Q.Differentiate between the following:-

(i) Red algae vs brown algae:

• Red algae (Rhodophyceae) owe their red colour to the pigment r-phycoerythrin; brown algae (Phaeophyceae) owe their olive-to-brown colour to the xanthophyll fucoxanthin.
• Red algae store food as floridean starch; brown algae store it as mannitol or laminarin.
• Red algae have no flagella and their gametes and spores are non-motile; brown algae have two unequal, laterally attached flagella on their motile cells.

(ii) Liverworts vs mosses:

• In most liverworts the body is a flat, dorsiventral thallus (as in Marchantia); in mosses the gametophyte is a leafy axis with spirally arranged leaves.
• Liverworts reproduce asexually by gemmae in gemma cups; mosses reproduce vegetatively by fragmentation and by budding on the secondary protonema.
• The moss gametophyte passes through a protonema stage and its sporophyte is more elaborate than that of a liverwort.

(iii) Homosporous vs heterosporous pteridophyte: …

1. Red algae and brown algae. Both are algae, but they belong to different classes and are easy to tell apart once you know what to look at. Red algae, the Rhodophyceae, get their characteristic red colour from a red pigment, r-phycoerythrin, which is present in such quantity that it masks the other pigments. Brown algae, the Phaeophyceae, range from olive green to brown, and how brown they appear depends on how much of the xanthophyll pigment fucoxanthin they contain. The two also differ in the food they store: red algae lay down floridean starch, whose structure is close to that of amylopectin and glycogen, while brown algae store complex carbohydrates as mannitol or laminarin. A third clear difference is motility — red algae have no flagella at all, so their spores and gametes are non-motile, whereas brown algae bear two unequal flagella attached at the side of their motile cells.
2. Liverworts and mosses. These are the two groups of bryophytes. In most liverworts the plant body is thalloid, a flat dorsiventral sheet with a distinct upper and lower surface that lies pressed against the ground, as in Marchantia. In mosses the conspicuous gametophyte is instead a leafy axis, an upright slender stalk bearing leaves arranged in a spiral. They also differ in how they multiply without sex: liverworts characteristically produce gemmae, green multicellular buds formed inside little cup-shaped gemma cups, while mosses reproduce vegetatively by fragmentation and by budding on the secondary protonema.
   Note

   The moss gametophyte begins life as a protonema — a creeping, branched, filamentous green stage — before the leafy plant appears, and the moss sporophyte is more elaborate and better developed than that of a liverwort. …