AP Biology. Ecosystems

Transcription

1 Ecosystems

2 Studying organisms in their environment organism population community ecosystem biosphere

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

4 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

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

6 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

7 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

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

9 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! sun 17% growth only this energy moves on to the next level in the food chain 33% cellular respiration 50% waste (feces) energy lost to daily living

10 Food chains 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 Level 4 Tertiary consumer top carnivore Level 3 Secondary consumer Level 2 Primary consumer Level 1 Producer Decomposers carnivore heterotrophs herbivore autotrophs Bacteria sun Fungi

11 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?

12 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.

13 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.

14 Ecological pyramid Loss of energy between levels of food chain sun ,000 1,000,000,000

15 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

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

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

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

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

21 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

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

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

25 Transpiration Remember transpiration?

26 Breaking the water cycle Deforestation breaks the water cycle groundwater is not transpired to the atmosphere, so precipitation is not created QuickTime and a TIFF (Uncompressed) decompressor are needed to see this picture. forest desert desertification

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

28 Studying ecosystems Hubbard Brook Experimental Forest 38 acre deforestation 7800 acres

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

30 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

31 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.