Real-World Importance - Lab Report Example

REAL WORLD IMPORTANCE Ecological communities are an assemblage of population of two or more species of different nature, all occupying the same geographical area. In ecology therefore, has groups of organisms that live in a specific location at specific time will be called a community. Communities are influenced by different factors. These factors can be either biotic or abiotic factors (Hollar p33). .This laboratory report discusses an experiment that was done to determine factors that affect a rotting log in an ecological community. Biodiversity has been done on a high level by researchers and ecologist alike. This report looks at diversity of different species and draws conclusion about the findings. In community ecology, there is a study of how species interact within themselves in a given community. This study considers variables such as structure, abundance, distribution and demography. Further, some patterns of ecology like equitability, food web, productivity, and species richness and community assembly are considered in modern study of communities in ecology. Background History. In a community, species interact in different ways. There has been a cleavage on how community works in the field of ecology. There are different biotic and abiotic factors that affect the way species in a community interact. Competition, mutualism, parasitism, commensalism and predation are some of the biotic factors that affect the way a community exists. Depending on how the factors interplay, a community may change within a given time frame, thus looking different from the way it was before. Competition occurs when there are finite resources to be used by an increasing population of different species. Competition is a very important limiting factor in biomass, population size and richness of species. There exist different types of competition. Competition can happen between individuals in a direct manner, or between populations or species. Interference competition is that which happens when an individual of a species directly interferes with another individual in other species. For example, if a hound makes a kill and is chased from it by a lion, this is called interference competition. (Hollar p 66). When Deers fight during a rut, this is a manifestation of competition in form of interference. This takes form of aggression between individuals. Individuals interfere with others through survival, foraging, preventing others from reproduction and physical prevention of others to establish a habitat. Exploitative competition is another biotic factor that affects a community. This is an indirect form of competition. It happens through limiting resource between species. This resource acts as an intermediate factor between the competing species. When species use resources, they deplete the available amount to other species. (Hollar p 84) As well as competing for resources, species can compete for space. When a member of a given species consumes resources, they can be depleted to ensure members of other species do not get access. This is the most common form of competition in nature. An example can occur in terms of dry spells and the one resource that would be very important would be water. Pastures would dry up and the streams that are available may feel the overload in this particular dry spells. (Parsons p 134). Apparent competition is a biotic factor that affects species in a given community. Here, two species share the same predator. Population of two species can be reduced by predation without presence of exploitative competition. For instance, an apparent competition can happen between two species, A and B. A and B are, say, preys of species C. If species A increase in number, there will be a decrease in species B because this increase will mean C increases. An increase in predator C means species B will be hunted most. Predation is another biotic factor that affects population of species in a community. In this scenario, one species hunts another for food. It is called a positive-negative relationship such that one species benefits while the other loses. In this competition, some species kill their prey before feeding on it. Others just feed on a live prey. (Parsons p 33). Lions for example, kill their prey before feeding on it. This is different from vampire bat that feeds on a cow while alive. This again affects the size of the species that are found in a community. Mutualism is an interaction between species where the relationship is more symbiotic. In this interaction, both species benefit from the relationship. An example is the Rhizobium bacterium that is found in leguminous species. Commensalism is another biotic factor that affects composition of species in a community. (Stadler & Dixon p 24). Here, one organism benefits while the other is not benefited and not harmed. The one that benefits is known as commensal while the one that is unharmed is called the host. This is a complex subject that can be done in greater length as how communities can relate to each mutually. This report will focus on the Biotic and abiotic factors. Abiotic factors can also affect the composition of species in an ecological community. This includes the chemical composition of the ecology, the air quality, availability of water and other necessary chemicals needed for life. Some species do well in absence of oxygen while others cannot function in its absence. Other species thrive in areas that have high acidity while others need an alkaline environment. (Parsons p 135).When these factors alter in a community, the composition and population of species is altered. Aims and Objectives The main aim and objectives of this experiment were to identify the types of species that exist in different rotting logs and then estimate their prevalence. This was to help to predict the factors affecting the ecological composition of species in a rotting log. Experimental Procedure Two types of rotting logs were identified and their contents put in different funnels. Students used the dichotomous key to identify different types of species in the funnels. Species in funnel A were identified and those in funnel B were identified too. The number of each species was counted and the prevalence calculated. The results were tabulated ad inferences drawn from them. Results After the study, the type and number of species was tabulated as shown in the tables below. Sample A Species Frequency Ants 600 Crustaceans 11 Ear wig 1 Centipede 1 Beetles 2 Cockroaches 2 Sample B Species Frequency Ear wig 4 Crustaceans 1 Ants 100 A rotting log was the best suited for the study because it is an organic material. Most living organisms feed on organic material. Those that do not feed on the logs can feed on the organisms that live in the log. The log is also best suited because it has a variety of species living in it and can be easily accessed within a school environment. Simpson Index was used to determine prevalence for each species The index is given by p= 1-√{∑n(n-1)}÷ √{N(N-1)} For sample A N=617 The term √{N(N-1)} therefore becomes 616.5 √{∑n(n-1)} for ants is 599.5 Dominance value is 0.0275 Crustaceans are 11 √{∑n(n-1)} for Crustaceans is 10.488 Dominance is 0.983 Ear wig is 1. √{∑n(n-1)} for Crustaceans is 0 The dominance cannot be calculated because it is infinity Same is for centipede Cockroaches are 2 √{∑n(n-1)}is 1.4142153 Dominance 0.9977 Same dominance for beetles In sample B N= 105 The term √{N(N-1)} therefore becomes 104.49 Air wig is 4 √{∑n(n-1)}is 3.46 Dominance is 0.03315 Ants are 100 √{∑n(n-1)}is 99.49 Dominance is 0.0477 Crustaceans give a complex number and are not statistically significant. A low dominance value shows that there is a high diversity of the species. From all the samples, cockroach has the highest diversity while Crustaceans have the lowest diversity. This means that the cockroaches are preys in the community. Work cited Berkes F. Sacred Ecology. Publishing Company. Rosen Publishing 29 East 21st Street New York. 2008. Hollar S. Ecology .Publishing Company .Britannica Educational Publishing. 2011 Parsons W.Michael. Biotic and Abiotic Factors Associated with Fusarium Ear Rot of Maize Caused byFusarium Verticillioides.. Publishing Company Pro Quest. 2008 Stadler B & Dixon F.G Anthony Mutualism .Publishing Company Cambridge University Press 2008 Read More