Diversity+in+Ecosystems

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Biological Diversity in an Ecosystem
===The stability and efficiency of an ecosystem are directly related to the biological diversity. The loss of one species from a biologically diverse ecosystem is less significant than from a more simple ecosystem. ===

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 * __Role of Organisms in their Environment__** There are many reasons for the large diversity of the tropical rainforests. These are the main two; 1) The rainforests are said to be the oldest biomes. The organisms contained within the rainforests have had the largest amount of time to diversify, which would explain the large amount of species they contain ("Tropical"). 2) The rainforests have an extremely large amount of niches. This makes it more likely for speciation to occur within a species, which would eventually lead to new species forming by divergent evolution (G. 2001). All the organisms within the rainforest ecosystem have an important role in the food chain. The main decomposers of organic matter that falls to the forest floor are fungi, bacteria, moss, termites and earthworms. When they break down the dead organic material left by plants and animals, they release nutrients that plants benefit from. The main producers in the tropical rainforests are the estimated 200-300 tree species and many species of floor plants such as shrubs and fruit plants. The herbivores include insects, caterpillars, and monkeys. These all feed off of the plants and trees. The carnivores include puma and ocelots, which feed on the herbivores. The carnivores help maintain stable levels of other animals within the ecosystem, as do the herbivores with the plants. Because there are so many tree species, this allows for many niches in the other levels of the rainforest. These include the herbivores and carnivores ("Rainforest" 2008).   ======

__**Effects an Increase or Decrease of a Species has on the Ecosystem**__
An increase or decrease of a species (either human or naturally caused) may have many different effects on an ecosystem. The effects may be positive or negative, depending on the situation presented. In the rainforest there is a great amount of diversity. An example of the effects of a decrease of a species on an ecosystem can be seen through a study done by the American Natural History Muesum on beetles in the Amazon Rainforests. The beetles have many niches in their environment, such as assisting plant pollination, and decomposing larger organisms. When the forests were cut into small sections (deforestation). The insects that normally inhabit the deep forest, had decreased in both abundance and number of species in the forest fragments. When populations become too small, individuals have difficulty finding mates. This may result in inbreeding, which may eventually lead to an even greater decrease in the population. The decrease of the beetles puts a gap in the food chain. This decrese in insects also creates a decrese of other species. In contrast to smaller forest fragments and forest edges, the interiors of large fragments often have fewer insects for small mammals, birds, and frogs( which do not travel to the forests' edges) to feed on. But, being food for other animals is not the only niche these bettles have. Thier major niche is decomposition. The study showed that the rate at which leaves break down on the forest floor is only one-third as fast as in undisturbed forests, becuase of the loss of insect diversity. The //amount// of insects has not decreased, but the species that was specifically adapted to decomposing the dead leaves has disapeared. Because of this slowed rate of decomposition, the nutrients in the dead leaves are not being recycled into the soil for living plants (Didham 1998). An example of the effects of an increase of a species on an ecosystem can be seen by a study done at the University of Pittsburg on deer. Due to human factors, white-tailed deer populations have increased dramatically throughout many forests in North America in the past 50 years. This increase in deer populations negatively impacts plant populations through increased consumption, trampling, and soil compaction. In addition to reducing the number of plants, high amounts of deer also reduce the amount of plant diversity in the ecosystem (Knight 2000).  In the Chaparral biome, the dry, woody shrubs are commonly ignited by lightning and careless human activities. This causes brushfires in the summer and autumn because it is very densly poplated with the shrubs. Some of the shurbs are adapted to fire; they produce seeds that only germinate after they are burned. Also, some shurbs have the adaptation of fire resistent roots. These contain food reserves that allow the roots to resprout quickly and use mineral nutrients released by the fire. The shrub's niche is to repopulate the area after the fire occurs. Its adaptations allow it to do so (Campbell 2001). <span style="font-family: 'Trebuchet MS',Helvetica,sans-serif"> Biodiversity is the changes from differnt forms of life on the planet. Saving the diversity throughout all ecosystems is important to the living creatures there, and even humans. In the past 50 years, a massive decline in biodiversity has been accellerating. Yet harmful limiting factors, such as disease, have been on the increase. Right now, there is a strongly supported theory that the two are connected, but it is undergoing testing. (EPA) Also, humans play a big part in the decline of biodiversity. Humans and their interactions with wild creatures have a direct connection with the condition of the environment's diversity. When the biodiversity is greater, so is well-being of the ecosystem. Meaning, healthy diversity means a healthy ecosystem for all. In the future, humans will experience the after effects of the decline in biodiversity. Directly, humans could suffer the loss of an important food source. Indirectly, humans caould suffer the loss of something only to find that it could affect the purity of clean water. However, if looking to investigate the populations and numbers oneself, one must look at a very general graph of the population due to natural variability. (Australian Gov.)
 * __Species' Adaptations and Niches in the Environment__**
 * __Examine and explain what happens to an ecosystem as biological diversity changes__**

the diversity of an ecosytem is directly related to the ecosystem's stablity and efficiency. When a species is lost, the abilty of the ecoysytem to remain stable is lessened and it's efficiency is depleted. An example of this is in the western US. Humans didnt like the wild coyotes that were existant, so they sent up traps called "coyote-getters". THese traps composed of a piece of meat, that when the wolf pulled away, it would get spread with cyanide in the face. This cut off so many coyotes that the ecosystem crumbled because there were no predattors to pray on the rat populations. When the human finnally realized how unstable this ecosystem became, they had to take measures to change it. They had to import coyotes to re-establish the efficiency and stablility of the ecosystem (Hiebert 2002). <span style="font-family: Georgia,serif"><span style="font-family: Georgia,serif"><span style="font-family: 'Trebuchet MS',Helvetica,sans-serif">
 * __Relationship between Species' Loss and Bio-Diversity__**

When two species have specialized interactions with one another, a positive or negative effect is concluded. To find if the interaction is positive or negative can be difficult to determine, it can not just be observed through a species population or dispertion. The interaction could have been a result of coevolution or because of eviromental pressure. An example being the relationship between flowers and insects. The most common being, honey bees. Honey bees depend on the nector in flowers for their food source, while the flowers depend on the bees to pollinate them. Flowers have bright colors and different scents to attract the bees to themselves. If this process continues, both species will have accomplished their "goal" while providing the other aid for their survival ("Proving" 2008). <span style="font-family: 'Trebuchet MS',Helvetica,sans-serif"> In the forests of the Rocky Mountains, the lynx and the snowshoe hares have population cycles that are dependent on each other. The lynx have a diet consisting primarily on snowshoe hares. When the lynx population is low, the hare population increases because there is less lynx to feed on them. As the birth rate of the hares rise, the lynx have more food availability, which in turn causes their population to rise. When this happens, the hare population decreases because of the large amount of predators. This depletes the hare population which then makes the lynx population decrease due to the absence of food. This a continuous cycle over time (Campbell 2001). <span style="font-family: Georgia,serif">
 * __Specialized Interactions Effect Survival of both Species__**
 * <span style="font-family: Georgia,serif">[[image:http://www.pgc.state.pa.us/pgc/lib/pgc/wildlife/photolib/snowshoe_hare.jpg width="223" height="177" align="center" caption=""Snowshoe Hare""]]

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