This video, we're going to briefly summarize the 4 types of community interactions, their effect on fitness, and cover some important notes. The first type of community interaction that we covered in our lesson was competition. Competition is a minus minus interaction where the fitness of all competing organisms is negatively affected. Recall that competition can lead to either competitive exclusion and local extinction of the weaker competitor when there's complete niche overlap between the competing species, or competition could lead to resource partitioning and character displacement when there's only partial niche overlap between the competing species.
The next type of community interaction that we covered in our lesson was exploitation, which is a plus minus interaction, meaning that one organism is benefiting at the cost of another organism being harmed. Recall that there are 3 main types of exploitation, which are predation, herbivory, and parasitism. The next type of exploitation that we covered in our lesson was mutualism, which is a plus plus interaction where both organisms benefit from the interaction. Mutualism is common in nature and some species may actually depend on each other for survival, and we call this obligate mutualism.
Last but not least, commensalism is a plus zero interaction, where one organism benefits and the other organism is neutrally affected, meaning that it is not affected. Commensalism often involves using another organism or its byproducts as shelter, food, transportation, or habitat.
This here concludes our summary and I'll see you all in our next video.