Bellringer

“As more individuals are produced that can possibly survive, there must…be a struggle for existence, either one individual with another of the same

species, or with the individuals of distinct species, or with the physical conditions of life.”

- Charles Darwin

How does this quote relate to niches and

competition?

Section 2

How Species Interact with Each Other

I. An Organism’s Niche

A. _____ the unique role of a species within an ecosystemniche

1. A niche includes an organisms:

a. physical homeb. environmental factorsc. species interactions

3. Think of a niche as the organism’s job or function

2. Habitat is different from nichea. Habitat is location

B. Niche example, Fruit Bat:

1. Lives in trees and caves

2. Pollinates flowers3. Spreads seeds4. Interacts with hawks

and owls

II. Ways In Which Species Interact

A. ___________ relationship in which different individuals or populations attempt to use the same limited resource

Competition

1. Can occur:

a. Between speciesb. Within speciesc. Indirectly

B. Between species:

1. Lions, Hyenas, and Cheetahs all compete for the same food on the African savannah’s

C. Within species:1. Two different loblolly pines growing close to

each other

a. Think of this as more of a resource limitation

III. Indirect Competition:

1. Both mice and man will consume crops such as corn, however in this relationship these organisms will rarely interact

A. Two closely relates species sharing a habitat resulting in Niche restriction or Niche differentiation: Examples…

3. Two species of mice, one nocturnal and one diurnal, both feed on insects. They feed at different times

2. Two monkey species feed at different heights within a tree

IV. Predation, Parasitism, Mutualism, and Commensalism

A. Predator/Prey – One organism eating another Example: snake (predator) eating a mouse (prey)

B. Parasitism – An organism that takes nourishment from an organism

1. Two parts:

a. Parasite – organism that feeds on another organism

b. Host - organism that is providing nourishment to the parasite

2. Different from a predator b/c the parasite spends all or most of its life in or on the host

C. Mutualism – Two organisms living in harmony helping each other out

1. A butterfly and a flower. How do they help each other?

D. Commensalism – One species benefits, the other is not harmed but doesn’t benefit

Describe the relationship between the following organisms. How are each an example of commensalism?