1. Catalyst
Why is it important that nutrients cycle?

3. Burning of fossil fuels and wood
Figure 55.14b
CO2 in atmosphere
Photosynthesis
Photo- synthesis
Cellular respiration
Burning of fossil fuels and wood
Phyto- plankton
Consumers
Figure Exploring: Water and Nutrient Cycling
Consumers
Decomposition 3

4. Movement over land by wind
Figure 55.14a
Movement over land by wind
Evaporation from ocean
Precipitation over land
Precipitation over ocean
Evapotranspira- tion from land
Figure Exploring: Water and Nutrient Cycling
Percolation through soil
Runoff and groundwater 4

5. Decomposition and sedimentation
Figure 55.14c
N2 in atmosphere
Reactive N gases
Industrial fixation
Denitrification
N fertilizers
Fixation
Runoff
Dissolved organic N
NO3–
Terrestrial cycling N2
NH4+
NO3–
Aquatic cycling
Denitri- fication
Figure Exploring: Water and Nutrient Cycling
Decomposition and sedimentation
Assimilation
Decom- position
NO3–
Fixation in root nodules
Uptake of amino acids
Ammonification
Nitrification
NH3
NH4+
NO2– 5

6. Today.
Review Cycles
Vocab
Clip Review
Begin Food Web.

7. Energy, Mass, and Trophic Levels
Autotrophs build molecules themselves using photosynthesis or chemosynthesis as an energy source
Heterotrophs depend on the output of other organisms
© 2011 Pearson Education, Inc.

8. Energy flow primary producers (autotrophs)
to primary consumers (herbivores)
to secondary consumers (carnivores)
to tertiary consumers (carnivores that feed on other carnivores)
© 2011 Pearson Education, Inc.

9. Microorganisms and other detritivores Secondary and tertiary consumers
Figure 55.4
Sun
Key
Chemical cycling
Energy flow
Heat
Primary producers
Primary consumers
Detritus
Figure 55.4 An overview of energy and nutrient dynamics in an ecosystem.
Microorganisms and other detritivores
Secondary and tertiary consumers 9

10. Detritivores
(decomposers) are consumers that derive their energy from detritus, nonliving organic matter
© 2011 Pearson Education, Inc.

11. Trophic Structure
the feeding relationships between organisms in a community
It is a key factor in community dynamics
Food chains link trophic levels from producers to top carnivores
© 2011 Pearson Education, Inc.

12. A terrestrial food chain A marine food chain
Figure 54.13
Carnivore
Quaternary
consumers
Carnivore
Carnivore
Tertiary
consumers
Carnivore
Carnivore
Secondary
consumers
Carnivore
Figure Examples of terrestrial and marine food chains.
Herbivore
Primary
consumers
Zooplankton
Plant
Primary
producers
Phytoplankton
A terrestrial food chain
A marine food chain

13. Food Webs
A food web is a branching food chain with complex trophic interactions
© 2011 Pearson Education, Inc.

14. Humans Smaller toothed whales Baleen whales Sperm whales Elephant
Figure 54.14
Humans
Smaller
toothed
whales
Baleen
whales
Sperm
whales
Elephant
seals
Crab-
eater
seals
Leopard
seals
Birds
Fishes
Squids
Figure An Antarctic marine food web.
Carniv-
orous
plankton
Euphau-
sids
(krill)
Cope-
pods
Phyto-
plankton

15. Trophic Efficiency and Ecological Pyramids
Trophic efficiency is the percentage of production transferred from one trophic level to the next
It is about 10%
© 2011 Pearson Education, Inc.

16. Tertiary consumers 10 J Secondary consumers 100 J Primary consumers
Figure 55.11
Tertiary consumers
10 J
Secondary consumers
100 J
Primary consumers
1,000 J
Primary producers
Figure An idealized pyramid of net production.
10,000 J
1,000,000 J of sunlight 16

17. Big ideas overview.
Clip
Now – MN Food Webs