-
- Glossary
of Terms for Freshwater Algae
-
- A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
|
|
|
aerial |
Growing in a habitat above the ground
or water |
akinete |
A thick-walled spore that can survive
harsh conditions and functions as an asexual resting stage |
algaenans |
Hydrocarbon polymers that help some
algal cells resist decay |
anisogamy |
Sexual reproduction involving two
types of gametes of different sizes or shapes |
antheridium |
A cell that produces male gametes |
apical cell |
Cell located at the end of a filament
or thallus |
aplanospore |
A nonflagellate spore that may be
genetically capable of producing flagellated cells under the
right conditions; produced by divisions of the parent cell |
araphid diatom |
Diatom lacking a raphe structure on
either valve |
areolae |
Pores or perforations in the siliceous
valves of diatoms |
asexual reproduction |
Reproduction involving the cells
of a single parent |
autocolony |
A miniature version of the parent
colony produced asexually by one of its cells; a coenobium |
autospore |
A nonflagellate spore |
axial |
A chloroplast located in the center
of a cell along its longitudinal axis |
|
|
basal |
Concerning the base of a thallus
or filament |
benthic |
Inhabiting the bottom of an aquatic
environment |
biflagellate |
Cells with two flagella |
bloom |
Visible or nuisance algal growth
often associated with nutrient-rich conditions |
blue-green algae |
See cyanobacteria |
brackish |
Slightly salty waterbodies |
|
|
calyptra |
Thickened or enlarged tip of a cyanobacterial
filament |
- charophyceans or
- charophyte green algae
|
The group of green algae most closely
related to the land plants, includes the zygnematalean algae
(Spirogyra and the desmids) as well as several other genera
and the stoneworts |
chlorophyll-a |
Primary photosynthetic pigment in
algae and higher plants |
chlorophyll-b |
Photosynthetic pigment found in higher
plants, green algae, and some euglenoids |
chlorophyll-c |
Photosynthetic pigment found in chrysophytes,
synurophytes, diatoms, tribophytes, dinoflagellates, cryptophytes,
and brown algae; includes c1 and c2 components |
- chlorophyceans
|
Green algae |
chloroplast (plastid) |
Membrane-bound organelle involved
in photosynthesis |
chrysophytes |
Mixotrophic algae with golden-brown
pigmentation |
chytrids |
Group of small, colorless fungi that
may parasitize algal cells |
chromatophore |
An organelle that contains pigments;
i.e. a plastid |
cingulum (pl. cingula) |
In the dinoflagellates, a transverse
groove that usually holds the transverse flagellum; another term
for girdle band |
coenobium (pl. coenobia) |
A type of colony with a genetically-predetermined
morphology and number of cells; each cell of the parent colony can
produce an autocolony that is an
exact replica of the parent colony |
coenocytic |
Multinucleate and lacking tranverse
cell walls; siphonous |
conjugation |
In the zygnematalean algae, sexual
reproduction involving nonflagellate gametes that combine in
a special tube or structure; see also lateral
and scalariform conjugation |
contractile vacuole |
A membrane-bound vesicle that expands
and contracts to expel excess water |
cross walls |
Transverse cell walls |
cyanelles |
The blue-green plastids of the glaucophytes
that originally resulted from an endosymbiotic event |
cyanobacteria |
Photosynthetic bacteria with a characteristic
blue-green color, commonly known as the blue-green algae |
cytokinesis |
Division of the cytoplasm during
cell division |
|
|
desmid |
A group of unicellular or filamentous
green algae; see also placoderm desmids
and saccoderm desmids |
detritus |
Dead or decaying organic matter |
diatoms |
Photosynthetic microalgae with siliceous
cell walls |
dioceious |
Organisms in which male and female
(or + and -) gametes are produced on different individuals |
dinoflagellates |
Unicellular algae that are often
covered in thick, armoured plates |
double false branching |
Growth pattern that occurs when a
filament breaks apart (often at a dead cell or heterocyst) and
both pieces emerge through the mucilage sheath and continue to
grow |
|
|
embryophytes |
The group consisting of bryophytes
and vascular plants |
endosymbiont |
An organism that lives inside another,
benefitting both individuals |
epilithic |
Growing on the surface of rock or
stone |
epiphytic |
Growing on the surface of plants
or other algae |
eutrophic |
Waters rich in dissolved nutrients
(especially nitrogen and phosphorus); leads to accelerated growth
of algae and plants that depletes oxygen levels and reduces biodiversity |
euglenoids |
