classical limiting factors - abiotic, organisms must conform or regulate themselves

• temperature - changes biochemical structure/function, influence chemical reaction rate
  • ectotherm (poikilotherm) - cold-blooded w/ slower metabolisms
  • endotherm (homeotherm) - warm-blooded
  • heterotherm - regulators that don’t always regulate themselves
  • Thermal Primacy Paradigm - every organism must deal w/ temperature
• oxygen - doesn’t follow same patterns as temperature
  • facultative anaerobes - needs oxygen to reproduce, doesn’t need it to survive
• water - can have too much or too little
  • used to adjust solute content
• pressure - lighter substances float, heavier ones sink
• light - needed in some form by most organisms
• pH - primarily w/ halophiles
  • no organism can handle 0 or 14 pH

responses to environmental change -

• passive - no response
  • either no point, no need, or response will lead to worse conditions
  • maybe inability to sense the change
• behavioral - 1st line of defense
  • takes place within seconds/minutes
  • needs sense, ability to move, another place to go to
  • physiological - constrict blood vessels, etc
• biochemical/physiological - takes hours/days
  • internal change w/ acclimation/acclimatization
  • growing thicker coats of fur during winter
• adapt/evolve - genetic change passed on
  • involves an entire population
  • “Allen’s Rule” - mammals in cold areas have shorter ears/limbs to reduce surface area across which to lose heat

species interactions - competition for food/space >> displacement of weaker organisms

• symbiosis - 2 or more kinds of organisms get in a relationship
• competition - uses limited resources >> harms both organisms
• neutralism - doesn’t affect anyone’s fitness
• commensalisms - favors 1 organism, doesn’t do anything for other
• parasitism - hurts 1 organism, helps other
  • parasites can make hosts more vulnerable to predators >> passes along
  • ectoparasites - feeds on exterior
  • endoparasites - feeds in interior
  • parasitoids - insects that lay eggs in living hosts
• amensalism - hurts 1 organism, doesn’t do anything for other
• mutualism - favors both organisms