ECOLOGY
Ecology is the study of how living things interact with each other and their environment. Earlier this year we learned about the levels of organization within an organism: cell-tissue-organ-organ system-organism. Now we are looking at the levels of organization starting at an individual (i.e., organism) and ending with the biosphere (i.e., earth). Individuals consist of the same species. A group of individuals is a population. Several populations make up a community. An ecosystem includes both biotic (living) and abiotic (non-living) things within an area. Ecosystems within a certain climate are called biomes, and all the biomes put together make up the biosphere.
Energy flows through an ecosystem. Energy is captured from the sun in a process called photosynthesis. Producers, or autotrophs, are organisms that make their own food through this process. The energy is transferred when an organism eats or is eaten. Consumers, or heterotrophs, must eat food to get energy. We can trace the flow of energy using food chains and food webs. Food chains, or food webs begin with producers. Primary consumers eat the the producers, secondary consumers eat the primary consumers, and tertiary consumers eat the secondary consumers. Consumers can also be categorized by what they eat. Herbivores eat plants, carnivores eat meat, omnivores eat plants and meat, and scavengers feed on dead animal and plant material present in their habitat.
What is the role of decomposers in the food chain? Look below!
The transfer of energy can also be represented by an energy pyramid. Producers make up the first trophic level (feeding level). Only 10% of the energy is available to the organisms at the next trophic level. Most of the energy is lost in the form of heat. Based on the energy pyramid below, what type of food would give you the most energy?
ecology_2014-km.ppt | |
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ecology_notes-km.docx | |
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Ecological Relationships: Can't we all just get along?
There are relationships between organisms within a habitat. In a predator/prey relationship, you either eat or are eaten. Competition occurs when two or more living things compete for the same resource(s). If two types of organisms try to occupy the same niche, one will lose out. Symbiosis is a close, long-term relationship between two or more organisms. There are 3 types of symbiotic relationships: Mutualism, Commensalism, and Parasitism. At least one organism in these relationships benefit.
There are relationships between organisms within a habitat. In a predator/prey relationship, you either eat or are eaten. Competition occurs when two or more living things compete for the same resource(s). If two types of organisms try to occupy the same niche, one will lose out. Symbiosis is a close, long-term relationship between two or more organisms. There are 3 types of symbiotic relationships: Mutualism, Commensalism, and Parasitism. At least one organism in these relationships benefit.
For Mutualism, both organisms benefit. An example of mutualism is a sea anemone and a clownfish.
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For Commensalism, one organism benefits, while the other is unaffected. An example is barnacles on a whale.
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For Parasitism, one organism benefits, and the other is harmed. This loa loa nematode (worm) can cause blindness.
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better_symbiosis_power_point.ppt | |
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environmental_enigma_worksheet.pdf | |
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Ecology Study Guide | |
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We use graphs to represent population growth. Some of the factors that can affect the size of a population include births, deaths, immigration (in), and emmigration (out). Population graphs help ecologists to look at changes in population size. When the conditions are ideal, there is exponential growth (j-curve). When limiting factors, such as limited resources, space, and disease exist, the growth of the population slows down when it reaches its Carrying Capacity (K). This is called logistic growth (s-curve). A Human population graphs tell a story of our history.
Biodiversity, or diversity of living things, is very important for a healthy ecosystem. Sometimes organisms are introduced from other places. These Invasive species are not native to the area. They take over and reduce or even eliminate the native organisms. They harm the environment by reducing biodiversity.