Basic Concepts of Environment

Ecology

The science that studies the inter-relationship among organisms and their environment and among various ecosystems.

Biogeography

The study of the distribution of plants and animals and related ecosystems; the geographical relationships with related environment over time. Biogeography is essentially a spatial ecology.

Biosphere

That area where the atmosphere, lithosphere, and hydrosphere function together to form the context within which life exists. In other words, it is an intricate web that connects all organisms with their physical environment.

Ecosphere

Another name of Biosphere.

Ecosystem

self-regulating association of living world such as plants, animals, microorganisms, with their non-living world such as physical and chemical environment. This term was introduced by A.G. Tansley in 1935. In 1969, Odum deed ecology as �the study of the structure and function of nature.�

Ecotone

A boundary transition zone between adjoining ecosystems that may vary in width and represent areas of tension as similar species of plants and animals compete for the resources.

Photosynthesis

The joining of carbon dioxide and oxygen in plants, under the influence of certain wavelengths of visible light; re leases oxygen and produces energy-rich organic material (sugar and starch).

Nearly all the energy of marine and terrestrial organisms rewired for proper functioning (and to evolve) comes directly or indirectly from the sun. The sun produces enormous quantities of energy�some in the form of visible light, a tiny portion of which strikes the Earth. Only about one part in 2000 of the light that reaches the Earth�s surface is captured by organisms, but that �small� input of energy powers all the growth of living things. Light energy from the sun is trapped by chlorophyll, in organisms called producers (certain bacteria, algae, and green plants) light energy from the sun is trapped by chlorophlly and changed into chemical energy.

The chemical energy is used to build simple carbohydrates and other organic molecular-food which are then used by the plant itself or are eaten by animals (or other organisms) called consumers. Because light energy is used to synthesis molecules�rich stored energy, the process is called photosynthesis (photo=light, syn + thesis=to place together) is used for growth, repair, movement, reproduction, and the other functions of organisms. The metabolism of food eventually produces waste heat, which flows away from Earth into the coldness of space.

Components of an Ecosystem

An ecosystem consists of:

(1) Biotic (living) and

(2) Abiotic (non-living) components.

Biotic (Living) Component

These include living organisms such as plants, animals and, micro-organisms. The biotic components of an ecosystem consist of:

A. Producers (plants) or autotrophs

Usually plants that are capable of photosynthesis are known as the producers or autotrophs. Producers also include micro-organism such as bacteria near ocean vents that are capable of chemosynthesis.

B. �Consumers or heterotrophs

These include animals which can be primary consumers (herbivorous) or secondary or tertiary consumers (carnivorous and omnivorous).

C.� Decomposers or Detritus

Bacteria, fungi and insects which degrade organic matter of all types and restore nutrients to the environment. The producers will then consume the nutrients, thus completing the cycle.

Abiotic (Non-living) Component

Abiotic components include climate such as temperature, light, humidity, precipitation, gases, wind, water, sea-waves, soil, pH, salinity, substratum, minerals, topography, and habitat. Critical in each ecosystem the flow of energy and the cycling of nutrients and water. Non-living (abiotic) components set the stage for ecosystem operations.

Light, Temperature, Water and Climate

The pattern of solar energy receipt is crucial in both terrestrial and aquatic ecosystems. Solar energy enters an ecosystem by way of photosynthesis, with heat dissipated from the system at many points. The duration of sun exposure is the photoperiod. Along the equator, days are almost 12 hours in length; however, with increasing distance from the equator, seasonal effects become pronounced on the duration of daylight. Plants have adapted their flowering and seed germination to seasonal changes in insolation.

Air and soil

Temperatures determine the rates at which chemical reactions proceed. Significant temperature factors are seasonal variation, duration and pattern of minimum and maximum temperatures, and average temperature.

Operation of the hydrologic cycle and water availability depend on precipitation/evaporation rates and their seasonal distribution. Water quality is essential with regard to its mineral content, salinity, and levels of pollution and toxicity. Also, daily weather patterns over time create regional climates, which in turn affect the pattern of vegetation and ultimately influence soil development. All of these factors work together to establish the parameters (limits) for ecosystems that may develop in a given location.

Alexander von Humboldt (1769-1859), an explorer, geographer, and scientist, deduced that plants and animals recur in related grouping wherever similar conditions occur in the abiotic environment. After several years of study in the Andes Mountains of Ecuador and Peru, he described a distinct relationship between altitude and plant communities, and developed the Life Zone Concept. As he climbed the mountain, he noticed that the experience was similar to that of travelling away from the equator towards higher latitudes.

This zonation of plants with altitude is noticeable on any trip from lower valleys to higher elevations. Each life zone possesses its own insolation, temperature, and precipitation relationships and therefore its own biotic communities.

Beyond these general conditions, each ecosystem further produces its own microclimate, specific to individual sites. For example, in forests the insolation reaching the ground is reduced. A pine forest cuts light by 20-40 per cent, whereas a birch-beech forest reduces it by as much as 50-75 per cent. Forests are also five per cent more humid than non-forested landscapes, have warmer winters and cooler summers, and experience reduced winds. Such highly localised micro-ecosystems are evident along the mountain trail, where changes in exposure can be seen easily.

In brief, an altitudinal zonation of plants and animals form distinctive communities. Each life zone possesses its own temperature, humidity and precipitation relationship.

Photoperiod

The duration of sun exposure is the photoperiod.

Chemosynthesis

The synthesis of organic compounds from inorganic compounds using energy stored in inorganic substances such as sulphur, ammonia, and hydrogen. Energy is released when these substances are oxidized by certain organisms. Some unusual forms of marine life depend on chemosynthesis. Overall, chemosynthetic production of food is very small in comparison to photosynthetic production. Organisms at the bottom of oceans and in dark caves develop through the process of chemosynthesis.

Community

A convenient biotic subdivision within an ecosystem is known as community. It is formed by interactions among populations of living animals and plants. An ecosystem is the interaction of many communities with the abiotic physical components of environment. For example, in a forest ecosystem, a specific community may exist on the forest floor, whereas another community functions in the canopy of leaves high above.

Written by princy

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