Branches of Ecology & Ecological Factors

Branches of Ecology & Ecological Factors

• The ecological studies are based on three main aspects— levels of organisation, taxonomic affinities & types of habitat.

The branches of Ecology

1. On the basis of levels of organisation:

There are two branches of ecology on the basis of levels of organisation—Autecology & Synecology.

i. Autecology:

Auto (= on itself) + Ecology = Autecology.
Autecology is the study of relationship of individual species to its environment. For example: Organism ecology.

ii. Synecology:

Syn (= together) + Ecology = Synecology. Synecology is the study of relationship of group of organism and their environment. 
Synecology is subdivided into 'population Ecology', 'Community Ecology', 'Ecosystem Ecology' etc.

2. On the basis of Taxonomic Affinities:

Taxonomy is concerned with the classification of things, especially organisms (plants & animals). For example: Plant Ecology & Animal Ecology.

3. On the basis of Habitat:

Habitat is the place where organism live. On the basis of habitat, ecology is divided into two categories—

i. Terrestrial Ecology: For example, Forest ecology, Grassland ecology, Desert Ecology etc.

ii. Aquatic Ecology: For example, Marine ecology. Freshwater ecology etc.

Ecological Factors

• The factors that affect flora and fauna directly or indirectly are called Ecological or Environmental Factors, In short, Ecological factors are known as Eco Factors.
• There are two kinds of ecological factors — Abiotic & Biotic factors.

A. Abiotic Factors

• Non-living factors are called Abiotic factors. For example, light, temperature, humidity (water), wind topographic (physical features of an area viz. rivei mountain etc), edaphic (soil) etc.

1. Light:

Light is an important climatic factor. Most of the plants need light for photosynthesis process to make their food. Animal community is dependent on plants for their food. Though the Sun emits a wide spectrum of light, only long waves (infra-red portions of visible light) and short waves (ultra-violet) are important ecologically. By means of light, many animals are able to move about freely and to carry on the necessary activities of life. Ultraviolet light is both beneficial and harmful to animals. Vitamin D is synthesised in the skin and hair under the influence of UV light. However, too much exposure to UV rays may lead to skin cancer (including melonama).

Plants are divided into three types on the basis of Photoperiod (total length of the daily light period to which plants are exposed)—

1. Long-day plants: e.gWheat, barley, oat, henbane etc.
2. Short-day plants: e.g. Rice, Soyabean, cotton, sorghum/jowar etc.
3. Day-neutral plants: e.g. Rose, almost flowers of winter season, sunflower, tomato, chilli, tobacco etc.

plants are divided into two types on the basis of sunlight—

1. Photophilous/Heliophilous (Sunlight loving} plants: e.g. Birch, cactus, sugercane, maize etc.
2. Sciophilous/Heliophobus (Shade loving /Sun fearing) plants: e.g. Fern, several herbaceous plants etc.

2. Temperature:

Temperature is the degree of hotness or coldness of a susbstance. Temperature is needed for motion and reproducution of a organism. Total degree of heat received by the plants is called Thermoperiod.

Obviously thermoperiodic effects are distinct from photoperiodic effects (caused by duration of light). An average of 10°C to 45°C temperature is essential for biological functioning. Respiratory function of plants increases with rising temperature. On the basis of temperature, plants are divided into four categories—

3. Humdity:

Atmospheric moisture in the form of invisible vapair is called humidity. Humdity plays an important role in life of plants and animals. Proccess such as transpiration, absorption of water etc. are much influenced by humidity.

4. Wind:

Wind is an important abiotic eco factor. Wind affects soil erosion, pollination, seeds dispersal etc. According to speed, winds are classified as follows : Breeze-5-50 km/h, Gale-50-100 km/h, Storm-100-125 km/h, Hurricane More than 125 km/h.

5. Topographic:

Topographic factors are concerned with the physical geography of the earth in the area. Height, slope, expose etc. of topography affects plants and animals in many ways.

6. Edaphic (Soil):

Man depends on plants and plants grows in soil. Thus soil plays an important role in the life of plants and animals. The constituent parts of the soil are—Soil water (25%), Soil air (25%), Mineral matter (40%), Organic matter or Humus (10%).

