ecological factors: the relationship between organisms and their environment limiting factors and ecological niche.
Var =
_gaq _gaq means any chemical component, physical, biological, which can affect the lifestyle of an organism, its ability to exploit the resources. The set of ecological factors can be divided into two major groups: Monday, February 21, 2011
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biotic and abiotic factors The former are represented by interspecific interactions (competition) and interspecific (
predation, mutualistic symbiosis, parasitism etc. ...). The second are factors such as climate, light, chemical and physical properties of soil, etc. ...
ecological factors can be divided in resources and
conditions. A resource is something that can be exploited by an agency to perform its core functions, resource that can be consumed (but not limited nutrients) and that if it becomes limiting may slow growth and reproduction of an organism. Light is an example of a resource, the plants through the photosynthesis process transforms light energy into chemical energy of bond which is then used for the synthesis of organic compounds, nutrients, which can be absorbed and assimilated by organisms directly or indirectly . Resource so as ecological factor to which organisms of the same species or different species can compete. Condition is a factor that can not be consumed (temperature, humidity, etc ...) but which can affect the behavior of an organism and its ability to exploit the resources. A resource can also be provided, for example, always take the light, we mentioned a few lines above that may have importance from the photosynthetic process carried out by plants, the alternation of light and dark period of the seasonal variations of light can affect the bloom or reproduction of organisms. Water is a key resource as exploited by living to balance the water balance, the ' humidity (in water is a compoent fundamental) may affect the transpiration of the bodies and then their water balance.
Every organization has to every ecological factor tolerance limits beyond which the ecological factor becomes limiting, preventing the reproduction of organisms, life, etc. .. regardless of the fact that other ecological factors in the environment in which 'organism lives are not limiting.
"Every body in the face of environmental factors has a tolerance range between a minimum and a maximum that determines what is its ecological optimum."
(
Law tolerance Shelford ).
1) Each species, each factor has an optimum environment in which growth can flourish. 2) When one or more factors are limiting the species have a tolerance within which they survive waiting for better conditions.
3) Beyond this limit, the species may not result in a certain environment. Hence the existence of one or more species is determined by a combination of chemical factors, physical, falling within the range of tolerance and that they may determine its survival in an ecosystem.
Liebig;
it was in principle applied to the nutritional needs of plants: " Plant growth is affected by the minimum amount of nutrient."
each nutrient absorbed by a plant is used in proportion to that limiting. Semplice? In realtà è più complesso di quello che sembra, sebbene possa essere "semplice" riuscire ad individuare in condizioni sperimentali il limite di tolleranza di un organismo nei confronti di determinati fattori, in natura non è così semplice individuarlo. Una popolazione può essere influenzata nel tempo da vari fattori limitanti (temperatura, pH, salinità ecc...).
I corollari di queste leggi hanno grande valenza sia pratica che teorica perchè ci permettono di spiegare le risposte degli organismi ai fattori limitanti: 1)Popolazioni diverse, hanno diversi limiti di tolleranza nei confronti di fattori ecologici diversi 2)Le popolazioni costituite da individui che have greater tolerance are adaptable to significant changes of the ecosystem.
3) The limits of each factor may be influenced by changes in other ecological factors (many plants change their sensitivity to solar radiation depending on the humidity of the ecosystem which in turn can have strong influences on transpiration and water balance).
4) There are organisms that can tolerate situations worse than those tolerated (some agencies go into hibernation for example) with strategies of avoidance, such as reproduction occurs only under optimal conditions.
5) The health of the individual has a fundamental role in changing the limits of tolerance.
steno
(wide) or Eurit
and stenotic to indicate that agencies have areas of tolerance for large or small temperature variations.
The magnitude of the tolerance against different factors is called ecological value.
Abbiamo accennato al fatto che per ciascuno dei fattori ecologici dai quali dipende la sopravvivenza di un organismo o di una specie si possono definire un minimo e un massimo entro i quali la specie è vitale a valori di optimum. Ad as a plant grows in areas that have a temperature between 5 and 10 ° C with an optimum of 8 ° C. Similarly can be defined all the factors that regulate the life processes of an organization, light, heat, soil acidity and so on. They can be combined in various ways each of them interpreted as a dimension. The different factors that make possible the life of an organism can be identified as a "multidimensional space" in which those processes occur pursued by the bodies which can be determined
identified from the set of ecological factors upon which the survival bodies. But the concept of space does not lend itself very well to the description of factors and interactions between organisms. If we did so we will just describe in too brief an ecosystem as something undifferentiated as well as the organisms that live within it, but we must keep in mind that every body which is part of a living system is different, and lives in different ecological areas, other areas of tolerance and factors determining the behavior, it follows that the process is much more complicated than expected.
Ecological niche And here comes in the concept of ecological niche in which non si fa altro che mette in evidenza l'importante ruolo funzionale di un organismo (concetto che vale non solo per singoli individui ma anche per popolazioni e specie) in un dato ecosistema. Nel concetto di nicchia ecologica vengono presi in considerazione le interrelazioni tra organismo e l'ambiente nel quale esso vive:
1) Intervallo di tolleranza verso i fattori chimici e fisici. 2)Le risorse che utilizza, come gli organismi di cui si alimenta.
3)Interazioni con altre componenti dell'ecosistema ad esempio organismi con cui compete per le risorse. 4)Il ruolo fondamentale che gli organismi giocano nel ciclo della materia.
A niche can be represented graphically than one dimension: for example, temperature, two dimensions, temperature and humidity and so on.
or three, temperature, humidity, and size of prey.
... axes are indicated areas of tolerance of the species to the three variables. Obviously here we have represented more than three factors, but if we imagine a number of factors (the set of all the requirements of the species is created a pattern of n dimensions). It follows that it is extremely difficult to represent and measure all the parameters that represent an ecological niche. In the latter graph, the balls are an external 
fundamental niche: that all ranges of resources that can be used by organisms in the absence of disturbing factors or competitors for these resources. The inner sphere represents a niche
made: that is the portion of the niche occupied by a species in the presence of competitors and biotic and abiotic constraints. But we will speak more in future posts. 
fundamental niche: that all ranges of resources that can be used by organisms in the absence of disturbing factors or competitors for these resources. The inner sphere represents a niche 
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