1. Ecology Chapter 5 : How Ecosystems Work 5.1 Energy Flow in Ecosystems
5.2 The Cycling of Matter
5.3 How Ecosystems Change
All information is from and/or adapted from : Environmental Science Copyright 2013 Houghton Mifflin Harcourt Publishing Company
Pictures are cited within the picture and are from the Teacher DVD, unless otherwise noted in the picture’s citation

2. OBJECTIVES: Section 1 Energy Flow in ECOSYSTEMS
Describe how energy is transferred from the sun to producers and then to consumers.
Describe one way in which consumers depend on producers.
Identify two types of consumers.
Explain how energy transfer in a food web is more complex than energy transfer in a food chain.
Explain why an energy pyramid is a representation of trophic levels.

3. Section 1: Energy Flow in Ecosystems
Life Depends on the Sun
Energy from the sun enters an ecosystem when plants use light energy to make sugar molecules.
This happens through a process called photosynthesis.

4. Photosynthesis is the process by which plants, algae, and some bacteria use sunlight, carbon dioxide, and water to produce carbohydrates and oxygen.

5. Section 1: Energy Flow in Ecosystems
Life Depends on the Sun
** From Producers to Consumers
Because plants make their own food, they are called producers.
A producer is an organism that can make organic molecules from inorganic molecules.
Producers are also called autotrophs, or self- feeders.
Most producers get their energy directly from the sun by absorbing it through their leaves.

6. Section 1: Energy Flow in Ecosystems
Life Depends on the Sun
** From Producers to Consumers
Organisms that get their energy by eating other organisms are called consumers.
A consumer is an organism that eats other organisms or organic matter instead of producing its own nutrients or obtaining nutrients from inorganic sources.
Consumers are also called heterotrophs, or other-feeders.
Consumers get their energy indirectly by eating producers or other consumers.

7. Section 1: Energy Flow in Ecosystems
Life Depends on the Sun
**An Exception: Deep-Ocean Ecosystems
Deep-ocean communities of worms, clams, crabs, mussels, and barnacles exist in total darkness on the ocean floor, where photosynthesis cannot occur.
The producers in this environment are bacteria that use hydrogen sulfide present in the water.
Other underwater organisms eat the bacteria or the organisms that eat the bacteria.

8. Check for Understanding
QUESTION: RELATE: How do producers and consumers get energy from the sun?
ANSWER:
Sample of an acceptable answer:
A producer gets energy from the sun through photosynthesis.
A consumer get energy from the sun INDIRECTLY, by eating other organisms that eat plants or organisms the eat other organisms that have eaten plants.

9. Section 1: Energy Flow in Ecosystems
What Eats What
Organisms can be classified by what they eat.
Producers – makes its own food using light energy (photosynthesis) or chemical sources (chemosynthesis)
Examples: grasses, ferns, cactuses, flowering plants, trees, algae, some bacteria
Consumers – gets energy by eating producers or other consumers
Examples: mice, starfish, elephants, humans

10. Section 1: Energy Flow in Ecosystems
What Eats What
Types of Consumers:
Herbivores - eat producers
Example: cows, sheep, deer, grasshopper
Carnivores – eat other consumers
Examples: lions, hawks, snakes, sharks
Omnivores – eat both producers and consumers
Example: bears, pigs, gorillas, humans
Decomposers – break down organic matter from dead organisms
Example: fungi, bacteria

11. Section 1: Energy Flow in Ecosystems
Cellular Respiration: Burning the Fuel
An organism obtains energy from the food it eats.
This food must be broken down within its body.
The process of breaking down carbohydrates to yield energy is called cellular respiration.
Cellular respiration occurs inside the cells of most organisms.

12. Section 1: Energy Flow in Ecosystems
Cellular Respiration: Burning the Fuel
During cellular respiration, cells absorb oxygen and use it to release energy from food.
Through cellular respiration, cells use glucose (sugar) and oxygen to produce carbon dioxide, water, and energy.

13. Section 1: Energy Flow in Ecosystems
Cellular Respiration: Burning the Fuel
Part of the energy obtained through cellular respiration is used to carry out daily activities.
Excess energy is stored as fat or sugar.

14. Section 1: Energy Flow in Ecosystems
Energy Transfer
Each time an organism eats another organism, an energy transfer occurs.
This transfer of energy can be traced by studying food chains, food webs, and trophic levels.

15. Section 1: Energy Flow in Ecosystems
Energy Transfer
** Food Chains
A food chain is a sequence in which energy is transferred from one organism to the next as each organism eats another organism.

16. Section 1: Energy Flow in Ecosystems
Energy Transfer
** Food Webs
Ecosystems, however, almost always contain more than one food chain.
A food web shows many feeding relationships that are possible in an ecosystem.

17. Section 1: Energy Flow in Ecosystems
Energy Transfer
** Trophic Levels
Each step in the transfer of energy through a food chain or food web is known as a trophic level.
A trophic level is one of the steps in a food chain or food pyramid; examples include producers and primary, secondary, and tertiary consumers.
Each time energy is transferred, some of the energy is lost as energy in the form of heat.
Therefore, less energy is available to organisms at higher trophic levels.
One way to visualize this is with an energy pyramid.

18. Section 1: Energy Flow in Ecosystems
Energy Transfer
** Energy Pyramid

19. Section 1: Energy Flow in Ecosystems
Energy Transfer
** Energy Pyramid
Each layer of the pyramid represents one trophic level.
Producers form the base of the energy pyramid, and therefore contain the most energy.
The pyramid becomes smaller toward the top, where less energy is available.

20. Section 1: Energy Flow in Ecosystems
Energy Transfer
** How Energy Loss Affects an Ecosystem
Decreasing amounts of energy at each trophic level affects the organization of an ecosystem.
Energy loss affects the number of organisms at each level.
Energy loss limits the number of trophic levels in an ecosystem.

21. OBJECTIVES: TO BE COMPLETED SECTION 1: ENERGY FLOW IN ECOSYSTEMS
Describe how energy is transferred from the sun to producers and then to consumers.
____________________________________________ ____________________________________________ ____________________________________________ ____________________________________________
Describe one way in which consumers depend on producers.

22. OBJECTIVES: TO BE COMPLETED SECTION 1: ENERGY FLOW IN ECOSYSTEMS (continued)
Identify two types of consumers.
1) ____________________________________
2) ____________________________________
Explain how energy transfer in a food web is more complex than energy transfer in a food chain.
____________________________________________ ____________________________________________ ____________________________________________ ____________________________________________

23. OBJECTIVES: TO BE COMPLETED SECTION 1: ENERGY FLOW IN ECOSYSTEMS (continued)
Explain why an energy pyramid is a representation of trophic levels.
____________________________________________ ____________________________________________ ____________________________________________ ____________________________________________

24. Ecology Chapter 5 : How Ecosystems Work 5.1 Energy Flow in Ecosystems
5.2 The Cycling of Matter
5.3 How Ecosystems Change
All information is from and/or adapted from : Environmental Science Copyright 2013 Houghton Mifflin Harcourt Publishing Company
Pictures are cited within the picture and are from the Teacher DVD, unless otherwise noted in the picture’s citation

25. OBJECTIVES: Section 2 The Cycling of Matter
Describe the short-term and long-term process of the carbon cycle.
Identify one way that humans are affecting the carbon cycle.
List the three stages of the nitrogen cycle.
Describe the role that nitrogen-fixing bacteria play in the nitrogen cycle.
Explain how the excess use of fertilizer can affect the nitrogen and phosphorus cycles.

26. Section 2: The Cycling of Matter
The Carbon Cycle
The carbon cycle is the movement of carbon from the nonliving environment into living things and back to the environment.
Carbon is the essential component of proteins, fats, and carbohydrates, which make up all organisms.
CHO-CHO-CHO (Carbohydrate 1:2:1)
CHO – (lipid/fat, no specific amounts)
CHOSN (protein)
CHOPN (nucleic acid)

27. Section 2: The Cycling of Matter
The Carbon Cycle

28. Section 2: The Cycling of Matter
The Carbon Cycle
Carbon exists in air, water, and living organisms.
Producers convert carbon dioxide in the atmosphere into carbohydrates during photosynthesis. (carbohydrates- sugars)
Consumers obtain carbon from the carbohydrates in the producers they eat. (carbohydrates- sugars)

29. Section 2: The Cycling of Matter
The Carbon Cycle
During cellular respiration, some of the carbon is released back into the atmosphere as carbon dioxide.
Some carbon is stored in limestone, forming one of the largest “carbon sinks” on Earth.

