Transfers of Energy and Matter (IB Topic C4.2)

Essential Idea(s): Energy and matter flow through ecosystems via food chains and webs, emphasizing the roles of autotrophs and heterotrophs, energy losses at trophic levels, carbon cycling, and the interactions between photosynthesis and respiration.

Unit Length: 6 Lessons (No AHL for this unit)

Guiding Questions

◊ What is the reason matter can be recycled in ecosystems but energy cannot?

◊ How is the energy that is lost by each group of organisms in an ecosystem replaced?

Materials:

Self-Teaching Slides	Quizlet Vocab Set
Teaching Slides	Notes Template

IB Statement(s) and Objective(s)
C4.2.1: Ecosystems as open systems in which both energy and matter can enter and exit Define ecosystem Compare open and closed systems State that ecosystems are open systems C4.2.2: Sunlight as the principal source of energy that sustains most ecosystems State that sunlight is the primary energy source for most ecosystems Outline one example of an exception of sunlight as the principal energy source in most ecosystems C4.2.3: Flow of chemical energy through food chains Define food chain and food web State the meaning of the arrow in a food web or chain Identify producers and consumers in a food chain Identify the apex predator in a food chain C4.2.4: Construction of food chains and food webs to represent feeding relationships in a community Draw a sample food chain, labeling the producer, primary consumer, secondary consumer and tertiary consumer C4.2.5: Supply of energy to decomposers as carbon compounds in organic matter coming from dead organisms Outline the role of decomposers in a food web Describe the feeding behaviors of consumers List three example consumer organisms Describe the feeding behaviors of detritivores List two example detritivore organisms Describe the feeding behaviors of saprotrophs List two example saprotroph organisms C4.2.6: Autotrophs as organisms that use external energy sources to synthesize carbon compounds from simple inorganic substances Define carbon fixation State the reason why autotrophs must “fix” carbon C4.2.7: Use of light as the external energy source in photoautotrophs and oxidation reactions as the energy source in chemoautotrophs Compare the energy source and carbon source in chemoautotrophs and photoautotrophs List examples of photoautotrophs and chemoautotrophs Outline how oxidation reactions serve as a source of energy in iron-oxidizing bacteria C4.2.8: Heterotrophs as organisms that use carbon compounds obtained from other organisms to synthesize the carbon compounds that they require Define heterotroph Outline the functions of digestion, assimilation and synthesis of carbon compounds in heterotrophs C4.2.9: Release of energy in both autotrophs and heterotrophs by oxidation of carbon compounds in cell respiration State that both autotrophs and heterotrophs perform cellular respiration to produce ATP Describe cellular respiration as an oxidation reaction C4.2.10: Classification of organisms into trophic levels Define trophic level C4.2.11: Construction of energy pyramids Describe the shape of and units of an energy pyramid Draw a pyramid of energy given data for an ecosystem C4.2.12: Reductions in energy availability at each successive stage in food chains due to large energy losses between trophic levels Outline three reasons why the amount of energy decreases at higher trophic levels State the average amount of energy passed through each trophic level of a food chain C4.2.13: Heat loss to the environment in both autotrophs and heterotrophs due to conversion of chemical energy to heat in cell respiration Outline the reason why cellular respiration releases heat C4.2.14: Restrictions on the number of trophic levels in ecosystems due to energy losses Explain the reasons why heat created by living organisms is eventually lost from the ecosystem C4.2.15: Primary production as accumulation of carbon compounds in biomass by autotrophs Define biomass Define primary production (gross and net) State the unit of primary production Outline why different biomes will vary in their capacity to accumulate biomass C4.2.16: Secondary production as accumulation of carbon compounds in biomass by heterotrophs Define secondary production Explain why secondary production is lower than primary production in an ecosystem State the use of quantifying secondary production C4.2.17: Constructing carbon cycle diagrams State the conditions under which an ecosystem is a carbon source C4.2.18: Ecosystems as carbon sinks and carbon sources Define sequestration in relation to a carbon sink Define sink, pool and flux as related to the carbon cycle State the unit of measure for carbon flux values C4.2.19: Release of carbon dioxide into the atmosphere during combustion of biomass, peat, coal, oil and natural gas Define combustion State the products of a combustion reaction Define peat Outline the formation of peat Outline the formation of coal Outline formation of oil & natural gas Outline formation of biofuels C4.2.20: Analysis of the Keeling Curve in terms of photosynthesis, respiration and combustion Sketch a graph of the annual fluctuation in atmospheric CO2 concentration Define Keeling Curve Explain the annual fluctuation in atmospheric carbon dioxide concentration in terms of photosynthesis and respiration Explain the reason for the long term trend depicted in the Keeling curve C4.2.21: Dependence of aerobic respiration on atmospheric oxygen produced by photosynthesis, and of photosynthesis on atmospheric carbon dioxide produced by respiration State the source of atmospheric oxygen Explain the interdependence of aerobic respiration and photosynthesis C4.2.22: Recycling of all chemical elements required by living organisms in ecosystems List the common elements needed by organisms State that chemical elements can be recycled but energy can not

