Biol-302 Botany, Spring 2007
Velma Matthew, TA – Kathy Boothby
Lab 4: Unicellular Algae, & Multicellular Algae.
Phylum: Dinophyta (Dinoflagellates)
Family: Ceratiaceae and Peridiniaceae
Genera: Ceratium and Peridinium
- Look at the prepared slides of Ceratium and Peridinium, and draw each. On both, be sure to label the flagellar grooves.
- How many flagella do dinoflagellates have? Two
What is the name of the plates that help dinoflagellates maintain their shape? What are these plates made of? Plates are called theca. They are made of cellulose.
Family: Xanthophyceae (Yellow-green algae)
- Prepare a slide of Vaucheriafrom the culture in class and also look at the prepared slides of Vaucheria for comparison.
a. Draw and label the coenocytic (multinucleate) filaments, chloroplast, antheridia, and oogonia. Note: that there are no septa in the coenocyte.
Phylum: Phaeophyta (Brown algae [Kelp])
Genera: Ectocarpus, Fucus, & Laminaria
- Prepare a slide of Ectocarpus viriabilis from the culture in class. Ectocarpus are an ancient lineage of brown algae that have isomorphic alternation of generations.
- What is meant by isomorphic alternation of generations?
- Identify and draw a unilocular sporangium and a plurilocular sporangium. How do these two structures differ?
Unilocular has one internal compartment in which meiosis occurs followed by mitosisproducing numerous zoospores.
Plurilocular has many internal compartments, each compartment will form one zoospore inside.
- Look at preserved specimens of Fucus on the herbarium sheets. Find the thickened midrib and the swollen receptacles at the tips of some blades. These receptacles are covered with small protuberances called conceptacles. You may also be able to see an air bladder.
- Draw and label Fucus with receptacles.
- After viewing macroscopic anatomy, look at prepared slide of a cross section of a receptacle. Draw and label conceptacle, oogonium, and antheridium.
- Look at preserved specimens of Laminaria.
- Draw and label the holdfast, stipe, and blade (lamina)
- After viewing macroscopic anatomy, look at prepared slide of a blade cross section. Draw and label the sorus (a cluster of sporangia with spores) on the surface of the blade, and the cortex.
Phylum: Rhodophyta (Red algae)
- Look at prepared specimens available. Be able to distinguish between redalgae and the members of the Phaeophyta phylum.
a. Prepare a slide of Polysiphonia californica from the culture in class and look at a prepared slide of Polysphonia for comparison. Draw and label the pericarp, carpospores, tetrasporangia/ tetraspores, and spermatangia.
Phylum: Chlorophyta (Green algae)
- Prepare a slide of Oedogoniumfrom the culture in class.
a. Draw and label antheridia, sperm (w/in anteridia), oogonium, egg, andvegetative cell.
At the gross morphological level Phaeophyta are brown-green or brown in color and Rodophyta are red in color.
Phylum: Chlorophyta (Green algae)
Genera: Spirogyraand Volvox
Normally green in color, the chloroplast of Spirogyra is twisted like a spiral staircase. Mats of Spirogyra filaments float just beneath the surface of the water. A bloom causes a grassy odor and clogs filters at water treatment plants.
- Prepare a slide of Spyrogyrafrom the culture in class.
a. Draw and label filament, cell, and chloroplast.
What is the shape of the chloroplast and how are they arranged w/in the cell? Is the cytoplasm streaming in your material?
The chloroplast is helical in shape and spirals just beneath the plasma membrane
Volvox forms a sphere of 500 or more cells, which can be seen without using a microscope. The cells have two flagella that move the colony through the water. Volvox reproduces by forming daughter colonies that can be seen as darker spheres within the colony. An excess of nitrogen encourages the growth of Volvox and may cause "blooms" during the summer months. During blooms in the shallow ponds at fish hatcheries, the large numbers of Volvox cause damage to the gills of young fish. When present in large numbers Volvox gives water a fishy odor.
- Prepare a slide of Volvoxfrom the culture in class.
a. Draw a colony of Volvox. Identify an individual cell, the adult colony, and a juvenile colony.
b. Where are the flagella on Volvox?
c. Do they reproduce sexually, asexually, or both? Both