Energy Energy Flow in Ecosystems Energy flows, but matter is - PowerPoint PPT Presentation

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 (CO 2 , H 2 S, CH 4 ) 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 (N 2 ) • 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 (PO 4 3- ) 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