Figure no.1 (Ecosystem of plants and animals)
 Article:

In this article, the term ecology and its branches are described. The scope of ecology is also discussed in this article.

Ecology:

It is the study of the interaction of biotic and abiotic components.

It is the study of relationships of living and non-living.

German zoologist Ernst Haeckel in1866 described the term ecology as

Okos - Household

Logos- Discussion, thought, study.

Branches of Ecology:

Autecology:

It is the study of the relationship of a single population community.

Synecology:

It is the study of the behavior of different organisms. It is also called behavioral ecology.

Other Branches of Ecology:

Ecophysiology, Evolutionary Ecology, Chemical Ecology, Applied Ecology, Population Ecology, Community Ecology, Ecosystem Ecology, Plant Ecology, Insect Ecology, Animal Ecology, Forest Ecology

Specialized Branches of Ecology:

Biogeochemistry, Biogeography, Ecological Succession, Ecotoxicology,

Functional Ecology, Global ecology, Marine ecology, Microbial ecology,

Micro ecology, Paleoecology, Soil ecology, Theoretical ecology, urban ecology.

Ecology plays an important role in many fields like ecological design and engineering, economics, human ecology and anthropology, social ecology, health, and environmental ecology.

Ecological health also inspired others such as industrial ecology, media ecology, and information ecology.

Scope of Ecology:

Ecology attempts to tell us

       I.           Why particular kinds of organisms can be living in one place not another?

    II.          The factor that controls the number of particular kinds of organisms and maintains them at a certain level and their principles that may allow to predict the future behaviors of groups or organisms.

Practical applications of ecology:

Human impact on the environment study in applied ecology (consists of conservation ecology, restoration ecology, and landscape ecology.

Applications of ecological principles to Resource Management have led us to improve various fields such as Forestry (deforestation, Afforestation, Reforestation) Monoculture, Wildlife Management, Range Management (where animals graze) Fishery Management.

Ecologist Study:

Structural, functional, and behavioral adaptations of organisms about their environment.

·       Interrelations between species and their populations and communities.

·   Local and geographic distribution of organisms.

·    Regional variation in organism abundance.

·   Temporal changes in distribution, abundance, and behaviors of organisms.    

·   Ecological Succession:

Change and replacement of species in a community by a gradual process.

The sequence of change is predictable. It takes place hundreds or thousands of years. Succession occurs following a distribution in an ecosystem.

Succession regenerates or creates communities after a distribution. It is a sequence of biotic changes. Damaged communities are regenerated. New communities have grown in previously inhabited areas.

Ecological succession is the observed process change in the species structure of an ecological community over time. The community begins with relatively few pioneer plants and animals and develops through increasing complexity until it becomes stable as a climax community.

Climax Community:

Community which is equally favored by all climatic factors.

Succession occurs in all natural environments. Each environment has a particular name that expresses the nature of its ecological succession.

Types of Ecological Succession:

There are two main types of ecological succession.

1)    Primary Succession:

The process of growing plant life in an area where no life previously existed.

2)    Secondary Succession:

The process of re-stabilization that follows a disturbance in an area where the life have formed an ecosystem.

1)    Primary Succession:

Primary Succession begins with the pioneer species.

Pioneer Species:

The first species to colonize a disturbed area like lichens that can grow directly on rocks begin the breakdown of rocks to form soil. When rock begins to break and crack soil forms and small plants can take roots. Large plants continue to move in until the bare ground is covered with life.

Secondary Succession:

Type of ecological succession that occurs on a soil where ecosystem previously existed.

Due to a disturbance to the ecosystem, something that upsets the natural balance may be natural (floods) or man-made (deforestation). Secondary succession starts in a habitat where communities are destroyed by damaging events.

When an existing community has been disturbed such as a fire, tornado, etc. and the soil remains intact, the area starts to return to its natural community because these habitats previously supported life.

Secondary succession unlike primary succession begins on a substrate that already bards soil. In addition, the soil contains a native seed bank. Soil is already in a place where secondary succession can take place 5-10 times faster than primary succession.

After a disturbance pioneer species moved in followed by other species in a somewhat predictable sequence.

Examples of Natural Disturbance:

Tornadoes, Floods, Tree falling, Fire, Hurricanes and diseases.

Examples of Man-made Disturbance:

Deforestation, Pollution, Urbanization, Harvesting.

Stages of Secondary Succession:

1)    Early:

Small plants with short lifecycles contain rapid seed dispersal. They are environment stabilizers (pioneer species).

2)    Middle:

Plants are typically long-lived, have slow seed dispersal, and usually larger life cycles.

3)    Late:

Plants and animal species are associated with older more mature ecosystems, larger seed dispersal, better competition, and slow growth.

Climax Community:

The final stage of succession will last as long as there is no disturbance.

Each stage of succession begins with changes in the ecosystem that enable or prevent certain species from moving in better soil, less light, and more competition as the ecosystem matures.

Some changes may help other species called facilitation e.g. (Dogwood trees grow well under the shade of larger trees. 

Some changes may hinder other species called inhibition e.g. (black walnut produces a chemical that keeps other plants from growing near it.

Secondary successions begin in habitats where communities were destroyed by some kind of events but the soil remains intact.

Secondary succession example:

Succession on abandoned cropland and farms. Grass and weed will develop first due to the high abundance of their seeds. Pines will take root in the soil followed by oak, hickory, and dogwood plants.

Soil Water Classification:

Hygroscopic water, Capillary water, gravitational water.

Hygroscopic Water:

Around the soil particles very thin layer/film of water is present. These films are held by strong forces that cause the water molecules to be changed in a semisolid form.

Capillary Water:

The water that moves into and is held in the soil by capillary forces or about the attraction or repulsion between a solid and a liquid.

Gravitational Water:

When the soil has been wet then the water drained out from the soil is called gravitational water. Because of the pull of gravity, the water moves downward.