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March 18th 2013 ECOLOGY REVIEW 1 Ecological Organization Biosphere Biome Ecosystem Population Organism/Individual Community Ecological Organization Terms A. Community is a group of different populations that live in the same area B. Population is a group of the same species that lives in the same area C. Individual is one organism D. Biosphere is the part of the Earth in which life exists E. Ecosystem all the organisms that live in a particular place, together with their nonliving environment F. Biome is a group of ecosystems that have the same climate and communities Energy Flow In an ecosystem, we have two categories of organisms: Producers / Autotrophs make their own food either through photosynthesis or chemosynthesis create chemical energy for all consumers examples: plants, bacteria, algae Consumers/ Heterotrophs rely on other organisms for their energy fall into one of the following categories Herbivore : eats only plants Carnivore : eats only meat Omnivore : eats both plants and meat Scavenger: eats dead animals Decomposer : breaks down dead material examples: all animals, fungi and some bacteria Energy Flow A food chain shows the flow of energy through an ecosystem. The arrow in a food chain shows the transfer of ENERGY from organism to organism. The organisms in food chains are assigned to trophic levels: Producer Primary Consumer Secondary Consumer Tertiary Consumer Quaternary Consumer Each trophic level receives only 10%of the energy from the level before – the other 90% is used by that organism for its own metabolism. Energy Flow Food chains in an ecosystem become interconnected into a complex food web. What are the primary consumers? Are there any tertiary consumers? Can any organism in this food web be classified in more than one trophic level? If the grasshopper were removed from this food web, which organisms would be affected? How? A population of bass was introduced into this ecosystem. They primarily feed on zooplankton and detritus. How would the balance of the ecosystem be changed? Answers to Food Web What are the primary consumers? Zooplankton, Ribbed Mussels, Grasshopper Are there any tertiary consumers? yes, the hawk Can any organism in this food web be classified in more than one trophic level? no If the grasshopper were removed from this food web, which organisms would be affected? How? The shrew’s population would decrease because they’d have less food The marsh grass would increase because the grasshopper wouldn’t be eating them A population of bass was introduced into this ecosystem. They primarily feed on zooplankton and detritus. How would the balance of the ecosystem be changed? Feeding on a producer and a primary consumer so would be both a primary and secondary consumer Ecological Pyramids There are three types of ecological pyramids: a. Energy Pyramids – show amount of energy available at each trophic level Biomass Pyramids – show mass of living organisms at each trophic level Number Pyramids – show how many living organisms at each trophic level. All three pyramids resemble each other when shown graphically. Biogeochemical Cycles There are three main cycles of nutrients in an ecosystem: water cycle, carbon cycle and nitrogen cycle. Nitrogen Fixation is when bacteria in the soil change the atmospheric nitrogen into nitrates and ammonia Denitrification is when bacteria in the soil change nitrates and ammonia back into atmospheric nitrogen Carbon Cycle Carbon can be cycled by: Respiration, Photosynthesis, Erosion, Volcanic Activity, and Decomposition Water Cycle PRECIPITATION CONDENSATION EVAPORATION RUN OFF March 19th 2013 ECOLOGY REVIEW 2 Ecological Relationships An organism’s habitat is the physical location in which it lives. An organism’s niche is the way that it interacts and participates in the ecosystem. A niche includes: Reproductive patterns Feeding relationships Habitat Competition The competitive exclusion principle says that no two organisms can occupy the same niche in the same habitat because the level of competition would eliminate one. Ecological Relationships Symbiosis – a close living relationship between two organisms or two species. Mutualism – both organisms benefit + / + Parasitism – one benefits and one is harmed + / Commensalism – one benefits and one is unaffected + / 0 Succession Succession is a change from one ecosystem to a more stable ecosystem over time. Primary succession occurs on land where soil previously existed. Solid rock from volcanic eruption or glaciers receding Pioneer species come in to form soil from the rock. Examples are lichens and