1. Interdependence of Organisms
Review:
Energy Flow in Ecosystems

2. All living things need energy
All living things need energy. Essentially all the energy on earth comes ____________ .
FROM THE SUN!!!

3. Trophic Levels
You may have learned these were called energy levels!
Organisms are assigned to trophic levels based on the organism’s source of energy.
1st trophic level
2nd trophic level
3rd trophic level

4. Autotrophs Also called producers
Make their own food using energy from sunlight or inorganic molecules.
Examples: Blue green algae and plants

5. Heterotrophs
Organisms that rely on autotrophs or other heterotrophs as their source of nutrients and energy.
Known as consumers

6. Heterotrophs can be classified base on what organisms they consume.
Herbivores eat plants or other primary producers.
Carnivores eat herbivores or other consumers.
Omnivores eat producers and consumers.
Detritivores eat dead organisms.

7. Decomposers
Break down dead organisms and return molecules to the soil so they can be used by plants as nutrients .
Examples: bacteria, fungi

8. Visualizing Food Chains

9. Energy Pyramids
The energy in each trophic level can be visualized as an energy pyramid.

10. Energy Pyramid Why is only 10 % passed to the next trophic level?
Each trophic level is represented by a block.
Lowest trophic level (producers) on the bottom.
Energy stored by the organisms at each trophic level is about one-tenth the energy stored by the organism in the level below.
Why is only 10 % passed to the next trophic level?

11. “Loss” of Energy in a Food Chain
Where does the energy go?
Aids in the mechanical work (running, breathing, and eating, etc.)
Ultimately it is lost as HEAT.
When a consumer eats a producer, the consumer will also store about one-tenth of the energy it receives.
Where does the rest go???
There is potential energy stored in the chemical bonds of the producer.

12. As you move up the trophic levels in an ecosystem what is lost?
HEAT!!! ??
How much heat is lost?

13. Another measurement in a food chain--
Since all organisms are made roughly of the same organic molecules in similar proportions, a measure of their dry weight is a rough measure of the energy they contain.
What is “dry weight”?
Scientists call it BIOMASS!

14. Biomass Pyramid
Make observations about the data shown here.
In most ecosystems, the combined weight of the producers is greater than the combined weight of the consumers.

15. pyramid of numbers- each tier represents the number of organisms at each trophic level.

16. Why is this significant?
Read this quote--
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)
Why is this significant?

17. Which of these options could feed more people?
And less energy is “lost” in the process!

18. Closing Activity--
You have been given $1 million to help a third world country.
You can either—
A. Use the money to buy supplies and teach the people to raise cattle Or
B. Use the money to buy supplies and teach the people to farm grains
Write a paragraph explaining which would you choose to do and why?

19. Cycling of Matter

20. Where does our energy come from? How does the energy get to Earth?
The energy from the Sun travels as light to the Earth.
Energy moves in one direction—its unidirectional—from the Sun to the Earth.
The SUN!!

21. What about nutrients? The SUN!! Add video They must be recycled! Why?
The amount of water, carbon, and nitrogen is static and has to be recycled on our planet to be used again.
The SUN!!

22. How are nutrients recycled?
The Water Cycle
The Nitrogen Cycle
The Carbon Cycle

23. The Nitrogen Cycle

24. Background Information The Nitrogen Cycle
DID YOU KNOW????
Nitrogen, N2, makes up 79% of Earth’s atmosphere.
Most organisms cannot use it in this form (N2), so we rely on bacteria to break the N2 bond during nitrogen fixation, which binds nitrogen to hydrogen to form ammonia (NH3).
Nitrogen-fixing bacteria are found in the nodules on the roots of beans, birch and alder trees and some other plants.

25. Processes of The Nitrogen Cycle
Ammonification
Nitrogen Fixation
Nitrification
Assimilation
Denitrification
Find them on your Nitrogen Cycle Diagram!

