Multicellular green algae, brown and red algae
Answers are for parents and teachers.
1
Draw the life cycle of Ulothrix (asexual and sexual reproduction).
Asexual: cell → 4–8 zoospores → new thread. Sexual: isogametes → zygote → 4 cells → new thread.
2
List 5 points on the importance of algae.
Give oxygen, feed fish, food for people (kelp, nori), livestock feed, source of agar and iodine.
3
Make a comparison table of green, brown and red algae (colour, habitat, example).
Green — fresh water: Chlorella, Ulothrix, Spirogyra; brown — sea: kelp; red — sea: Nemalion, Porphyra, Phyllophora.
4
If each cell of an Ulothrix thread of 6 cells forms 4 zoospores, how many zoospores can the thread release? (4 × 6)
24
5
Why are algae “lower” plants but mosses “higher” plants? Guess as preparation for the next lesson.
Mosses have a stem and leaves (with rhizoids) and form multicellular sex organs; algae do not.