1. ENERGY FLOW IN ECOSYSTEMS

2. ENERGY FLOW IN ECOSYSTEMS
HOW ENERGY MOVES THROUGH ECOSYSTEMS
The flow of energy is the most important factor that controls what kind of organisms live in an ecosystem and how many organisms it can support.

3. ENERGY FLOW IN ECOSYSTEMS
HOW ENERGY MOVES THROUGH ECOSYSTEMS
THE PRIMARY ENERGY SOURCE
Producers use light to make (food) organic compounds.
These compounds are either broken down to release energy or the compounds are further assimilated and are reformed into the bodies of other organisms that eat the producers (plants).

4. ENERGY FLOW IN ECOSYSTEMS
HOW ENERGY MOVES THROUGH ECOSYSTEMS
PRIMARY PRODUCTIVITY – the amount of organic material that the photosynthetic organisms of an ecosystem produce.

5. ENERGY FLOW IN ECOSYSTEMS
HOW ENERGY MOVES THROUGH ECOSYSTEMS
PRODUCERS – organisms that make their own food from energy and carbon atoms in their environment; autotrophs.
CONSUMERS - Organisms that must obtain energy to build molecules by consuming (eating) other organisms; heterotrophs.

6. ENERGY FLOW IN ECOSYSTEMS
HOW ENERGY MOVES THROUGH ECOSYSTEMS
FOOD CHAIN – linear pathway of energy transfer in an ecosystem.

7. ENERGY FLOW IN ECOSYSTEMS
HOW ENERGY MOVES THROUGH ECOSYSTEMS
FOOD WEB – a network of interconnected food chains in an ecosystem.

8. ENERGY FLOW IN ECOSYSTEMS
HOW ENERGY MOVES THROUGH ECOSYSTEMS
A food chain shows the flow of energy through the different trophic levels.
Arrows are used to indicate the direction in which the energy flows.

9. ENERGY FLOW IN ECOSYSTEMS
HOW ENERGY MOVES THROUGH ECOSYSTEMS
TROPHIC LEVEL – a group of organisms that have the same source of energy; a step in a food chain.

10. ENERGY FLOW IN ECOSYSTEMS
HOW ENERGY MOVES THROUGH ECOSYSTEMS
Some ecosystems contain a trophic level of carnivores that consume other carnivores.
These tertiary consumers and quaternary consumers are not found in every ecosystem.

11. ENERGY FLOW IN ECOSYSTEMS
HOW ENERGY MOVES THROUGH ECOSYSTEMS
TROPHIC LEVELS
Trophic levels are the means in which ecologists study how energy is transferred in an ecosystem. Every organism is assigned into a trophic level by ecologists.
HERBIVORE
CARNIVORE
OMNIVORE
DECOMPOSER
“DETRITIVORE”

12. ENERGY FLOW IN ECOSYSTEMS
HOW ENERGY MOVES THROUGH ECOSYSTEMS
HERBIVORES – organisms that only eat plants or algae.
CARNIVORES - Flesh eating (meat eating) organisms.
OMNIVORES – animals that eat both plants and animals.

13. ENERGY FLOW IN ECOSYSTEMS
HOW ENERGY MOVES THROUGH ECOSYSTEMS
DETRITIVORES – organisms that obtain their energy by feeding on dead organisms or wastes. Also referred to as scavengers.
DECOMPOSERS - organisms that cause decay.

14. ENERGY FLOW IN ECOSYSTEMS
HOW ENERGY MOVES THROUGH ECOSYSTEMS
What is a forage fish? A forage fish is any fish eaten by large predatory fish, seabirds or marine mammals. They are usually abundant and often swim in large schools. Forage fish are an important link in the marine food web because they transfer energy between primary and secondary producers, such as plankton, to top predators such as seabirds and larger fish.
Dolphin
Forge Fish
Plankton

15. ENERGY FLOW IN ECOSYSTEMS
One of the important things scientists want to know is what kinds of fish are available to seabirds. In other words, what are the choices on the menu for a seabird dining at its ocean café? Scientists also need to know the fish's depth and location in the water, and how many fish there are. Scientists want to know how old, how nutritious, and how fattening the fish are. To answer these questions scientists collect a sample of fish each year by a variety of methods. These methods include beach seining, cast netting, bottom trawling, and mid water trawling. Hydroacoustic equipment and SCUBA diving is also used to study fish. Looking inside Pacific halibut stomachs to see what kinds of forage fish is a gross but effective technique to see what they are eating.

16. ENERGY FLOW IN ECOSYSTEMS
ENERGY IS LOST IN A ENERGY PYRAMID
ENERGY PYRAMID – diagram that depicts each trophic level in an ecosystem and how much energy is stored in each trophic level.
BIOMASS – the dry weight of tissue and other organic matter found in a specific ecosystem.

17. ENERGY FLOW IN ECOSYSTEMS
The energy pyramid pictured illustrate the loss of food energy along the food chain. Energy is required in order for an animal or plant to carry out its life processes. Since animals cannot capture and use the sun's energy directly, they must eat plants. The plants along with oxygen and water provide the animal with its energy needs.
If we examine the energy pyramid, we see that each feeding level is smaller than the feeding level directly below it. There must be more plants (producers) than plant eaters (herbivores) and more plant eaters than meat eaters (carnivores).
The amount of energy available to the next higher level is only a fraction of the energy of the previous level. Only a small part of the sun's energy is ever used by the plants in the production of food. Of the energy containing material stored in the leaf, some are used by the plant for its life processes. Not all of the material eaten by the herbivore can be used. Some of the plant material cannot be digested and this material passes out of the animal's body as solid waste. This waste material becomes the first link in a decomposer food chain.

18. ENERGY FLOW IN ECOSYSTEMS
ENERGY IS LOST IN A ENERGY PYRAMID
A small portion of chemical energy stored in the chemical bonds of food is retained when transferred to the next trophic level.
As energy is transferred to the different trophic levels some energy is lost as heat. Heat has limited use in living organisms. So there will be less and less useable energy that will be transferred up the food chain.

19. ENERGY FLOW IN ECOSYSTEMS
ENERGY IS LOST IN A ENERGY PYRAMID
An energy pyramid is a diagram used by ecologist to show the amount of useable energy that is available and that is transferred to each trophic level.
TROPHIC LEVELS ARE LIMITED
10 kg of grain that is consumed
would only build 1 kg of human
tissue. Because of this
all food chains are usually
only have 3 to 4 members.