Human Ecology – Geography – UGC NET – Notes

Ecology

Ecology is studied with particular reference to plants or to animals, hence the topics Plant ecology and Animal ecology. Since plants and animals are intimately interrelated, study of plant ecology or animal ecology alone is bound to be imperfect and inadequate.

So plant and animal ecology are to be given equal emphasis and it is better to study them under the term Bio-ecology. The term Synecology denotes ecological studies at the community level while the term Autecology denotes ecological studies at the species level.

Definition

Ecology is concerned with the study of interrelationships between organisms and their environments. Two distinct components of environment can be identified: Abiotic (nonliving or nonorganic, sometime called the physical environment) and Biotic (living or organic). These two components, are, however, very much interdependent and sometime it becomes difficult to separate biotic components from the abiotic ones, especially when environment is looked at as a factor for determining man’s biology and culture (Odum, and Barrett, 2005).

Ecology is a purely scientific discipline which aims to understand the relationships between organisms and their wider environment. Like any science, the outcomes of ecological studies do not dictate ethical or political actions. It is important to make this distinction because the environmental movement has endowed the word ‘ecology’ with political connotations. It is right that ecology should inform politics, but as a student of ecology it is imperative to consider ecological research from a rigorous scientific viewpoint (Begon, et.al, 2006).

• Odum has defined ecology as the study of the structure and the function of nature.
• Andrewartha has defined ecology as the scientific study of the distrivution and abundance of organisms.
• Charles J. Kreb has defined ecology as the Scientific study of the interaction that determine the distribution and abundance of organisms.

History of Ecology

In a sense ecology is the new name of ‘Natural history’. Man’s interest in natural history dates back to prehistoric times. The carving and pictures discovered in France and Spain speak on the observation of the cave-dwellers about the fauna and flora around them.

The writings of Romans and Greeks bear evidences of their interest in natural history. The Histories of Animals’ of Aristotle (384-322 B.C.) is a famous contribution in this line.

The first naturalist to give a systemised knowledge about the relation existing bet-ween living organisms and environment was Buffon. In a series of work in 1749, he stressed on habits and adaptations. After this, outstanding advances were made in the study of natural history in the eighteenth and nineteenth centuries.

Darwin’s Naturalistic voyage round the world, Wallace’s Island of life and many other work stimulated the knowledge of Biology to a great extent. However, the term ecology was first coined by German Biologist, Haeckel in 1878.

The science of ecology after undergoing a several hundreds of years gestation period has emerged today as a matured, honoured and scholarly discipline in biological science.

Scope of Ecology

The solution of a particular ecological problem requires several lines of approach. None of this constitute an end in itself but each one of these makes important contribution in making the picture complete.

Habitat Ecology:

Habitat ecology is the type of natural environment in which a particular species of an organism live, characterized by both physical and biological features.

Ecosystem Ecology:

Organisms obtain energy either through photosynthesis or by consuming other organisms. These energy transformations are associated with the movements of materials within and between organisms and the physical environment.

Thus, the interaction between the biotic and abiotic components called an ecosystem is the sub-field of ecology called ecosystem ecology. Issues of interest at this level is how human activities affect food webs, energy flow and global cycling of nutrients.

Population Ecology:

Population ecology constitutes organisms of the same species living in the same place and same time. It may comprise of the dynamics of a single population of any living thing (earthworm, fox, whale, pine tree etc.) or may focus on how two populations (predator and its prey or parasite and its host) interact with each other.

At the level of population, evolutionary changes take place. It is also related directly to the management of fish and game populations, forestry and agriculture. Population ecology is also fundamental to our understanding of the dynamics of disease.

Community Ecology:

Populations of many different organisms in a particular place are tied to one another by feeding relationships and other interactions. These relationships of the purview of community ecology. interacting populations are called ecological communities and their study is under

Community studies is principally on how biotic interactions such as predation, herbivory and competition influence the numbers and distributions of organisms. It has particular relevance in our understanding of the nature of biological diversity.

Landscape Ecology:

These are of ecological fields whose study requires the synthesis of several other sub-fields of ecology. Landscape ecology is one that emphasizes the inter-connections among ecosystems of a region.

Restoration Ecology:

It relates to the re-establishing of the integrity of natural systems that have been damaged by human activity.

Ecotoxicology:

It is the study of the fate and action of human-made substances, such as pesticides and detergents, in the natural world. Ecotoxicology focuses on the way in which human-made substances affect human health. Eco-toxicologists often use other animals, such as fish or small invertebrates, as models for the action of the particular toxic substance under study.

Environmentalism, conservationism and preservationism are social or political movements and not branches of ecology. Roadside trash pickups and city tree planting drives are well-intentioned public beautification and cleanup activities, but such activities are not science. Although everyone applauds such civic responsibilities, they however, do not increase our understanding of the natural world.

The subfields of ecological studies provide ways to think about the various approaches in ecology. However, in many cases, individual ecologists conduct work that crosses boundaries of these subfields. The natural curiosity of most ecologists, along with the complexity of nature, often encourages broad approaches. Ecological study, thus, is an integrative science, one that requires great innovation, breadth and curiosity.

Evolutionary Ecology:

Evolutionary ecology emphasises the impact of evolution on current patterns and human induced changes. It relates to how animals choose mates, determine the sex of their offspring, forage for food and live in groups, or how plants attract pollinators, disperse seeds, or allocate resources between growth and reproduction. Evolutionary ecologists are particularly interested in how form and function adapt organisms to their environment.

Behavioural Ecology:

It is concerned with explaining the patterns of behaviour in animals.

Organismal Ecology:

Organismal ecology is the study of an individual organism’s behaviour, morphology, physiology, etc. in response to environmental challenges. It looks at how individual organisms interact with biotic and abiotic components. Ecologists research how organisms are adapted to these non-living and living components of their surroundings.

Individual species are related to various adaptations like physiological adaptation, morphological adaptation, and behavioural adaptation.

Molecular Ecology:

The study of ecology focuses on the production of proteins and how these proteins affect the organisms and their environment. This happens at the molecular level.

DNA forms the proteins that interact with each other and the environment. These interactions give rise to some complex organisms.

The values of landscape ecology are:

(a) It emphasises on larger land areas of interacting ecosystems, i.e., next higher level of organisation above the local ecosystem, and

(b) Its tendency to compartmentalize. We study a lake or forest ecosystem but landscape ecology considers the connections between them. For example, herons forage in the lake, nest in the forest and, thus, the herons move nutrients from water to land.