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Ecology and the Environment (Ac Bio Chapters 3 - 6) (Honors Bio – Unit 5) Ecology: study of interactions among/between organisms and their environment LEVELS OF ORGANIZATION Biosphere (AKA ecosphere): All parts of planet in with life 11 km below surface of ocean to 8 km above Earth’s surface Levels of Organization in Biosphere: Individual Species Similar - can breed / Produce fertile offspring Groups of same Species, in same area Community Groups of different populations together in same area Population Ecosystem Biome Communities & Abiotic factors Ecosystems w/ same climate & Similar dominant communities FOOD CHAINS/WEBS ENERGY FLOW Autotrophs – make own food photosynthetic – use light NRG + CO2 to make carbs (glucose) + O2 chemosynthetic – use chem. NRG to make carbs Heterotrophs – rely on other orgs for NRG/food Herbivores – eat only autotrophs Carnivores – eat other heterotrophs Omnivores – eat both autotrophs & heterotrophs Detritivores – eat dead organisms Decomposers – break down organic matter What is the difference between a decomposer and a Detritivore? both get nutrition from dead organic matter detritivores actually eat organic matter turning it into POOP (earthworms eating their way through soil, vultures eating dead deer) decomposers secrete enzymes into the dead stuff to break down organic matter then absorb resulting molecules (bacteria & fungi). All detritivores are decomposers. All decomposers are not detritivores. Energy Flow: One direction: from sun (or inorganic compounds) to autotrophs to heterotrophs Food Chain: Series of steps in which organisms Transfer energy by eating/being eaten Food Web: Links all food chains in ecosystem Trophic Level: step in food chain Decomposers/detritivores Break down dead organisms Or organic waste for NRG Top level carnivores = (have no predators) Second level carnivores = eat other carnivores First Level Carnivores = eat herbivores Herbivores = second trophic level Autotrophs = first trophic level Ecological Pyramid: Compares amnts of NRG or matter in trophic Levels of food chains/webs Energy Pyramid 10% of NRG available 170 Within 1 trophic 1,700 Level is passed to 17,000 Organisms in 170,000 Next level Other 90%?? Used by organisms AT that Level OR lost as heat Biomass Pyramid Compare amount of biomass at Each level Represents amount of food available for each level Pyramid of Numbers Shows numbers Of Individuals at each level Pyramid of Numbers Corresponding BIOMASS PYRAMID!! Cycling of Matter in the Biosphere http://icue.nbcunifiles.com/icue/files/nbclearn/site/video/widget/NBC_Learn _Video_Widget2.swf?CUECARD_ID=65227 Biogeochemical cycles: Living organisms transform matter and Recycle chemicals (atoms) Water Cycle Runoff & seepage condensation Root uptake Water = solvent Makes up 60 – 70 % of the weight in living organisms molecule w/ 1 oxygen atom & 2 hydrogen atoms Covalently bonded. H2O neutral (10+ and 10-) polar molecule: One end has a net – charge, other end has a net + charge. Hydrogen bond: weak (weaker than ionic and covalent) attraction (bond) between opposite ends of polar molecules Cohesion: attraction of oppositely chgd. ends of adjacent water molecules, causes Water to “bead” on smooth surfaces creates surface tension - allows small bugs/ animals to walk on water. Adhesion: attraction between molecules of Different substances causes meniscus, capillary action Water dissociates (separates) into two Ions (charged particles): Hydroxyl ion OH- Hydrogen H+ If you apply electric voltage across two water-filled beakers and separate them, The water stretches from beaker to beaker, creating a bridge that defies gravity. Water bridges were discovered 120 years ago, but no one has ever been sure why they do not collapse. One theory is that the voltage makes water molecules line up, creating a “dielectric” tension that stops the bridge from falling. Another argues that surface tension—the tendency of a water’s surface to shrink inwards—keeps the bridge aloft. Now, researchers believe that water bridges rely on both strategies. The results could help engineers develop electrowetting, a method of using electricity to adjust the adhesion of fluids to a screen that is expected to be used in the next Generation of e-book readers. pH scale –concentration of H+ ions in solution Acid: more H+ ions than OH- ions pH less than 7 Neutral: = amounts of OH- and H+ ions pH exactly 7 (pure water) Base: more OH- ions than H+ ions pH greater than 7 Carbon Cycle (gaseous cycle) CO2 in Atmosphere CO2 in Ocean Carbon released: Respiration Decomposition Erosion Volcanic activity Mining Cutting/burning forests Burning fossil fuels Carbon removed: photosynthesis