Energy:

Movement In Ecosystems

Yellowstone Wolves Case Study

He’s Tagged!

Reintroduced into the park in 1995...stolen from Canada!

They eat deer...

And elk...

And horse...

And lamb...

And cow...

Why is it environmentally

harmful to remove top

predators like the wolf?

Discuss with your partner

and make a list.

Elimination of Top Predators...

No more leftover carrion to feed scavengers

(vultures, bears, ravens)

Elimination of Top Predators...

No more controlling populations of lower organisms on food chain

Elimination of Top Predators...

Loss of stability in food web

Elimination of Top Predators...

Grass/vegetation habitat decreases

Elimination of Top Predators...

Increase in soil erosion/compaction

Energy Flow in

Ecosystems Producers

Consumers

Decomposers

Producers: Phototrophs

Use sun to produce sugar(photosynthesis)

Plants, Algae (Phytoplankton), Bacteria

PS is 1 % efficient!

Producers: Chemotrophs

Use H2S to produce sugars

(chemosynthesis)

Bacteria

Producers: Chemotrophs

Consumers: Heterotrophs

Break down stored sugars (aerobic respiration)

C6H1206 + 6H2O + 6O2 ----> 6CO2+12H2O+ Energy

Consumers: Heterotrophs

GIR

AF

FE

!

Primary Consumers: Herbivores, eat producers

Consumers: Heterotrophs

Secondary Consumers: Carnivores, eat primary consumers

Consumers: Heterotrophs

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Tertiary Consumers: Eat secondary consumers, top, apex predators

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Decomposers: Saprotrophs/ Detritivores

Feed off dead organic matter in soil, release nutrients.

Fungi and Bacteria

Importance of Decomposers

1. Make vital elements available to primary producers.

Convert organic material into inorganic materials that producers can use in soil or water.

Chains vs Webs

Simple vs Complex

Trophic Levels: Energy flows from one trophic level to another

Simpson’s FOOD WEB

FOOD WEBS

Show multiple ways energy can move through an ecosystem

More connections, more stable in a changed environment

Bye Energy!

Orgs are not 100% efficient

Only 10% of energy at 1 level makes it to the next level (90% lost as heat)

Heat Energy Loss

Less energy as you go up = no more than 3-4 levels in a food chain

Pyramid of Numbers

Shows # of individuals at each trophic level

Biomass: Mass of organic material

Not a typical pyramid shape

Consumers may eat most of

producers as they are made

Pyramid of Biomass

Pyramid of biomass for hypothetical grassland

Biomass (g/m2) Trophic level

Tertiary consumers

(snakes)

Secondary consumers

(toads)

10

100

Primary consumers

(grasshoppers)

1,000

Pyramid of Energy

Always a pyramid shape

Energy lost as you go 10% rule

So, Why Should We All Be

Vegetarians?

Go

Bla

nk !

Pyramid of energy for river ecosystem

Kilocalories per m2 per year Trophic level

6 13 Tertiary consumers

(largemouth bass)

67 316 Secondary consumers

(bluegill)

1,890 Primary consumers

(caddisfly larva)

11,977 Primary

producers (aquatic

plants)

Respiration

Gross primary productivity

8,833

Net primary productivity

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Gross Primary Productivity (GPP)

Rate at which energy is capturedduring Photosynthesis

HIGH

LOW

Net Primary Productivity (NPP)

Energy that

remains in

plants after

respiration;

available to

consumers

NPP= GPP -

- Resp.

What Ecosystems Have High NPP?

Per unit area: