Midterm 1 Flashcards
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)
What is phenotypic plasticity?
Same genotype, but different phenotype (possibly due to environment)
What are micro satellites, and how are they useful?
Parts of the genome that do not code for proteins; allow us to study variation that is invisible to the eye (Same as DNA fingerprinting)
Define abundance.
Number of individuals in a given area
Define disparity.
How physically different species are from one another.
What is phylogenetics?
Ways in which living things are related to one another through common ancestors
Define sister taxa.
Closest relatives descended from a single recent ancestor
What is a root in a phylogenetic tree?
Common ancestor shared by all species depicted
What are branches in a phylogenetic tree?
Connections between ancestors and descendants
What are terminal nodes?
Usually represent living species, whereas internal nodes are usually extinct ancestors
What is topology?
Order of branching reflecting ancestor-descendant relationships
What is cladistics?
Classification based strictly on evolutionary relationships
What are clades?
Evolutionary groups; group of species that includes the last ancestor that they shared and all its descendants; also known as monophyletic groups
What are paraphyletic groups?
When one descendant is left out of a clade
Define convergent evolution.
Features evolve more than once in independent lineages as a similar adaptation under similar environmental pressures (ex. wings)
Define homology.
Sharing ancestral traits
Define homoplasy.
Having traits that are similar but evolved independently
What is genetic variation?
DNA differences among individuals within a population/species; changes by mutation, natural selection, genetic drift and gene flow
What are mutations?
Random errors in DNA replication (NOT because of challenges); do NOT occur in order to directly benefit the organism
What is natural selection?
Non-random differences in survival/reproduction among individual entities on the basis of differences in heritable characteristics; populations become more divergent
What is genetic drift?
Random changes in allele frequencies in a population; Caused by sampling error (Greater impact with smaller sample size); Population becomes more divergent
Define founder effects.
Subset of a population moves, and creates a new population elsewhere
Define population bottleneck.
Drastic reduction in population size gives an unrealistic representation of the original population
What is gene flow?
The sharing of genes among populations; makes 2 different populations more similar; prevents populations from diverging.
What is evolution?
The study of both adaptive and non-adaptive change over time in populations, the origin and extinction of species, and the relationships among living things
What is ecology?
The study of interrelationships between organisms and both living (biotic) and non-living (abiotic) components of their environments
What is physiology?
The study of organism structure and function, including homeostasis and encompassing cells, tissues, organs, and body systems
