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SYMBIOSIS
The term symbiosis (from the Greek:, sym,
"with"; and, biosis, "living") commonly describes
close and often long-term interactions between
different biological species. The term was first
used in 1879 by the German mycologist,
Heinrich Anton de Bary, who defined it as: "the
living together of unlike organisms".
Mutualism
Mutualism is a biological interaction between individuals of
two different species, where both individuals derive a fitness
benefit, for example increased survivorship. Similar interactions
within a species are known as co-operation.
An example of mutual symbiosis is
the relationship between Ocellaris
clownfish that dwell among the
tentacles of Ritteri sea anemones.
The territorial fish protects the
anemone from anemone-eating fish,
and in turn the stinging tentacles of
the anemone protect the clownfish
from its predators (a special mucus
on the clownfish protects it from the
stinging tentacles).
Red-billed Oxpecker, Buphagus erythrorhynchus of east Africa
Yellow-billed Oxpecker, Buphagus africanus of most of sub-saharan Africa.
Nile Crocodile (Crocodylus niloticus) with Egyptian Plover or
Crocodile Bird (Pluvianus aegyptius)
Lichens
Organism A
Organism B
Benefit?
Benefit?
Mycorrhiza
Organism A
Organism B
Benefit?
Benefit?
Commensalism
…is a term employed in ecology to describe a relationship between two living
organisms where one benefits and the other is not significantly harmed or
helped (like a bird living in a tree).
The word derives from the Latin com mensa, meaning sharing a table.
Remoras (shark suckers) on a nurse shark
Barnacles on a whale
Parasitism
• Parasitism is a type of symbiotic
relationship between organisms of
different species in which one, the
parasite, benefits from a prolonged,
close association with the other, the
host, which is harmed.
• The harm and benefit in parasitic
interactions concern the biological
fitness of the organisms involved.
Parasites reduce host fitness in
many ways. Parasites increase their
fitness by exploiting hosts for food,
habitat and dispersal.