IB Statement(s) and Objective(s)

C4.2.1: Ecosystems as open systems in which both energy and matter can enter and exit

Define ecosystem
Compare open and closed systems
State that ecosystems are open systems

C4.2.2: Sunlight as the principal source of energy that sustains most ecosystems

State that sunlight is the primary energy source for most ecosystems
Outline one example of an exception of sunlight as the principal energy source in most ecosystems

C4.2.3: Flow of chemical energy through food chains

Define food chain and food web
State the meaning of the arrow in a food web or chain
Identify producers and consumers in a food chain
Identify the apex predator in a food chain

C4.2.4: Construction of food chains and food webs to represent feeding relationships in a community

Draw a sample food chain, labeling the producer, primary consumer, secondary consumer and tertiary consumer

C4.2.5: Supply of energy to decomposers as carbon compounds in organic matter coming from dead organisms

Outline the role of decomposers in a food web
Describe the feeding behaviors of consumers
List three example consumer organisms
Describe the feeding behaviors of detritivores
List two example detritivore organisms
Describe the feeding behaviors of saprotrophs
List two example saprotroph organisms

C4.2.6: Autotrophs as organisms that use external energy sources to synthesize carbon compounds from simple inorganic substances

Define carbon fixation
State the reason why autotrophs must “fix” carbon

C4.2.7: Use of light as the external energy source in photoautotrophs and oxidation reactions as the energy source in chemoautotrophs

Compare the energy source and carbon source in chemoautotrophs and photoautotrophs
List examples of photoautotrophs and chemoautotrophs
Outline how oxidation reactions serve as a source of energy in iron-oxidizing bacteria

C4.2.8: Heterotrophs as organisms that use carbon compounds obtained from other organisms to synthesize the carbon compounds that they require

Define heterotroph
Outline the functions of digestion, assimilation and synthesis of carbon compounds in heterotrophs

C4.2.9: Release of energy in both autotrophs and heterotrophs by oxidation of carbon compounds in cell respiration

State that both autotrophs and heterotrophs perform cellular respiration to produce ATP
Describe cellular respiration as an oxidation reaction

C4.2.10: Classification of organisms into trophic levels

Define trophic level

C4.2.11: Construction of energy pyramids

Describe the shape of and units of an energy pyramid
Draw a pyramid of energy given data for an ecosystem

C4.2.12: Reductions in energy availability at each successive stage in food chains due to large energy losses between trophic levels

Outline three reasons why the amount of energy decreases at higher trophic levels
State the average amount of energy passed through each trophic level of a food chain

C4.2.13: Heat loss to the environment in both autotrophs and heterotrophs due to conversion of chemical energy to heat in cell respiration

Outline the reason why cellular respiration releases heat

C4.2.14: Restrictions on the number of trophic levels in ecosystems due to energy losses

Explain the reasons why heat created by living organisms is eventually lost from the ecosystem

C4.2.15: Primary production as accumulation of carbon compounds in biomass by autotrophs

Define biomass
Define primary production (gross and net)
State the unit of primary production
Outline why different biomes will vary in their capacity to accumulate biomass

C4.2.16: Secondary production as accumulation of carbon compounds in biomass by heterotrophs

Define secondary production
Explain why secondary production is lower than primary production in an ecosystem
State the use of quantifying secondary production

C4.2.17: Constructing carbon cycle diagrams

State the conditions under which an ecosystem is a carbon source

C4.2.18: Ecosystems as carbon sinks and carbon sources

Define sequestration in relation to a carbon sink
Define sink, pool and flux as related to the carbon cycle
State the unit of measure for carbon flux values

