AP Biology Ecosystems

AP Biology biosphere ecosystem community population Studying organisms in their environment organism

AP Biology Essential questions  What limits the production in ecosystems?  How do nutrients move in the ecosystem?  How does energy move through the ecosystem?

AP Biology Ecosystem  All the organisms in a community plus abiotic factors  ecosystems are transformers of energy & processors of matter  Ecosystems are self-sustaining  what is needed?  capture energy  transfer energy  cycle nutrients  capture energy  transfer energy  cycle nutrients

AP Biology biosphere Ecosystem inputs constant input of energy energy flows through nutrients cycle nutrients can only cycle inputs  energy  nutrients inputs  energy  nutrients Don’t forget the laws of Physics! Matter cannot be created or destroyed

AP Biology Participants in an Ecosystem  Primary producers-autotrophs that make up the first trophic level of any ecosystem  Ex-plants, phytoplankton, & some bacteria  Consumers-heterotrophs that feed on the tissues, products, and remains of other organisms  Ex=herbivores, carnivores, omnivores, parasites, detritivores, decomposers

AP Biology Decomposers vs Detritivores  Detritivores eat particles of decomposing matter(detritus)  Types-  Scavengers-animals that feed on carrion, dead plant matter, or refuse. Ex-buzzards, ants, & vultures  Decomposers break down organic remains and wastes off all organisms and return nutrients to earth  Ex-bacteria, protists, and fungi

AP Biology Energy flows through ecosystems sun producers (plants) loss of energy secondary consumers (carnivores) secondary consumers (carnivores) primary consumers (herbivores) primary consumers (herbivores)

AP Biology Inefficiency of energy transfer  Loss of energy between levels of food chain(only 10% is transferred b/t trophic levels)  To where is the energy lost? The cost of living! only this energy moves on to the next level in the food chain 17% growth 50% waste (feces) 33% cellular respiration energy lost to daily living sun

AP Biology  Trophic levels  feeding relationships  start with energy from the sun  captured by plants  1 st level of all food chains  food chains usually go up only 4 or 5 levels  inefficiency of energy transfer  all levels connect to decomposers Food chains Fungi Level 4 Level 3 Level 2 Level 1 Decomposers Producer Primary consumer Secondary consumer Tertiary consumer top carnivore carnivore herbivore Bacteria autotrophs heterotrophs sun

AP Biology Food webs  Food chains are linked together into food webs  Who eats whom?  a species may weave into web at more than one level  bears  humans  eating meat?  eating plants?

AP Biology Types of Food Webs  Grazing food web-energy flows mostly into herbivores, carnivores, then decomposers  Detrital food web-energy from producers flows mainly into detritivores and decomposers.

AP Biology Biological Magnification in Food Webs  In biological magnification, some chemical substance is passed from organisms at one trophic level to those above and becomes increasingly concentrated in body tissues.  By 1995, people in the US were spreading more than 1.25 billion pounds of toxins per year! (insecticides, herbicides, fungicides…)  Example- The peregrine falcon almost became extinct as a result of biomagnification of DDT (a pesticide). DDT has been banned since the 70’s.

AP Biology Ecological pyramid  Loss of energy between levels of food chain 1,000,000, , sun

AP Biology  Types of ecological pyramids  Biomass pyramid-depicts the dry weight of all of an ecosystem’s organisms at each tier  Energy pyramid-illustrates how the amount of usable energy diminishes as it is transferred through an ecosystem  Pyramid of numbers-shows how population size decreases as you go from producer to consumer

AP Biology

consumers decomposers abiotic reservoir nutrients made available to producers geologic processes Generalized Nutrient cycling consumers producers decomposers abiotic reservoir nutrients ENTER FOOD CHAIN = made available to producers geologic processes Decomposition connects all trophic levels return to abiotic reservoir

AP Biology  In a biogeochemical cycle, an essential element moves from the environment, through ecosystems, then back to the environment.  Ex: O2,H,C,N, & P

AP Biology Carbon cycle CO 2 in atmosphere Diffusion Respiration Photosynthesis Plants and algae Plants Animals Industry and home Combustion of fuels Animals Carbonates in sediment Bicarbonates Deposition of dead material Deposition of dead material Fossil fuels (oil, gas, coal) Dissolved CO 2 abiotic reservoir:  CO 2 in atmosphere enter food chain:  photosynthesis = carbon fixation in Calvin cycle recycle:  return to abiotic:  respiration  combustion abiotic reservoir:  CO 2 in atmosphere enter food chain:  photosynthesis = carbon fixation in Calvin cycle recycle:  return to abiotic:  respiration  combustion

