1. Ecology: Energy Flow and Nutrient Cycles
Essential Questions:
How does Energy Flow through the Earth?
How do Nutrients Cycle through the Earth?
How are these processes related to each other to sustain life on Earth?

2. What is Energy? Recap!
Remember the source of all energy comes from the Sun.
Also, one requirement of all living things is to use energy for cell processes!
How do we Calculate and Show how that energy is distributed through nature?
First we need to know what energy flow is.
Then how energy flows through the Earth.
Autotrophs trap that energy and convert it into chemical energy (sugar) through photosynthesis.
Heterotrophs obtain that energy by consuming autotrophs or other heterotrophs and release it through cellular respiration.

3. What is Energy Flow? Key Vocabulary:
Energy and matter passes through ecosystems when organisms metabolize other organisms.
Key Vocabulary:
Producers: organisms which produce their own food, also called autotrophs. (Plants, Algae, Phytoplankton, etc)
Consumers: organisms which obtain their food from other organisms, also called heterotrophs. (Everything else!)
Primary consumers consume producers.
Secondary consumers consume other consumers
Detritivores: feed on plant and animal remains and other dead matter.
Decomposers: organisms which break down dead and decaying matter.

4. Energy Flows in One Direction
Heterotrophs eat the autotrophs (consumers)
Sun or inorganic compounds
Heterotrophs eat other heterotrophs (carnivores)
Autotrophs (producers)

5. So, How much of the sun’s energy ends up in the food we eat?
How much energy is stored/ transferred?
10% Rule:
10% of energy at one trophic level can be used by consumers at the next trophic level.
Trophic Level:
Each step in a feeding relationship.
This means that 90% is lost…
Where does all of the energy go?!
In this example black dots represent energy units.

6. Where does the “lost” energy go?
How much of the sun’s energy ends up in the food we eat?
Where does the “lost” energy go?
Energy is “lost” when paper burns.
Where does the energy go? How do you know?
Background Information
-- Energy does not recycle.
-- As you have learned, energy can be passed from one state or organism to another when chemical bonds are broken and reformed, but some energy is lost during these processes.
-- Where does this energy go? Does it just disappear?
-- Think of what you have learned about respiration and burning calorie energy when you run, or burning the carbon energy in firewood.
-- What do you feel? Heat! 
Table of Contents

7. How much of the sun’s energy ends up in the food we eat?
Which foods require the most energy to make? What does this mean for humans as top-level consumers?
Background Information
-- From the farm to your fork, energy goes through a lot to get from the sun to your body.
-- We humans have constructed a food system that requires lots and lots of energy to produce food.
-- Think of all the energy required to grow, irrigate, harvest, process, package, reprocess, repackage, prepare in the grocery store, cook in the kitchen, and finally dispose of one night's dinner, it's a ton!
-- Considering growing and harvesting alone, it is estimated that about 3 calories of energy are used to make just 1 calorie of food.
-- Taking processing and transportation into account, the estimate is about 7 to 10 calories of energy required to produce 1 calorie of food.
-- Compare an ear of corn to one hamburger.
-- Which requires the most energy to grow, fertilize, irrigate, harvest, process, and distribute?
-- Based on what you know about trophic levels and energy transfer, which do you expect to retain more of the sun's energy?
Images: (UMICH 2009)
Join this friendly farmer for lunch to talk about how the sun's energy reaches your plate!

9. How can we display this data in a logical manner?
How much of the sun’s energy ends up in the food we eat?
"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."
What is the energy advantage to being a primary consumer
rather than a secondary consumer?
Which foods require the most energy to make? What does this mean for humans as top-level consumers?
How can we display this data in a logical manner?
Background Information
-- It is estimated that about one third of the solar energy (from light from the sun) is actually converted by plants into their structure.
-- From the available energy stored in plants, herbivores (primary consumers) only store about 10% in their bodies.
-- The other 90% is used to go about daily life, grow, and reproduce, or it is lost. 
-- Ultimately, secondary consumers get very little of the energy from sunlight that reaches the earth.
-- The basic rule of thumb is that at each trophic level, or stage in a food web, only 10% of the energy available can be used.
-- The fewer the trophic levels in a food web, the less energy lost.
Quote: G. Tyler Miller, Jr. (1971)

10. Displaying Data: Ecological Pyramids
Represent relationships among trophic levels, each reducing at higher and higher levels.
Energy: amount of incoming energy.
Biomass: mass of living tissue.
Numbers: number of organisms.

14. What is Nutrient Cycling?
Biogeochemical cycles: passage of matter from one organism to another in the biosphere.
Nutrients are finite (not like the Sun which supplies constant energy), so they must be (re)cycled through various parts of nature.
Relies heavily on Decomposers and movement through the cycle (not getting “stuck” in one area)
The Five (5) Major Biogeochemical Cycles:
Carbon, Water, Nitrogen, Sulfur, Phosphorous.