C4.2.19: Release of carbon dioxide into the atmosphere during combustion of biomass, peat, coal, oil and natural gas

Define combustion
State the products of a combustion reaction
Define peat
Outline the formation of peat
Outline the formation of coal
Outline formation of oil & natural gas
Outline formation of biofuels

C4.2.20: Analysis of the Keeling Curve in terms of photosynthesis, respiration and combustion

Sketch a graph of the annual fluctuation in atmospheric CO2 concentration
Define Keeling Curve
Explain the annual fluctuation in atmospheric carbon dioxide concentration in terms of photosynthesis and respiration
Explain the reason for the long term trend depicted in the Keeling curve

C4.2.21: Dependence of aerobic respiration on atmospheric oxygen produced by photosynthesis, and of photosynthesis on atmospheric carbon dioxide produced by respiration

State the source of atmospheric oxygen
Explain the interdependence of aerobic respiration and photosynthesis

C4.2.22: Recycling of all chemical elements required by living organisms in ecosystems

List the common elements needed by organisms
State that chemical elements can be recycled but energy can not


Activities: ⓟ = podcast / ⍰ = inquiry 5 / ⓦ = Write it / Ӕ = The academy / Ⓡ = Read it
ⓟ/ⓦ: The Creature that is Part-Time Animal; Part-Time Plant (💁/👭 max 2) People tend to love mixotroph carnivorous plants (like venus fly traps), but most also don’t know there IS such a thing as photosynthesizing animals. Tiny slugs from the species Elysia chlorotica show us that sometimes, our classification categories like “plant” vs animal” or “autotroph vs mixotroph” are not as clearly defined as we’d like. Watch the TEDEd video describing the slug, then discuss: 1) How is it that an animal can do photosynthesis? 2) Should Elysia chlorotica be classified as a heterotroph, an autotroph, or a mixotroph? 3) Is this an example of endosymbiosis – why or why not? …and whatever else you want to discuss. Ⓛ: Create Your Own 24-hour Food Web (💁/👭 max 2) You,lucky human, sit at the top of a very complex food web. A simple tracking of 24-hours of your food intake can show this quite clearly. Follow the steps in this presentation and create your own food web to show just how elaborate your own personal food web is. ⓟ/ⓦ: A Trillion Trees vs. Bill Gates: Is Planting Trees a Good Idea for Storing all that anthropogenic CO2? (💁/👭 max 2) Bill Gates recently upset quite a few people in the tree-planting community when he essentially said that planting trees as a means of fighting climate change is pretty much a waste of time. The trillion trees organization has been attempting to fight climate change by planting, well, a trillion trees. The logic is simple: trees take in CO2 and store it, making them our cheapest, easiest, and most natural carbon capture technology. Bill Gates says otherwise. Who’s right? Outline a basic plan by which you can answer this question, focusing on the numbers. Here’s some guidance: How much CO2 can the average tree take in? How much CO2 do you need to take in to offset climate change effects? How many trees would it take? …see how far you can get in deciding if Bill Gates is just a jerk, or making a valid point. (And go here if you want to cheat) Ⓛ (Virtual Lab): From Phytoplankton → Orcas: Build an Energy Pyramid (💁/👭 max 2) Take the following example of a food web from the Puget Sound (a complex estuarine ecosystem system near Washington state, USA) and determine the biomass required to sustain a single orca whale for one year. In doing so, you’ll see why there’s little room for top predators in any food web. Make a copy of the presentation and fill in the questions as indicated. Ⓛ (Lab Design): Satellites and Climate Change (💁/👭 max 2) Imagine you’ve been given the keys to the satellites that generate these amazing time-lapse images from NASA. Plan an experiment to collect data that will reveal the effects of climate change over a 50-year period. Include the following: A research question: What exactly are you investigating with the satellites? A hypothesis: Clearly explain what relationship you predict will occur. A methodology: In this case, you should answer: What data will the satellite return to you that will enable you to evaluate your research question? ————————————- *Extras: The Science of Buried Tea Bags* Here’s a freebie for one of you: There’s a pretty brilliant IA waiting to be done that piggybacks off this article. And it just might be the easiest IA ever done. See me if you think you’ve got the idea and you’re interested in doing it. Class-wide Activity: Modeling Energy Transfer in a Food Chain (from biologyforlife.com)