1. Energy Flow in Ecosystems

2. Each organism has a role in the movement of energy through the ecosystem.
An organism’s energy role is determined by how it gets its energy and how it interacts with living things in its ecosystem.
As noted from the activity, organisms obtain their energy from different sources. The role is part of the organism’s niche in the ecosystem.

3. An organism’s energy role in an ecosystem may be that of a producer, consumer, or decomposer.

4. Energy first enters most ecosystems as sunlight.
Organisms such as plants, algae, and some bacteria capture the energy of sunlight and store it as an energy source through the process of photosynthesis.
These organisms use the sun’s energy to turn water and carbon dioxide into molecules such as sugars and starches through photosynthesis. (discuss formula).
Carbon dioxide + Water + Sunlight Glucose + Oxygen

5. An organism that can make its own food is a producer.
Producers are the source of all food in an ecosystem.
As you have learned, organisms that carry out photosynthesis are called autotrophs. Another word for autotroph is producer.

6. What substances are needed for photosynthesis?
What substances are produced?
What would happen if you put a large piece of cardboard over an area of grass for about a week?
If you were a producer, what attributes would you possess?
If you could come up with a book or movie title for either photosynthesis or the role of a producer (autotroph), what would it be?

7. Consumers depend on the producers for food and energy.
An organism that obtains energy by feeding on other organisms is a consumer.
Consumers depend on the producers for food and energy.
Remember - heterotrophs cannot make their own food. Another word for heterotroph is a consumer.

8. Consumers are classified by what they eat.
Consumers that eat only plants are called herbivores.
Caterpillars, cattle, and deer are herbivores.
This term herbivore comes from the latin word “herba”, which means grass or herb, and “vorare”, which means to eat.

9. Consumers that only eat animals are called carnivores.
Lions, spiders, and snakes are examples of carnivores.
Some carnivores are scavengers that feed on the bodies of dead organisms.
Vultures, hyenias, and catfish are examples of scavengers.
Carnivore - The latin word for flesh is “carnis”, and to eat is “vorare” (flesh eaters).

10. Consumers that eat both plants and animals are called omnivores.
Crows, goats, and most humans are examples of omnivores.
Omnivore – latin word “omni” means all.

11. Two major groups of decomposers are bacteria and fungi.
Organisms that break down waste and dead organisms and return the raw materials to the environment are called decomposers.
Two major groups of decomposers are bacteria and fungi.
Molds and mushrooms are examples of fungi.
While obtaining energy for their own needs, decomposers return simple molecules to the environment.
What would happen if there were only producers and consumers in an ecosystem. Organisms would continue to take water, minerals, and other materials – all these materials would run low. If materials were not replaced, new organisms would not grow. If waste and dead organisms were not removed, they would pile up until they overwhelm the living. Organisms in an ecosystem produce waste and eventually die. Other Organisms are needed to take care of this waste.

12. Name three organisms that are consumers.
Name two organisms that are decomposers.
Compare and contrast herbivores and carnivores.
Which would you rather be – a producer, consumer, or decomposer? Why?
If each of these roles in an ecosystem (producers, consumers, and decomposers) had jobs in the real world, what would it be? Why?

13. Energy enters most ecosystems as sunlight and is changed into sugar and starch molecules by producers.
This energy is transferred to each organism that eats a producer, and then to other organisms that feed on these consumers.
The movement of energy through an ecosystem can be shown in diagrams called food chains or food webs.

14. A food chain is a series of events in which one organism eats another and receives energy.
Look at the diagram. The first organism in a food chain is always a producer such as grass. The second organism is a consumer that eats the producer called a first-level consumer. The mouse is the first-level consumer. A second-level consumer eats the first-level consumer. The kestrel is the second-level consumer.

15. A food web consists of many overlapping food chains in an ecosystem.
A food chain shows one possible path along which energy moves through an ecosystem. However, you do not eat the same thing every day – neither do most consumers. A more realistic way to show the flow of energy through an ecosystem is a food web. (discuss food web diagram and trace the path of energy through the producers, consumers, and decomposers).

16. What is the first organism in a food chain and why?
What is the source of energy for most ecosystems?
Draw a simple food chain (other than example given) and label each organism as a producer, first-level consumer, and second-level consumer.
Why are food webs a more realistic way of portraying ecosystems than food chains?
Due to an environmental catastrophe, all the plankton in the salt water biome of the world has been eliminated. Knowing that plankton is a producer for the majority of first-level consumers, how would this affect your food web as a human?
Come up with a song title to describe any level of the food chain or food web.

17. When an organism in an ecosystem eats, it obtains energy.
The organism uses some of that energy to move, grow, reproduce, and carry out life’s activities.
As a result, only some of the energy is available to the next organism in the food web.
All organisms need energy to maintain its daily life’s functions.

18. The most energy is available at the producer level.
A diagram called an energy pyramid shows the amount of energy that moves from one feeding level to another in a food web.
The most energy is available
The most energy is available at the producer level.
At each level in the pyramid, there is less available energy than at the level below.

19. An organism needs 90% of its energy for life functions or is lost as heat to the environment.
Therefore, only 10% of energy at one level is transferred to the next higher level.
As a result, most food webs only have 3 or 4 feeding levels. Organisms at higher feeding levels of an energy pyramid do not necessarily require less energy that organisms at lower levels. However, so much energy is lost at each level, the amount of energy in the producer level, limit the consumers an ecosystem can support. As a result, there are fewer organisms at the highest level of a food web.

20. What is the purpose of an energy pyramid?
Use your knowledge of food chains and the energy pyramid to explain why the number of mice in a grassland ecosystem is greater than the number of hawks.
Reviewing the levels of the energy pyramids, what position would you want? Why?
Using the poetic element “alliteration”, describe an energy level in the energy pyramid.

21. The End … ?