Symbiosis
Sym- together
Bio- life/living
Osis- Condition of
What is Symbiosis?
 When
at least two organisms live together
in a way that benefits at least one of the
organisms
 Can occur in all of the kingdoms
 Can occur with organisms from different
kingdoms
 There are three types of symbiosis:
mutualism, commensalism, parasitism
Why?
 Can
provide benefits to both organisms
 Allows organisms to survive in the same
environmental niche
 Helps an organism to avoid competition
 Can prevent an organism from becoming
“prey”
Commensalism
 One
organism is helped and the
other organism is neither helped
nor harmed

Certain species of
crab carry venomous
sea urchins on their
backs

Gives the crab
protection from
predators

Man of War fish live
among the poisonous
tentacles of the
Portuguese Man-ofWar jellyfish

Gives the fish
protection from
predators

Here, the Anemone
crab, a filter feeder,
lives among the
tentacles of a giant
sea anemone.

Tucked safely among
the tentacles, it can
filter its food from the
water.

Zebra crabs cling to a
”fire urchin.”

The venomous spines
protect the crabs from
predators.

The remora attaches
itself to a shark with a
suction cup and eats
scraps from the
shark’s meals

The shark is not
harmed, but also does
not benefit. Only the
remora benefits.
Mutualism
 When
both organisms receive
some benefit from the relationship

The African
honeyguide bird and
the honey badger
(ratel)

The bird finds honey
bee nests and makes
a special call to attract
the badger, who
breaks open the hive
so both can eat

Tick bird and
rhinoceros; Ox-pecker
and ox

The birds get food
(ticks) and protection
and the rhino and ox
get parasites removed

The crocodile opens its
mouth to let the
Egyptian plover (a bird)
pick leeches off of its
gums

The crocodile is rid of a
parasite and the plover
gets a meal

Cleaner wrasses
remove parasites
from larger fish
 They have been
known to set up
“cleaning stations”
where fish can come
to get cleaned

Wrasses get food and
other fish get parasites
removed

Bees travel from
flower to flower to
collect nectar

The flowers get
pollinated and the
bees get nectar to
make honey

There is a protozoan
in the gut of a termite
that helps it to digest
the cellulose in the
wood

The protozoan gets its
food delivered and has
a place to live and the
termite has help in
digestion

Tube worms deep at
the bottom of the
ocean have bacteria
that live inside them

The tube worms bring
in the nutrients and
chemicals and the
bacteria convert them
into food for the tube
worm
Parasitism
 One
organism is helped and the
other organism is harmed and
possibly killed
 A parasite can live on or in its
“host” organism

A tapeworm attaches
to the intestinal wall of
its host and absorbs
nutrients

This harms the host
because its nutrients
are being diverted to
the parasite

Fleas bite and suck
the blood of animals


Ticks can bite and
hang on while they
suck the blood of
animals
Both can transmit
disease

Leeches attach to
their victims and inject
an anti-coagulant to
keep the blood from
clotting

Leeches get a meal,
and the organism
loses blood and can
get open wounds
which can become
infected.
Mimicry

Some people consider mimicry a form of
symbiosis
 However, mimicry only involves one organism

The organism may imitate another living thing (or a
non-living thing such as a rock or a stick), but it does
not derive an actual benefit from what it is mimicking