Long Answer TypeExplain why sexual reproduction in angiosperms is said to take place through double fertilization and triple fusion.
How are the male and female gametophytes of pteridophytes and gymnosperms different from each other?
In bryophytes, the dominant phase is represented by a gametophytic plant. The gametophyte is independent, photosynthetic, thalloid phase. Antheridia and archegonia are formed on the gametophyte. These organs are multicellular. These organs bear the respective gametes, that is male and female gametes respectively. The antheridium produces biflagellate antherozoids, the archegonium is flask shaped and produces a single egg.
Water is the medium used for the transfer of antheridium to archegonium. The flagella present in the antheridium provide motility to the gamete. the two gametes and the process of fertilisation take place. The zygote formed does not undergo meiosis immediately after the fertilization and forms a multicellular body called sporophyte.
The sporophyte is smaller , dependent on the gametophyte and remains attached to the gametophyte and derives nutrition from it. Some cells of the sporophyte undergo reduction division and give rise to the haploid spores which germinate to produce gametophyte.
Thus, the gametophyte is the dominant phase and occupies a major part of the lifespan of the bryophyte.
Multiple Choice QuestionsA Prothallus is
A structure in pteridophytes formed before the thallus develops
A sporophytic free living structure formed in pteridophytes
A gametophyte free living structure formed in pteridophy
A primitive structure formed after fertilization in pteridophytes
Protonema is
Haploid and is found in mosses
Diploid and is found in liverworts
Diploid and is found in pteridophytes
Haploid and is found in pteridophytes
The giant Redwood tree (Sequoia sempervirens) is a/an
Angiosperm
Free fern
Pteridophyte
Gymnosperm
Which one of the following statements is wrong?
Golden algae are also called desmids
Eubacteria are also called false bacteria
Phycomycetes are also called algal fungi
Phycomycetes are also called algal fungi
Select the correct statement
Salvinia, Gingko and Pinus all are gymnosperm
Sequoia is oneis one ot the talles trees
The leaves of gymnosperm are not well adapted to extremes of climate
The leaves of gymnosperm are not well adapted to extremes of climate
Isogamous condition with non-flagellated gametes is found in
Chlamydomonas
Spirogyra
Volvox
Volvox
Which of the following are likely to be present in deep sea water?
Archaebacteria
Eubacteria
Blue-green algae
Blue-green algae
Switch
