Logistic function

Introduction: The reason I chose this topic is because in my country Ethiopia the rapid growth of population alarmed me, just around the 1965 our population was very low however in the past few years it has tripled form 20 million to over 100 million. This was when my interest in my countries population developed. Population is one of the conversational topics when talking about a countries profile, in view of the fact that it plays a huge role, in a countries work force, consumption and economy

There are a number of factors that can contribute to the growth of a population and these trends can be seen in a number of species. It is generally believed, from an ecological perspective, that populations will display either an exponential of logistic growth rate. If optimal environments are consistently maintained with no biotic or abiotic limiting factors (excess food, excess space availability, optimum climactic environment, no predation, etc) then a population will grow in an exponential

The answers are found in Ch. 1–4 of the text. 1. Provide a brief summary of the history of the environmental movement? 2. Explain the main point concerning exponential growth and whether it is good or bad. Compare exponential growth to a logistic growth curve and explain how these might apply to human population growth. What promotes exponential growth? What constrains population growth? 3. Compare predictions for human population growth in developed countries versus developing countries

Competitive model (Appendix A), or where one species relies on another species to stay alive, called a Predator/Prey Model (Appendix B). Initially, the Lotka-Volterra predator-prey model was stated by Alfred K. Lotka. This was a similar equation to the logistic equation which was proposed by Pierre-François Verhulst in 1838. By 1926, Vito Volterra, who was a physicist and a mathematician, also had published the same set of equations identical to that of Volterra. Later on the model was

Discussion Commonly speaking, the theoretical and practical outcome of corresponding experiments done before should be similar with the results of this time. “The exponential model approximates population growth in its early stage. Table 3.4.1 shows the numbers generated by an organism that doubles at each cycle. Table 3.4.1: Number of Generations: 0 1 2 … 10 … 25 … 40 … 72 Number of Organisms: 1 2 4 … 1024 3.4 x 10^7 1.1 x 10^12

Competition in ecosystems has become central to the study of ecology, and has been implicated as a major factor behind the patterns of species abundance and distribution. Though often studied together, abundance and distribution are two distinct designations, abundance being the density of a species in a given area, and the spatial arrangement of that species in an area is referred to as the distribution (Brown, 1984). In ecological terms competition refers to a fight between two organisms, of the

However, exponential growth does not last long in the nature. Exponential growth is bad since continuously high reproduction rate for a species places extreme pressure on ecosystems. Logistic growth curve explains how exponential growth is stopped by limiting factors like natural resources. A population might grow sharply at the beginning but as the limiting factors (like water, space, food, predators, and disease) come into play, the

Escherichia Coli, or E. coli, resides in the large intestine where it assists digestion and make up essential molecules like Vitamin K. For the most part, E. Coli poses no threat although there are few disease causing strains that can cause mild to severe food poisoning by finding its way into food supply (Timmons, Trzepacz, Duboinis-Gray). Enteropathogenic Escherichia coli, or EPEC, is a strain of diseasing causing E. Coli that is the leading cause of death in children with diarrhea in many parts

Chapter 40 Exam – Student Copy 40.1 Multiple-Choice Questions 1) Trees are rare in the savanna biome because of A) insufficient annual precipitation. B) acidic soils. C) extreme winter temperatures. D) large variations in seasonal rainfall. E) permafrost. 2) Which of the following statements best describes the effect of climate on biome distribution? A) Average annual temperature and precipitation are sufficient to predict which biome will be found in an area. B) Seasonal fluctuation of temperature

53.1 Dynamic biological processes influence pop. density, dispersion, & demographics Density & Dispersion Density - # of individuals per unit area or volume: the # of oak trees per square kilometer in the Minnesota county or the # of Escherichia coli bacteria per milliliter in a test tube Dispersion - pattern of spacing among individuals within the boundaries of the pop. Density: A dynamic perspective Pop. ecologists estimate density from an index (indicator) of pop. size, such as the # of nests