Population – group of individuals of the same speciesliving in the same area, potentially interacting

Community – group of populations of different speciesliving in the same area, potentially interacting

What are some ecological interactions?

Why are ecological interactions important?

Interactions can affect distribution and abundance.

Interactions can influence evolution.

Think about how the following interactions can affectdistribution, abundance, and evolution.

Types of ecological interactions

competition

predation

parasitism

mutualism

commensalism

symbiosis

Competition – two species share a requirement for alimited resource reduces fitness of one or both species

Predation – one species feeds on another enhancesfitness of predator but reduces fitness of prey

herbivory is a form ofpredation

Parasitism – one species feeds on another enhancesfitness of parasite but reduces fitness of host

Mutualism – two species provide resources or servicesto each other enhances fitness of both species

Commensalism – one species receives a benefit fromanother species enhances fitness of one species; noeffect on fitness of the other species

Symbiosis – two species live together can includeparasitism, mutualism, and commensalism

Organizing ecological interactions

effect on species 1

effect onspecies 2

+ 0 -

+

0

-

mutualism

predationherbivoryparasitism

predationherbivoryparasitism

commensalism

commensalism

competition

competition

competition