1 ASEXUAL REPRODUCTION. Asexual reproduction results from mitotic cell division
(mitosis). During asexual reproduction, one cell, called the parent cell, divides into two identical daughter cells. The new organisms, called offspring, are genetically identical to the parent cell.
There is no fusing (joining) of cells in this type of reproduction.
Asexual reproduction is more common in invertebrate animals than in vertebrate animals. Unicellular and multicellular plants can reproduce both asexually and sexually. Common types of asexual reproduction include binary fission, budding, sporulation, regeneration, and vegetative propagation.
2 BINARY FISSION. Binary fission is the simplest type of asexual reproduction. During binary fission, a one.celled organism divides by mitosis to form two daughter cells of equal size. Both the nucleus and the cytoplasm divide equally. The chromosomes of the offspring are identical to that of the parent. Amebas, paramecia, and bacteria reproduce by binary fission
3. BUDDING. A type of asexual reproduction in which a new organism develops as an outgrowth of the parent is called budding. The new organism, called the bud, is a tiny duplicate of the parent organism. In budding, the nucleus divides equally and the cytoplasm divides unequally. The bud and the parent may separate from each other or may remain together and form a colony. Budding occurs in unicellular organisms, such as yeast, and in multicellular organisms, such as the hydra
4. SPORULATION. Spores are specialized asexual reproductive cells that contain a nucleus and a small amount of cytoplasm. Spores are surrounded by tough protective coats that enable them to survive unfavorable conditions, such as extreme heat or cold, for long periods of time. When environmental conditions become favorable, each spore can.
5. REGENERATION. Regeneration is the development of a new organism from a part of the parent organism. For example, in starfish, a single arm can develop into a new starfish. Starfish eat oysters and oyster fishermen once tried to kill starfish by cutting them into pieces. Instead of dying, each starfish piece grew into a new starfish.
Regeneration can also mean the replacement of lost body parts. For example, lobsters are able to grow a new claw to replace one that has been lost. Regeneration of lost body parts occurs mostly in invertebrates. Other animals that can regenerate are planaria and sponges
6. VEGETATIVE PROPAGATION. Vegetative propagation is a form of asexual plant reproduction. In vegetative propagation, a part of a plant--a root, stem, or leaf, grows into a new plant. The new plant is exactly the same as the parent plant. Commercial growers use vegetative propagation rather than seeds when they want to be sure the offspring is identical to the parent. Seedless fruits and vegetables have to be reproduced by this method. In addition, growers use this type of reproduction because it is fast, easy to use, and usually successful.
Vegetative propagation can occur naturally or artificially. Natural vegetative propagation occurs naturally without human interference. Types of natural vegetative propagation include tubers, runners, rhizomes and bulbs. Artificial vegetative propagation occurs as a result of human activities. Two common methods of artificial vegetative propagation are cuttings and grafting .
- Division of cytoplasm and nucleus, including duplication of chromosomes.
form two identical Adaughter@
cells, the nucleus of the dividing cell goes through four stages and an-in
- First phase of mitosis. Nuclear
membrane begins to disappear.
- Second phase of mitosis. Chromosome
pairs line up along the equator.
- Third phase - the chromosomes split apart.
- Fourth phase - cell pinches off to form two new cells.
- normal growth between division