Organisms that are unicellular or
colonial, colorless or pigmented, and may move with an undulating,
shape-changing motion (see metaboly) |
eyespot |
A light-sensitive, red-pigmented
spot usually found in the cell anterior of some flagellated algal
cells or reproductive cells; sometimes called a stigma
|
|
|
false branching |
Single false branching occurs when
a filament breaks apart (often at a dead cell or heterocyst)
and one piece emerges through the mucilage sheath and continues
to grow; see also double false branching |
flagellum (pl. flagella) |
A long, whiplike organelle that usually
protrudes from a cell and is used for motility |
fragmentation |
Type of asexual reproduction where
the parent thallus breaks into pieces to form new individuals;
may be accidental or genetically programmed |
frustule |
The siliceous components of a diatom cell; i.e. the valves
and girdle bands |
fucoxanthin |
A brown carotenoid pigment used in
photosynthetis, found in the golden-brown
and brown algae |
|
|
gametes |
Reproductive cells |
gas vesicles |
In cyanobacteria, cylindrical structures
used to increase cell bouyancy |
gas vacuoles |
Sometimes synonymous with gas vesicles,
also refers to a group of gas vesicles |
- girdle band or
- cingulum (pl. cingula)
|
- In diatoms, the rings or bands of silica encircling the valves
where they overlap.
- In desmids, the short wall segments oriented transversely
at the central portion of the cell
|
glaucophytes |
A group of algae that contain blue-green
plastids called cyanelles, sometimes
called Glaucocystophytes |
golden-brown algae |
Algal groups with golden pigmentation;
i.e. the chrysophytes, synurophytes,
haptophytes, and diatoms |
gone |
In the desmids, a cell derived from
zygote germination that may not have the typical morphology of
that species |
grana (pl.) |
Stacks of thylakoids found in the
discoid chloroplasts of land plants and some green algae |
green algae |
Morphologically diverse group of
algae with green-pigmented chloroplasts |
|
|
hair cells |
Elongate, usually colorless cells
or extensions of cells found at branch apices, increases surface
area for nutrient and gas exchange and may protect the cells
from herbivory |
halophilic |
Inhabiting a salty environment |
haploid |
Having a single set of chromosomes |
heterocyst |
In some cyanobacteria, a large, thick-walled
cell involved in nitrogen fixation |
heteropolar |
Filaments with distinct basal and
apical components or cells that are assymetrical along the transverse
axis |
heterotrophic |
Organisms that feed on organic matter
from external sources, and are osmotrophic
or phagotrophic |
holdfast cells |
Structure that attaches a thallus
or filament to the substrate |
- hormogonium
- (pl. hormogonia)
|
In filamentous cyanobacteria, short,
usually motile segments that break off from the main filament
and are used for asexual reproduction and dispersal |
hypnospore |
A thick-walled resting cyst |
hypnozygote |
A thick-walled, nonmotile resting
zygote that remains dormant for a period of time until germinating
when conditions improve; found in green algae, dinoflagellates,
and some other flagellated organisms |
|
|
intercalary |
Located in the middle of a thallus,
not on the end |
isogamy |
Sexual reproduction involving two
types of gametes that function differently but are morphologically
identical |
isopolar |
Symmetrical along the tranverse axis,
having the same morphology at both ends |
isthmus |
In desmids, the constricted region
between the two semicells that usually contains the nucleus |
|
|
lateral conjugation |
Conjugation
where two cells on the same filament reproduce within a
conjugation tube |
littoral zone |
Region near the shore of lakes, ponds,
or large rivers |
lorica |
A protective covering surrounding
flagellated cells of some algal groups |
|
|
meristem |
Portion of a thallus where the cells
are able to divide and produce new growth |
metaboly |
Shape-changing motion of the euglenoid
genera that does not involve flagellar movements |
metaphytic |
Growing among the floating microscopic
community in the littoral zone that is often associated with
aquatic plants |
mixotrophic |
Cells with both photosynthetic
and heterotrophic or phagotrophic
nutrition |
monoecious |
Organisms in which male and female
(or + and -) gametes are produced on the same individual |
monophyletic |
A group of organisms that share a
single common ancestor |
multicellular |
Composed of more than one cell |
multinucleate |
Having many nuclei |
|
|
necridic cells (necridia) |
Dead cells in cyanobacteria that
disrupt the main filament to produce false branching or hormogonia |
