optimal foraging theory - states that natural selection favors those most efficient

• foragers feed on prey that maximize energy return
• balance between looking for prey, hiding from predators
• might have genetic basis rather than learning (due to zebra finch behavior)

territoriality - keeping exclusive use of home range

• defense against intrusion by others
• can waste energy, expose oneself to predators
• balance between costs/benefits of defending territory

habitat - determined by resources, how well organism survives, amount of competition

• 5 major zones - salt water (70%), terrestrial (29%), freshwater, estuary (where freshwater meets saltwater), endoparisitic
• streams not connected >> easier for specialization >> more freshwater species than saltwater

Justus Van Liebig - “Law of the Minimum”

• plants need certain type/amount of nutrients
• miss an essential part >> die

Victor Shelford - principle of tolerance limits (maximum)

• too much of something can also inhibit growth
• growth occurs best under a certain range of conditions
• factors will vary seasonally, geographically, throughout life
• placed in area of stress >> some organisms increase fitness
• generalist - have wide tolerance
• specialist - have narrow tolerance
• hormesis - opposite effect in small doses than in high doses