Energy:

Movement In Ecosystems

Yellowstone Wolves Case Study

Reintroduced into the park in

1995…stolen from Canada!

He’s Tagged!

They eat deer…

And elk…

And horse…

And lamb…

And cow…

So…

“I went

fishing and

all I caught

was this

stupid

wolf”

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!

• Use H2S to produce sugars

(chemosynthesis)

• Bacteria

Producers: Chemotrophs

Producers: Chemotrophs

Consumers: Heterotrophs

• Break down stored sugars (aerobic respiration)

• C6H1206 + 6H2O + 6O2 ----> 6CO2

+12H2O+ Energy

Consumers: Heterotrophs

• Primary Consumers: Herbivores, eat producers

DE

ER

!

Consumers: Heterotrophs

• Secondary Consumers: Carnivores, eat primary consumers

Consumers: Heterotrophs

• Tertiary Consumers: Eat secondary consumers, top, apex predators

Gre

at W

hite

Decomposers: Saprotrophs

• 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

Bu-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 indiv. 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

• Always a pyramid shape

• Energy lost as you go 10% rule

Pyramid of Energy

So, Why Should We All Be

Vegetarians?

Go

Bla

nk!

Gross Primary Productivity (GPP)

• Rate at which energy is captured during PS

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: