BIOLOGY 11DM MRS. HAUGHTON ASEXUAL REPRODUCTION BIOLOGY 11DM MRS. HAUGHTON
SEXUAL AND ASEXUAL REPRODUCTION Reproduction is the way in which organisms (parents) produce new individuals (offspring) of their own species. The two types of reproduction are Asexual and Sexual
Comparing Asexual and Sexual Reproduction One parent. Mitosis responsible for offspring formation. Offspring identical to parent and one another (clones). No variety Two parents. Meiosis makes sex cells that fuse together. Genes are mixed so offspring different from parents and one another. Variety
Advantages of Asexual Reproduction Offspring all exactly alike and like parents. Less risky way of reproduction (simple). Happens very quickly.
Disadvantages of Asexual Reproduction Since all offspring the same, they will be vulnerable to all the same illness and problems. Organisms cannot adapt to changes easily. Overcrowding, competition and death more likely to occur.
Examples of Asexual Reproduction BINARY FISSION in Amoeba Organism grows to a certain size. The nucleus then cytoplasm with all structures duplicates and divides. Two new identical organisms formed which then grow.
Examples of Asexual Reproduction BUDDING IN YEAST
Examples of Asexual Reproduction SPORE FORMATION IN BREAD MOULD Some threads (filaments) of bread mould grow upright and form spore cases. The spores are later released to grow new filaments on a new source of food.
Plants also reproduce asexually. Two ways are: Natural (vegetative/storage organs form) Artificial (man manipulates plants)
After photosynthesis, plants store extra glucose as starch or other sugars. These storage organs ensure that food is available when a new organism is ready to grow from the existing parent plant.
NATURAL VEGETATIVE PROPAGATION Examples are: (see page Concise for pix) Underground stem (ginger, Irish potato) Above ground stem (sugarcane) Roots (carrot) Underground leaves (onion) Fruits Seeds
UNDERGROUND STEM RHIZOME (ginger) CORM (dasheen)
UNDERGROUND STEM STEM TUBER (Irish potato) STEM TUBER (Irish potato)
ABOVE-GROUND STEM SUGARCANE CELERY
ROOTS TAP ROOTS (carrot) TAP ROOTS (turnip)
UNDERGROUND LEAVES BULB (onion) BULB (Lilly)
Other ways that plants reproduce asexually are: (see page Concise for pix) Runners (pumpkin, strawberry) Suckers (Banana, plantain) Leaf buds (leaf of life)
RUNNERS
SUCKERS
LEAF BUDS
ARTIFICIAL ASEXUAL PLANT REPRODUCTION Done by man to assist in reproduction. Cutting Budding / Grafting
CUTTING
BUDDING / GRAFTING