1. Wednesday, September 20 Ecology - HS-LS2-4
Use mathematical representations to support claims for  the cycling of matter and flow of energy among organisms in an ecosystem
Today’s agenda:
Common assessment
Warm up
Mini-lecture
SEP 5: use mathematics and computational thinking
Disciplinary core idea: LS2.B: Cycles of Matter and Energy Transfer in Ecosystems
Biomass, trophic levels, ecosystems

2. Warm up
How can you convert this chain into an ecological pyramid in which species with the most energy are at the bottom?

3. Pyramid of Energy
In a Energy Pyramid, each level represents the amount of energy that is available to that trophic level.
With each step up the pyramid, energy decreases

4. Ecological Pyramids 90,000 Secondary 200,000 Primary Consumers
Tertiary
Consumers
90,000
Secondary
200,000
Primary Consumers
1,500,000
Primary Producers

5. 10% rule
10%
90% lost as heat

6. Thursday, September 21 Ecology - HS-LS2-4
Use mathematical representations to support claims for  the cycling of matter and flow of energy among organisms in an ecosystem
Today’s agenda:
Warm up
Mini-lecture
Practice
SEP 5: use mathematics and computational thinking
Disciplinary core idea: LS2.B: Cycles of Matter and Energy Transfer in Ecosystems
Biomass, trophic levels, ecosystems

7. Warm up
Can an energy pyramid be inverted? EXPLAIN!

8. Warm up – answer key
Energy pyramids are never inverted, because energy is always lost from one trophic level to the next.
As energy flows through the food chain, there is a dramatic drop in the amount of energy each trophic level retains.

9. 10% rule
10%
90% lost as heat

10. Biomass Pyramid
Biomass – the total mass of living matter at each trophic level
As you move up the pyramid, there is less biomass because there is less energy available at that trophic level
Usually ecologists use Biomass Pyramids to determine the amount of energy

11. Biomass Pyramid 10kg Tertiary Consumer 50kg Snakes Secondary Consumer
Owls
50kg Snakes
100kg Mice
900kg Grasses
Tertiary Consumer
Secondary Consumer
Primary Consumer
Producer

12. Biomass pyramids - exception
Even though a biomass pyramid shows the total mass of organisms at each level, it doesn’t necessarily represent the amount of energy available at each level.
For example, the skeleton and beak of a bird will contribute to the biomass but aren’t available for energy.

13. Can a biomass pyramid be inverted?

14. Can a biomass pyramid be inverted?
In a pond ecosystem, the mass of phytoplankton (major producers) at any given point will be lower than the mass of the heterotrophs, such as fish and insects. This is explained as the phytoplankton reproduce very quickly, but have much shorter individual lives.

15. Inverted biomass pyramid

16. Pyramid of Numbers
The Pyramid of Numbers represents the number of organisms present at each trophic level
The relative number of organisms at each trophic level decreases because there is less energy available to support the organisms

17. Can a pyramid of number be inverted?

18. Can a pyramid of number be inverted?
Example 1
Example 2

19. Practice
If 100% of the energy is available at the first trophic level, what percentages of the energy are available at the second and third trophic levels? Explain why

20. Check your understanding
If 100% of the energy is available at the first trophic level, what percentages of the energy are available at the second and third trophic levels? 1%
10%
100%

21. Friday, September 22 Ecology - HS-LS2-4
Use mathematical representations to support claims for  the cycling of matter and flow of energy among organisms in an ecosystem
Today’s agenda:
Practice
SEP 5: use mathematics and computational thinking
Disciplinary core idea: LS2.B: Cycles of Matter and Energy Transfer in Ecosystems
Biomass, trophic levels, ecosystems

22. As you watch the video clip
Describe what you saw happening in the video?
What questions do you have?
Name one living and one non living thing in the video?
Explain how the living organisms in this video interacted with the non living things.

23. Think
Why can’t a food chain have 10 links?

24. Why can’t a food chain have 10 links?
The longer the food chain the less raw energy is available to the ones near the top.
Energy transfer is at a 10% rate from one level to another. If we start with plants at 100% the next level up will receive 10%. So they have to eat a lot of grass to meet their nutritional needs. The next one up receives 1% and so on. So the longer the food chain the more of that lower level must be eaten to maintain their health and well being. That would mean a very large carnivore would have to eat constantly to maintain their level. This could wipe out all those animals living below them in the chain.

