energy flow - davis school district · energy flow objectives: describe how energy flows through...
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Energy Flow
Objectives:
Describe how energy flows through ecosystems.
Explain how food chains and webs model feeding relationships.
Identify trophic levels in a food chain or web.
Producers
Organisms that produce food for themselves and other organisms
A producer gets its energy by making it!
Producers use energy from sunlight to make food by photosynthesis.
Examples: include plants, algae, and certain bacteria
Lupine, buckwheat, lomatiums, and other wildflowers carpet the trail to Ben Lomond Peak on the Wasatch-Cache National Forest, Utah.
Consumers
Consumers
Consumers get energy from eating producers and other animals.
Consumers cannot make their own food.
Organisms that depend on other organisms for food
Herbivores = Consumers
consume producers such as plants or algae
They are a necessary link between producers and other consumers.
Examples include deer, rabbits, and mice
Carnivores = Consumers
eats only other animals (consumers)
Examples: lions, polar bears, hawks, frogs, salmon, and spiders
Omnivores = Consumers
eats both plants (producers) and animals(consumers)
Examples: humans, black bears, gulls, crows, and some species of fish.
Decomposers
When organisms die, they leave behind ENERGY and MATTER in their remains.
Decomposers:
Break down these remains and other wastes and release simple inorganic molecules back to the environment.
Get their energy by eating dead stuff!
Examples: Bacteria & Fungi
Banana Slugs Unpeeled
Millcreek Canyon
Scavengers = Decomposers
Consume the soft tissues of dead animals
Examples: vultures, raccoons, blowflies.
Detritivores = Decomposers
consume detritus—the dead leaves, animal feces, and other organic debris that collects on the soil or at the bottom of a body of water.
On land examples: earthworms, millipedes, and dung beetles
In water examples: “bottom feeders” such as sea cucumbers and catfish.
Food Chains
A food chain represents a single pathway through which energy and matter flow through an ecosystem.
Most organisms consume—and are consumed by—more than one species.
Producer
• Dunaliella salina
• Makes own food
• Usually a plant
• Photo-synthesis
Primary Consumer
•Brine shrimp
•Usually an herbivore
•Primary must eat plants
•Consumer can eat more than plants
Secondary Consumer
• Wilson’s phalarope
• Eats primary consumer
• Can be omnivore or carnivore
Tertiary Consumer
• Marsh Hawk
• Eats secoary consumer
• Typically a carnivore
A cloud of Wilson's phalaropes fly above Farmington Bay, Utah Life in the Great Salt Lake
Producer
• Rice Grass
• Makes own food
• Usually a plant
• Photo-synthesis
Primary Consumer
•Utah Prairie Dog
•Usually an herbivore
•Primary must eat plants
•Consumer can eat more than plants
Secondary Consumer
• Black-footed ferret
• Eats primary consumer
• Can be omnivore or carnivore
Producer
• Black brush
• Makes own food
• Usually a plant
• Photo-synthesis
Primary Consumer
• Bighorn Sheep
• Usually an herbivore
• Primary must eat plants
• Consumer can eat more than plants
Secondary Consumer
• Cougars
• Eats primary consumer
• Can be omnivore or carnivore
Food Chain: Models how matter and energy flow through an ecosystem
Solar Energy
• Sun
Chemical Energy
• Glucose Molecules
Mechanical Energy
•Animal eats and uses it to live
Heat Energy
• Back into space
Food Webs
A food web represents multiple pathways through which energy and matter flow through an ecosystem.
It includes many intersecting food chains.
Most organisms eat, and are eaten, by more than one species.
Trophic Levels: the feeding positions in a food chain or web
Trophic Level
Type of Organism
Where It Gets Food
Example
1st Producer Makes its own food
Plants make food
2nd Primary
Consumer
Consumes producers
Mice eat plant seeds
3rd Secondary Consumer
Consumes primary
consumers
Snakes eat mice
4th Tertiary
Consumer
Consumes secondary consumers
Hawks eat Snakes
Trophic Levels and Energy
Energy is passed up a food chain or web from lower to higher trophic levels.
Only about 10 percent of the energy at one level is available to the next level.
What happens to the other 90 percent of energy?
Trophic Levels and Energy
What happens to the other 90 percent of energy?
Used for metabolic processes
Given off to the environment as heat
Trophic Levels and Biomass
Less energy is available at higher trophic levels
there are usually fewer organisms at higher trophic levels
Organisms tend to be larger in size at higher trophic levels
Numbers of organisms tend to be smaller at higher trophic levels
Biomass is the total mass of organisms at a trophic level
Less biomass at higher trophic levels
Energy Pyramid
Shows the amount of energy available at each step of a food chain
Top Level
Carnivore
Carnivores; Omnivores
Herbivores
Producers
Energy Pyramid
Shows the amount of energy available at each step of a food chain
Energy Of Tertiary Consumers
Energy of Secondary Consumers
Energy of Consumers
Energy of Producers