Download Lab 4: Unicellular Algae, and Multicellular Algae

Lab 4: Unicellular Algae, and Multicellular Algae
Dinophyta: text pages 303-305
Ceratium & Peridinium
Chrysophyta
Vaucheria: Common name is water felt. It is found in moist soil and in both
quiet and running waters. The alga body is coenocytic (tubular) with multiple nuclei.
Sexual reproduction is oogamous. The oogonia (female structure) and anteridia (male
structure) form as lateral protuberances. The oogonia in globular and the anteridia is
hook shaped as it reaches out to make contact with the oogonia.
Phaeophyta: text pages 316-321
Ectocarpus: page 319 Ectocarpus is a common filamentous brown algae found
growing on rocks and larger algae. At cool temperatures the unilocular sporangia is
favored. They are enlarged cells in which meiosis occurs followed by mitosis which
forms zoospores. The zoospores are haploid and give rise gametophytes.
At warmer temperatures the plurilocular sporangie predominate. They are composed of
many small cuboidal cells. The contents of each of these cells develops into a zoospore.
The zoospers are diploid and give rise to sporophytes.
Fucus: page 319, life cycle page 321 Fucus is a common Northern Hemisphere
genus of algae. Plants are less than a meter in length. Each branch has a thickened
midrib and thinner tissue on either side. Some species form gas bladders that provide
buoyancy when the plant is submerged in calm water. Fucus forms specialized
reproductive structures at the end of its branches called receptacles. Just beneath the
surface of receptacles are spherical cavities called conceptacles where gametes are
produced. Depending on the species the male (antheridia) and female (oogonia)
structures may be found within one conceptacle or in conceptacles on different plats.
Laminaria: page 319, life cycle page 320 The plant may reach three meters or
more in length. The plant is divided into the blade, stipe and holdfast. The blade is the
most conspicuous part and grows from its base and is worn away at its apex. The stipe is
a cylindrical stem-like region, which may vary in length depending on the species. The
hold-fast does as its name implies, attaches it to a substrate.
Rhodophyta:
Polysiphonia: pages 325-326, Common filamentous red algae
Chlorophyta:
Oedogonium: page 333 A common filamentous green alga found in relatively
calm freshwater habitats. Antheridial cells occur within the filament. Each antheridial
cell is much shorter than a vegetative cell. Antheridial cells often occur in a series. One
or two sperm will form in each antheridial cell. Sperm are chemically attracted to the
oogonia. Oogonia are enlarged cells with a single egg inside. The sperm will enter
through a pore in the wall of the oogonium and fertilize the egg.
Spirogyra: Common name water silk
Spirogyra cells contain one or more chloroplasts that spiral around the periphery of the
cell. Spirogyra reproduces by conjugation only. Spirgyra has no flagellated cells or
stages in its life cycle.
Volvox: A Volvox colony can have up to 50,000 individual cells. The cells are
arranged in a layer around the periphery of the colony. The two flagella of each cell are
oriented out into the surrounding water. The inside of the colony is a mixture of water
and mucilage. New daughter colonies form within the colony. Volvox can reproduce
asexually and sexually.