30. Section 2: The Cycling of Matter
The Carbon Cycle
Carbon stored in the bodies of organisms as fat, oils, or other molecules, may be released into the soil or air when the organisms dies.
These molecules may form deposits of coal, oil, or natural gas, which are known as fossil fuels.
Fossil fuels store carbon left over from bodies of organisms that died millions of years ago.

31. Section 2: The Cycling of Matter
The Carbon Cycle
** How Humans Affect the Carbon Cycle
Humans burn fossil fuels, releasing carbon dioxide into the atmosphere.
Increased levels of carbon dioxide contribute to climate change.
Carbon dioxide is a greenhouse gas along with water vapor and other gases.
Greenhouse gases absorb and re-radiate infrared energy, warming Earth.

32. Check for Understanding
QUESTION: RELATE: Explain how the carbon emission from an 18-wheeler truck, (such as the one pictured) enters and exits producers such as the trees in your local neighborhood.
ANSWER:
Sample of an acceptable answer:
Carbon dioxide emitted from the truck enters the trees through photosynthesis.
Plants use carbon dioxide, water, and sunlight to produce sugar and oxygen.

33. Section 2: The Cycling of Matter
The Nitrogen Cycle
The nitrogen cycle is the process in which nitrogen circulates among the air, soil, water, plants, and animals in an ecosystem.
All organisms need nitrogen to build proteins, which are used to build new cells.
Nitrogen makes up 78 percent of the gases in the atmosphere.

34. Section 2: The Cycling of Matter
The Nitrogen Cycle
Nitrogen must be altered, or fixed, before organisms can use it. (N2)
Only a few species of bacteria can fix atmospheric nitrogen into chemical compounds that can be used by other organisms.
These bacteria are known as nitrogen-fixing bacteria.

35. Section 2: The Cycling of Matter
The Nitrogen Cycle
Nitrogen-fixing bacteria are bacteria that convert atmospheric nitrogen into ammonia.
These bacteria live in nodules on the roots of plants called legumes, which include beans, peas, and clover.
The bacteria use sugar provided by the legumes to produce nitrogen containing compounds such as nitrates. (nitrogen and oxygen)
Excess nitrogen fixed by the bacteria is released into the soil.

36. Section 2: The Cycling of Matter
The Nitrogen Cycle

37. Section 2: The Cycling of Matter
The Nitrogen Cycle
** Decomposers and the Nitrogen Cycle
Nitrogen stored within the bodies of living things is returned to the nitrogen cycle once those organisms die.
Decomposers break down decaying plants and animals, as well as plant and animal wastes.
After decomposers return nitrogen to the soil, bacteria transform a small amount of the nitrogen into nitrogen gas, which then returns to the atmosphere to complete the nitrogen cycle.

38. Section 2: The Cycling of Matter
The Phosphorus Cycle
Phosphorus is an element that is part of many molecules that make up the cells of living organisms.
Plants get the phosphorus they need from soil and water, while animals get their phosphorus by eating plants or other animals that have eaten plants.
The phosphorus cycle is the cyclic movement of phosphorus from the environment to organisms and then back to the environment.

39. Section 2: The Cycling of Matter
The Phosphorus Cycle

40. Section 2: The Cycling of Matter
The Phosphorus Cycle
Phosphorus may enter soil and water when rocks erode. Small amounts of phosphorus dissolve as phosphate, which moves into soil, water, and groundwater.
Plants absorb phosphates in the soil through their roots.

41. Section 2: The Cycling of Matter
The Phosphorus Cycle
Some phosphorus washes off the land and ends up in water bodies.
Because many phosphate salts are not soluble in water, they sink to the bottom and accumulate as sediment.

