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Alternate generation

資料來源 : Webster's Revised Unabridged Dictionary (1913)

Alternate \Al*ter"nate\ (?; 277), a. [L. alternatus, p. p. of
   alternate, fr. alternus. See {Altern}, {Alter}.]
   1. Being or succeeding by turns; one following the other in
      succession of time or place; by turns first one and then
      the other; hence, reciprocal.

            And bid alternate passions fall and rise. --Pope.

   2. Designating the members in a series, which regularly
      intervene between the members of another series, as the
      odd or even numbers of the numerals; every other; every
      second; as, the alternate members 1, 3, 5, 7, etc.; read
      every alternate line.

   3. (Bot.) Distributed, as leaves, singly at different heights
      of the stem, and at equal intervals as respects angular
      divergence. --Gray.

   {Alternate alligation}. See {Alligation}.

   {Alternate angles} (Geom.), the internal and angles made by
      two lines with a third, on opposite sides of it. It the
      parallels AB, CD, are cut by the line EF, the angles AGH,
      GHD, as also the angles BGH and GHC, are called alternate
      angles.

   {Alternate generation}. (Biol.) See under {Generation}.

Generation \Gen`er*a"tion\, n. [OE. generacioun, F.
   g['e]n['e]ration, fr.L. generatio.]
   1. The act of generating or begetting; procreation, as of
      animals.

   2. Origination by some process, mathematical, chemical, or
      vital; production; formation; as, the generation of
      sounds, of gases, of curves, etc.

   3. That which is generated or brought forth; progeny;
      offspiring.

   4. A single step or stage in the succession of natural
      descent; a rank or remove in genealogy. Hence: The body of
      those who are of the same genealogical rank or remove from
      an ancestor; the mass of beings living at one period;
      also, the average lifetime of man, or the ordinary period
      of time at which one rank follows another, or father is
      succeeded by child, usually assumed to be one third of a
      century; an age.

            This is the book of the generations of Adam. --Gen.
                                                  v. 1.

            Ye shall remain there [in Babylon] many years, and
            for a long season, namely, seven generations.
                                                  --Baruch vi.
                                                  3.

            All generations and ages of the Christian church.
                                                  --Hooker.

   5. Race; kind; family; breed; stock.

            Thy mother's of my generation; what's she, if I be a
            dog?                                  --Shak.

   6. (Geom.) The formation or production of any geometrical
      magnitude, as a line, a surface, a solid, by the motion,
      in accordance with a mathematical law, of a point or a
      magnitude; as, the generation of a line or curve by the
      motion of a point, of a surface by a line, a sphere by a
      semicircle, etc.

   7. (Biol.) The aggregate of the functions and phenomene which
      attend reproduction.

   Note: There are four modes of generation in the animal
         kingdom: scissiparity or by fissiparous generation,
         gemmiparity or by budding, germiparity or by germs, and
         oviparity or by ova.

   {Alternate generation} (Biol.), alternation of sexual with
      asexual generation, in which the products of one process
      differ from those of the other, -- a form of reproduction
      common both to animal and vegetable organisms. In the
      simplest form, the organism arising from sexual generation
      produces offspiring unlike itself, agamogenetically.
      These, however, in time acquire reproductive organs, and
      from their impregnated germs the original parent form is
      reproduced. In more complicated cases, the first series of
      organisms produced agamogenetically may give rise to
      others by a like process, and these in turn to still other
      generations. Ultimately, however, a generation is formed
      which develops sexual organs, and the original form is
      reproduced.

   {Spontaneous generation} (Biol.), the fancied production of
      living organisms without previously existing parents from
      inorganic matter, or from decomposing organic matter, a
      notion which at one time had many supporters; abiogenesis.
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