BIO 469 Lecture 18: Invertebrate Symbioses
13 Jun 2018
School
Department
Course
Professor
Invertebrate Symbioses
● Greek “living together”
● Anton de Bary - studied lichens (mid-1800’s)
● “The living together of different species”
● Included parasitism but excluded associations of short duration
● Symbioses are associations between different species that persist for long periods
(relative to the generation time of the interacting organisms)
● Types of symbioses
○ Mutualism = both partners benefit from the relationship in some way
○ Commensalism = broadly, the benefit to one of the partners may be nutritional
or protective
○ Parasitism= a one-sided relationship in which one partner benefits at the
expense of the other
● Terminology
○ Host = multi-celled organism; larger
○ Symbiont = single-celled organism; smaller organism
■ Can have host and symbiont both single-celled
○ Endosymbiont = resides inside the host organism; can be intracellular
(endocytobiosis)
○ Obligate symbiosis = partners in the symbiosis are not found outside of the
association
○ Facultative symbiosis = partners are also found free-living
■ Zooxanthellae ( corals and in water column)
● Photoautotrophic symbioses
○ Tridacnid clams - thick mantle tissue with pigments, ocelli and zooxanthellae
● Chemoautotrophic Symbioses
○ Bacteria, use hydrogen sulfide and oxidized it and use energy produced during
this to
○ Teredo sp. - ship worm
○ Gills contain bacteria that produce enzymes that help digest cellulose in wood
○ Angler Fish, Lantern fish, Deep water squid
■ Symbioses with bioluminescent bacteria that may live within specialized
organs
○ Euprymna scolopes (bobtail squid) and Aliivibrio fischeri
○ Deep sea vents; Riftia pachyptila (Hydrogen sulfide/anoxic environment)
Siboglinid tube worm
● Serial Endosymbiosis Theory (SET)
○ Organelles of eukaryotic cells (mitochondria, chloroplasts) may have arisen by
successive symbiotic events
■ DNA of chloroplasts and mitochondria is different from that of host
nucleus
■ Sequence homology between nucleic acids of chloroplasts and
mitochondria and those of free-living bacteria
● Examples
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Anton de bary - studied lichens (mid-1800"s) Symbioses are associations between different species that persist for long periods. Included parasitism but excluded associations of short duration (relative to the generation time of the interacting organisms) Mutualism = both partners benefit from the relationship in some way. Commensalism = broadly, the benefit to one of the partners may be nutritional or protective. Parasitism= a one-sided relationship in which one partner benefits at the expense of the other. Can have host and symbiont both single-celled. Endosymbiont = resides inside the host organism; can be intracellular (endocytobiosis) Obligate symbiosis = partners in the symbiosis are not found outside of the association. Facultative symbiosis = partners are also found free-living. Zooxanthellae ( corals and in water column) Tridacnid clams - thick mantle tissue with pigments, ocelli and zooxanthellae. Bacteria, use hydrogen sulfide and oxidized it and use energy produced during this to. Gills contain bacteria that produce enzymes that help digest cellulose in wood.
