Name: _____________________________ Date: _________________ Class: ______
Lesson 14: Relationships between Organisms
Pages 120 – 123
Standards: S7L4d
Organisms in an ecosystem constantly interact. The three major types of interactions among
the organisms in an ecosystem are ____________, _____________, and _____________.
Define the following terms:
competition: ________________________________________________________
predation: _________________________________________________________
predator: __________________________________________________________
prey: _____________________________________________________________
List some examples of traits of predators that help them capture their prey.
_______________________________________________________________________
List some examples of traits that prey have that help them avoid being captured.
_______________________________________________________________________
Describe the pattern that occurs between the populations of predators and prey over time.
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
What is symbiosis? ________________________________________________________
3 types of symbiosis: __________________, _________________, and _______________
1. _____________________ describes the relationship in which both species benefit.
a. Ex. ________________________________________________________
Name: _____________________________ Date: _________________ Class: ______
2. _____________________ describes a relationship in which one species benefits.
The other species is neither ________________ nor _____________.
a. Ex: ________________________________________________________
3. _____________________ describes a relationship in which one organism lives on or
inside another.
a. What is the difference between a parasite and a host? _________________
__________________________________________________________
b. How is the parasite–host relationship different from the predator-prey
relationship? ________________________________________________
___________________________________________________________
___________________________________________________________
c. Examples:
i. Live on host: ____________________________________________
ii. Live in host: ____________________________________________
---------------------------------------------------------TEST PRACTICE:
0. Humans have bacteria inside their intestines. The bacteria help to digest some foods and
they produce vitamins that the body cannot manufacture. In turn, the bacteria have a place
to live and a constant supply of food. What type of relationship exists between humans and
these bacteria?
a. Parasitism
b. Mutualism
c. Predation
d. Commensalism
1. Two populations with limited resources experience
a. competition. b. commensalism.
c. predation.
d. parasitism.
2. Predators have relationships with prey. In a similar way, parasites have relationships with
Name: _____________________________ Date: _________________ Class: ______
a. competitors.
b. mutuals.
c. hosts.
d. other parasites.
Two types of bacteria were grown in the same culture. The graph below shows how their
populations changed over time. Use the graph to answer question 3.
3. When the populations were grown separately, they each grew much larger. Why were the
results different when they were grown together?
a. They competed for limited resources.
b. One type of bacteria transformed into another.
c. Neither type of bacteria cold withstand the heat of the single culture.
d. The different types of bacteria developed a symbiotic relationship.