Biotic Factors

Biotic factors also affects the life of plants and animals. Under natural conditions, organism live together influencing each other's life and establish relationship. The common examples of such relationship are given below—

1. Symbiosis:

Symbiosis means live together. A relationship between two different living being close to one another and depending on each other benefiting from each other in particular ways is known as symbiosis, e.g Algae and fungus live together and form Lichen (Pronounced as Liken) etc.

2. Parasittism:

The relationship between two organism in which one benefits at the expense of the other is called parasitism, e.g. Bacteria, Virus, Cuckoo (Hindi name Koyal, as we know that cuckoos do not build nest their own, but deposit their eggs in the nests of crows) etc.

3. Commensalism:

An association between two organism in which one benefits and the other derives neither benefits nor harm is called commensalism. e.g. Remora & Shark (Remora rides under the shark and feeds the leftovers of their host shark's meals), Tree frog and plants (Tree frog uses plants as their protection), Heron (Bagula) and cattle (cattle egrets eat the insects strirred up by cattle when they are grazing) etc.

4. Predation:

Predation is a biological interaction where one organism, the predator, kills and eats another organism, the prey e.g. Grass (prey) & Grass hopper (predator), Small fish (prey)k Large fish (predator) etc.

5. Seprophytism:

(Sapro = to decompose). Saprophytism is a mode of nutrition in which organism obtain food from dead organism (non-living organic matter— detritus, organism that feed on dead organism— detritivore/decomposer/saprotroph). e.g. Bacteria, Fungi, Mushroom etc.

Glossary (Ecology)

Deep Ecology: The term 'deep ecology' was first coined by Norwagian activist and philospherArniesNaess in 1972. This term is a related to environmentalism. It is considered as a movement or a concept that pleads radical measures to protect the natural environment irrespective of their effects on human welfare. Thus, deep ecology is an ecocentric philosophy or view point of radical environmental movement that considers humans as equal to other organism within the global ecosystem.

The reverse philosophy/view point of deep ecology is 'shallow Ecology', It is anthropocentric i.e. human-centric.

Ecosophy: The term 'ecosophy' was introduced by Amies Naess. He defined 'ecosophy' as a philosophy of ecological harmony or equilibrium in the global natural ecosystem or environmental system.

Ecotone: A boundary and/or transition area (zone) between two or more communities or biomes. For example: Estuary (where fresh water and sea water confluent and exchange their water) etc.

Footprint: The ecological foot print is a method to measure human demand on natural capital. It is expressed as the minimum area of land required to completes sustain the life of a person is called his ecological footprint. It is measured in global hectare (gha). Huminity's ecological footprint is more than 1.5 that is we require 50% more than the Earth's are to sustain our consumption of natural resources.

Habitat: The place where an organism lives is called its habitat. For example, the habitat of a whale—Ocean, the habitat of a tiger—forest etc. Habitat also refer to the place occupied by an entire biological community. For example, a large number of species are found in a forest habitat.

Niche: The word Niche is derived from Latin word nidus meaning nest and the word nidus is further converted into French word nicher meaning make a nest. The term Niche was coined by American biologist Joseph Grinnel in 1917. In ecology, Niche means the place of an organism within its community or ecosystem. An ecossytem consists of a number of overlapping and ineracting niches. A niche is unique for species that means no two species have exact identical niches. Each specie makes or arranges its own distinct nest.

Overshoot: Overshoot means pass swiftly beyond or cross the limit. We are consuming resources faster than they can regenerate and creating waste faster than it can be obsorbed. This is called ecological overshoot. While this can be done for a short while, overshoot ultimately leads to the drastic depletion of resources on which our well-being depends.

Sere: The entire sequence of communities that successively change in a particular area is called 'sere'.

Succession: The successive replacement of communities in an area over a period of time is called ecological succession. Both abiotic and biotic components are involved in such changes. There are two types of succession—Primary and Secondary succession.

Primary Succession: Succession occuring on previously unoccupied sites is called primary succession. For example Rock out crop, Glacial moraine etc.

Secondary Succession: The reappearance and establishment of communities in the area where once ecological communities existed, but destroyed due to some reasons. For example Reappearance of forest community in the place of fire-destroyed forest community etc.

Note: The secondary succession starts with the growth of grasses & weeds. Next small plants begin to grow and there after the sequence is similar to that of primary succession.

Transition: The concept of Ecological Transition was first introduced by American anthropologist John W.Bennatt (1915-76) in 1976.