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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
Gre
at W
hite
Tertiary Consumers: Eat secondary consumers, top, apex predators
https://www.y
outube.com/w
atch?v=XuNe
acjghQU
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
Ha
rco
urt
Bra
ce
& C
om
pa
ny
ite
ms a
nd
deri
ved ite
ms
copyri
ght
©1998 b
y H
arc
cutt
Bra
ce &
Com
pany
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: