1. Chapter 21-1 Species Interactions
Notes and Organizer
Predation
Predator-
Prey-
Natural Selection, the major mechanism of ____________________favors
_________________that improve the efficiency of predators at finding,
_____________________and consuming prey.
A predator’s survival depends on its ability to __________________food, but a prey’s
survival depends on its ability to _________________being captured.
Mimicry
Deception is important in _____________________________defenses.

2. In a defense called____________________, a harmless species resembles a
_______________________or___________________species.
The harmless mimic is ______________________because it is often mistaken to be its
_____________________look alike.
Draw an example of a mimic.
Plant-Herbivore Interactions
Animals that eat plants are called ______________. Through natural selection, plants
have evolved ________________________ that protect them from being eaten. Physical
defenses such as ____________________, spines and _________________ hairs and
tough _______________ can make a plant difficult to ________________.
Plants have also evolved a range of chemical defenses. They synthesize
____________________ from products of their metabolism, called
____________________ compounds, that are __________________________, irritating
or _____________________. Examples are:
Many medicines are derived from secondary compounds.
Examples are:

3. Parasitism
A species interaction that resembles predation in that one individual is harmed and
the other benefits.
Parasite-
Host-
Ectoparasites-
Endoparasites-
Draw an example of an ectoparasite. Draw a picture of an endoparasite.

4. Competition
Competition results from fundamental _____________________.
___________________________ is the use of the same limited __________________ by
two or more ____________________.
________________________________ is when one species is
___________________________ from a community due to
________________________. One species uses a resource more
___________________________ and has a ____________________________
advantage over the other.
Competition and Community Structure
Character Displacement-
Finches have different ______________beaks which can eat ________________sizes of
seeds. These finches do not _______________for the same ______________source
because of the ____________differences.

5. What are some other examples of character displacement?
Competition is most intense between similar species using the
_______________resources.
Resource partitioning-
Examples are:
Competition is less intense and the _______________are able to ______________better.
Mutualism and Commensalism
Mutualism-
Some _____________________relationships are so close that neither
_________________could live _________________the other.

6. ________________________is a major mutualistic relationship that
__________________the whole world.
Commensalism-
One example is _________________eating insects that are ________________out by
___________________. The _________________is not harmed and does not
_________________but the _________________clearly benefit from the
_____________________.
Mutualism Commensalism
Draw an example of mutualism and commensalism.
Essential Questions
1. Explain how predators differ from parasites. Give an example of each kind
of organism.

7. 2. Some harmless flies resemble bees and wasps. What is this mechanism
called? Evaluate its importance as a defense mechanism.
3. Describe two chemical defenses of plants.
4. Explain the advantage of character displacement and give an example.
5. How can similar birds occupy the same area without occupying the same niche?
6. How is mutualism and commensalism different from each other?