ENERGY FLOW:

Where does the Energy Go?

(fig 34.2, 34.3)

Laws of Thermodynamics…

1. Energy is neither created or destroyed, only transferred

2. With every transfer, some energy is lost to HEAT (or other less available form of energy)

A little vocab…

Autotroph- an organism that can make its own foodAlso called PRODUCERS

Heterotroph- an organism that cannot make its own food and must obtain it from eating

BIOTIC COMPONENTS of an ECOSYSTEM

PRODUCERS

(produce food)

Chemoautotrophs- bacteria that use inorganic chemicals like ammonia, nitrites, sulfides to make food)

Photoautotrophs-use energy from the sun…produce most of the organic nutrients for the biosphere

CONSUMERS(consume food)

Need a preformed souce of organic nutrients

Consumers can be :Primary/Secondary/

Tertiary(See next)

DECOMPOSERS(Break down dead organic matter)VALUABLE- release inorganic

nutrients for plants to take up

Ex- nonphotosynthetic bacteria, fungi

DETRITUS= partially decomposed matter in the water or

soil

What does each arrow represent?

Kinds of Consumers

All consumers are heterotrophs

Examples-ScavengersPrimary/1st levelSecondary/ 2nd levelTertiary/ 3rd level

Kinds of consumers continued…

Herbivore : Feed on grass and other plantsPrimary Consumers

Carnivore : Eat animalsCarnivores that eat Herbivores

Secondary ConsumersCarnivores that eat other carnivores

Tertiary ConsumersOmnivore : Eat both plants and animals.

FOOD CHAINS…

Food Chains show how matter and energy move through an ecosystem

A weakness in the chain…

Food chains can only have up to about 5 links … Why?

because the animals at the end of the chain would not get enough nutrients and energy.

So…most animals are part of more than one food chain in order to meet their requirements…

This creates…

FOOD WEBS

Interconnected food chains. They express all the possible feeding

relationships at each trophic level in a community.

IMPORTANT POINT:Arrows are drawn from food source to

consumers (substitute “eaten by” for arrows)

All food is NOT created equal…

TROPHIC LEVELS: All the organisms that feed at a particular link in a food chain

10% rule: In general only about 10% of the energy from one trophic level is available to the next!!!

Biomass Pyramid

The total amount of living material present in each trophic level (a feeding step in a food chain).

NOTE: are there more autotrophs or heterotrophs?

WHY?

Pyramid of Numbers

Each bar in the pyramid represents the size of the populatoin at that trophic

level

Pyramids of Energy

Each bar in the pyramid represents the energy available within that trophic level

Which of the following organisms are producers?

1

2

3

4

5

6

7

8

9

0

1 2 3 4 5 6 7 8 9 0

11% 11%

100%

5%

95%

5%5%

0%

5%5%

1. 1

2. 2

3. 3

4. 4

5. 5

6. 6

7. 7

8. 8

9. 9

10. 0

Which of the following organisms are consumers?

1

2

3

4

5

6

7

8

0

1

2

3

4

5

6

7

9

0

1 2 3 4 5 6 7 8 9 0

94%

89%

0%

94%

6%

89%

83%

94%94%

89%

1. 12. 23. 34. 45. 56. 67. 78. 89. 910. 0

Which of these are primary consumers?

0%

83%

44%

11%

22%

11%

78%

0%

56%

11% 1. 12. 23. 34. 45. 56. 67. 78. 89. 910. 0

8

1

2

3

4

5

6

7

9

0