Branches of Ecology & Ecological Factors

Branches of Ecology & Ecological Factors

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

The Branches of Ecology

1. Based on the Levels of Organization

There are two branches of ecology on the basis of levels of organization—autecology and Synecology.

Autecology

• Auto (on itself) + Ecology = Autecology.

• Ecology is the study of the relationship of an individual species to its environment.

For example: organism ecology.

Synecology

• Syn (together) + Ecology = Synecology.

• Synecology is the relationship of a group of organisms and their environment.

Synecology is subdivided into 'population Ecology,' 'Community Ecology,' 'Ecosystem ecology,' etc.

2. Based on Taxonomic Affinities

• Taxonomy is concerned with the classification of things, especially organisms (plants & animals).

For example, plant ecology & animal ecology.

3. Based on Habitat

• Habitat is the place where organisms live. Based on habitat, ecology is divided into two categories—

Terrestrial Ecology

• For example, Forest ecology, Grassland ecology, Desert ecology, etc.

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.

• The relation between abiotic & biotic factors is called Holocoenosis.

Abiotic Factors

Non-living factors are called abiotic factors.

For example: Light, temperature, humidity (water), wind, topographic (physical features of an area, viz., river, mountain, etc.), edaphic (soil), etc.

1. Light

• Light is an important climatic factor.

• Most of the plants need light for the photosynthesis process to make 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.

• Utilizing light, many animals can move about freely and 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 rays may lead to skin cancer (including melanoma).

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

a. Long-day plants: e.g., Wheat, barley, oats, henbane, etc.

b. Short-day plants: e.g., Rice, Soyabean, cotton, sorghum/jowar, etc.

c. Day-neutral plants: e.g., Rose, almost flowers of winter season, sunflower, tomato, chilli, tobacco, etc.

In another way, plants are divided into two types based on sunlight -

• Photophilous/Heliophilous (Sunlight-loving) plants: e.g., Birch, cactus, sugarcane, maize, etc.

• 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 substance.

• Temperature is needed for the motion and reproduction of an organism.

• The total degree of heat received by the plants is called the Thermoperiod. 

• Thermoperiodic effects are distinct from photoperiodic effects (caused by duration of light).

• An average of 10°C to 45°C is essential for biological functioning.

• The Respirator function of plants increases with rising temperature.

• Based on temperature, plants are divided into four categories - 

3. Humidity

• Atmospheric moisture in the form of invisible vapor is called humidity.

• Humidity plays an important role in the lives of plants and animals.

• Processes 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, seed 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, exposure, etc. of topography affect plants and animals in many ways.

6. Edaphic (Soil)

• Man depends on plants, and plants grow 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 affect the life of plants and animals. Under natural conditions, organisms live together, influencing each other's lives and establishing relationships. The common examples of such a relationship are given below—

1. Symbiosis

A relationship between two different living beings close to one another and depending on each other, benefiting from each other in particular ways, is known as symbiosis.

Example: Algae and fungi live together and form Lichen (Pronounced as Liken), etc.

2. Parasitism

The relationship between two organisms in which one benefits at the expense of the other is called parasitism.

Example: Bacteria, Virus, Cuckoo (Hindi name Koyal, as we know that cuckoos do not build their own nest, but deposit their eggs in the nests of crows), etc.

3. Commensalism

An association between two organisms in which one benefits and the other derives neither benefits nor harm is called commensalism.

Example: Remora & Shark (Remora rides under the shark and feeds on 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 stirred 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.

Example: Grass (prey) & Grass hopper (predator), Small fish (prey) & Large fish (predator), etc.

5. Saprophytism

Sapro is equal to decompose. Saprophytism is a mode of nutrition in which organisms obtain food from deadorganismsm (non-living organic matter— detritus organisms that feed on dead organisms— detritivore/decomposer/saprotroph).

Example: Bacteria, Fungi, Mushrooms, etc.

Glossary (Ecology)

Deep Ecology

• The term 'deep ecology' was first coined by Norwegian activist and philosopher Arnies Naess in 1972.

• This term is related to environmentalism.

• It is considered a movement or a concept that pleads for radical measures to protect the natural environment irrespective of their effects on human welfare.

• Thus, deep ecology is an ecocentric philosophy or viewpoint of the radical environmental movement that considers humans equal to other organisms within the global ecosystem.

• The reverse philosophy/viewpoint 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.

Example: Estuary (where fresh water and sea water are confluent and exchange their water), etc.

Footprint

• The ecological footprint is a method to measure human demand on natural capital.

• It is expressed as the minimum area of land required to completely sustain the life of a person is called his ecological footprint.

• It is measured in global hectares (gha).

• Humanity's ecological footprint is more than 1.5 that is we require 50% more than the Earth's area to sustain our consumption of natural resources.

Habitat

• The place where an organism lives is called its habitat.

  • Example: The habitat of a whale is the ocean, the habitat of a tiger is—forest, etc.

• Habitat also refers to the place occupied by an entire biological community.

Niche

• The word Niche is derived from the Latin word nidus, meaning nest, and the word nidus is further converted into the French word nichmeaningnito ng make a nest.

• The term Niche was coined by American biologist Joseph Grinnell in 1917.

• In ecology, Niche means the place of an organism within its community or ecosystem.

• An ecosystem consists of a number of overlapping and interacting niches.

• A niche is unique for species, which means no two species have identical niches.

• Each species makes or arranges its own distinct nest.

Overshoot

• Overshoot means to pass swiftly beyond or cross the limit.

• We are consuming resources faster than they can regenerate and creating waste faster than it can be absorbed.

• 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 occurring on previously unoccupied sites is called primary succession.

Example: Rock outcrop, Glacial moraine, etc.

Secondary Succession

• The reappearance and establishment of communities in the area where once ecological communities existed, but were destroyed for some reason.

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 thereafter 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.

Final Thoughts 

Ecology is a comprehensive study that reveals the interconnectedness of all living and non-living components of the Earth. By understanding the levels of organization—from autecology focusing on a single species, to synecology examining communities—we gain insight into how species survive, adapt, and interact.

The division of ecology based on taxonomic affinities and habitats underscores the diverse relationships that shape ecosystems, whether in terrestrial or aquatic environments.

The role of ecological factors is vital, as both abiotic factors like light, temperature, and soil, and biotic factors such as symbiosis, parasitism, and predation, directly influence life forms. Concepts like niche, habitat, succession, and ecological footprint remind us of our responsibility toward environmental balance.

Ultimately, ecology teaches that humans are part of a delicate global system. Ignoring ecological limits through overshoot risks depleting the very resources that sustain life. Embracing philosophies like deep ecology and ecosophy promotes harmony with nature, ensuring sustainability for future generations. By respecting the intricate web of life, we protect not only biodiversity but also our survival.