Sponge: Set up Cornell Notes on pg. 39 Topic: 4.2 Energy Flow-Pyramids Essential Question: Why are energy transformations never 100% efficient? Explain and give examples. BIOZONE: P C.2 Energy pyramids Key Vocabulary: Energy Pyramid Gross production Net production Why are energy transformations never 100% efficient? Explain and give examples. Text: P

Understanding Energy released from carbon compounds by respiration is used in living organisms and converted to heat

Cellular respiration and heat Inside a grasshopper, chemical energy is used for cellular respiration Glucose originally produced by the grass is converted into CO² and H₂O This chemical reaction generates a small amount of heat in each of the g.h.’s cells Any heat generated by cellular reparation is lost to the environment

Cellular respiration and heat If the grasshopper is eaten, some of the chemical energy in its body (protein) is passed on to the next organism If the grasshopper dies and is not eaten, detritivores and decomposers will use its available energy

Understanding Living organisms cannot convert heat to other forms of energy

Heat cannot be recycled Law of conservation of energy states that energy cannot be created or destroyed, only converted from one form to another Photosynthesis: Light energy  chemical energy Cellular respiration: Chemical energy  ATP Heat (once lost, cannot be used again) Second law of thermodynamics states that when energy is transferred, a proportion of it is lost as heat energy

Understanding Heat is lost from ecosystems Guidance: Understand that there is a continuous but variable supply of energy in the form of sunlight but that the supply of nutrients in an ecosystem is finite and limited

Heat cannot be recycled Heat is “lost” from the ecosystem It will be passed from one tropic level to the next If energy cannot be recycled how come we don’t run out of energy???? The sun! If for some reason the sun stops shining, because it is blocked from Earth by clouds or particles of some sort, then the food chain is affected

Energy Loss Only chemical energy can be used by the next trophic level AND only a small amount of the energy which an organism absorbs is converted into chemical energy No organism can utilize 100% of the energy present Typically only 10% of the energy available is used from the previous step in a food chain 90/10 rule

The 10% Rule 1m46s

Pyramid of Energy A pyramid of energy is used to show how much and how fast energy flows from one trophic level to the next in a community Each level in the food chain contains much less energy than the level below it

Because energy is lost, each level is always smaller than the one before It would be impossible to have a 3 rd trophic level wider than the 2 nd because organisms cannot create energy, they can only transfer it inefficiently The energy will eventually flow through decomposers

There are also other ways that energy loss occurs

Main Reasons for Energy Loss: Not all of the organism is swallowed as a food source (some parts are abandoned) Not all of the food swallowed can be absorbed and used in the body Some organisms will die before being eaten by an organism from the next trophic level There is considerable loss due to cellular respiration at all trophic levels (movement, maintenance of body temp..) Eventually ALL the energy which flows through the ecosystem is lost as metabolic heat!

Skill Quantitative representations of energy flow using pyramids of energy Guidance: Pyramids of energy should be drawn to scale and should be stepped, not triangular Use proper terms: primary consumer, secondary…

Construct a pyramid of energy In an ecosystem, the producers make 10,000 kJ m⁻² yr⁻¹ of energy (assume a 90% loss) Draw an energy pyramid, TRY TO DRAW TO SCALE Label all parts (trophic levels, kJ m⁻² yr⁻¹ ) P 38

Construct a pyramid of energy In an ecosystem, the producers make 10,000 kJ m⁻² yr⁻¹ of energy Primary consumers (T2) Secondary consumers (T3) Tertiary consumers (T4) Primary producers (T1)

Each level only gains about 5-20% of energy! Each level loses up to 80-95% of its energy as heat! 1 J Quaternary Consumers Add any missing labels kJ m⁻² yr⁻¹

Primary Production Gross production: the total amount of energy trapped in the organic matter produced by plants per area per time in kilojoules (kJ) or the amount of light energy that is converted into chemical energy. Net production: the gross production minus the energy lost through respiration Gross production – Respiration = Net Production

The gross annual primary productivity of a particular swampland ecosystem is found to be 25,000 kJ m⁻² yr⁻¹. If respiration by the swampland producers is 15,000 kJ m⁻² yr⁻¹ per year, what is the net annual primary productivity for this ecosystem, in kJ m⁻² yr⁻¹ ? GPP-R=NPP GPP= 25,000 kJ m⁻² yr⁻¹ R=15,000 kJ m⁻² yr⁻¹ 25,000 kJ m⁻² yr⁻¹ - 15,000 kJ m⁻² yr⁻¹ = 10,000 kJ m⁻² yr⁻¹ P 38

Construct an energy pyramid: Classwork Trophic Level Energy passed to the next trophic level Energy lost as metabolic heat Energy lost as detritus

– =

________+________+____________+___________=________ Organic waste Decomposers Metabolic Loss Solar Energy not used Total Energy from sun (kJ) Gross production____________________- respiration_______________________=net production__________________

Construct an energy pyramid Using the data from your worksheet please construct a pyramid of energy Draw an energy pyramid, TRY TO DRAW TO SCALE Label all parts (trophic levels, kJ m⁻² yr⁻¹ ) Detritivores/decomposers do not fit into pyramid Bottom P 38

Tertiary Consumers kJ m⁻² yr⁻¹ Primary Producers kJ m⁻² yr⁻¹ Primary consumers kJ m⁻² yr⁻¹ Secondary Consumers kJ m⁻² yr⁻¹ Construct an energy pyramid

Sponge: Set up Cornell Notes on pg. 41 Topic: C.2 Energy Pyramids and biomass Essential Question: None. BIOZONE: NONE C.2 Energy Pyramids and Biomass Key Vocabulary: Biomass Feed conversion ratio (FCR) Text: P

Skill Comparison of pyramids of energy from different ecosystems

Comparing pyramids of energy When comparing the energy pyramids of two different ecosystems you will notice differences in their efficiency Notice Cedar Bog has no tertiary consumers -the lower productivity of the plants makes it unable to support higher levels

Comparing pyramids of energy

Notice, that organisms at higher and higher trophic levels are increasingly more efficient – Carnivores are the most efficient + +

Understandings The percentage of ingested energy converted to biomass is dependent on the respiration rate

Biomass Biomass: is an estimate of the total (dry) mass of all the organisms within that trophic level dry weight of an organism measured in g m⁻² yr⁻¹ (Grams per meter squared per year) we use dry weight, because the actual weight of the organisms includes a large amount of water (which is not organic matter). Water must be removed by drying. Three hundred trout are needed to support one man for a year. The trout, in turn, must consume 90,000 frogs, that must consume 27 million grasshoppers that live off of 1,000 tons of grass. -- G. Tyler Miller, Jr., American Chemist (1971)

Guidance: Students should be clear that biomass in terrestrial ecosystems diminishes with energy along food chains due to loss of CO₂,H₂O, and other waste products, such as urea

Pyramids of biomass Pyramids of biomass are similar in shape to pyramids of energy The higher trophic levels have a lower total biomass per unit area of an ecosystem Like energy, biomass is lost during respiration at each level Glucose is broken down for energy and converted into CO² and H₂O CO² and H₂O are excreted and the biomass of glucose is lost

Application Conversion ratio in sustainable food production practices

Sustainable food production The feed conversion ratio (FCR) is a measure of the efficiency of an animal’s ability to convert feed mass into increased body mass (or the desired output) – Shows us how much energy is being lost during the transfer from plants to animals – The “output” is what we want from our animal Dairy cow  milk Cow/chicken/pig/fish  meat – The lower the FCR, the more energy that is being conserved or gained

Sustainable food production FCR= mass of food eaten body mass gain Ex: 8 kg food = 8 1 kg of weight gain

Sustainable food production Animals with low FCR can be seen to be efficient users of food

Sustainable food production Fish farmers are trying to lower the FCR to 1 – the amount of feed would equal the “fish mass” gained 1:1 – Therefore nothing would be lost and everything is gained Tegel Poultry of New Zealand have reported FCR as low as 1.38 on a consistent basis

Crash Course: Ecosystem Video (start 4m-9m) Take bullets P. 40

BIOZONES have been assigned as of 9/25/15