APES 1: Organism Interactions & Feedback
4 ways organisms interact
- competition
- compete for available resources (food, mating partners, etc.)
- occurs between both the same and different kinds of organisms
- predation
- hunt and kill other organisms to supply their energy needs
- occurs between different kinds of organisms,
- cooperation
- live together and help each other
- occurs between the same kind of organisms
- ex) herds, packs, colonies, families, etc.
- symbiosis
- live in close association with another kind of organism
- occurs between different kinds of organisms,
resource
- anything needed by an organism for life
- ex) nutrients, water, light, space
limiting factor
- a nutrient in short supply or one that cycles slowly
- this LIMITS the growth of the population
symbiosis
- %%mutualism%%
- a relationship where both organisms benefits
- ex) insects transfer pollen between plants as they gather nectar for food
- commensalism
- a relationship where one organism benefits; the other is neither harmed nor helped
- hermit crabs make homes in shells abandoned by snails
- ==parasitism==
- a relationship where one organism benefits; and the other is harmed in some way
- ex) ticks feed on dog’s blood
feedback
- any process that increases or decreases a change to the system
feedback loop
- a feedback process where an output of matter, energy, or information is fed back into the system as an input and leads to changes in that system
positive feedback loop
- causes systems to change further in the same direction
- increases change to a system
- ex) melting of a polar ice cap, increased erosion due to decreasing vegetation
negative feedback loop
- causes systems to change in the opposite direction
- decreases change to a system
- ex) reproduction, overgrazing, less reproduction