|
|
oligotrophic |
Waters low in nutrients and organic
production, typically rich in biodiversity |
oogamy |
Sexual reproduction involving the
fusion of a small, flagellated male gamete with a larger, nonflagellated
female gamete |
oogonium (pl. oogonia) |
A female reproductive structure capable
of producing one or more eggs |
osmotrophic |
Organisms that feed on dissolved
organic molecules absorbed from the outside environment |
|
|
parietal |
Near the outer or peripheral surface
of a cell or thallus; commonly used to describe chloroplasts
situated along the cell wall |
pellicle |
The surface covering of euglenoid
cells composed of proteinaceous strips in a helical pattern |
periphytic |
Growing attached on the surfaces
of plants, other algae, or other substrates |
phagotrophic |
Organisms that feed by ingesting
particulate organic carbon or intact cells |
phototaxis |
Movement in response to light |
photosynthetic |
Organisms that use sunlight as an
energy source to synthesize carbohydrates from carbon dioxide
and water |
phylogenetic |
Concerning the relationships of evolutionary
development |
phytoplankton |
Floating or swimming microscopic
algae and cyanobacteria |
placoderm desmids |
Unicellular or pseudofilamentous
desmids with cell walls made up of two parts of different ages
separated by a central isthmus that are covered in pores |
plastid |
See chloroplast |
polar nodule |
In cyanobacteria, thickened regions
where the heterocyst cell wall attaches to a vegetative cell |
polyeders |
In Hydrodictyon and Pediastrum,
polygonal cells produced from zygote germination that give rise
to new coenobia |
polyphyletic |
A group of organisms descended from
more than one ancestor, may be more closely related to other
organisms outside of the taxonomic group |
protoplasm, protoplast |
The living substance of a cell |
pseudofilament |
Loose chain of individual cells held
together by mucilage or attached at the end walls, rather than
sharing a common cell wall as in a true filament |
pyrenoid |
A proteinaceous structure associated
with algal chloroplasts that often forms storage compounds |
|
|
quadriflagellate |
Cells with four flagella |
|
|
raphe |
In diatoms,
a slit in the valve face that allows the cell to move along a
substrate |
rhizoid |
Rootlike extensions usually used
to attach a thallus to the substrate |
|
|
saccoderm desmids |
Desmids with a homogeneous cell wall
that lacks pores; are not differentiated into two semi-cells |
scalariform conjugation |
Conjugation
involving two filaments that allign laterally and form conjugation
tubes between adjacent cells in a ladder-like arrangement |
semicell |
In placoderm
desmids, one-half of a cell |
sexual reproduction |
Reproduction involving the cells
of a single parent |
silica deposition vesicle |
Involved in the formation of the
siliceous valves of diatoms and siliceous scales of chrysophytes
and synurophytes |
siphonous |
See coenocytic |
striae |
Term used to described elongated
markings on the cell walls of desmids and diatoms |
subaerial |
Growing on or near the earth's surface |
sulcus |
In dinoflagellates, a longitudinal
groove in the ventral side of the cell that holds the longitudinal
flagellum |
suture |
In dinoflagellates, the regions between
thecal plates |
syngamy |
The fusion of two gametes during
fertilization |
synurophytes |
- Motile flagellates covered by siliceous scales; the scaled
chrysophytes
|
|
|
terminal |
Located at the end of a thallus |
thallus |
General form of an alga that,
unlike a plant, is not differentiated into stems, roots, or leaves |
thylakoid |
Flattened membranous sacs that form
the chloroplast membranes |
tribophyte algae |
See yellow-green
algae |
trichome |
A filament of a blue-green alga or
cyanobacterium |
trichogyne |
In some charophycean green algae
and in the red algae, the elongated portion of the female reproductive
structure that recieves the male gametes |
turbidity |
Measure of the cloudiness of a waterbody
due to suspended particles |
|
|
unicellular |
Composed of a single cell |
uniseriate |
Composed of a single row of cells. |
|
|
valve |
In the diatoms, the two siliceous
halves of the cell wall |
vegetative cells |
Cells involved in growth, nutrition,
or asexual reproduction, but not sexual reproduction |
vesicles |
SDV, gas |
|
|
yellow-green algae |
Rare algae with yellow-green pigmentation;
the tribophyte algae |
|
|
zoospore |
A flagellated spore |
zygospore |
A thick-walled resting spore formed
from the fusion of gametes or a fertilized oogonium |
zygote |
The cell resulting from the fusion
of two gametes |