1. How Ecosystems Work

2. Big Ideas
The flow of energy, cycling of materials, and ecological succession combine to affect how an ecosystem works.
Organisms need energy to survive. Some organisms can convert directly from the sun, others get their energy indirectly from the sun.
The cycling of materials such as carbon, nitrogen, water and phosphorous keep nutrients balanced in an ecosystem.

3. Section 1: Energy Flow In Ecosystems
Describe how energy is transferred from the sun to producers and then consumers
Explain what a food chain and food web are
Explain why an energy pyramid is a representation of trophic levels
Terms: photosynthesis, producer, consumer, decomposer, cellular respiration, food chain, food web, trophic levels

4. What makes an ecosystem like this “work?”

5. Life Depends On The Sun Average Star 93 million miles away
Nuclear Fusion
No Sun, No Life

6. Life Depends on the Sun
ALL organisms need a constant supply of energy or they die
Why do plants grow upwards?

7. Life Depends on the Sun
The ultimate source of almost all energy for organisms is the SUN.
What did you eat? (Nuclear Powered?)
Only some deep sea creatures do not get energy from sun
Mmmm, solar energy tastes good!

8. Life Depends on the Sun
Photosynthesis: plants use the suns energy, water and CO2, to make energy.
Base of ALL food chains

9. Almost all organisms depend either directly or indirectly on photosynthesis

10. How do other Organisms Use Energy
Most organisms spend large amounts of time/energy in search of food and a mate.

11. How do other Organisms Use Energy
Cellular Respiration: processes of breaking down food to yield energy
Gives energy to walk, read, grow, think, run, fight diseases
Excess stored as fat

12. Glucose (sugar) + Oxygen yields carbon dioxide, water and energy
REACTANTS PRODUCTS

13. Energy Transfer in an Ecosystem
Producer: an organism that makes it own food.
Plants
Autotrophs, self-feeders
Use sunlight
Base of all food chains

14. From Producer to Consumer
Consumer: gets it energy by eating producers or other consumers
Heterotrophs
Indirectly solar powered

15. Types of Consumers Herbivore: eats only producers (vegetarian)
Cows, sheep, deer, grasshopper, mice, rabbits

16. Types of Consumers Carnivore: eats other consumers
Lion, hawks, snakes, alligator, whales

17. Types of Consumers Omnivore: eats both producers and consumers
Bears, pigs, raccoons and most humans

18. Types of Consumers Decomposer: breaks down dead decaying organisms
Critical to ecosystem health
Returns nutrients
Fungus, bacteria

19. Energy Transfer
Each time one organism eats another, energy is transferred
Ecosystems are all about energy flowing from one organism to another

20. Energy Transfer Who are the producers? Consumers? Herbivores?
Carnivores?
Omnivores?
Decomposers?
Where does the energy start?

21. Energy Transfer
Food Chain: linear sequence in which energy is transferred from one organism to another
Starts with producers

22. Energy Flow
Food Web: shows many feeding relationships that are possible in a ecosystem
More complex and realistic

26. Energy Flow
Trophic Level: each step which energy is transferred

27. Energy Pyramid

28. Energy Flow
Why are there fewer organisms at the top? (Why fewer Hawks than the other birds they prey on)
Why aren’t there more than 4-5 trophic levels in a energy pyramid?

29. Energy Flow At each trophic level about 90% of energy is lost
Cellular respiration
Lost to body heat and carry out living

30. Energy Flow
Why are there fewer organisms at the top? (Why fewer bears than the fruit they feed on)
Why aren’t there more than 4-5 trophic levels in a energy pyramid?