mosses. After soil is established, grass, shrubs and trees follow from smallest to largest. Secondary succession occurs after an ecosystem is destroyed by natural disasters or human activities. Soil is already formed and remains after ecosystem is destroyed. Succession begins with grasses and then shrubs and trees quicky follow. Populations There are three types of population growth: 1. Linear – never occurs in real populations 2. Exponential – will occur in all populations as long as there is an unlimited supply of resources. Populations 3. Logistic – once a population reaches carrying capacity, growth will slow and the population will stabilize. Carrying capacity is the maximum number of organisms of a species that an ecosystem can support. Populations will fluctuate around the carrying capacity, occasionally above it and occasionally below it – this happens with availability of resources Populations Limiting Factors – anything that limits an organism’s ability to survive. 1. Density-dependent – the effect of the factor depends on the size of the population. predation, parasitism, disease 2. Density-independent– will effect all populations the same regardless of size. Natural disasters & human activities Populations Human population is growing exponentially. Technology has allowed us to get past the carrying capacity. Medical advances Agricultural practices Nature keeps population in check with disease and disasters. Demography – the study of the human population Immigration – organisms moving into a population Emigration – organisms moving out of a population Age-structure – the number of organisms in a population at each age group Environmental Problems Global Warming An excess of greenhouse gasses is trapping rays from the sun here on earth, which is raising global temperatures. Greenhouse gases = carbon dioxide (CO2), methane, and nitrous oxide. Effects of global warming – More severe weather patterns Rising sea level Change in crop ranges Increased respiratory diseases Environmental Problems Biodiversity & Habitat Destruction Biodiversity is the variety of organisms in an ecosystem. The more we disturb habitats, the more we decrease biodiversity. Organisms can be classified as threatened, endangered, or extinct when biodiversity is threatened. Pesticide Use DDT – a banned pesticide that caused many problems in birds of prey through biological magnification. Biological magnification – an increase in toxins as you move up the trophic levels in a food chain. March 20th 2013 BIOCHEMISTRY REVIEW pH 1. The amount of Hydrogen ions in solution is the pH of a substance. 2. A low number on the pH scale means that an acid is present. 0-6 on the scale is acidic Examples: lemons Stomach acid Vinegar Soft drinks pH 3. pH of 7 means the substance is Neutral. Examples: Water 4. A high number on the pH scale means a Base is present. 8-14 on the scale is basic Examples: Bleach Ammonia Soap Tums or Rolaids 5. Buffers prevent major changes in pH these help maintain Homeostasis in the body. Biomolecules 1. The four Biomolecules are: Carbohydrates Lipids Nucleic Acids Proteins 2. They all contain carbon, oxygen and hydrogen Carbohydrates 1. Simple Carbohydrates are sugars they have ose endings like glycogen and glucose. 2. Sugar can be tested by using Benedicts solution. The solution turns from Blue to Orange. 3. Complex carbohydrates are long chains of sugars that store energy for cells they are commonly called starches. 4. Starches can be tested by using Iodine it turns from brown to black/purple. Lipids: 1. Lipids are more commonly known as Fats or Waxes and are hydrophobic or dislike water. 2. They make up the membranes of cells which are composed of a lipid bilayer. 3. They are used to store energy in the body in long chains these chains are made out of Fatty acid and Glycerol molecule. 4. Lipids are found by using a Brown Paper bag test. Nucleic Acids: 1. Nucleic acids include DNA and RNA. 2. Nucleic acids store and transmit genetic materials. Proteins: 1. Proteins are made up of chains of Amino acids. 2. Proteins are used for growth and repair of cells. They also are used for commutation between cells. Enzymes: 1. Enzymes are a class of Proteins that assist in chemical reactions by speeding up the reaction. They act as Biological Catalysts. 2. Enzymes speed up reactions by lowering the activation energy needed to get the reaction started. Enzymes: 3. Enzymes can be denatured or made so they no longer work correctly by Heating, or Changes in PH. 4. Enzymes work like a Lock and a Key they are specific to the reaction. 5. Label the structure below: Enzyme, Substrate, Active Site.