Symbiosis
What is common?
• In a tropical ocean,a remora fish uses a
structure on top of its head to attach itself
to the belly of a shark and get a free ride.
• A honey guide bird in Africa leads a furry
ratel to a wild beehive.With its sharp claws,
the ratel rips open the hive.The ratel laps up
the honey as the honey guide bird dines on
bee wax.
It is Symbiosis !!
Types of Symbiosis
Symbiosis
Mutualism
Commensalism
Parasitism
Mutualism
• Advantages for both
partners
Cleaning Symbiosis
• The drawing shows
the Nile crocodile
opening its mouth to
permit the Egyptian
plover to feed on any
leeches attached to its
gums.
• Cleaning symbiosis is
more common in fish.
Another Example of Mutualism
• Many of the bacteria live in our large intestine. They feed
on food in the gut and do not harm us. And some probably
help us by producing vitamins; that is, the relationship is
mutualistic.
• The goby fish and snapping shrimp live in a sandy burrow
built by the shrimp. Because the shrimp is nearly blind, it
keeps one of its long feelers on the goby. When danger
approaches, the goby warns its partner with flicks of its
fins, and both partners retreat to their burrow. Neither of
them can survive on their own.
Commensalism
• One partner living on
the other with no
obvious effect on the
second.
Examples of Commensalism
• The remora fish and the shark. The dorsal fin of
the remora is modified into a sucker with which it
forms a temporary attachment to the shark. When
the shark feeds, the remora picks up scraps. The
shark makes no attempt to prey on the remora.
• Some species of barnacles are found only as
commensals on the jaws of whales. And there are
other species of barnacles found only as
commensals on those barnacles.!
More
• High in the branches of a tree, fierce hawk
called osprey builds a big, flat nest for its
eggs. Sparrows set up their homes beneath
the osprey’s nest for protection. Osprey feed
on fish anyway.
Parasitism
• One partner living on
the other with
detrimental effect on
the second
A parasite is an organism that
• Lives on or in the body of another organism
(the host)
• From whose tissues it gets its nourishment,
and
• To whom it does some damage
Parasites damage their host in two
major ways, by consuming its tissues, e.g.,
hookworms and/ or liberating toxins
• Animals are parasitized by viruses, bacteria,
fungi, flatworms (tapeworms and flukes),
and insects (fleas, lice).
• Plants are parasitized by viruses, bacteria,
fungi, and a few other plants.
Check your understanding
What kind of symbiosis is it?
The Light-Organ Symbiosis of Vibrio
fischeri and the Hawaiian squid
•
During the day the bobtailed squid
remains buried in the sand of
shallow reef flats. As the sun sets,
the nocturnal animal emerges from
its safe hiding place and searches
for food. In the moonlit night, the
squid would appear as a dark
silhouette when it swims through the
water and would be easily detected
by predator fish from below. It is
thought that the squid camouflages
itself by projecting light downward
from its light organ. Inside the light
organ are luminescent bacteria that
produce the light.
The Nutritional Symbiosis of
Buchnera and Aphids
•
Aphids are plant pests, capable of
causing major agricultural damage.
They feed on plants by piercing
them with syringe-like mouth parts
and sucking the sap out of the
phloem, resulting in a diet that is
rich in carbohydrates and deficient
in amino acids. Some of these
amino acids cannot be synthesized
by the insect but are supplied by
symbiont. The interaction of the two
partners dates back 150 to 250
million years and both have become
so dependent on each other that
under natural conditions they cannot
exist without each other.
What kind of Symbiosis?
• Your relationship with your pet
• The relationship of a dog and a flea
• Orchids survive in dense, shadowy jungles
by growing on tall trees to get plenty of
sunlight and absorbing water and nutrients
off the tree bark.
• Humans and microscopic organisms called
mites living in their eyebrows.
What kind of Symbiosis?
• Diseases-causing bacteria and viruses and
humans
• Fungi that causes athlete’s foot
• Cuckoos lay their eggs in other bird’s nests.
When the baby cuckoo hatches, it pushes
the eggs and young of its foster parents out
of the nest. Foster parents are tricked into
feeding and caring for the cuckoos.