F.Y.B.A. (ENG)
SEM : 1
MDC 101 - A (UNIT - 1)
ECOLOGY
Ecology has its roots in Natural History, which is as old as human civilisation itself. with truth, man has been involved with ecology in a practical sense, if unintentionally, from early history. For survival in ancient times, every individual was required to have extensive awareness of his environment, i.e., of the forces of nature as well as the plants and animals around him. Primitive tribes that depended upon hunting, fishing, and food collecting required thorough knowledge of their surroundings in order to survive. Later, the adoption of permanent agricultural life emphasised the importance of learning practical ecology for successful plant and animal domestication.
Ecology
is the scientific study of organisms' interactions with their environments. It
includes the study of living creatures, their interactions with one another,
and their interactions with non-living components of their habitats, such as
climate, geology, and resource availability. Ecology studies how creatures
adapt to their surroundings, how organism populations change over time, and how
ecosystems function and respond to various objects.
Etymology
The term ecology is derived from two Greek words: Oikos, which means "household," "home," or "place to live," and "logos," which means "Study of" or "knowledge."
DEFINITIONS
"Ecology is the science treating the reciprocal
relations of organisms and the external world."
Ernst Haeckel
"Ecology is the scientific study of the interactions
that determine the distribution and abundance of organisms."
Charles Krebs
"Ecology is the study of the structure and function of
nature."
Eugene
P. Odum
"Ecology is the scientific study of the relationships
between living organisms and their environments."
Peter
J. Bowler
These definitions emphasise the fundamental principles of
ecology, which include studying animals in their natural surroundings,
analysing interactions and linkages, and investigating how ecosystems and
populations function and react to environmental changes. Ecology is critical to
understanding and managing environmental concerns as well as efforts to
conserve.
HISTORY OF ECOLOGY
Ecology history is a complex and varied field that
has changed over time. It is the scientific investigation of the interactions
between organisms and their environments.
There are numerous references to ecological themes in our ancient Indian texts. Many references to ecological principles may be found in Vedic works such as the Vedas, Samhitas, Brahmanas, and Aranyakas-Upanishads (1500 BC-600 BC).
The Indian medicine treatise Charaka-Samhita (1st Century AD-4th Century AD) and the surgical tract Sushruta-Samhita (1st Century AD-4th Century AD) show that individuals throughout this time period had a thorough awareness of plant and animal ecology. These publications include animal categorization based on habit and habitat, land classification based on soil type, climate, and vegetation, and descriptions of plants native to various areas.
Charaka Samhita states that air, land, water, and seasons are necessary for life and that dirty air and water are harmful to one's health.
Early Observations (Pre-19th Century)
In the fourth century BC, there was a similar understanding of environmental difficulties in Europe. The value of environmental studies was recognised by the early Greek thinkers. Hippocrates, in his work 'On Airs, Waters, and Places,' underscored the importance of ecological background for medical students, emphasising the role of water, air, and place on human health and disease.
The Greeks and Romans, for example, had a start into natural history and the connections between species and their environments. These views, however, were frequently founded on philosophical and observational rather than empirical approaches.
Aristotle (384-322 BCE)
Aristotle contributed much to our understanding of the natural world. He wrote extensively about animals and their behaviours, classifying them according to their qualities. While his study was not specifically ecological, his classification and observation of various species helped to early natural history and understanding of Earth's diversity.
Theophrastus (c. 371–c. 287 BCE)
The Enlightenment (18th Century)
In the early eighteenth century Anton-van Leeuwenhoek (1632-1723), the microscopist, pioneered the study of food chain and population regulation which have grown into the major areas of modern ecology.
Several decades later, European naturalists made substantial contributions to ecological theory. In his work Natural History (1756), the French naturalist Georges Buffon (1707-1788) made a significant attempt to systematise knowledge concerning the relationship of animals to the environment.
During the Enlightenment, thinkers such as Carl
Linnaeus and Jean-Baptiste Lamarck made fundamental contributions to our
understanding of the natural world. Linnaeus devised the system of binomial
classification for classifying species, while Lamarck provided early theories
on evolution and adaptation.
