life emerge, and the cells can perform all activities essential for life. 
2. The ‘tissue’ can be understood as a group of similar cells having a common function. 
3. At the ‘organ’ level of organization, two or more tissues work together for a particular function. 
4. The ‘organ system’ level of an organization refers to the working together two or more organs for a specific function. 
5. The term ‘organism’ in the level of organization means the study of individual organisms and their interaction with their environments. 
6. The term ‘population’ denotes a group of individuals of any one species of organism. 
7. The term ‘community’ signifies the ‘biotic community’, which includes a greater or lesser number of species populations in a given area. 
8. The biotic community and abiotic environment function as an ecological system or ‘ecosystem.’ 
9. In ecology, ‘landscape’ is defined as a heterogeneous area composed of a cluster of interacting ecosystems repeated similarly throughout. 
10. The term ‘biome’ refers to an extensive regional or sub-continental system characterized by a significant vegetation type or other identifying landscape aspect. 
11. The term ‘ecosphere’ is designated to the most extensive and self-sufficient biological system, which consists of all the living organisms of Earth interacting with the physical environment as a whole. 

Each level in the level of organization is interdependent with other levels. For example, an organism cannot survive long without its population. Likewise, the community cannot exist without the cycling of nutrients and energy flow in the ecosystem. 

The Emergent Property Principle

The emergent properties can be regarded as those characteristics that cannot be predicted by studying components of a particular ecological level or unit. Emergent properties are those possessed by a collection or complex system, not by individual members. An example can understand in biology; the heart is made up of heart cells, which don’t have the property of pumping blood on their own. The whole heart is needed for pumping blood. The emergent properties help to increase the chances of survival of living organisms by assisting them to adapt to their environments. The emergent properties can be better illustrated by these two examples: one from the physical realm and another from the ecological realm.

1. The combination of hydrogen and water in a specific molecular configuration produces water in a liquid state whose properties differ from that of a gaseous state. 
2. When a coral is produced by the evolving together of an algae plant and a coelenterate animal, an efficient nutrient cycling mechanism is created, which enables the combined system to maintain a high productivity rate in an aquatic ecosystem with low nutrient content.  

A few examples of emergent properties in the level of organization are as follows: 

• At the population level of organization, examples of emergent properties are sigmoid growth for population growth, population regulation, genetic evolution, and social organization. At this level, the ability to communicate and work together for the species’ survival also comes under the emergent property. 
• At the ecosystem level of organization, the emergent property is the interaction between an environment’s communities and non-living things. 

The person who studies the field of ecology is known as an ecologist. Ecologists study the relationship between living things and their environment, their biotic and abiotic resources. The ecologists may be professional research scientists or teachers. The role of ecologists has been summarized as follows: 

Ecologists study the effect of human actions on other living beings and their environment and try to mitigate the adverse effects.

Ecologists investigate the interactions between organisms and the environment across ecosystems of all sizes, ranging from microbial communities to the whole earth. 

Ecologists often try to predict the effect of a particular set of circumstances on the organism, population, community, or ecosystem. Based on predictions, they try to find ways to control the situation. 

Ecologists give their efforts to maintaining the endangered species of wildlife by predicting and formulating effective conservation policies. 

Ecologists involve in the conservation of biodiversity to preserve the ecosystem services like protection of the chemical quality of natural water, restoration of wetland habitats, etc.

Ecologists are also involved in protecting the crops by predicting the favorable conditions of plantation, growth, and harvesting. 

Ecologists try to minimize the effect of severe pest attacks like locust attacks by predicting when and where they are likely to occur and taking appropriate action.

Ecologists have an essential role in solving environmental issues like pollution, rapidly increasing unplanned development activities, and global climate change. Ecologists can play a dynamic role in building a sustainable future for everyone’s typical home, ‘planet earth’.