42. Section 2: The Cycling of Matter
The Phosphorus Cycle
** Fertilizers: Nitrogen & Phosphorus Cycles
Fertilizers, which people use to stimulate and maximize plant growth, contain both nitrogen and phosphorus.
Excessive amounts of fertilizer can enter terrestrial and aquatic ecosystems through runoff.

43. Section 2: The Cycling of Matter
The Phosphorus Cycle
** Fertilizers: Nitrogen & Phosphorus Cycles
Excess nitrogen and phosphorus can cause rapid growth of algae.
Excess algae can deplete an aquatic ecosystem of important nutrients such as oxygen, on which fish and other aquatic organisms depend.

44. Check for Understanding
QUESTION: RECOGNIZE How do algal blooms harm aquatic ecosystems ?
ANSWER:
Sample of an acceptable answer:
Algal blooms can harm aquatic ecosystems by depleting their nutrients, such as oxygen.

45. OBJECTIVES: TO BE COMPLETED SECTION 2: The Cycling of Matter
Describe the short-term and long-term process of the carbon cycle.
____________________________________________ ____________________________________________ ____________________________________________ ____________________________________________
Identify one way that humans are affecting the carbon cycle. ____________________________________________ ____________________________________________ ____________________________________________ ____________________________________________

46. OBJECTIVES: TO BE COMPLETED SECTION 2: The Cycling of Matter (continued)
List the three stages of the nitrogen cycle.
1) ___________________________________________
2) ___________________________________________
3) ___________________________________________
Describe the role that nitrogen-fixing bacteria play in the nitrogen cycle.
____________________________________________ ____________________________________________ ____________________________________________ ____________________________________________

47. OBJECTIVES: TO BE COMPLETED SECTION 2: The Cycling of Matter (continued)
Explain how the excess use of fertilizer can affect the nitrogen and phosphorus cycles.
____________________________________________ ____________________________________________ ____________________________________________ ____________________________________________

48. Ecology Chapter 5 : How Ecosystems Work 5.1 Energy Flow in Ecosystems
5.2 The Cycling of Matter
5.3 How Ecosystems Change
All information is from and/or adapted from : Environmental Science Copyright 2013 Houghton Mifflin Harcourt Publishing Company
Pictures are cited within the picture and are from the Teacher DVD, unless otherwise noted in the picture’s citation

49. OBJECTIVES: Section 3 How Ecosystems Change
List two types of ecological succession.
Explain how a pioneer species contributes to ecological succession.
Describe how lichens contribute to primary succession.
Explain what happens during old-field succession.

50. Section 3: How Ecosystems Change
Ecological Succession
Ecosystems are constantly changing.
Ecological succession is a gradual process of change and replacement of the types of species in a community.
Each new community that arises often makes it harder for the previous community to survive.

51. Section 3: How Ecosystems Change
Ecological Succession
** Primary Succession
Primary succession is a type of succession that occurs on a surface where no ecosystem existed before. It begins in an area that previously did not support life.
Primary succession can occur on new islands created by volcanic eruptions, in areas exposed when a glacier retreats, or any other surface that has not previously supported life.
Primary succession is much slower than secondary succession. This is because it begins where there is no soil.

52. Section 3: How Ecosystems Change
Ecological Succession
** Primary Succession
A pioneer species is a species that colonizes an uninhabited area and that starts an ecological cycle in which many other species become established.
Over time, a pioneer species will make the new area habitable for other species.
The first pioneer species to colonize bare rock are usually bacteria and lichens, which can live without soil.
The growth of lichens breaks down the rock, which with the action of water, begins to form soil.

53. Section 3: How Ecosystems Change
Ecological Succession
** Secondary Succession
Secondary succession occurs on a surface where an ecosystem has previously existed. It is the process by which one community replaces another community that has been partially or totally destroyed.
Secondary succession can occur in ecosystems that have been disturbed or disrupted by humans, animals, or by natural process such as storms, floods, and earthquakes.

