Symbiotic Relationships
Purpose of Activity: To get students to think critically about the relationships that organisms
have with one another.
Learning Outcomes
−investigate and interpret dependencies among species that link the survival of one
species to the survival of others
− identify examples of symbiotic relationships (e.g., organisms that benefit other
organisms by providing habitat, food, means of fertilization, or a source of oxygen)
− classify symbiotic relationships as mutualism, commensalism, parasitism
Directions:
1) Label each scenario on the attached sheets as an example of either mutualism,
commensalism, or parasitism.
2) Answer the challenge question that follows the chart.
Definitions:
Mutualism – A symbiotic relationship between two different types of organisms
that is beneficial to both organisms.
Commensalism – A symbiotic relationship between two different types of
organisms in which one of the partners benefits and the other neither benefits nor
loses.
Parasitism – A symbiotic relationship between two different types of organisms in
which one of the partners is harmed and the other one benefits.
Organisms:
Bar n acle/
Wh ale
Cu cko o /
War b ler
Rem o r a/
Sh ar k
Ost r ich /
Gazelle
Mist let o e/
Sp r u ce
Silver f ish /
Ar m y An t
Oxp ecker /
Rh in o cer o s
Mo u se/ Flea
Ho n ey Gu id e
Bir d /
Bad g er
Hu m an /
Tap ew o r m
Co w b ir d /
Biso n
Symbiotic
Relationship
(mutualism,
commensalism,
or parasitism)
Brief Overview of Relationship
Bar n acles cr eat e h o m e sit es b y at t ach in g
t h em selves t o w h ales. As t h e b ar n acle is a f ilt er
f eed er , it also g et s access t o m o r e w at er (an d m o r e
f o o d ) d u e t o t h e r elat io n sh ip . Wh ale is u n af f ect ed .
A cu cko o lays it s egg s in t h e n est o f t h e w ar b ler .
Th e cu cko o ’s eg g s h at ch f ir st an d t h e y o u n g kick
t h e w ar b ler eg g s o u t o f t h e n est . Th e w ar b ler r aises
t h e cu cko o b ab ies an d t h e w ar b ler b ab ies ar en ’t
h at ch ed .
Rem o r as at t ach t h em selves t o a sh ar k ’s b o d y. Th ey
t r avel w it h t h e sh ar k an d f eed o n t h e lef t o ver f o o d
scr ap s af t er t h e sh ar k h as f in ish ed it s m eal. Th e
sh ar k is u n af f ect ed as it ’s d o n e eat in g an yw ay.
Ost r ich es an d g azelles f eed n ext t o each o t h er .
Th ey b o t h w at ch f o r p r ed at o r s. Becau se t h e visu al
ab ilit ies o f t h e t w o sp ecies ar e d if f er en t , t h ey can
each id en t if y t h r eat s t h at t h e o t h er an im al m ay
n o t see as r ead ily. Bo t h sp ecies b en ef it .
Mist let o e ext r act s w at er an d n u t r ien t s f r o m t h e
sp r u ce t r ee t o t h e d et r im en t (ill ef f ect ) t o t h e
sp r u ce.
Silver f ish live an d h u n t w it h ar m y an t s an d sh ar e
t h e p r ey. Th ey n eit h er h elp n o r h ar m t h e an t s.
Oxp ecker s (b ir d ) f eed o n t h e t icks f o u n d o n a
r h in o cer o s. Bo t h sp ecies b en ef it …t h e o xp ecker
g et s f o o d an d t h e r h in o g et s r id o f a p ar asit e.
A f lea f eed s o n a m o u se’s b lo o d t o t h e m o u se’s
d et r im en t
Ho n ey g u id e b ir d s aler t an d d ir ect b ad g er s t o b ee
h ives. Th e b ad g er s t h en exp o se t h e h ives an d f eed
o n t h e h o n ey f ir st . Next t h e h o n ey g u id e b ir d s eat .
Bo t h b en ef it
Tap ew o r m s r esid e in h u m an in t est in e an d t ake
n u t r ien t s f r o m t h e h u m an .
As b iso n w alk t h r o u g h g r ass, in sect s b eco m e act ive
an d ar e seen an d eat en b y co w b ir d s. Th is
r elat io n sh ip n eit h er h ar m s n o r b en ef it s t h e b iso n .
Organisms:
Yu cca Plan t /
Yu cca Mo t h
Wr asse Fish /
Black Sea Bass
Clo w n Fish /
Sea An em o n e
Hu m an /
E. co li
An t /
Ap h id
Tr ees/
Ep ip h yt es
Deer /
Tick
Mar ib o u St o r k/
Bee
Symbiotic
Relationship
(mutualism,
commensalism,
or parasitism)
Brief Overview of Relationship
Yu cca f lo w er s ar e p o llin at ed b y yu cca m o t h s. Th e
m o t h s lay t h eir eg gs in t h e f lo w er s w h er e t h e
lar vae h at ch an d eat so m e o f t h e d evelo p in g seed s.
Bo t h b en ef it .
Wr asse f ish f eed o n t h e p ar asit es f o u n d o n t h e
b lack sea b ass’s b o d y (u su ally in t h e m o u t h ). Den t al
f lo ss f o r f ish —b o t h sp ecies b en ef it
Clo w n f ish live am o n g an em o n es act in g as a lu r e
f o r t h e sea an em o n e’s p r ey. Th e clo w n
f ish g et s p r o t ect io n an d sh elt er f r o m t h e
an em o n e.
E. Co li is a b act er ia t h at lives in t h e g u t o f h u m an s.
Th e h u m an p r o vid es t h e id eal h ab it at f o r e co li
r ep r o d u ct io n an d t h e e co li p r o vid es t h e ext r a
vit am in K t h at w e u se.
An t s o f f er p r o t ect io n f o r t h e ap h id s w h o (h ave n o
p r o t ect ive f eat u r es o f t h eir o w n ) w o u ld o t h er w ise
w o u ld b e f o o d f o r all so r t s o f o r g an ism s. Th e
ap h id s “r ep ay ” t h e an t s b y p r o vid in g h o n eyd ew (a
liq u id t h ey secr et e) f o r t h e an t s t o u se as f o o d .
Ep ip h yt es ar e a class o f p lan t s t h at g r o w in t h e
cr o o ks o f t r ee b r an ch es. Th ey sim p ly use t h e t r ee
b r an ch es as a w ay t o b e h ig h er —clo ser t o t h e
su n lig h t n eed ed f o r p h o t o syn t h esis. Th e t r ees
ar en ’t af f ect ed b y t h is r elat io n sh ip .
Th e t ick f eed s o f f t h e b lo o d o f t h e d eer . Th e d eer
is n eg at ively af f ect ed .
Th e st o r k u ses it s saw -like b ill t o cu t u p t h e d ead
an im als it eat s. As a r esu lt , t h e d ead an im al car cass
is accessib le t o so m e b ees f o r f o o d an d eg g lay er s.
Th e st o r k is n eit h er h ar m ed n o r h elp ed b y t h is
r elat io n sh ip .
Challenge: Why is it that one organism always benefits from a symbiotic
relationship? ie. Why isn’t there another type of symbiotic relationship where
neither organism benefits? ____________________________________________
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