25. Ecological Pyramid
Which level has the most energy?
Which level has the most organisms?
Which level has the least organisms?
Which level has the least energy?

26. Decomposers

27. Why is energy lost with each trophic level?

28. Why is energy lost with each trophic level?
Energy is lost with each trophic level
~90% is released to the environment as heat
~10% of the energy is used

29. Build an energy pyramid

30. Work on your trophic lab activity!

31. What kind of pyramid is this?
tertiary
consumers
secondary
primary
producers
75 g/m2
150g/m2
675g/m2
2000g/m2
Biomass

32. What kind of pyramid is this?
tertiary
consumers
secondary
primary
producers 5
5000
500,000
5,000,000
Pyramids of numbers.
Shows the numbers of individual organisms at each trophic level in an ecosystem
A vast number of producers are required to support even a few top level consumers.

33. Justify Think Pair Share
Which organism in the food chain is going to have to eat the most food to meet their energy needs? What does this mean for survival?
In a food chain, energy is passed from one link to another. When a herbivore eats, only a fraction of the energy (that it gets from the plant food) becomes new body mass; the rest of the energy is lost as waste or used up by the herbivore to carry out its life processes (e.g., movement, digestion, reproduction). Therefore, when the herbivore is eaten by a carnivore, it passes only a small amount of total energy (that it has received) to the carnivore. Of the energy transferred from the herbivore to the carnivore, some energy will be “wasted” or “used up” by the carnivore. The carnivore then has to eat many herbivores to get enough energy to grow. Because of the large amount of energy that is lost at each link, the amount of energy that is transferred decreases each time. The further along the food chain you go, the less food (and hence energy) remains available.

34. Kinds of consumers ____________ consumer who eats producers.
______________ consumer who eats only other consumers
_______________consumer who eats producers and consumers
_______________ consumer who breaks down dead organisms

35. Energy When one organism eats another, energy is __________
Food __________show the flow of energy from one organism to another (just one way flow)
Food __________ are more complicated: each organism eats more than one organism and is eaten by more than one organisms

36. What do these diagrams have in common?
1. Food Chain: Single path
3. Food Pyramid
2. Food Web: many paths

37. Arrange the following into a food web
Arrange the following into a food web. (Include arrows and group them by producers, consumers and decomposers)

38. Ultimate energy source!

39. Producers: get energy from the sun

40. Consumers: get energy from producers

41. Decomposers: Breakdown dead materials – include fungus and bacteria

43. In this food chain, the spiders are –
A producers
B primary consumers
C competitors
D secondary consumers D

44. Wolves and hawks are at the same trophic level because they –
A both live on land
B are both large mammals
C both eat primary consumers
D have similar hunting patterns

45. Which organisms in this food web can be described as both primary and secondary consumers?
A Hawks
B Weasels
C Raccoons
D Mice

46. Energy used by producers in a grassland food web is provided by —–
A sunlight
B photosynthesis
C oxygen
D carbon dioxide A

47. In this diagram of a marine food web, which term describes the sea turtle?
A Aquatic herbivores
B Autotrophic producers
C Third-level consumers
D Primary decomposers C

48. The diagram represents different levels of a marine food pyramid
The diagram represents different levels of a marine food pyramid. Between which two levels is the greatest amount of energy transferred? D
A R and Q
B S and R
C T and S
D U and T

49. According to this food web, which of the following are omnivores?
A Snakes
B Rabbits
C Mice
D Grasshoppers

50. A A small plot with 500 corn plants and 100 grasshoppers
The diagram shows a standard pyramid of numbers that indicates the number of individual organisms in a community. Which of the following situations would form a pyramid showing more consumers than producers? D
A A small plot with 500 corn plants and 100 grasshoppers
B One pond with 300 producers and one snake
C An 11,000 m3 lake with 75 fish and one alligator
D One giant oak tree with 10,000 insects and 10 lizards

51. The diagram above is intended to show relationships in an ecosystem
The diagram above is intended to show relationships in an ecosystem. What do the arrows represent? D
A The direction of population migration
B Differences in dietary habits
C Progressively smaller organisms
D The direction of energy flow

52. In this food pyramid, which level contains the greatest amount of energy?
A Tertiary consumers
B Secondary consumers
C Primary consumers
D Producers