РефератыИностранный языкEcEcology Essay Research Paper In the original

Ecology Essay Research Paper In the original

Ecology Essay, Research Paper


In the original Greek "oikos" means,


"house". So ecology is "the study of the house" the


place where you live, or the environment which


technically includes all those factors, both nonliving


and living, that affect an organism. Ecology then is


the study of the interactions of organisms in their


environment includes both the living (biotic) and


physical (abiotic) factors of the environment. It’s


also the science, which formulates and tests


hypotheses about environment. Ecology is the


relationships, identification and analysis of


problems common to all areas. Ecology studies


the population and the community, evaluates cause


and effects of the responses of populations and


communities to environmental change.


POPULATIONS The population is defined as an


assemblage of individuals of a single species that


live in the same place at the same time. Also,


biologists add an additional condition: the


individuals in a population must interact with each


other to the point of being able to interbreed.


Population is important to understanding many


important ecological and evolutionary phenomena.


Ecologists can use information from population


ecology to predict the success of a given species


or assemblage of species. One attribute of


populations that is observed in nature is their


dispersion, or the way in which individuals are


distributed in a given area. Typically, biologists


refer to three types of dispersion: – Clustered


(aggregated), Regular (evenly spaced), Random


(irregularly spaced) Populations showing a


clustered pattern are common in nature and are


found among many different types of organisms.


Clustered dispersion patterns are often due to


environment heterogeneity. Regular dispersion


patterns are relatively rare in nature and occur


when a resource is scarce. A good example of


regular spacing occurs in animals that exhibit


territoriality, a phenomenon in which animals


establish an area for themselves and fight off all


other individual seeking to invade that area.


Regular dispersion patterns can also be observed


in plants. Random patterns can be found in a


variety of organisms (trout in lake or maple trees in


a forest). Regardless of which organisms, the


number of births almost always has the potential to


be greater than the number of deaths. In other


words populations of all species have the capacity


to grow. That property is crucial importance to the


success of all species. However, all species will


not increase under all circumstance, but instead


they can, given appropriate conditions. There are


two models of population growth: the exponential


model and the logistic model. One of the most


basic models of population biology is the


exponential growth equation, which is: )N/)t =


rmaxN This equation states that, in a growing


population, the rate of change in population size is


determined by the maximal intrinsic rate of


increase (rmax) multiplied by the number of


individuals in that population (N). If a population


growth very quickly we called that an exponential


increase and its growth curve has a J-chaped


called J-chaped curve. A population cannot


continue to grow indefinitely because this equation


contains additional term called the carrying


capacity (K) which is not fixed, but carrying


capacity is constantly affected by many factors,


both biotic (living) and abiotic (non-living). The


logistic population growth predicts that


populations will grow rapidly at first. However, as


the number of individuals in the population (N)


approaches the carrying capacity (K), the


population growth rate eventually slows to zero,


and the population stabilize at K. The result is a


sigmoidal or S-shaped curve which is often


divided into three phases: the first is called the lag


phase (the period of slow growth that occurs


when population numbers are low). The second is


the log phase, which occurs when growth rate


accelerates and becomes relatively rapid. The


third is the saturation phase, during which


population growth decelerates as N approaches


K. All species have a well-defined life history that


involves a

beginning of life, a juvenile and


reproductive phase and death. There are two


important parameters of a population: survivorship


(how long one live) and fecundity (how many


offspring one leaves). Survivorship is the number


still living at the beginning of each age interval. The


number of deaths determines the death rate during


a given period of time divided by the number still


living at the beginning of the time period.


COMMUNITIES A community is an assemblage


of populations that interact with one another and


the effects that they have on each other often


greatly influence their ability to survive and


reproduce. Because they are assemblages of


different species, communities have properties that


make them unique from individual organisms and


populations. Some communities simply blend


gradually into others and for this reason are called


open comments, forest communities are like that,


as different vegetable types blend together.


Conversely, closed communities have more


definite borders; few organisms pass from one


community to another. In these types of


communities, fewer organisms move in and out, so


they are more isolated in terms of energy and


nutrients. Despite the fact that communities can


sometimes be difficult to define, ecologists have


been able to identify a lot of attributes by which


communities can be described and analyzed.


These include – Species composition which is the


most fundamental attribute of a community. It’s


simply a list of species of which the community is


comprised. Communities vary tremendously in


their composition. – Frequency is a measure of


how often we find a species in a community. -


Distribution, or how species are arranged in a


community – Diversity is a measure of the variation


in a community, has two components. The first is


richness, which is the number of species in the


community. The second component is called


evenness, which is the degree to which the


different species are represented in a community. -


Stability is the concept of the ability of a


community to handle disturbance or to resist being


disturbed. It also can refer to resilience of a


community (that is, its ability to recover quickly


from a disturbance. Certain communities can be


called "fragile’ which is used to refer to


communities that have low stability when faced


with human disturbance. Competition involves a


struggle for limited resource. Exploitative


competition is the use of the same resources in


which one competitor has greater access than the


other to the resources is. Interference competition


is actual fighting over resources. Intraspecific


competition is between members of the same


species and interspecific competition is between


different species. The competition exclusion


principle is that no two species can occupy the


same niche at the same time. Because the niche of


an organism (the way in which it interacts with its


environment) is often dependent on how it fares in


competition with its neighbors, both kind of


competition is important in the structure of the


community. BIOMES Biome is defined as large,


distinct and recognizable associations of life. More


precisely, a biome is a particular array of plants


and animals within a geographic area brought


about by distinctive climatic conditions. Their plant


associations than those of animals, not only usually


identify biomes more because the first is far more


obvious, but also because it determines the


second. Ecologists recognize about a dozen major


biomes, each one forms under a certain prevailing


climate and has a characteristic type of plant and


animal life. Some examples of biomes include


grassland, deserts, and deciduous forests. Biomes


may be subdivided into communities.


CONCLUSION For this paper, I read a lot of


books and did a lot of research on Internet. I


learned a lot about ecology, population,


communities and biomes. It’s very hard to write


about this subject in only five pages. My first draft


was constituted of eight pages so I cut a lot of


details. However, I pass a lot of time to do this


paper and energy and I really enjoyed it. I hope it


will be the same for you

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