AP Biology Birds Herbivores Plants amino acids Carnivores Atmospheric nitrogen loss to deep sediments Fish Plankton with nitrogen-fixing bacteria Nitrogen-fixing bacteria (plant roots) Nitrogen-fixing bacteria (soil) Denitrifying bacteria Death, excretion, feces Nitrifying bacteria soil nitrates excretion Decomposing bacteria Ammonifying bacteria Nitrogen cycle abiotic reservoir:  N in atmosphere enter food chain:  nitrogen fixation by soil & aquatic bacteria recycle:  decomposing & nitrifying bacteria return to abiotic:  denitrifying bacteria abiotic reservoir:  N in atmosphere enter food chain:  nitrogen fixation by soil & aquatic bacteria recycle:  decomposing & nitrifying bacteria return to abiotic:  denitrifying bacteria

AP Biology  Nitrogen fixation-bacteria convert gaseous nitrogen to ammonia  Denitrification-conversion of nitrate or nitrite to gaseous nitrogen or nitrogen oxide by certain bacteria in the soil  Human activities add nitrogen to ecosystems. Use of fertilizer and fossil fuel burning are examples

AP Biology

Phosphorus cycle Loss to deep sediment Rocks and minerals Soluble soil phosphate Plants and algae Plants Urine Land animals Precipitates Aquatic animals Animal tissue and feces Animal tissue and feces Decomposers (bacteria and fungi) Decomposers (bacteria & fungi) Phosphates in solution Loss in drainage abiotic reservoir:  rocks, minerals, soil enter food chain:  erosion releases soluble phosphate  uptake by plants recycle:  decomposing bacteria & fungi return to abiotic:  loss to ocean sediment abiotic reservoir:  rocks, minerals, soil enter food chain:  erosion releases soluble phosphate  uptake by plants recycle:  decomposing bacteria & fungi return to abiotic:  loss to ocean sediment

AP Biology Lakes Runoff Percolation in soil Evaporation Transpiration Precipitation Oceans Solar energy Aquifer Groundwater Water cycle Water vapor abiotic reservoir:  surface & atmospheric water enter food chain:  precipitation & plant uptake recycle:  transpiration return to abiotic:  evaporation & runoff abiotic reservoir:  surface & atmospheric water enter food chain:  precipitation & plant uptake recycle:  transpiration return to abiotic:  evaporation & runoff

AP Biology Transpiration Remember transpiration?

AP Biology Breaking the water cycle  Deforestation breaks the water cycle  groundwater is not transpired to the atmosphere, so precipitation is not created forest  desert desertification

AP Biology Repairing the damage  The Greenbelt Movement  planting trees in Kenya  restoring a sustainable ecosystem  establishing democracy  empowering women Wangari Maathai Nobel Peace prize 2004

AP Biology Studying ecosystems Hubbard Brook Experimental Forest 7800 acres 38 acre deforestation

AP Biology Effects of deforestation Concentration of nitrate (mg/l ) Year Deforestation nitrate levels in runoff 40% increase in runoff  loss of water 40% increase in runoff  loss of water  60x loss in nitrogen  10x loss in calcium  60x loss in nitrogen  10x loss in calcium loss into surface water loss out of ecosystem! Why is nitrogen so important?

AP Biology A Global Water Crisis  Most water on Earth is too salty to drink (around 75%)  2/3 of fresh water is used to irrigate fields  About ½ of the US population taps into groundwater for drinking water that can be contaminated.  If the US population and water depletion continues, our freshwater supply will be in danger.  Important terms:  Salinization-a build up of salt in soil that stunts crop plants and decreases yields.  Desalination-removal of salt from sea water

AP Biology Greenhouse Gases, Global Warming  The greenhouse effect occurs when greenhouse gases trap heat in the lower atmosphere.  This makes Earth’s surface warm enough to support life.  Natural processes and human activities are adding more greenhouse gases to the atmosphere.  Examples: carbon dioxide, CFCs, methane, & nitrous oxide  This results in a result in global warming and climate change.