Ecosystems and Energy - nausetschools.org · Matter and Energy •Energy enters, flows through, and...
Transcript of Ecosystems and Energy - nausetschools.org · Matter and Energy •Energy enters, flows through, and...
Ecosystems and Energy
Energy Flow in Ecosystems
Energy flows, but matter is recycled
Matter and Energy
• Energy enters, flows through, and exits an ecosystem
• Chemical nutrients cycle within ecosystems through biogeochemical cycles (carbon, nitrogen, phosphorus, water)
Matter and Energy
• Energy enters from the sun as radiation, moves as chemical energy transfers through food webs, and exits as heat radiated back into space
Matter and Energy
Energy Flow
• Energy flows through ecosystems from the sun through producers to consumers
• Organisms within food webs and food chains interact
• Food webs and food chains are dependent on primary productivity
Primary Producers (Phototrophs)
• Plants, photosynthetic protists (algae), chemosynthetic and photosynthetic bacteria (cyanobacteria)
• Convert solar energy into chemical energy (glucose) through photosynthesis
Primary Producers (Chemotrophs) • Chemosynthetic bacteria (prokaryotes) are the
primary producers of the deep-sea hydrothermal vent communities
• Convert inorganic chemicals (CO2, H2S, CH4) into organic molecules (sugars) through chemosynthesis
Primary Productivity
• Primary productivity: The amount of light energy converted to chemical energy (organic molecules) by autotrophs (photosynthetic and chemosynthetic) during a given time period in an ecosystem
• Starting point for ecosystem metabolism
• Influenced by changes in regional and global climates and in atmospheric composition
Primary Productivity
• Food webs and food chains are dependent on primary productivity – why?
• Represents the storage of chemical energy that will be available to consumers in an ecosystem
GPP and NPP
• Gross primary productivity (GPP): total primary production in an ecosystem (the amount of energy from light, or chemicals, converted to chemical energy of organic molecules per unit time
• Net primary productivity (NPP): equal to the GPP minus the energy used by the primary producers for autotrophic respiration
Net Primary Productivity (NPP)
Global Primary Production
Terrestrial Primary Production
Terrestrial Primary Production • Temperature and moisture are the main
factors controlling primary production in terrestrial ecosystems
Aquatic Primary Production
Aquatic Primary Productivity
• Ocean phytoplankton are responsible for approximately 50% of the global biosphere net primary production
• Global annual ocean primary production has decreased due to an increase in global sea surface temperature – why? (thermocline)
• Light and nutrients are limiting factors
Light and Nutrient Limitation
• Solar radiation drives photosynthesis (not the only variable controlling primary production)
• Limiting nutrients are elements that must be added for production to increase, such as nitrogen and phosphorus
Calculating Primary Production
• Use the textbook to explain how to calculate primary production in your notes.
• Write down the equation in your notes.
• More math….yes!!
Consumers (Heterotrophs)
• Herbivores, carnivores, omnivores, detritivores, decomposers
Role of Decomposers
Trophic Levels and Ecological Pyramids
Trophic Levels
• A trophic level is the position that an organism occupies in a food chain or food web (what it eats, what eats it)
Ecological Pyramids
• Graphical representations designed to show the biomass or bioproductivity at each trophic level in a given ecosystem
• Energy pyramid, biomass pyramid, and pyramid of numbers
Energy Pyramid
• A graphical representation of energy flow in a community of organisms
Trophic Efficiency
• Trophic efficiencies are generally only about 10% (90% of the energy available at one trophic level not passed on)
Trophic Efficiency
Pyramid of Net Production
Biomass Pyramid and Numbers Pyramid
• Biomass pyramids represent the total dry mass of all organisms in one trophic level
• Numbers pyramids show the number of individual organisms in one trophic level
• By the way, I really miss school and you all! I’m sorry that you have to learn Ecology on your own, but you are all super smart and I know you can do it! Hang in there. I hope you all have a nice Thanksgiving break.
Mrs. Simpson
Ok, now on with the note taking…..
Biogeochemical Cycles
Cycle inorganic and organic nutrients between organisms and the
environment
Cycling of Matter
• Organisms must exchange matter with the environment to grow, reproduce and maintain organization
• Molecules and atoms from the environment are necessary to build new molecules
Molecules Essential for Life
• Carbohydrates – composed of C, H, and O, monomer is a monosaccharide
• Lipids – composed of C, H, and O, monomers are fatty acids and glycerol
• Proteins – composed of C, H, O, N, and S in trace amounts, monomers are amino acids
• Nucleic Acids – composed of C, H, O, N and P, monomers are nucleotides
Carbon
• Carbon moves from the environment to organisms where it is used to build the essential organic molecules
• Carbon is used in storage compounds and cell formation in all organisms
Carbon in the Environment
• Carbon found in something non-living is called inorganic carbon
• Inorganic carbon is found in rocks (limestone), shells, the atmosphere and the oceans
• Living organisms must “fix” inorganic carbon into organic carbon to build the organic compounds necessary for life
Carbon Cycle – Draw a diagram of the carbon cycle in your notes.
Nitrogen and Phosphorus
• Nitrogen moves from the environment to organisms where it is used to build proteins and nucleic acids
• Phosphorus moves from the environment to organisms where it is used to build nucleic acids, certain lipids, and ATP (cell energy)
Nitrogen in the Environment • The main reservoir for inorganic nitrogen is the
atmosphere – 80% nitrogen gas (N2)
• During nitrogen fixation, bacteria (and other processes) fix inorganic nitrogen into forms that can be used by living organisms to synthesize organic compounds
Nitrogen Cycle – Draw a diagram of the nitrogen cycle in your
notes.
Phosphorus in the Environment
• Most inorganic phosphorus in found in sedimentary rock of marine origin
• Phosphorus is also found in soil and dissolved in the oceans
• Weathering of rocks adds phosphates (PO43-)
to the soil which plants can absorb
Phosphorus Cycle – Draw a diagram of the phosphorus cycle
in your notes
Water
• Living systems depend on the properties of water that result from its polarity and hydrogen bonding
• Living organisms are mostly made of water (think cytoplasm and extracellular fluids!)
• Universal solvent supports cell reactions
• Acts as a delivery system between cells
Water Cycle – Draw a diagram of the water cycle in your notes
Water Cycle