Population – group of individuals of the same species living in the same area, potentially interacting Community – group of populations of different species living in the same area, potentially interacting What are some ecological interactions?

Why are ecological interactions important? Interactions can affect where an organism lives (distribution) and how many there are (abundance). Interactions can influence evolution or adaptation. Think about how the following interactions can affect distribution, abundance, and evolution.

Types of ecological interactions competition predation parasitism mutualism commensalism symbiosis

Competition – two species share a requirement for a limited resource  reduces fitness of one or both species Trees competing for sun Mice competing for food

Competition – two species share a requirement for a limited resource  reduces fitness of one or both species American Bison Competing for a female.

predation – 1 species hunts, kills and eats another species 1 species benefits and other species life is lost. Herbivory predation

Mutualism – two species provide resources or services to each other  enhances fitness of both species Fungus (base) and algae(nutrients) produce lichens. Clown fish and sea anenome bacteria and plant roots: the bacteria changes nitrogen gas into usable nitrogen and the plants roots provide nutrients for t bacteria to survive. Ants aerate and soil which helps with drainage and turning the soil. (cultivating)

Parasitism – one species feeds on another  enhances fitness of parasite but reduces fitness of host Head lice Tick Hookworm in animal feces Corn Blight caused by a fungus. mistletoe

Commensalism – one species receives a benefit from another species  enhances fitness of one species; no effect on fitness of the other species Tree limb provides a base for growth. Ray provides transport

Symbiosis – two species live together  can include parasitism, mutualism, and commensalism

Organizing ecological interactions effect on species 1 effect on species mutualism predation herbivory parasitism predation herbivory parasitism commensalism competition