1. Symbiotic Relationships The close association between two or more organisms of different species

2. Mutualism (+, +) a relationship where each of the organisms benefit, sometimes they cannot survive without each other Ex: Fungi + Algae = Lichen Acacia tree and Acacia Ants

3. Parasitism (-. +) one organism benefits (the “parasite”) and the other (the host) is generally harmed Ex: fleas, ticks

4. Competition (-, -) Two or more organisms competing for limited resources resulting in both organisms being harmed without either being consumed Ex: males fighting over females or vice versa….