Q5. Give one example each of isogamy with flagellated gametes, isogamy with non-flagellated gametes, anisogamy and oogamy.
Ulothrix; Spirogyra; Eudorina; Volvox or Fucus (NCERT page 24).
Q6. Which is not a brown alga: Laminaria, Sargassum, Porphyra, Fucus?
Porphyra, a red alga (NCERT pages 26–28).
Q7. Which class has chlorophyll c, and which has chlorophyll d?
Phaeophyceae (a, c); Rhodophyceae (a, d) (NCERT Table 3.1).
Q8. Describe the zoospores of most brown algae.
They are biflagellate and pear-shaped, with two unequal, laterally attached flagella (NCERT page 27).
Q9. What is floridean starch similar to in structure?
Amylopectin and glycogen (NCERT page 27).
Q10. Why were artificial systems of classification found unsatisfactory?
They were based on a few characters, so they separated closely related species, and they gave equal weight to vegetative and sexual characters, although vegetative characters are more easily affected by the environment (NCERT page 23).
Q11. What is numerical taxonomy?
Classification, now easily carried out with computers, in which numbers and codes are assigned to all observable characters and the data are processed, so that each character gets equal importance and hundreds of characters can be considered (NCERT page 24).
Q12. Assertion: red algae can grow at great depths in the ocean. Reason: red algae have no flagella. Are both true, and does the reason explain the assertion?
Both are true (NCERT page 27 and Table 3.1), but the reason does not explain the assertion: NCERT does not link the lack of flagella to the depth at which red algae grow. Beyond the NCERT text: the usual explanation is that phycoerythrin absorbs the blue and green light that reaches deep water.