1. Ecosystem Structure
a. Biological populations and communities
b. Ecological niches
c. Interactions among species
d. Keystone species
e. Species diversity and edge effects
f. Major terrestrial and aquatic biomes
2. Energy Flow
a. Photosynthesis and cellular respiration
b. Food webs and trophic levels
c. Ecological pyramids
3. Ecosystem Diversity
a. Biodiversity
b. Natural selection
c. Evolution
d. Ecosystem services
4. Natural Ecosystem Change
a. Climate shifts
b. Species movement
c. Ecological succession
5. Natural Biogeochemical Cycles
a. Carbon, nitrogen, phosphorus, sulfur, water, conservation of matter
