Asexual Reproduction • Asexual – the production of a new organism with out the fusion of sex cells. ONE parent is involved.
Uncontrolled Cell Division • Cancer cells divide uncontrollably
Asexual Reproduction • One parent involved • New organism produced by mitotic cell division of parent cell • Offspring is identical to parent
Types of Asexual Reproduction • Binary Fission • One celled organism undergoes division • Equal division of the organism • Ex. Ameba, Paramecium
2. Budding • Unicellular: yeast • New cell detaches or remains on parent to form a colony • Unequal division of cytoplasm
b. Multicellular: hydra • Multicellular bud grows off the side of the parent
3. Sporulation (multicellular) • Spores released and develops new individuals • Ex. Bread Mold
4. Regeneration – (invertebrates) • Development of an entire new organism from a part of the original • Undifferentiated cells – not specialized • Replacement of lost structures Ex. Starfish, planaria
5. Vegetative Propagation • Type of asexual reproduction that occur in plants. • New plants develop from roots, stems, or leaves of the parent plant
Natural: • Bulbs – enlarged underground stem with thick leaves. Ex. Onions & Tulips • Tubers – enlarged underground stem with buds. Ex. Potato • Runners – stems that grow along the ground. Ex. Strawberries • Rhizomes – short pieces of woody, underground stems. Ex. Ferns, poison ivy.
2. Artificial: • Cuttings – a piece of stem or leaf is cut from the plant and placed in soil or water a new plant develops. Ex. Geranium, rose, grape. • Layering – bending stems into the ground to produce new plants. Ex. Raspberry plant • Grafting – stem is cut from one plant and attached to stem of another plant allows for combination of desirable traits. Ex. Seedless oranges, different types of apples on one tree.
Advantages of Vegetative Propagation • Speed • Seedless fruits • Desirable characteristics
Results of Asexual Reproduction • Offspring is genetically identical to the parent • Same hereditary information.
Cloning • A way of making identical genetic copies. • Has been done with sheep, pigs.
Steps • Scientists take a parent cell nucleus and extract it. • Scientists take an egg cell from a female and remove the nucleus. • The nucleus from the parent cell is put into the egg cell. • The egg cell can then be implanted into a female for full development.