1. Unit #10: Ecology (Part 4) ECOSYSTEMS
Ms. Day
AP Biology

2. Introduction to Ecology
Study of interactions between living and non living things.
Explains how living organisms affect each other and the world they live in.

3. Habitat & Niche Habitat is the place a plant or animal lives
“the address”
Niche is an organism’s role in life
“its address and its job”
All resources used by that organism

4. Biotic Factors of the Biosphere
ALL LIVING PARTS OF AN ECOSYSTEM
Think: “BIO” means “life”
Plants
Animals
Fungi
Decomposers
I’m
BIOTIC!!!

5. Abiotic Factors of the Biosphere
ALL NON-LIVING PARTS OF AN ECOSYSTEM
Think: “A” means “anti/against”
Climate
Water/Rainfall, Light, Temperature, Wind/air currents
Rocks and soil
Particle size, Mineral composition, pH
Periodic disturbances
fire, flood, earthquake, etc.

6. Organizing life
Interactions between organisms fit in into different levels according to complexity

7. LEAST inclusive (SPECIFIC) MOST inclusive (BROADEST)
Levels of Life
ORGANISM
1 living thing: made of cells/DNA, uses ATP, reproduces, responds to stimuli, grows/develop
SPECIES
group of the same organisms that can interbred
POPULATION
group of the same organisms living in the same place at the same time that can interbreed
COMMUNITY
group of the DIFFERENT organisms (populations) living in the same place at the same time
ECOSYSTEM (includes BIOMES)
All abiotic (nonliving) and biotic factors in an area
BIOSPHERE = all the ecosystems together on Earth
MOST inclusive (BROADEST)

8. TERRESTRIAL BIOMES

11. Trophic Structure in Ecosystems
Ecosystems divided into trophic levels (feeding levels)
Primary producers—autotrophs (mostly photosynthetic but can be chemosynthetic)
Primary consumers—herbivores
Secondary consumers—carnivores that eat herbivores
Tertiary consumers—carnivores that eat other carnivores
Detrivores/Decomposers—consumers that eat dead or decaying matter

12. Food Chain: shows energy pathway
Arrow head = predator
Arrow tail
= prey

13. Food Webs
Feeding relationships woven into elaborate interconnec-tions between species

14. Sun = GENERALLY supplies all energy to ecosystems
RECALL…
Sun = GENERALLY supplies all energy to ecosystems

15. Energy Flow in Ecosystems
Each level has different amount of stored chemical energy
When you go UP a level, some energy is lost
Gross primary productivity (GPP)= total chemical energy made by producers
TOTAL PHOTOSYNTHESIS (adds biomass)
Net primary productivity= total chemical energy – energy used for cellular respiration by plants
TOTAL PHOTOSYNTHESIS -CELLULAR RESPIRATION

17. CALLED 10% rule (trophic efficiency)
~10% of energy at each level converted to new biomass
CALLED 10% rule (trophic efficiency)

18. Biomass = amount of living matter in a given habitat
LOTS OF BIOMASS HERE

19. Toxins in the Environment
In some cases, harmful substances persist for long periods in an ecosystem
One reason toxins are harmful is that they become more concentrated in successive trophic levels
biological magnification
toxins concentrate at higher trophic levels, where biomass is lower
Zooplankton
0.123 ppm
Phytoplankton
0.025 ppm
Lake trout
4.83 ppm
Smelt
1.04 ppm
Herring
gull eggs
124 ppm
Concentration of PCBs