...FAQ: Biodiversity and Ecosystems Question 1: What is meant by succession, and what factors are responsible for succession? Answer 1: Succession is the order in which an ecosystem becomes established. It is the process by which species within a community replace one another in a given ecosystem. Usually, the complexity of the communities increases as they are replaced. Succession is triggered by a disturbance (fire or storm) or newly created open areas (deforestation). Ecological succession has several levels including primary and secondary succession. Primary succession involves pioneer species, which are usually the first ones to colonize open areas. They are hardy species and include things like microbes, mosses, and lichens. Eventually, the pioneer species become replaced by climax species. Climax species only occur after a long period without disturbance. Climax species are usually long-lived and require a stable environment. Question 2: How can natural selection lead to the development of new species? What are the prerequisites and the limitations? Answer 2: Natural selection was first proposed by Charles Darwin in his book Origin of Species. Natural selection is the process by which certain gene combinations give an organism a certain advantage over the others in a population. This trait then becomes selected as the population continues to reproduce. For example, suppose a certain mouse can run faster than any of the other mice in a population. The mouse will have a better...
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...Grasslands are one of the most widespread vegetation types worldwide, accounting for nearly one fifth of the earth’s land .They represent the most important sources of livestock forage, biodiversity, and contribute to the aesthetics and diversity of rural landscapes. Furthermore grasslands play a vital role in global carbon cycling and biodiversity of conversation. There are six terrestrial biomes with which grassland is a part. The five other includes tundra, desert, taiga, deciduous forest and tropical rainforest. Grassland biome includes prairies and open fields and has a wild distribution. It is subjected to all variations of temperature in the temperate zones, from freezing to extremely cold temperatures. It undergoes all the vicissitudes of seasonal climatic factors of wind, rain, and etc. (Elton, C.S., 1927). Elton, C.S. on his book on “The Ecology of Invasion by Animals and Plants, 1958” added that, the physical factors that affect grasslands include temperature, light intensity, wind direction and wind velocity, amount of rain or breeding places. First, temperature being an important factor affects animals inhabiting grasslands in such way that any changes in the temperature can affect the optimum temperature required by these animals, therefore alters their metabolic body activities. Light intensity is another factor that affects grasslands because producers in that area undergoes photosynthesis which requires light that will be used up by animals that depend on plants...
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...2/13/2014 ECOLOGY: Terminology • Greek oikos, meaning “household,” combined with the root logy, meaning “the study of.” • literally the study of households including the plants, animals, microbes, and people that live together as interdependent beings on Spaceship Earth. 2/13/2014 7 Ecological Concepts Introduction to Natural Sciences Ecology has been defined by the Ecological Society of America (1993) as: The Four Laws of Ecology 1. Everything is connected to everything else. 2. Everything must go somewhere. 3. Nature knows best. 4. There is no such thing as a free lunch. • The scientific discipline that is concerned with the relationships between organisms and their past, present, and future environments. • These relationships include physiological responses of individuals, structure and dynamics of populations, interactions among species, organization of biological communities, and processing of energy and matter in ecosystems 2/13/2014 8 2/13/2014 10 Nature consists of a number of systems called “spheres”: • • • • • The atmosphere (air and what is in it) The hydrosphere (water in its liquid form) The lithosphere (land, rocks and below) The biosphere (all the living organisms) The anthroposphere (human system) Anthroposphere • The built environment (buildings, roads, and other infrastructure) • Agriculture (also called the Primary Sector) • The manufacturing industry (also called the Secondary Sector) • The service industry (also called the...
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...Marine aquatic ecosystems are considered to be the largest of the aquatic ecosystems on Earth. They have a high salinity and include bodies of water such as the ocean, lagoon, the deep sea, and sea floors. Once of the marine ecosystems that has been a central focus, especially recently, is the Gulf of Mexico. The Gulf of Mexico is located off of the Atlantic Ocean, and it is considered to have a tropical climate. According to epa.gov, The Gulf of Mexico is the ninth largest body of water in the world. Some of the species or habitants that dwell in the gulf are different types of whales, dolphins, sea turtles, and sea-birds. Along the sea floor there are coral reef situated. There are also large birds The Gulf of Mexico produces a variety of resources that we use. One of the main resources is the fisheries provided in the gulf. Fisheries in the gulf are considered one of the most productive in the world. In 2010, the estimated shellfish and commercial fish harvest from the gulf fisheries was estimated to be about 1.3 billion pounds (epa.gov). Agriculture is definitely affected by the Gulf of Mexico. There is currently an area that is called the dead zone. Within this area of the gulf, there is an excessive supply of nitrogen in this area due to fossil fuel combustion, crop cultivation, and synthetic nitrogen fertilizers. With the increase of nitrogen, there is a process that is called hypoxia that will occur. Many people believe that the species in the fisheries will be...
