Asexual Reproduction Notes.

Asexual Reproduction

It always involves the offspring inheriting its genetic material from a single parent.The offspring develop from ordinary body cells (somatic cells) produced by the parent.The offspring are genetically identical to the parent (clones).No gametes are produced or used.

Advantages:

  • Fast and easy.

  • It allows for vast numbers of offspring to be produced in the shortest period.

  • When used in agriculture, it allows us to produce many more individuals with the desired traits or characteristics.

Disadvantages:

  • Lack of genetic variation in the offspring.

Methods of asexual reproduction:

Binary Fission:

  • Typical method of unicellular organisms.

  • The parent cell simply undergoes a mitotic division.

  • The two resulting daughter cells then live independently as separate organisms.

Budding:

  • Often performed by simple animals.

  • The parent develops an outgrowth (bud) from its body.

  • As the bud matures, it will eventually break free and move away from the parent.

  • If it settles in an appropriate location it will develop and function on its own.

Spore Production:

  • The parent organism produces one or more spore-forming structures (fruiting bodies).

  • These release extraordinarily large numbers of spores into the environment.

  • Each spore consists of one or more cells surrounded by nutrient layers and a protective outer casing.

  • Fungi and some primitive plants mainly utilize this method of reproduction.

Fragmentation:

  • The body of the parent organism is broken or divided into several parts.

  • Each part regenerates the tissues and parts that it is missing.

  • Certain types of simple animals perform this without the intent of doing so.

Vegetative Propagation:

  • The offspring develop from runners, stolons, tubers, or other parts of the plant and are extensions of the parent’s body.

  • (similar to budding in animals).

  • This can also be done by “rooting” stems or leaves that are taken from the parent plant.

  • This may be promoted with the use of “rooting” hormones.

Grafting:

  • A portion of the parent, usually a stem or branch, is grafted onto the existing rootstock of another plant.

  • Often used in horticulture to produce duplicates of very desirable plants

  • Quicker than propagation because the root systems are already established.