Storing Carbon Underground: Burial/decomposition of dead organisms Nitrogen Cycle (gaseous cycle) needed by ALL organisms to Make (amino acids) and nucleic acids proteins Nitrogen gas (N2) makes up 78% of atmosphere, cannot be used directly by living organisms Nitrogen fixation: Bacteria living in roots of Legumes convert N2 into Ammonia – usable by autotrophs Decomposers return nitrogen to the soil as ammonia Denitrification: Soil bacteria convert nitrates Into nitrogen gas Nitrogen Cycle (Gaseous Cycle) N2 in Atmosphere NH3 Ammonia NO3and NO2- Nitrates/Nitrites Phosphorus Cycle (sedimentary cycle) needed to make DNA, ATP, phospholipids (cell membranes), bones! Doesn’t enter atmosphere like C, O, N Stays in rock & soil minerals & ocean sediments Plants pull phosphate from soil/water, Combine into organic compounds – then cycle Through food web How do we get phosphorus into our bodies?? A Sedimentary Cycle Fertilizers 3 numbers on label separated by dashes. example: 5-10-5. Numbers = percentage by weight of 3 major nutrients plants need: N-P-K in that order. 10 pound bag of fertilizer labeled 5-10-5: 5% nitrogen 10% phosphorus Other 80% comprised of other nutrients and filler. Limiting Nutrient Nutrient scarce or cycles slowly limits primary productivity (rate at which Organic matter is created by producers) Algal Bloom Too much nutrient (fertilizer, Phosphates in detergents) – Runs Off into water, algae grows fast, Algae Dies off & decomposes (using oxygen), fish die BIOMES Habitat: where organism lives (address) Includes biotic and abiotic factors physical & biological Conditions where Niche: organism lives ANDWay it uses those conditions (job) Place in food chain, physical conditions needed, How & when it reproduces Interactions in A Community When organisms try to use same Competition Resources at same time Competition Exclusion Principle No two species can occupy the same niche In the same habitat at the same time Predation One captures and Feeds on another Symbiosis Two species live closely together Mutualism Both benefit Commensalism One benefits, other neither Helped or harmed Parasitism parasite lives in or on host & Causes harm to host Ecological Succession: Change in ecosystem over time Primary Succession No soil exists Pioneer species (lichens) first break down rock, make soil Climax community: stable Secondary Succession Ecosystems return to original state After disruption (forest fire, farming) Ecosystems and Communities Impact of Climate Weather: Day to day condition of Atmosphere at particular Time and place Climate: Average, yr. after yr. Conditions of temp. and Precipitation for region Climate zones Determined by latitude (angle of heating) Polar Zones Cold, sun’s rays strike at low angle No. & So. Poles Tropical Zones Near the equator Receive (nearly) direct sunlight year round Always warm Temperate Zones Arctic Circle Tropic of Cancer Tropic of Capricorn Antarctic Circle Between polar zones & tropics Affected by changing angle of sun Ranges from hot to cold, depending on season Wind and Ocean Currents -Caused by unequal heating of Earth’s surface -Distribute/transport heat throughout biosphere Prevailing Winds: air near equator rises Air near poles sinks Upwelling Water at poles sinks Water at equator rises Winds move surface water Land Masses (microclimates) Interfere with air masses / wind currents Rain Shadow -Air is cooled as it moves over mountain -Drops moisture (rain) on one side -Other side is dry (the rain shadow) Biome Complex communities, cover large Area, specific soil & climate Conditions, specific plant & animal Life (with adaptations for survival) Two main components of climate: Temperature Precipitation Terrestrial BIOMES Only 30% of Earth is “land” Polar 1) Taiga (Boreal Forest) 2) Tundra (ice desert) Coldest biome Permafrost: permanently frozen subsoil Freezing/thawing topsoil damages plant roots Short scrubby plants 3) Mountains (Alpine biomes) Temperate Biomes 1) Taiga (Boreal Forest) 2) Northwest Coniferous Forest pine trees (conifers), bears 3) Temperate Forest 4) Temperate Grassland Deciduous trees: Lose leaves in fall 5) Temperate Woodland/shrubland 6) Desert Grassland distributions Tropical Biomes 1) Tropical Rain Forest Hot & wet year round Most diverse biome Canopy Dense covering of leaves 50-80 m above forest floor Understory Shorter trees and vines in shade of canopy 2) Tropical Dry Forest Deciduous trees: Drop leaves in dry season to Conserve water 3) Tropical Savanna Grasslands, warm, less Rainfall than dry forest, more Than desert 4) Desert Dry, hot during day – some colder at night Evaporation is Greater than precipitation Cover 30% of Earth’s land (all deserts combined) Aquatic Biomes Freshwater Biomes 