Midterm 1 Flashcards
(50 cards)
Where did zebra mussels (Dreissena polymorpha) come from?
Eastern Europe (Black and Caspian Sea)
How did zebra mussels likely migrate to Canada?
Most likely transported in ballast water of an ocean liner that crossed the Atlantic Ocean.
When/where were zebra mussels first reported in North America?
1988; in Lake St. Clair
How many freshwater mussel species are in North America?
About 300
What family of mussels is native to Ontario?
Unionidae (41 species)
What is obligate parasitism?
The organism (ex. Unionidae mussels) must parasitize a host at some stage to complete their reproductive cycle
What does dioecious mean?
Separate males and females (like most Unionids).
How do Unionids reproduce?
Males release sperm into water through exhalant siphon, which are taken up by females downstream through their inhalant siphon.
Where do Unionid embryos mature?
Embryos develop inside modified pouches of the female’s gills (marsupium)
What are Unionid larvae called?
Glochidia
What are lures?
Adaptations by adult Unionid mussels to attract a host fish to allow their glochidia to attach to.
What are refuge sites?
Shallow areas of water where mussels are likely to be found
What are ‘druce’?
Zebra and quagga mussels (both invasive species)
What level of biological groupings is not considered part of a nested hierarchy?
Ecosystem, because it contains both environment and communities (comprised of more than just what’s below it).
What factors contribute to threats to native freshwater mussel biodiversity in the Great Lakes region?
Invasive species, ability of mussels to disperse, cargo ships, fisheries, habitat destruction, and agricultural runoff. (NOT daily weather fluctuations)
How do conglutinates work?
“Baits and Traps”; Glochidia are enclosed in membranous capsules that mimic host prey, then fish will approach and glochidia are released.
How does host capture work?
As fish approaches, the mussel physically grips host and pumps glochidia over gills.
What are the levels of biological organization?
Domain, Kingdom, Phylum, Class, Order, Family, Genus and Species
Define biodiversity.
Variability at each level, as well as within a species.
Define diversity.
Refers to the number of species in a taxonomic group or geographical area
Define ontogeny.
An individual’s development (involves significant changes in morphology)
Why are bissel threads useful?
They prevent juveniles from being washed downstream
What do zebra mussel infestations look like?
A mass of shells, but there is a big difference in size, colour, stripe pattern, etc.
What is intraspecific variation?
Variation in morphological traits within species (Can make it difficult to identify native mussels)