54. Section 3: How Ecosystems Change
Ecological Succession
** Secondary Succession
A climax community is the final, stable community in equilibrium with the environment.
Even though a climax community may change in small ways, this type of community may remain the same through time if it is not disturbed.

55. Check for Understanding
QUESTION: COMPARE: How is secondary succession different from primary succession?
ANSWER:
Sample of an acceptable answer:
Primary succession occurs where no ecosystem existed before.
Secondary succession occurs where an ecosystem previously existed.

56. Section 3: How Ecosystems Change
Ecological Succession
** Old Field Succession
Old-field succession is a type of secondary succession that occurs when farmland is abandoned.
When a farmer stops cultivating a field, grasses and weeds quickly grow and cover the abandoned land.
Over time, taller plants, such as perennial grasses, shrubs, and trees take over the area.

57. Section 3: How Ecosystems Change
Ecological Succession
** Secondary Succession

58. Check for Understanding
QUESTION: INFER: Why do you think smaller plants disappear after pine trees begin to grow?
ANSWER:
Sample of an acceptable answer:
Shade from the pine trees keeps smaller plants from receiving the sunlight they need to grow.

59. Section 3: How Ecosystems Change
Ecological Succession
** Fire and Secondary Succession
Natural fires caused by lightning are a necessary part of secondary succession in some communities.
Minor forest fires remove accumulations of brush and deadwood that would otherwise contribute to major fires that burn out of control.
Some animal species also depend on occasional fires because the feed on the vegetation that sprouts after a fire has cleared the land.

60. Check for Understanding
QUESTION: IDENTIFY: List two ways that fire can be beneficial to a forest community.
ANSWER:
Sample of an acceptable answer:
Two benefits include the removal of accumulated brush and the return of nutrients to the soil.

61. OBJECTIVES: TO BE COMPLETED SECTION 3: The Cycling of Matter
List two types of ecological succession.
1) ___________________________________________
2) ___________________________________________
Explain how a pioneer species contributes to ecological succession.
_____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________

62. OBJECTIVES: TO BE COMPLETED SECTION 3: How Ecosystems Change (continued)
Describe how lichens contribute to primary succession.
_____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________
Explain what happens during old-field succession.

63. Vocabulary to Know: Section 1 – – Energy Flow in Ecosystems
Photosynthesis – the process by which plants, algae, and some bacteria use sunlight, carbon dioxide, and water to reproduce carbohydrates and oxygen.
Producer – an organism that can make organic molecules from inorganic molecules; a photosynthetic or chemosynthetic autotroph that serves as the basic food source in an ecosystem.
Consumer – an organism that eats other organisms or organic matter instead of producing its own nutrients or obtaining nutrients from inorganic sources.
Decomposer – an organism that feeds by breaking down organic matter from dead organisms; examples include bacteria and fungi.
Cellular Respiration – the process by which cells produce energy from carbohydrates; atmospheric oxygen combines with glucose to form water and carbon dioxide.
Food Chain – the pathway of energy transfer through various stages as a result of the feeding patterns of a series of organisms.
Food Web – a diagram that shows the feeding relationships between organisms in an ecosystem.
Trophic Level – one of the steps in a food chain or food pyramid; examples include producers and primary, secondary, and tertiary consumers.

64. Vocabulary to Know: Section 2 – The Cycling of Matter
Carbon Cycle – the movement of carbon from the non-living environment into living things and back.
Nitrogen-Fixing Bacteria – bacteria that convert atmospheric nitrogen into ammonia.
Nitrogen Cycle – the process in which nitrogen circulates among the air, soil, water, plants, and animals in an ecosystem.
Phosphorus Cycle – the cyclic movement of phosphorus in different chemical forms from the environment to organism and then back to the environment.
Section 3 – SECTION TITLE
Ecological Succession – a gradual process of change and replacement in a community.
Primary Succession – succession that begins in an area that previously did not support life.
Secondary Succession – the process by which one community replaces another community that has been partially or totally destroyed.
Pioneer Species – a species that colonizes an uninhabited area and that starts an ecological cycle in which many other species become established.
Climax Community – a final, stable community in equilibrium with the environment