3% of Earth’s surface Flowing Water Rivers, streams, creeks, brooks Standing Water Lakes & Ponds Plankton: microscope life forms food for larger animals zooplankton - heterotrophs phytoplankton - autotrophs Wetlands Water covers (or is near surface) For part of year Bogs Acidic water Marshes Along rivers, no trees Swamps -Water flows slowly -Flooded forests Estuary -Where river meets ocean -Tides rise & fall -Food chains start w/ detritivores (clam, worms, sponges) -Incl. salt marsh, mangrove swamp Marine Zones About 70% of earth covered by salt water Photic Zone Upper layer, enough light for photosynthesis Aphotic Zone Permanently dark Chemosynthetic organisms Benthic Zone Ocean floor Sea star, anemone, marine worms Intertidal zone: Area of shoreline between low and high tides Organisms must be able to survive movement Of tidal waters, changes in salt levels Coral Reefs Found in warm clear waters of tropics & subtropics Very diverse life forms • Nearly 2/3 of the world’s population live along the coast/within 100 miles of it • Since 1990 the world has lost ~ ½ of its coastal wetlands due to development • in the past 200 yrs ~ 55% of the area of estuaries and coastal wetland in US have been destroyed/ damaged Population Ecology Populations Identified by: Range (geographic distribution) River Otter Range Density (number of individuals /unit of area Growth Rate Age Structure River Otter Density in Montana Factors affecting Population Size: Birth Rate Death Rate Immigration Rate Emigration Rate Exponential Growth: ideal conditions Unlimited resources reproduction occurs at constant rate Logistic Growth: growth slows or stops after a period of exponential growth why?? Resources become limited Slows /levels off when birth rate = death rate immigration = emigration ZPG: Zero Population Growth Carrying Capacity: largest number of individuals a given environment can support http://www.census.gov/popclock/ if everyone on planet consumed only what’s needed, 40 billion would be feasible Earth’s carrying capacity Limiting Factors: cause population growth to decrease Competition Predation Parasitism Disease Weather Natural Disasters Seasonal Cycles Human Activities Affects of Humans on the Biosphere Tragedy of the commons: Any resource that is free and accessible to Everyone may eventually be destroyed no one is responsible for Protecting resources, no one benefits From preserving resources Renewable Resource Ex: fresh water plants wind Can regenerate (alive) Can be replenished by biochemical cycles (nonliving) Nonrenewable Resource Ex: fossil fuels Cannot be Replenished by Natural process Sustainable Resource Utilization Way of using resources without Depleting them, without causing harm To environment Negative human impact on environment Soil erosion – loss of topsoil by water/wind -Desertification Deforestation Overfishing Air Pollution / smog Acid Rain: Nitrogen and sulfur from Burning fossil fuels combines With water vapor to form Nitric and sulfuric acids Ecological Footprint Land/water/Energy resources used and Needed to dispose of generated wastes (in relation to time) Biological Magnification Concentrations of harmful substances Increase in organisms at higher trophic Levels in food chains & food webs Ozone Depletion Ozone layer Molecules of O3, absorbs Harmful Ultraviolet (UV) radiation CFC’s (chlorofluorocarbons) ~propellants in Aerosol sprays ~coolants in Refrigerators, freezers, AC, ~Used in production of plastic Foams – can damage ozone Global Warming increase in average temp. of biosphere Since the late 19th century, avg. atmospheric Temperatures have risen about 0.6 oC Since 1980, avg. temp have risen between 0.2 and 0.3 oC Hypothesis: due to addition of CO2 from human activities Burning of fossil fuels Cutting and burning of forests Concentrations of carbon dioxide in Atmosphere have been rising for 200 years Evidence Greenhouse Effect: Natural & Necessary! Build up of gases (carbon dioxide, methane) Traps heat energy (like glass in a greenhouse) Natural greenhouse effect is intensified Possible Effects of Global Warming Rising sea levels / flooding Long term effects on ecosystems? Invasive Species Reproduce rapidly, lack parasites & predators Nutria – native to So. America – destroying Shoreline habitats in SE US Biodiversity Diverse ecosystems are More stable Threatened Biodiversity Altering habitats Hunting to extinction Introduction of toxic compounds into food webs Introduction of foreign species Extinction: when species disappears from All Or part of its range Endangered species: in danger of extinction Conservation Wise management of natural resources Preservation of habitats & wildlife Endangered Species Act National Parks Earth Day Earth Summit