1+The+Physical+Environment)

= What is Environmental Science? =

====Environmental science is the study of interactions among physical, chemical, and biological components of the [|environment]. Environmental Science provides an integrated, quantitative, and [|interdisciplinary] approach to the study of environmental systems====

= Definition of Environmental Terms =

What is ecology? Ecology is the branch of [|science] that studies the distribution and abundance of [|living organisms], and the [|interactions] between organisms and their [|environment]. The environment of an organism includes both its physical [|habitat], which can be described as the sum of local abiotic factors like [|climate] and [|geology], as well as the other organisms which share its habitat

What is a Species? In [|biology], a species is one of the basic units of [|biological classification] and a [|taxonomic rank]. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are often used, such as similarity of DNA, morphology or ecological niche. Presence of specific locally adapted traits may further subdivide species into [|subspecies].

Population A population is all the organisms that both belong to the same species and live in the same geographical area What is a Community? In [|ecology], a community is an assemblage of two or more populations of different species occupying the same geographical area

Ecosystems Ecosystem is a biological environment consisting of all the organisms living in a particular area, as well as all the nonliving, physical components of the environment with which the organisms interact, such as air, soil, water, and sunlight.[|[1]] It is all the organisms in a given area, along with the nonliving (abiotic) factors with which they interact; a biological community and its physical environment

Biosphere The biosphere is the global sum of all [|ecosystems]. It can also be called the zone of life on Earth. From the broadest [|biophysiological] point of view, the biosphere is the global [|ecological] system integrating all living beings and their relationships, including their interaction with the elements of the lithosphere, [|hydrosphere] and [|atmosphere] In [|physical geography] describes the combined mass of water found on, under, and over the surface of a [|planet]

Lithosphere In the [|Earth], the lithosphere includes the [|crust] and the uppermost [|mantle], which constitute the hard and rigid outer layer of the Earth

Habitat A habitat (which is [|Latin] for "it inhabits") is an [|ecological] or [|environmental] area that is inhabited by a particular [|species] of [|animal], [|plant] or other type of [|organism]. It is the natural environment in which an organism lives, or the physical environment that surrounds

Niche In [|ecology], a niche is a term describing the relational position of a [|species] or [|population] in its [|ecosystem] to each other; e.g. a dolphin could potentially be in another ecological niche from one that travels in a different [|pod] if the members of these pods utilize significantly different food resources and foraging methods. A shorthand definition of niche is how an organism makes a living. The ecological niche describes how an organism or population responds to the distribution of resources and competitors (e.g., by growing when resources are abundant, and when predators, parasites and pathogens are scarce) and how it in turn alters those same factors (e.g., limiting access to resources by other organisms, acting as a food source for predators and a consumer of prey)

Biomes Biomes are [|climatically] and [|geographically] defined as similar climatic conditions on the [|Earth], such as communities of [|plants], [|animals], and [|soil organisms], and are often referred to as [|ecosystems]. Biomes are defined by factors such as plant structures (such as [|trees], [|shrubs], and [|grasses]), leaf types (such as broadleaf and needle leaf), plant spacing ([|forest], [|woodland], [|savanna]), and climate

Ecotone An ecotone is a transition area between two adjacent but different [|plant communities], such as forest and grassland. It may be narrow or wide, and it may be local (the zone between a field and forest) or regional (the transition between forest and grassland). An ecotone may appear on the ground as a gradual blending of the two communities across a broad area, or it may manifest itself as a sharp boundary line.

Abiotic Factors Abiotic components are the nonliving components of the biosphere. Chemical and geological factors, such as rocks and minerals, and physical factors, such as temperature and weather, are referred to as abiotic components.

Biotic Factors Biotic components are the living things that shape an [|ecosystem]. They are, any living component that affects another [|organism]. Such things include [|animals] which consume the organism in question, and the living [|food] that the organism consumes.

Limiting Factors Of all abiotic and biotic factors that affect a population only one affects the population and limits its growth. This is known as the limiting factor. The factor may be too less in quantity or too much. For example, the limiting factor for a plant population near a chemical factory may be the soil pH.

Range of Tolerance Every population thrives in an optimal range of abiotic factors. Beyond this range, one finds less and less numbers of these organisms. In an ecosystem, it is harder to represent what this optimal range is, since a host of factors affect the survivability of this population. Often, the range is shown for each factor, and this is known as the range of tolerance.

[that Influence Ecosystem#Factors that Influence Ecosystem| Factors that Influence Ecosystem] A. Range of Tolerance 1. Abiotic Factors temperature water climate soil 2. [factors#Biological factors|Biotic Factors] intra and interspecific competition, predation/parasitism amensalism, mutualism  Limiting Factor: anything that tends to make it more difficult for a species to live and grow, or reproduce in its environment

Abiotic and Biotic: physical and biological factors can work in concert Limiting Factors ABIOTIC temperature water climate/weather soils (mineral component) BIOTIC competition: interspecific and intraspecific predation/parasitism amensalism mutualism

A limiting factor or limiting resource is a factor that controls a process, such as organism growth or species [|population], size, or distribution. The availability of food, predation pressure, or availability of shelter are examples of factors that could be limiting for an organism. An example of a limiting factor is sunlight in the rainforest, where growth is limited to all plants in the understory unless more light becomes available

Fundamental Niche The full range of environmental conditions and resources an organism can possibly occupy and use, especially when limiting factors are absent in its habitat. The fundamental niche describes the potential area and resources an organism is capable of using. But the presence of limiting factors such as direct competition with other organisms, the organism tends to occupy a [|niche] narrower than this.

Realized Niche The full range of environmental conditions (biological and physical) under which an organism can exist describes its fundamental niche. As a result of pressure from, and interactions with, other organisms (e.g. superior competitors), species are usually forced to occupy a niche that is narrower than this, and to which they are mostly highly [|adapted]. This is termed the [|realized niche].

Liebig’s law of minimum It states that [|growth] is controlled not by the total of resources available, but by the scarcest resource ([|limiting factor]). This concept was originally applied to [|plant] or [|crop] growth, where it was found that increasing the amount of plentiful [|nutrients] did not increase plant growth. Only by increasing the amount of the limiting nutrient (the one scarcest in relation to "need") was the growth of a plant or crop improved. This principle can be summed up in the aphorism, "The availability of the most abundant nutrient in the soil is as available as the availability of the least abundant nutrient in the soil

Shelford's law of tolerance Shelford's law of tolerance A law stating that the abundance or distribution of an organism can be controlled by certain factors (e.g. the climatic, topographic, and biological requirements of plants and animals) where levels of these exceed the maximum or minimum [|limits of tolerance] of that organism.