Learning Center
Plans & pricing Sign in
Sign Out



									Asexual vs. Sexual
   Asexual reproduction is the formation of
    new individuals from the cells of a single
    parent. It is very common in plants; less
    so in animals.
   Or in the case of cells, asexual
    reproduction is making a new cell that is
    the same as the parent cell.
   All plant organs have been used for
    asexual reproduction, but stems are the
    most common.
   In some species, stems arch over and take root at their
    tips, forming new plants.
   The horizontal above-ground stems of the strawberry
    produce new daughter plants.
   This photo shows the leaves of the plant
    Bryophyllum. Mitosis along the leaf
    margins produces tiny plantlets that fall
    off and form new plants.
   Some plants use their
    roots for asexual
   The dandelion is a common
   Trees, such as the poplar or
    aspen, send up new stems from
    their roots. In time, an entire
    grove of trees may form — all
    part of a clone of the original
   Commercially-important plants
    are often deliberately propagated
    by asexual means in order to keep
    particularly desirable traits (e.g.,
    flower color, flavor, resistance to
   Cuttings may be taken from the
    parent and rooted.
   Grafting is widely used to
    propagate a desired variety of
    shrub or tree. All apple varieties,
    for example, are propagated this
   In budding, offspring develop as
    a growth on the body of the
   In some species, e.g., jellyfishes
    and many echinoderms, the
    buds break away and take up an
    independent existence.
   In others, like corals, the buds
    remain attached to the parent
    and the process results in
    colonies of animals.
   Budding is also common among
    parasitic animals, e.g.,
   In parthenogenesis ("virgin birth"), the
    females produce eggs, but these develop
    into young without ever being fertilized.
   Parthenogenesis occurs in some fishes,
    several kinds of insects, and a few
    species of frogs and lizards.
   You don’t have to waste all that time
    finding a mate.

                     And you get to
                     pass on all of your
                     own genes!!!
   Sexual reproduction
    allows for greater
   “Bad genes” can get
    covered up by good ones
    from the other parent.
   Combinations of genes
    make it so organisms can
    better deal with changing
   The cell cycle asexually
    produces new body cells for:
     Repair
     Replacement
     Growth
 The cell cycle consists of
 three main parts.
  Interphase
  Mitosis
  Cytokinesis
 During
 interphase, the
 cell is preparing
 to divide by
 making more
 organelles and
 copying its DNA.
   Mitosis is when the cell is
    actually making the new cells.
    It consists of 4 steps or phases.
     Prophase
     Metaphase
     Anaphase
     Telophase
 During prophase, the
 chromatin condenses
 into chromosomes.
 Duringmetaphase,
 chromosomes line up in
 the middle of the cell
 Anaphase is when the
 chromosomes move to
 the opposite ends.
   In telophase, the
    chromosomes reach the
    opposite ends and the cell
    gets ready to actually split.
 During
 the cell
 divides into
 two cells.
   Produces new body cells
   Cell copies DNA once
   Cell splits once
   2 new (daughter) cells
   Daughter cells the same as the
    parent cells
   Daughter cells have the same
    number of chromosomes as the
    parent cells
   A different type of cells must be
    produced for sexual
   These different cell are called
    sex cells, or gametes
     Egg = female gamete
     Sperm = male gamete
   Since the gametes are going to
    unite to make a new organism, each
    gamete only needs to have half the
    genetic information as its parent
   In mitosis, the cell copied its DNA
    once and split once.
   In making sex cells, the cell has to
    copy it’s DNA once and then split
 Theprocess of making
 gametes by copying the
 DNA once, and splitting
 twice is called meiosis.
   Produces gametes (Sex cells)
   Cell copies DNA once
   Cell splits twice
   4 new (daughter) cells
   Daughter cells different from parent
   Daughter cells have the half the
    number of chromosomes as the
    parent cells
        MITOSIS                      MEIOSIS

   Produces body cells         Produces gametes
   Cell copies DNA once        Cell copies DNA once
   Cell splits once            Cell splits twice
   2 new (daughter) cells      4 new (daughter) cells
   New cells the same as       New cells different
    the parent cells             from parent cells
   Daughter cells have         Daughter cells have
    the same number of           the half the number of
    chromosomes as the           chromosomes as the
    parent cells                 parent cells
 rphase_X_400
    pc.jpg&imgrefurl= kv3NY
 ly_anaph
    qGVNdT90YA6eFDbU=&h=270&w=360&sz=41&hl=en&start=3&sig2=nzPNOMhAd0Iiy4oOk5Gssg&um=1&itbs=1&tbnid=9HdrVNA -
    SKYGuM:&tbnh=91&tbnw=121&prev=/images%3Fq%3Danaphase%26hl%3Den%26client%3Dfirefox -

To top