31. Section 1 Review
Describe how energy is transferred from the sun to producers and then consumers
Explain what a food chain and food web are
Explain why an energy pyramid is a representation of trophic levels
Terms: photosynthesis, producer, consumer, decomposer, cellular respiration, food chain, food web, trophic levels

32. Section 2: Cycling Matter
Explain how matter is cycle in the carbon, nitrogen and phosphorous cycles.
Identify ways that humans are impacting the carbon cycle.
Explain how excess use of fertilizer can lead to impacts for the nitrogen and phosphorous cycles.
Terms: carbon cycle, nitrogen cycle, nitrogen-fixation, phosphorous cycle

33. The Cycling of Material
Just like water – water cycle – other nutrients also move throughout the earth
Biogeochemical cycles
CARBON
NITROGEN
PHOSPHOROUS

34. Carbon Cycle
Carbon Cycle: process by which carbon is cycled between the atmosphere, land, water and organisms

35. Carbon Cycle Carbon “duct-tape” of life
Carbohydrates in cellular respiration
Fossil Fuels (coal, oil, natural gas) made from ancient dead decayed organisms… ancient carbon

36. Burning Fossil Fuels leads to what problems?
Burn anything that was/is living and what product do you get?

37. Carbon Cycle What is a product of cellular respiration?
What do you breathe out?

38. Carbon can move quickly or very slowly through cycle

39. Nitrogen Cycle
Nitrogen Cycle: process by which nitrogen is cycled through the atmosphere, bacteria and other organisms.

40. Nitrogen Cycle Nitrogen
Needed by all organisms for build cells (proteins)
78% of atmosphere (unusable by most organisms)
Decomposers break down animal waste releasing nitrogen to soil

41. Nitrogen Cycle
Nitrogen Fixation: bacteria that are able to take nitrogen in air and make it useful as plant fertilizer
On roots of plants
Critical to life

43. Phosphorous Cycle
Phosphorous Cycle: the movement of phosphorous from the environment to organisms and back.

44. Phosphorous Cycle Phosphorous: Teeth and bones
Nutrient for plant growth
Found in rocks and soil
Animal wastes contain phosphorous

45. Too Much Nitrogen and/or Phosphorous
Fertilizers put on plants contain both nitrogen and phosphorous
Too much fertilizer runs off into water
Causes Algae blooms

46. Algae blooms like this caused by excess nitrogen and phosphorous can kill fish and create “dead zones”

47. Section 2 Review
Explain how matter is cycle in the carbon, nitrogen and phosphorous cycles.
Identify ways that humans are impacting the carbon cycle.
Explain how excess use of fertilizer can lead to impacts for the nitrogen and phosphorous cycles.
Terms: carbon cycle, nitrogen cycle, nitrogen-fixation, phosphorous cycle

49. Section 3 How Ecosystems Change
Describe the types of ecological succession
Explain what pioneer species are
Terms: ecological succession, primary succession, secondary succession, pioneer species

50. Ecological Succession
Ecosystems constantly are changing (some fast some slowly)
Young Forests vs. Old Forest
Quick change like fire, or volcanic eruption

51. Ecological Succession
Ecological Succession: the gradual change and replacement of some or all species in a community
Neighborhood changes over time

54. Ecological Succession
Primary Succession: occurs on a surface where no ecosystem existed before (FIRST)
Rocks, sand dunes
Uncommon!

55. Ecological Succession
Secondary Succession: occurs on a surface where an ecosystem has previously existed
More common
Land Disturbed by humans, other animals
Flood, fire, volcano

56. Secondary ecological succession after a fire on the left
Fires are a natural part of many forest ecosystems

57. Ecological Succession
Pioneer Species: first organisms to colonize a newly available land
Lichens, bacteria, small plants often pioneers

58. Pioneer species in a parking lot crack

59. Ecological Succession
Climax Community: final stable community.
Continues to change in small ways, but fairly stable if undisturbed

61. Section 3 Review Describe the types of ecological succession
Explain what pioneer species are
Terms: ecological succession, primary succession, secondary succession, pioneer species

62. Chapter 5 Review
The flow of energy, cycling of materials, and ecological succession combine to affect how an ecosystem works.
Organisms need energy to survive. Some organisms can convert directly from the sun, others get their energy indirectly from the sun.
The cycling of materials such as carbon, nitrogen, water and phosphorous keep nutrients balanced in an ecosystem.

63. How is energy transferred from one organism to another?
Chapter 5 Review Questions
How is energy transferred from one organism to another?
What role to producers play? Consumers? Decomposers?
What is the difference between a herbivore and an omnivore?
Give an example of energy flow in a food chain.