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Ecology review: What is Ecology? (a brief review) • Ecology• the study of interactions between – organisms and organisms – organisms and their environment Where do we fit in? (What is our environment?) The Biosphere! Factors that effect us: 1. Abiotic Factors Moisture Wind/Air currents Light Temperature Soil • A• Bio- stands for non stands for living • Abiotic Factors- nonliving factors 2. Biotic Factors: • Biotic- Living factors What is the organization of Ecological Study? Organism Population Community Ecosystem Biosphere Levels of Organization • Individual- one organism (living) • Ex a moose Levels of Organization • Population- groups of individuals that belong to the species and live in the same area. (living-living same species) • Ex many moose Levels of Organization • Community- groups of different populations (more than one population or different groups of species) Ex many groups of moose beavers, trees, grass (all living) Levels of Organization • Ecosystem- all organisms in a particular area along with the nonliving. (living and nonliving) Ex many groups of moose beavers, trees, grass, rocks, water, mountains Levels of Organization • Biome- group of ecosystems that have the same climate and similar dominant communities • Biomes: tropical rain forest, tropical dry forest, tropical savannah, temperate grassland, desert, temperate woodland and shrubland, temperate forest, northwestern coniferous forest, boreal forest (taiga), tundra, mountains and ice caps Levels of Organization • Biosphere- all of the planet where life exhists, includes land, water, and, air • Life extends 8 km up and 11 km below the surface IN AN ECOSYSTEM: Organisms live in a Habitat Organisms fit into a Niche of the environment Habitat vs. Niche • Habitat- an area where an organism lives • Niche- an organisms role in its environment – The Long Version full range of physical and biological conditions in which an organism lives and the way in which the organism uses those conditions. Includes where in the food chain it is, where an organism feeds • Habitat is like an address in an ecosystem and a niche is like an occupation in an ecosystem. ENERGY FLOW Autotrophs vs. Heterotrophs Energy Flow (Trophic Levels) • Producers- make their own food • Consumers- get energy from consuming producers Producers • Producers- capture energy from sunlight or chemicals and use the energy to produce food. • Producers are autotrophs- they make food from their environment 2 main types of autotrophs • One type gets energy • Another type gets from the sun-by energy without photosynthesis light- by chemosynthesis Consumers • Consumers are heterotrophs- get energy from other organisms Types of Consumers • • • • Herbivores- eat only plants Carnivores- eat animals Omnivores- eat both plants and animals Detritivores- eat dead matter (plants and animals) Feeding Relationships • Energy flows through an ecosystem in one direction from: – – – – 1. the sun or inorganic compounds 2. To autotrophs (producers) 3. To heterotrophs (consumers) Decomposers get energy from decomposing dead organisms Food Chain- a series of steps in which organisms transfer energy by eating or being eaten. Food Web- A network of feeding relationships. (More realistic that a food chain) Food Web They can become very complex! Trophic levels • Each step in a food chain or a food web is called a trophic level. – Producers are the first trophic level – Consumers are the second, third, or higher trophic level • Each trophic level depends on the one below for energy Energy Pyramid • Only part of the energy stored in one level can be passed to the next- most energy is consumed for life processes (respiration, movement, etc., and heat is given off) • Only 10% of the energy available within one trophic level is transferred to organisms in the next trophic level Biomass Pyramid • Biomass- the total amount of living tissue within a given trophic level. • A biomass pyramid represents the amount of potential food available for each trophic level in an ecosystem. Energy Losses • Energy transfers are never 100 percent efficient • Some energy is lost at each step • Limits the number of trophic levels in an ecosystem • Energy flow is a one way path! (not a cycle) All Heat in the End • At each trophic level, the bulk of the energy received from the previous level is used in metabolism • This energy is released as heat energy and lost to the ecosystem • Eventually, all energy is released as heat Biogeochemical Cycles (Matter moving through the environment) • All living organisms need certain elements/compounds for life processes – Ex: your cells need C,H,O,P,N & S in order to live and reproduce (make more cell) • Cycles in nature keep these elements “moving” from organisms to organism (and sometimes into the atmosphere) Biogeochemical Cycles (Matter moving through the environment) • The flow of a nutrient from the environment to living organisms and back to the environment • Main reservoir for the nutrient is in the environment • Transfer rates to and from reservoir are usually lower than the rates of exchange between and among organisms. • Matter is recycled through an ecosystem – not one way flow Three Categories • Hydrologic cycle – Water • Atmospheric cycles – Nitrogen and carbon • Sedimentary cycles – Phosphorus and sulfur CYCLES IN NATURE Carbon Cycle • Carbon moves through the atmosphere and food webs on its way to and from the ocean, sediments, and rocks • Sediments and rocks are the main reservoir Carbon Cycle diffusion Atmosphere Bicarbonate, volcanic action carbonate Marine food TERRESTRIAL webs ROCKS Terrestrial Rocks photosynthesis Land Food Webs Soil Water Marine Sediments weathering Peat, Fossil Fuels Carbon in Atmosphere • Atmospheric carbon is mainly carbon dioxide • Carbon dioxide is added to atmosphere – Aerobic respiration, volcanic action, burning fossil fuels, decomposition of organic materials • Removed by photosynthesis Nitrogen Cycle • Nitrogen is used in amino acids and nucleic acids (all living organism need nitrogen to make proteins) • Main reservoir is nitrogen gas in the atmosphere • Decomposers are vital to convert ammonia into: 1. usable nitrites & nitrates for plants (nitrogen fixation) 2. nitrogen gas (denitrification = puts it back into the atmosphere) Phosphorus Cycle • Phosphorus is part of phospholipids and all nucleotides – What are these? • It is the most prevalent limiting factor in ecosystems • Main reservoir is Earth’s crust; no gaseous phase (it never enters the atmosphere – like carbon and nitrogen) Phosphorus Cycle mining excretion FERTILIZER GUANO agriculture uptake by autotrophs MARINE FOOD WEBS weathering DISSOLVED IN OCEAN WATER uptake by autotrophs weathering DISSOLVED IN SOILWATER, LAKES, RIVERS death, decomposition sedimentation death, decomposition leaching, runoff setting out uplifting over geolgic time MARINE SEDIMENTS ROCKS LAND FOOD WEBS