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...China’s Water Woes: A Tug of Water Between Economic Growth & Sustainable Development China’s Water Woes: A Tug of Water Between Economic Growth & Sustainable Development When we think about water, we never think of it in finite terms like we do with oil and other valuable resources we consume. After all, why should we think of water as a limited supply? Our entire planet is covered with 75 percent water. It is implausible to believe that countries would go to war over water as they have for oil. Due to rapid economic growth, China is increasingly becoming a water stressed country as it faces two major problems with its water resource management: water pollution and water shortage. The water crises needs to be examined in finite terms as its quantity and quality continues to have a strangle hold on China. “China’s economic boom has, in a ruthless symmetry, fueled an equal and opposite environmental collapse. In its race to become the world’s next superpower, China is not only draining its rivers and aquifers with abandon; it is also polluting what’s left so irreversibly that the World Bank warns of catastrophic consequences for future generations.” (Larmer 2008, 153) Rapid economic growth and along with an increase in population is fueling environmental degradation and is becoming increasingly detrimental to its current and future economic growth in China. The gap between economic growth and environmental...
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...Introduction Banana (Musaspp.) is the fourth most important global food commodity after rice, wheat and maize in terms of gross value production. At present, it is grown in more than 120 countries throughout tropical and subtropical regions and it is the staple food for more than400 million people (Molina and Valmayor, 1999). Among the production constraints, Fusarium wilt caused by the fungus Fusarium oxysporum f.sp cubense(Foc) is the most devastating disease affecting commercial and subsistence of banana production through out the banana producing areas of the world (Ploetz, 2005). The disease is ranked as one of the top 6 important plant diseases in the world (Ploetz & Pegg, 1997). In terms of crop destruction, it ranks with the few most devastating diseases such as wheat rust and potato blight (Carefoot andsprott, 1969). The disease almost destroyed the banana export industry, built on the Gros Michel variety, in Central America during the 1950’s (Stover, 1962). In addition, the widely grown clones in the ABB ‘Bluggoe’ and AAA ‘Gros Michel and Cavendish’ sub groups are also highly susceptible to this disease worldwide. Presently, Fusarium wilt has been reported in all banana growing regions of the world (Asia, Africa, Australia and the tropical Americas) except some islands in the South Pacific, the Mediterranean, Melanesia,and Somalia (Stover, 1962; Anonymous, 1977; Ploetz and Pegg, 2000). The fungus Focis the soilborne hyphomycete and is one of more than 100 formae...
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...THE KENYA UNIVERSITIES AND COLLEGES CENTRAL PLACEMENT SERVICE University of Nairobi, Kenya Science campus Telephone : 0723954927, 0734879662 Email : kuccps@uonbi.ac.ke Website : http://kuccps.uonbi.ac.ke P.O. Box 105166 – 00101 Nairobi KENYA UNIVERSITIES AND COLLEGES CENTRAL PLACEMENT SERVICE (KUCCPS) PROCEDURE FOR ONLINE APPLICATION FOR PLACEMENT TO UNIVERSITIES AND COLLEGES 2013 KCSE EXAMINATION CANDIDATES 1 INTRODUCTION The Kenya Universities and Colleges Central Placement Service (Placement Service) was established as a Body Corporate under Section 55 of the Universities Act No. 42 of 2012 with its functions being to, among others co-ordinate the Placement of Government Sponsored Students to Universities and Colleges. A placement Policy and procedure for placement was subsequently developed and approved by the Board of the Placement Service. Based on the total declared capacity for programmes under Government sponsorship, and the performance analysis of the 2013 K.C.S.E Examination results, the Placement Service has set the cut off point for admission to bachelors degree programme at B of 60 points for male candidates and B- of 58 points for female candidates. In addition, all Candidates with a minimum overall grade of C- are eligible to apply for diploma programmes. The Placement Service therefore wishes to inform the 2013 K.C.S.E Examination Candidates that the online application system will open for application on Monday, May 19, 2014 at 0000 hrs and will close on...
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