The ecosystem and its people

Clasified in Notes of Biology of Secondary School.

Written at July 16, 2009 on esEspañol, translated to enEnglish and with a size of 8,443 bytes.

Concept of ecosystem -
- System = set of interrelated elements
- Eco = system consisting of a biotope and a biocoenosis which produce many complex interactions between its components. (Biotope: a substrate comprising phic and chemical characteristics; biocenosis: all agencies) TYPES: 1. Ecost.terrestres: conditioned by climate, ecological factors are dependent on weather conditions, there is great diversity of ecosystems, 2. ecost.acuatico: according to water salinity are distinguished from salt water (marine) and freshwater see these in can be classified as a dynamic of its waters: calm waters (lakes) or flowing water (rivers)
biotope-biocinesis-interactions: the characteristics of the biotope influence living beings, there are big differences between people of different environment. (eg, arid regions plants and aquatic plants pinxo have very large leaves). In terrestrial factors are more influenced by climatic and edaphic (soil). the aquatic environment depends on physical and chemical properties of water.The caract.del beings can change the biotope, ie that the primitive atmosphere had oxygen by bacteria that carry out photosynthesis.
-interaction between abiotic factors: Any factor influencing the biotope demas.ej: wind favors the dynamics of water, marine and desecacion.Las at elevated temperatures may evaporate large quantities of water and cause increased salinity .
-interaction on abiotic components: ecosystem relationships occur between organisms of the same species but may also occur between different species.
-The population -
- Habitat = place where you normally live
- = Ecological niche role of a species in ecosistema.ej: bobcats prey on rabbits, their ecological niche includes conditions to survive.
-concept of a population: A group of organisms of the same species, same time and space so they have a high probability of mating and population share genes.la unlike individuals is immortal playback ensures its perpetuation.
-relations in the population: the most representative is that there are relationships between individuals, the relations that arise are competition and intraspecific associations:Intraspecific 1.competencia: main interaction within poblaciones.ej: an oak individuals compete for light and soil nutrients. 2) intraspecific associations: 2.1: family groupings: for the reproduction and protection of offspring, as in the sexual reproduction are mixed genes influences the choice of the genetic heritage, the pairing can be sist.de: monogamous (1max and 1hembra) or polygamous (1d a sex and several of the contrary), the latter can in turn be polygynous (1 maxo dominant with all the females) or polyandrous (1 female with 2 or more maxos) .2.2: gregarious clusters: obtaining temporary benefits: finding food, defending, or care for their crias.2.3: colonies and societies: populations organization compleja.individuos physical unit and from the same parent, in societies individuals are organized into castes.

-changes in the population -
-growth of a population: effects of a number is the number of individuals composing it, is often represented with the letter N. The variation of cash over a period of time (â?? N / t) is obtained by adding the n º of births (B) and immigrants (I), subtracting the dead who have no (M) and who have migrated (E): â?? N / t = B + EMI. the rate of population growth (r) calculated by dividing the population increase in a time peroiodo (â?? N / t) by cash (N). if environmental conditions are favorable, the effective population grows over time, the growth rate is positive (r> 0), the greater the higher the effective number of individuals reproductores.la population can not grow indefinitely because there is an environmental resistance: lack of food, competition for space .. then the growth rate stops (r = 0) or decays (r <0).carrying capacity (K) is the number of individuals in a given population that can sustain the ecosystem, the limit imposed by environmental resistance.
- What strategies are stocks?: The crecimientovaria much from species to otras.algunas tend to balance, like the oaks of the Mediterranean mature just changing the effective time.The other populations fluctuate sharply depending on factors as seasonal changes and nutrient availability include insects and gramineas.hay 2 main types: 1.poblaciones stable or in equilibrium are in equilibrium with the environment and your cash (N) approaches the carrying capacity ( K), therefore called "strategies of the K", correspond to bodies grandescon growth rate (r) small.2.poblaciones opportunistic cash are characterized by (N) of the population has important populations' fluctuaciones.generalmente are small animals that have a growth rate (r) high, so called "strategy of r".
-interacting populations in the ecosystem -
entreindividuos is unavoidable interaction of different species, these interspecific relationships have different implications and can be beneficial, harmful or indifferent.
interspecific-competition: when two or more species use the same resources or habitats, where resources are scarce just one species displacing another
"consumer-resource interactions: the most representative is the predation and parasites, in both the predator and the resource is benefited perjudicado.1.depredador: are organisms that kill other creatures for food they are called presas.2.parasitos: beings exploit others without killing them are called huespedes.viven exploited on the surface of host ticks are known as ectoparasites and inmates as had endoparasites.
-commensalism and tenants are interactions that are beneficial to one species but indifferent to otra.1.comensalismo a kind diner called benefits of feeding leftovers leaving a depredador.2.inquilinismo a kind obtained benefit when housed in another, the latter species it is housed in indiferente.un crab cavities of the sponge
-mutualism and symbiosis: 2especies cooperate to achieve a beneficio.1.mutualismo: relationship between the 2 species is not mandatory, ie the plants develop fruits that animals ingest the expelled undigested and help your dipersion.2.simbiosis: none of the 2 species can live separately, mycorrhizae (fungi associated with roots), a fungus associated with a feeding ground substance that give l roots and instead assists in the absorption of nutrients.
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Tags:biology,population changes,populations,populations interact in the ecosystem,ecosystem approach,ecological niche relationships in the population,intraspecific competition,intraspecific associations,stable populations
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