THE STEINHART AQUARIUM - Gulf of Guinea Science ...

chitin the tough, resistant organic substance that is
the major component of arthropod exoskeletons
chordate member of an animal phylum whose members
possess a notochord, a dorsal nerve cord, gill
slits, and a tail, at least at some stage of development
cilia hairlike structures that serve, especially in free
unicellular organisms, to produce movement or, in
higher forms, a current of fluid (e.g., sponges)
cirri (singular cirrus) short bristlelike projections from
the epidermis of certain invertebrates and fishes
clade a group of organisms that includes a common
ancestor and all of that ancestor’s descendants
cladogram a branching diagram indicating a hypothesized
sequence of evolutionary changes using cladistic
methodology
clone an organism derived from a founding individual
by asexual means that is genetically identical to the
founding individual
coelom a body cavity in which the digestive tract and
other internal organs are suspended
commensalism relationship between species that is beneficial
to one, but neutral or of no benefit to the other
compressed flattened from side to side
congeneric belonging to the same genus
conspecific belonging to the same species; individuals
or populations of the same species
consumer an organism that obtains nutrients and energy
by eating other organisms
convergence or convergent evolution the evolution
of similar characters in genetically unrelated species,
mostly because they have been subjected to similar
environmental selective pressures
countershading said of the coloration of an animal
whose ventral surface is lighter than its dorsal surface,
thus helping the animal blend into its background
when viewed from above or below
demersal sinking to or lying on the bottom; living on or
near the bottom and feeding on benthic organisms
denticle literally, “small tooth;” usually refers to modified
scales on some fishes, especially sharks and rays
deposit feeder an animal which takes in masses of
sediments and processes them through its digestive
tract to extract organic material
derived character state inferred to be a modified version
of the primitive condition of that character, and
to have arisen later in the evolution of the clade
desiccation removal of water; the process of drying
Glossary 309
detritivore organisms that live on dead organic matter,
usually in small particles
detritus fine, particulate debris, mostly derived from
the decomposition of plant and animal remains; often
an important source of nutrients in a food web
deuterostome an animal in whose embryonic development
the anus forms first and the mouth forms secondarily.
Deuterostomes are also characterized by
radial cleavage and by formation of the coelom from
outpocketings of the gut. Echinoderms and chordates
are deuterostomes
DNA “deoxyribonucleic acid;” the nucleic acid which
carries the genetic code of an organism; DNA is the
primary component of chromosomes
dichotomous dividing into two parts; branching;
paired
dichromatic members of a species having different coloration;
usually related to sexual or growth differences
dinoflagellate dominant planktonic algal form
diploid referring to cells having two sets of chromosomes
(2n): in animals, twice the number characteristic
of gametes; in plants, the chromosome number
characteristic of the sporophyte generation; in contrast
to haploid (1n)
diurnal active during the day
dominant 1) referring to an allele that is almost always
expressed, even if only one copy is present; 2)
used to describe a male fish which is the chief spawner
and which endeavors to exclude other males from
the spawning act
dorsal pertaining to the back or upper side of the
body
dorsal fin unpaired fin on the dorsal surface of fishes;
most often used for stabilization to prevent pitch and
roll. A few fish species (e.g., bowfin, moray eel, and
seahorse) use the dorsal fin for movement
ectotherm an organism that regulates its body temperature
by taking in heat from the environment or giving
it off to the environment; “cold-blooded”
ecosystem a major interacting system that includes
both organisms and their physical environment
ectoparasite a parasite that lives on the outside of its
host; opposite of endoparasite
endosymbiont a symbiotic organism that lives within
the body of an individual of an associated species.
endotherm an organism that uses metabolic energy to
regulate body temperature independent of the environment