Symbiotic Relationships

Symbiotic Relationships
What are Symbiotic Relationships??
• Symbiosis is the close relationship between two
or more organisms of different species, often but
not necessarily benefiting each member.
Ectosymbiosis and
• Ectosymbiotic- wherein one organism lives on
another organism
• Endosymbiotic- wherein one organism lives
inside another organism
Obligate and Facultative
• Obligate- the relationship is essential for the
life of at least one of the organisms
• Facultative- where the relationship is
beneficial to the organisms, but not essential
for survival
• The two organisms involved in this
relationship both benefit from each other.
Examples of
benefits are provided in each
Examples of Mutualism
• The Egyptian plover and the crocodile:
– The plover eats the decaying meat stuck in the
crocodiles teeth. The bird gets food and the crocodile
gets dental care.
• The clown fish and the sea anemone:
– The clown fish lives in the sea anemone. The
anemone gets nutrition from the fecal matter of the
fish and the fish gets protection from predators.
• The oxpecker and the zebra:
– The oxpecker lands on the zebra and eats ticks and
other parasites that live there. The oxpecker gets food
and the zebra gets pest control.
Examples of Mutualism
• The bee and the flower:
– Bees collect nectar from flowers which they make into
food. When they land on the flower they get pollen stuck
to their bodies. They spread this pollen to other flowers,
pollinating the plants.
• The spider crab and the algae:
– The spider crabs live on the shallow ocean floor. The algae
lives on the crabs. The algae helps the crabs blend in and
the algae gets a good place to live.
• The bacteria and the human:
– Bacteria lives in the intestines of humans. The bacteria
helps the human by digesting food that the human cannot.
They get a meal and the human is able to digest the food
they eat.
• In this relationship, one organism benefits
while the other is unaffected (doesn’t benefit
and isn’t harmed)
• What is happening in each relationship?
Examples of Commensalism
• The cattle egret and cows:
– When cattle graze, they stir up and move many insects
that were nesting in the grass. The egret then feeds
upon the insects.
• Sedentary crustaceans/barnacles:
– They attach themselves to rocks or whales. When the
whales travel the barnacles get access to nutrient rich
waters an sometimes food that is left behind y the
• The desert holly shrub:
– Provides shade for growing creosote bushed beneath
• The fringe toed lizard:
– Will stay in abandoned desert rat holes.
Examples of Commensalism
• The caribou and the artic fox:
– The fox follows the caribou while it looks for food. When the
caribou digs up the snow to get to the lichen underneath they
stir up some of the subnivean mammals. The foxes then hunt
these animals.
• Remora sharks and whales:
– The Remora sharks have an adhesive disk on their dorsal
surface. They use this to attach to whales and then feed on the
remains of the whale’s food.
• Birds and army ants:
– The birds follow the ants which stir the flying insects resting on
the ground. He birds then catch and eat the insects.
• Monarch and Viceroy butterflies
– The monarch butterfly contains cardiac glycosides which are
poisonous to vertebrates. This keeps animals from eating the
monarch butterflies. The viceroy butterfly mimics the monarch
butterflies patterns and therefore are not eaten.
• In this relationship, one organism is harmed
while the other benefits
• How do you think each represents parasitism or
how do you think the organism shown is
Examples of Parasitism
• Mosquitos: suck the blood of their prey
• Oak Treehoppers: suck sugar-rich juices from
the phloem of trees
• The squawroot: a flowering plant that gets
energy by tapping into an oak tree’s roots
• Sea Lamprey: A sort of temporary parasite.
The lamprey latches onto a fish and holds on
with its teeth and rasps away the skin. This
leaves an open wound for them to feed off of.
Examples of
• The horsehair worm: It starts as an egg in a
puddle. When the puddle dries out a
grasshopper usually comes along and eats it.
It then burrows into the insects gut and grows.
When it is an adult it produces chemicals that
make the insect seek out water and jump into
it. The worm will exit the grasshopper and
finish out its life in the puddle. The
grasshopper may survive the ordeal if it
doesn’t drown.
Examples of
• Cricket: It lives in an ant’s nest and disguises itself
with a chemical that makes the ants think it is just
another ant. It roams the nest and gets the ants
to feed it.
• Leeches: thought of as ectoparasites. They attach
to a vertebrate host and take a blood meal before
dropping off the host.
• Lice: Parasitize humans. They attach to the hairs
of the body or head and then suck blood from
the host. It is easy to remove the adults but not
the eggs.

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