Gilbert White (1720-1793)
Gilbert White, widely regarded as one of England's
earliest naturalists, detailed his observations of the natural world in and
around the village of Selborne in his book "The Natural History and
Antiquities of Selborne" (1789). His careful observations of birds,
animals, and plants in their natural settings laid the groundwork for
subsequent ecological field investigations.
The Birth of Ecology (19th Century)
The nineteenth century was an important period in
the birth and growth of ecology. The term "ecology" was coined during
this century, and several major events and persons set the framework for
ecology's establishment as a scientific subject. The theory of evolution by
natural selection, as articulated in Charles Darwin's book "On the Origin
of Species" (1859), had a major effect on ecological thinking. It
established a foundation for understanding how animals adapt to their
environments within time.
Ernst Haeckel, "Ecology" (1866)
In 1866, the German biologist Ernst Haeckel invented the term "ecology" in his publication of "General Morphology of Organisms". Ecology, according to Haeckel, is the study of the interactions between organisms and their environments. He was instrumental in developing the phrase and its intellectual context.
Humboldt, The Study of Nature
In the late 18th and early 19th centuries, German naturalist and explorer Alexander von Humboldt (1769-1859) led extensive scientific missions. His work, which included the multi-volume "Kosmos," emphasised nature's interconnectivity and the significance of researching the connections between species and their surroundings. Humboldt's writings and theories had a significant impact on the increasing science of ecology.
Darwin's Theory of Evolution (1859)
The theory of evolution by natural selection, as
given in Charles Darwin's foundational paper "On the Origin of
Species" (1859), had profound implications for ecology. Darwin's insights
provided a theoretical foundation for understanding the interactions between
animals and their ecological niches by explaining how species adapt to their
environments over time.
Late 19th and Early 20th Centuries
During this time, ecological studies began to
incorporate more experimental methodologies. Ecologists such as Charles Elton
and G. Evelyn Hutchinson pioneered work on themes like as food webs, population
dynamics, and community ecology. The development of limnology, the study of
freshwater ecosystems, was critical in expanding ecological understanding.
Charles Elton, Animal Ecology
During this time, British ecologist Charles Elton made important contributions to animal ecology. He conducted extensive fieldwork and studies, focusing on animal populations, their interactions, and the food webs they generated. Elton's classic work "Animal Ecology" (1927) emphasised the importance of field observations and experimentation.
G. Evelyn Hutchinson, Limnology
American ecologist G. Evelyn Hutchinson is widely considered as one of the founding leaders of modern limnology, the study of freshwater habitats. Hutchinson conducted extensive lake investigations and popularised the concept of the "niche" as a basic ecological concept. In ecology, his work emphasised the necessity of experimental and quantitative analysis.
Ecological studies in India, like elsewhere, began with a descriptive phase around the end of the nineteenth century. Forest officers (1875-1929) wrote descriptive reports of the woodlands. However, Prof P. Dudgeon of Allahabad University made the first complete ecological contribution in 1921 when he explained the role of environment in the succession of communities.
Extensive synecological studies on forest and grassland ecosystems, as well as autecological studies on trees, plants, and grasses, were conducted under the direction of Prof. R. Misra, who created a flourishing school of ecology at Banaras Hindu University by the 1960s.
Mid-20th Century
 |
| Sir Arthur Tansley |
Sir Arthur Tansley, a famous British botanist, introduced the concept of the Ecosystem or ecological system in 1935. This was an important development in the history of ecology.
The mid-twentieth century saw the birth of
theoretical ecology and the creation of mathematical models to describe
ecological processes. Pioneers such as Robert MacArthur and E.O. Wilson made
substantial contributions. This included recognising energy flow and nutrient cycling
within ecosystems.
Modern Ecology (Late 20th Century to Present)
Ecological research has grown to address current
environmental issues such as habitat loss, pollution, climate change, and
biodiversity conservation. The field of conservation biology evolved, with the
goal of protecting and preserving biodiversity. Technological advances, such as
remote sensing and DNA sequencing, have allowed ecologists to investigate
ecosystems at ever-finer scales and answer challenging ecological issues.
