SPECIES INTERACTIONS20.1

Interdependence

The relationship between plants, fungi, and animals that interact with one another is called INTERDEPENDENCE.

There are many different types of interdependence. In some of these relationships both organisms benefit, and in others only one organism benefits

Ways organisms interact with each other

1. Symbiosis: a relationship where at least one member benefits by the relationshipa) Predation (Predator/Prey) (+, -)b) Mutualism (+ ,+)c) Parasitism (+, -)d) Commensalism (+, 0)

2. Competition

Predator/Prey

A relationship where one organism, a consumer called a predator, eats or ingests another organism, the prey. The prey in this case is also some type of consumer.

Ex– fox and rabbit

Producer/Consumer

A relationship where one organism, the consumer (typically an animal), eats or ingests a plant, the producer.

A type of “predator/prey”

Mutualism

A relationship in which two different species benefit and are dependent upon the relationship.

Ex. Ants and the acacia tree Ants get a home &

food, and the tree gets protection

Parasitism

A relationship between two species in which one species, the parasite, nourishes itself to the harm of the other species, the host. Humans and

tapeworms Heartworm in dogs Athletes foot

Commensalism

A relationship in which one species derives food, shelter, or protection from another species without harming that organism or providing any benefits in return. The cattle egret

benefits when the ox walks and kicks ups bugs

The ox isn’t helped or hurt by the birds

Competition

Competition—two or more species use same limited resources

Results Reduction of both

species Elimination of one of the

competitors: Competitive Exclusion

Example Lions and hyenas both

compete for zebra