1. Studying organisms in their environment
biosphere

2. Community Ecology

3. Inter-species interactions
Symbiotic interactions
competition (-/-)
_______________________________________
2 species cannot coexist in a community if their niches are identical
predation / parasitism (-/+)
mutualism(+/+)
lichens (algae & fungus)
commensalism (+/0)
barnacles attached to whale

4. (+/+) mutualism
commensalism (+/0)
(-/-)
predation (+/-)
competition

5. Resource partitioning
Niche
_________________________________________
habitat = address, niche = job
Resource partitioning

6. Niche & competition
Competitive Exclusion
___________________________________________________________________________________

7. Predation drives evolution
Predators adaptations
___________________________
Prey adaptations
___________________
horns, speed, coloration
spines, thorns, toxins

8. Energy flows through ecosystems
sun
secondary consumers
(carnivores)
loss of energy
loss of energy
primary consumers
(herbivores)
producers (plants)

9. Effects of deforestation
40% increase in runoff
loss of water
60x loss in nitrogen
10x loss in calcium
loss into surface water 80
nitrate levels in runoff 40
loss out of ecosystem!
of nitrate (mg/l )
Concentration 4
Deforestation 2
Why is nitrogen so important?
1965
1966
1967
1968
Year

10. Food chains sun Trophic levels feeding relationships
Tertiary consumer
Trophic levels
feeding relationships
start with ______________
______________________.
captured by ___________
1st level of all food chains
food chains usually go up only 4 or 5 levels
inefficiency of energy transfer
all levels connect to ___________________.
top carnivore
Level 3
Secondary consumer
carnivore
Level 2
Primary consumer
heterotrophs
herbivore
Level 1
Producer
autotrophs
Fungi
Decomposers
Bacteria

11. Trophic structure Food chains feeding relationships
food chain usually 4 or 5 links = ________________
length of food chain limited by inefficiency of energy transfer

12. Energy transfer Energy in Energy through from the Sun
captured by ____________ =
______________________
Energy through
food chain
transfer of energy from autotrophs to _______________________ (herbivores to carnivores)
heterotrophs = ____________
herbivores
carnivores

13. Inefficiency of energy transfer
sun
Inefficiency of energy transfer
Loss of energy between levels of food chain
To where is the energy lost? The cost of living!
17%
growth
energy lost to daily living
only this energy moves on to the next level in the food chain
33%
cellular
respiration
50%
waste (feces)

14. Pyramids of production
_____________________________________________
how much energy is turned into biomass

15. Ecological pyramid sun ________________________________
can feed fewer animals in each level 1
100
100,000
1,000,000,000

16. Food webs Food chains are hooked together into ________________
Who eats whom?
a species may weave into web at more than 1 trophic level
bears
“there’s always a bigger fish”
What limits the length of a food chain?

18. Implications
Dynamics of energy through ecosystems have important implications for human populations
what food would be more ecologically sound?
We consume more than just food: water, energy, space/habitat