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Affinities of Anthoceros with other members.

Affinities of Anthoceros with other members. Anthoceros shows affinity with algae, members of Hepticopsida and Bryopsida of Bryophyta and Pteridophyta.The affinity and relationship of Anthoceros with green algae lies in the presence of a single large chloroplast together with a pyrenoid in cach cell of the gametophyte and in the formation of biciliated sperms. Anthoceros shows affinity with members of Hepaticopsida such as Riccia, Marchantia, etc. in the construction and structure of sex organs and in the apical growth of the thallus.It has affinity with members of Bryopsida i.e. Polytrichum, in the structure such as presence of columella, reduction of sporogenous tissue etc. and development of sporogonium. The spore production from amphithecium resembles the condition of that in Sphagnum. Anthoceros also shows sunken archegonium and development of antheridium from hypodermal initial cell like Pteridophyta. Highly developed sporophyte having photosynthetic tissue, functional stomata, i...

Isolating mechanisms" available in nature.

Discuss the different “isolating mechanisms" available in nature. The development of differentiation in sympatric populations which are  those inhabit the geographical area, will not interbreed even when kept  together. Such a situation results due to varied factors which are collectively  caused isolating mechanisms. Isolating Mechanisms :  The isolating mechanisms may be purely spatial  or may involve specific mechanisms covering reproductive isolation, which  will operate in sympatric population. Setbbins in his recent book, Processes  of Organic Evolution, classified reproductive isolation mechanisms into two  types: (a) Prezygotic mechanisms :   These prevent contact between species at  the time of active reproductive period or else the fertilization is checked even  if pollination may be effectively brought about. These may be:  (1) Spatial or  ecological isolation,  (2) Seasonal or temporal isolation,  (3)...

MCQ BIOLOGY (SOLVED) FOR NEET & JEE -15 JANUARY 2021

  1. Lyon's hypothesis ­L¡e¢Vl p­‰ pÇf¢LÑa ? (a) h¡lh¢Xl pwMÉ¡                                      (b) ­S­e¢VL LjfÉ¡¢V¢h¢m¢V            (c) ­S­e¢VL CeLjfÉ¡¢V¢h¢m¢V                       (d) ­p­¸VÊ¡¢ju¡­ll AhÙÛ¡e   2. HLSe Ù»£­m¡­Ll ¢nöl klinefelter ­l¡N q­u­Rz ¢nö¢Vl ­c­q h¡lh¢Xl pwMÉ¡ La ? (a) 1      (b) 2      (c) 3      (d) HL¢VJ eu   3. Hexaploid   Nj qm - (a) Triticum turgidum   (b) Triticum aestivum   (c) Triticum monococcum        (d) Triticum durum 4. pÉ¡m¡Ci¡l£ NË¢¿Û­a Ah¢ÙÛa puff h¡ h¡m¢hu¡e£ hmu ­L¡e L¡­kÑl p­‰ pÇf¢L...