Ch. 4.2
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.
I. What Is a Niche?
a. The range of ______in which a species ______and the way the species ______it needs.
II. Tolerance
a. Why would conditions outside the optimal range cause stress to an organism?
i. Outside the optimal ranges for a given factor, individuals must
1. ______to maintain homeostasis
2. so they have less energy left for ______
b. Each species has an ______and ______limit of tolerance for every external factor.
c. Beyond those limits, the species ______.
d. We call the factors mentioned above ______
III. Limiting Factors
a. Factors that affect an organism’s ability to ______in its environment,
i. such as
1. The availability of ______
2. The availability ______
3. ______
4. ______
5. are called ______.
b. A limiting factor is any ______or ______factor that ______the:
i. ______
ii. ______
iii. ______
iv. ______
v. Common Limiting Factors
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
IV. Tolerance and Limiting Factors
a. ______: the range of external conditions within which a species can survive and reproduce
i.
V. Competition
a. ______: between members of the same species
b. ______: between members of different species
VI. Competitive Exclusion Principle
a. No two species can occupy exactly the same ______in exactly the same ______at exactly the same ______.
b.
i. What happened over time to each species when grown alone?
1.
ii. What happened to each species when the species were grown together?
1.
iii. What resources would members of the two species be competing for?
3.
4.
VII. Dividing Resources
a. The ______explains why we rarely find species in natural communities with overlapping ______.
b. Competition creates ______for each species to ______the way that it uses resources to ______and ______.
c.
i. For instance, the three species of North American warblers shown here all live in the same ______and feed on ______.
ii. But one species feeds on ______
iii. Another feeds on ______,
iv. The third feeds in the ______.
v. The resources utilized by these species are ______yet ______
i. Do these species have the same habitat?
1.
ii. Do these species have the same niche?
1.
iii. What would happen if two of the warbler species tried to occupy the same niche in the same tree at the same time?
1.
VIII. Predator-Prey Relationships
a. Like competition, ______—the interaction in which a predator feeds on prey—can also shape communities.
b. Predators can affect the ______of prey populations in a community and determine the ______prey can ______and ______.
c. ______– the interaction in which one organism, the ______captures and feeds on another organism, the ______
d.
IX. Herbivory
a. The interaction in which an herbivore feeds on producers such as plants.
i. ______
ii. ______
iii. ______
iv. ______
X. Keystone Species
a. A ______is a single species that is vital to ecosystem ______.
b. Example:
i. ______, ______and ______
1. In the cold waters off the Pacific coast of North America, giant algae called ______form complex ecosystems called ______.
2. In that ecosystem, ______prey on sea ______
3. Those urchins are ______that graze heavily on the giant kelp.
4. A century ago, otters were nearly eliminated by hunting. Unexpectedly, the kelp forest nearly ______.
5. Without ______as predators, sea urchin populations ______. Armies of urchins devoured ______down to bare rock.
6. Without kelp to provide habitat, many other animals, including seabirds, ______.
7. In this community, ______were a ______
8. When otters were protected as an endangered species, their population ______.
9. Urchin populations ______, and kelp forests began to ______again.
ii. : Cheetahs
1. What might happen to grassland ecosystems in cheetah home ranges if cheetahs become extinct?
XI. Symbiosis:
a. ______
i. A relationship between two species in which ______ species ______
1. Ex: ______and ______help each other survive.
b. ______
i. A relationship in which ______organism lives inside or on another organism and ______it
1. Examples
a. ______
b. ______
c. ______
d. ______
e. ______
c. ______
i. A relationship in which ______organism ______and the other is neither ______nor ______
1. Examples
a. ______often attach themselves to a ______skin. The barnacles ______from the constant movement of water—which is full of food particles—past the swimming whale. Although the barnacles perform______to the whale, they ______harm it either