What is Ecology?
origin of word: oikos = the family household, logy = the study of
interesting parallel to economy = management of the household many principles in common – resources allocation, cost-benefit ratios
definitions: Haeckel (German zoologist) 1870: “By ecology we mean the body of knowledge concerning the economy of Nature - the investigation of the total relations of the animal to its inorganic and organic environment.”
Burdon-Sanderson (1890s): Elevated Ecology to one of the three natural divisions of Biology: Physiology - Morphology – Ecology
Andrewartha (1961): “The scientific study of the distribution and abundance of organisms.”
Odum (1963): “The structure and function of Nature.”
Definition we will use (Krebs 1972):
“Ecology is the scientific study of the processes regulating the distribution and abundance of organisms and the interactions among them, and the study of how these organisms in turn mediate the transport and transformation of energy and matter in the biosphere (i.e., the study of the design of ecosystem structure and function).”
The goal of ecology is to understand the principles of operation of natural systems and to predict their responses to change.
Ecology and Environment
Ecology is a branch of biology that involves the scientific studies of how living things (organisms) interact with each other and their environment. Anything that impacts on an organism during its lifetime in known as environment. Environmental influences can be divided into two different categories- biotic factors (the living influences) and abiotic factors (the nonliving influences)
An ecosystem is an interacting collection of organisms and the abiotic factors that affect them. Ecosystems encompass all the parts of a certain environment, including the living (biotic) plants and animals, and the nonliving (abiotic) components, such as soil, water, air and the sun’s energy.
Organization of an ecosystem
All living things require a continuous supply of energy to maintain life. Within an ecosystem, several different kinds of organisms can be identified. Organisms that trap sunlight for photosynthesis, resulting in the production of organic material from inorganic material, are called produers. There is a flow of energy from the sun into the living matter of plants.
The energy that plants trap can be transferred through a number of other organisms in the ecosystem, these organisms are called consumers.
If an organism dies, the energy contained within the organic compounds of its body is finally released to the environment as heat by organisms that decompose the dead body into carbon dioxide, water, ammonia and other simple inorganic molecules. These organisms of decay are called decomposers. Decomposers are things such as bacteria, fungi and other organisms that use the dead organism as a source of energy.
Every ecosystem contains species of plants and animals. Each species occupies its own ecological niche or functional role that it fulfills in the environment.
Table: Roles in an Ecosystem
| Classification | Description | Examples |
| Producers | Plants that convert simple inorganic compounds into complex organic compounds by photosynthesis. | Trees, flowers, grasses, ferns, mosses, algae |
| Consumers Herbivore Carnivore Omnivore Scavenger Parasites | Organism that rely on other organisms as food. Animal that eat plants and other animals. Eat plants directly. Eats meat. Eats plants and meat. Eats food left by others. Lives in or on another organism, using it for food | Deer, duck, cricket, vegeterian human Wolf, pike, dragonfly Rats, most humans Coyotes, skunks, vultures, crayfish Tick, tapeworm, many insects |
| Decomposer | Organism that returns organic compounds to inorganic compounds. Important component in recycling. | Bacteria, fungi |
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