Welcome to Class!
9-2 and 9-3
Complete the following:
 Glue vocab 4 and create 3 column chart
 Take out Homefun Assigned Vocabulary
 Take out Lab Report Heart Rate
Agenda
 Lecture notes on Community Interaction
 Foodweb Construction Lab
 Homefun:
 Assigned Vocabs (please print out just like the first time
you did)
Niches and Community Interactions
Learning Objectives
 Identify external factors that determine an organism’s
niche.
 Describe the role competition plays in shaping
communities.
 Describe the role predation and herbivory play in shaping
communities.
 Identify the three primary interdependent relationships
among organisms.
What Is a Niche?
The range of conditions in which a species lives and the way
the species obtains the resources it needs
Defining a Niche
Tolerance: the range of external conditions within which a
species can survive and reproduce
No
survival
No
survival
Competition
Intraspecific: between
members of the same species
Interspecific: between
members of different species
Competitive Exclusion Principle
No two species can occupy exactly the same niche in
exactly the same habitat at exactly the same time.
Dividing Resources
Spruce tree
Cape May Warbler
Bay-breasted Warbler
Yellow-rumped Warbler
Predator-Prey Relationships
One predator-prey cycle
Herbivory
• Size
• Growth
• Distribution
• Survival
Keystone Species
A keystone species is a
single species that is vital
to ecosystem stability.
Symbiosis: Mutualism
A relationship between two species
in which both species benefit
Clownfish and sea anemones
help each other survive.
Symbiosis: Parasitism
A relationship in which one organism lives inside or on
another organism and harms it
Symbiosis: Commensalism
A relationship in which one organism benefits and the other
is neither helped nor harmed
Vocabulary Review
Keystone species
Parasitism
Competitive exclusion
principle
Tolerance
Interspecific
Herbivory
Explains division of resources among
similar species
Helps define a species’ niche
One species benefits while harming
another
Between members of different species
A single species vital to ecosystem
stability
Affects the size and distribution of plant
populations in a community