16. Cycles of Nature: The Carbon Cycle
Carbon is the building blocks of life.
Definition of “Organic”
CO2 = Carbon Dioxide
Living things take in Oxygen and give off CO2 through Aerobic or Cell Respiration.
Plants take in CO2 through photosynthesis and produce Oxygen.
Organisms/Living things contain the most carbon in the Carbon cycle.
As organisms die and enter the soil, they eventually become fuel over millions of years (“fossil fuels.”)
Natural Processes of Volcanoes give off CO2

17. Where do we find carbon? Day One explore activity
“Where is the carbon?”
Essential Understandings
--All energy comes from the sun (photosynthesis)
--All living things are made of carbon
--Carbon is Recycled
Background Information
--Relate the image of carbon cycling to the activity done on day one.
--Make sure students understand how the pictures can be compared to the cycle image.

19. How Humans affect the Carbon Cycle
Greenhouse Gases
Excess CO2 in the atmosphere acts as a trap for heat and water vapor.
Global Warming
Warming of the Earth causes ice caps to melt, causing the ocean to change temperature and salinity, raising sea levels, changing climate & weather.
Deforestation and Habitat Destruction
Without Trees to undergo photosynthesis to
convert CO2 to Oxygen, Carbon levels will
continue to rise.
Removal of trees also harms biodiversity
(the amount of different organisms) and
habitats for organisms.

22. Cycles of Nature: The Water Cycle
Evaporation – Water taken into the atmosphere
Transpiration – Plants losing water through leaves
Precipitation – Water that falls from the atmosphere (rain, snow, hail, etc)
Runoff – Water that enters the ocean
Groundwater – Water that is absorbed into the ground
Water vapor is also given off by volcanic eruptions.
The Water Cycle helps cool the Earth preventing large changes in Global Temperatures.

23. How Humans affect the Water Cycle
Human Use of Water:
Agriculture
Dams and Deforestation
Urbanization (Living in Cities)
Overuse of Aquifers
Saltwater Intrusion (ocean)
Subsidence (lead to collapse)
Clean Water supply
1 billion people (16%) do
not have any access to clean water.
Can cause outbreaks of disease
Examples: cholera, hepatitis, mosquito breeding, etc.
Acid Rain (in combination with Nx and Sx)
Hurts plants, animals and buildings

25. Cycles of Nature: The Nitrogen Cycle
78% of the air is Nitrogen
Plants use nitrogen in their cellular processes
Nitrogen is present in our DNA and RNA and in
amino acids (proteins).
The food chain largely moves Nitrogen around.
Bacteria and Lightning takes Nitrogen gas and puts into a useable form (called Nitrogen Fixation)
Bacteria have a mutualisitic relationship with plants and live on their roots.

28. How Humans affect the Nitrogen Cycle
Humans contribute extra Nitrogen in the cycle due to fertilizers and animal waste (hog lagoons) that runoff into in the lakes and rivers.
Extra Nitrogen in the groundwater can interfere with blood/oxygen levels and cause blue-baby syndrome.
Excess Nitrogen can cause Eutrophication which causes aquatic life to die due to…
the low levels of oxygen (fish kills)
extra algae to grow (algal bloom.)
High levels of ammonia is also toxic to animals.

30. Cycles of Nature: Sulfur Cycle
important part of amino acids/proteins and plays role in forming shape of molecules
most sulfur is trapped in rocks and is broken down then taken up by plants
organisms eat the plants and take up S
organisms release S into the atmosphere through decomposition as Hydrogen Sulfide (H2S)
Human Impacts on the Sulfur Cycle:
Hydrogen sulfide combines with oxygen to form H2SO4, sulfuric acid; falls to the earth as acid rain.
The burning of fossil fuels release SO2; combines with atmospheric H2O and O2 to form acid rain.

32. Cycles of Nature: Phosphorus Cycle
Phosphorus is found in bones, teeth, DNA, and ATP (energy-storing molecule)
Naturally, phosphorus is found in rocks as calcium phosphate (Ca3(PO4)2)
As the rocks break down, phosphate is released into the soil where it is taken up by plants.
Human Impacts on the Phosphorus Cycle:
The phosphate is obtained through mining of certain deposits of calcium phosphate called apatite. Huge quantities of sulfuric acid are used in the conversion of the phosphate rock into a fertilizer products.
Run off is a major concern as animal waste fertilizer may collect in lakes.
Human sewage also causes problems as Phosphorus is only removed if there are tertiary treatments involved.

33. Recap!
Remember, Energy Flows as Nutrients Cycle!