Much of the recent interest in ecology stems from the
problems caused by rapid population growth and widespread deterioration of
environment due to pollution of air, soil and water. Ecological studies are now
increasingly geared to promote conservation and rational utilisation of natural
resources through international efforts such as Man and Biosphere Programme of
UNESCO , United Nations Conference on Human Environment held at Stockholm
in 1972, United Nations Environment Programme (UNEP), and World Wide Fund for
Nature (WWF). The science of ecology has much to contribute in solving the problems
of environment.
Subdivisions of Ecology
.
1.
Autecology
The study of individual species or individuals in relation
to their environment is known as autecology. It is focused with determining how
a specific species interacts with its biotic (living) and abiotic (non-living)
surroundings, which includes elements such as habitat, behaviour, physiology,
and adaptations. Autecologists examine the dynamics of specific species
populations, including factors that influence population growth such as birth,
mortality, immigration, and emigration rates. They also look into how
populations react to environmental change.
There are two approaches to Autecological studies
(a) Autecology of a species
Autecology of species is the study of individual species.
The ecological study of a specific species in isolation, focused on its
specialised interactions with its environment, is referred to as autecology.
Autecological studies provide researchers with insights into a species' unique
ecology requirements and behaviours, helping them to learn how it survives,
reproduces, and grows within its home. Understanding a species' behaviour is
critical in autecology. Territoriality, mating rituals, communication, and
responses to environmental signals are all studied by researchers.
(b) Population Ecology
Individuals of the same species are investigated in
population ecology. The study of groups of individuals of the same species
living in the same geographic area is known as population ecology. It aims to
understand the elements influencing population size, structure, and behaviour.
Population Parameters.
Population Size (N): The total number of individuals in a
population.
Population Density: The number of individuals per unit area
or volume.
Population Distribution: The spatial arrangement of
individuals within a population.
2.
Synecology
The study of the community of living organisms as a unit is
known as synecology. The following example may help to understand the
distinction between autecology and synecology. An autecological research would
be conducted if a neem tree (or several neem trees) or a crow (or several
crows) were studied in connection to the environment. A synecological approach
would be used if the study dealt with a forest ecosystem as a whole, with many
different buds, trees, and animals sharing the same region. Synecology is
concerned with understanding the numerous ecological interactions between
species. Predation, resource competition, mutualism (mutually beneficial
partnerships), parasitism, and commensalism (one species benefits while the
other is neither damaged nor assisted) are examples of these interactions.
Synecological studies can be of two types.
a) Community Ecology
Community ecology, also known as synecology, is a branch of
ecology that studies ecological communities, which are groupings of interacting
species that live in the same geographic area or habitat. It tries to
understand the communities' composition, organisation, dynamics, and ecological
processes. Community ecology is the study of a biotic (living) community
composed of interdependent plants and animals in a specific location. They look
into how ecological factors like resource availability, habitat complexity, and
disturbance affect these patterns.
b) Ecosystem Approach
Ecosystem Ecology is a relatively new field of study in
ecology. Ecosystem ecology is a branch of ecology that studies whole ecosystems
as functional units. It investigates the interaction between living species
(biotic components) and their physical and chemical surroundings (abiotic
components) within a certain geographical area or habitat. Ecosystem ecology
studies the flow of energy, nutrients, and matter across ecosystems, how
ecosystems respond to environmental changes, and the processes that govern
ecosystem structure and function.
It deals with the community of living creatures and their
environment as a natural unit. Ecosystems are defined by the movement of energy
from the sun to primary producers (plants) along a food web of trophic levels
(consumers). Ecosystem ecologists examine energy transmission, such as how
primary producers collect sunlight through photosynthesis and how energy moves
up the food chain by herbivores (an animal that feeds on plants), carnivores
(an animal that feeds on other animals), and decomposers (an organism whose
ecological function involves the recycling of nutrients by performing the
natural process).
3.
Habitat ecology
Habitat Ecology is the study of organisms' habitats or
environments and their effects on them. Habitat ecology is a subject of ecology
that studies specific habitats or settings as well as the interactions between
organisms and their surroundings within those habitats. It is also known as
habitat biology or habitat ecology science. Unlike some other branches of
ecology, habitat ecology focuses on specific types of ecosystems, attempting to
understand how the physical and biological characteristics of a habitat
influence the distribution, behaviour, and adaptations of the organisms that
live there.
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