26. How it works… Follow on your nitrogen cycle diagram!!!
1. Nitrogen-fixing bacteria convert N2 to NH3 (ammonia).
2. NH3 goes through nitrification by nitrifying bacteria to convert it to NO3 (nitrate).
3. NO3 is assimilated (taken up by the roots of plants.)
4. Denitrifying bacteria then convert the NO3 to N2 so it can return to the atmosphere during denitrification.
Is that the only way it works???

27. Strong Bonds Usable Nitrogen gas in our atmosphere is scarce.
The two atoms in atmospheric Nitrogen are held together by triple covalent bonds.

28. Scarcity of Nitrogen
Only lightning, volcanic action and certain bacteria can break the strong Nitrogen bonds.
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29. What about ammonification?
Ammonification is the production of ammonia by bacteria during the decay of urine.
The ammonia produced in this step can also be assimilated by plants or goes through nitrification.

30. Livestock farming creates a large amount of animal waste.
Use your knowledge of the nitrogen cycle to analyze the effect on the following scenario on the ecosystem involved.
Livestock farming creates a large amount of animal waste.
How would this affect the nitrogen cycle?
THINK: How would an abundance of rainfall make the effect of excess animal waste worse?

31. How would this affect the nitrogen cycle?
Use your knowledge of the nitrogen and carbon cycle to analyze the effect on the following scenario on the ecosystem involved.
A farmer over-fertilizes his crop. This leave excess nitrates in the soil.
How would this affect the nitrogen cycle?
THINK: How would runoff from a flood affect this situation?

32. Cycling of Matter
The Carbon Cycle

33. The Carbon Cycle

34. The Carbon Cycle
CO2 that is dissolved in water or is in the air is used during photosynthesis by plants, algae, and bacteria.
CO2 then returns to the air and water in one of three ways…

35. The Carbon Cycle CO2 returns to the air or water in three ways:
Cellular Respiration
-using oxygen to break down food
Combustion
-burning fossil fuels (coal, oil, natural gas)
Erosion
-limestone from sediment of decayed shells erodes releasing carbon.

36. The Carbon Cycle
Click on the link below to watch a short video on the carbon cycle
YouTube-What's the deal with carbon?

37. How would this affect the carbon cycle?
Use your knowledge of the carbon cycle to analyze the effect on the following scenario on the ecosystem involved.
A hotel developer decides to cut down a forest to make room for the next big resort.
How would this affect the carbon cycle?

38. How would this affect the carbon cycle?
Use your knowledge of the nitrogen and carbon cycle to analyze the effect on the following scenario on the ecosystem involved.
Jenny decides to leave her car (and her vehicle emissions) in the garage, and she takes the train to work instead.
How would this affect the carbon cycle?

39. Symbiotic Relationships

40. Why do organisms enter into relationships?
To meet three basic needs:
Food
Shelter
Protection/safety

41. Canadian Lynx and Snowshoe Hares

42. Acacia ants living within the Acacia tree

43. Crocodile and Plover Bird

44. Symbiotic Relationships
MUTUALISM
COMMENSALISM
PARASITISM
PREDATOR/PREY

45. Symbiotic Relationships
MUTUALISM
COMMENSALISM
Occurs when both organisms benefit.
+/+
PARASITISM
PREDATOR/PREY

46. Symbiotic Relationships
MUTUALISM
Occurs when both organisms benefit.
+/+
COMMENSALISM
Occurs when one organism benefits and the other organism neither benefits or is harmed.
+/o
PARASITISM
PREDATOR/PREY

47. Symbiotic Relationships
MUTUALISM
Occurs when both organisms benefit.
+/+
COMMENSALISM
Occurs when one organism benefits and the other organism neither benefits or is harmed.
+/o
Occurs when one organism (the parasite) benefits and the other (the host) is harmed.
+/-
PARASITISM
PREDATOR/PREY

48. Symbiotic Relationships
MUTUALISM
Occurs when both organisms benefit.
+/+
COMMENSALISM
Occurs when one organism benefits and the other organism neither benefits or is harmed.
+/o
PARASITISM
Occurs when one organism (the parasite) benefits and the other (the host) is harmed.
+/-
PREDATOR/PREY
Occurs when one organism (the predator) hunts another organism (the prey) for food.
+/-