ASEXUAL REPRODUCTION BIOLOGY 11 DM MRS HAUGHTON SEXUAL

ASEXUAL REPRODUCTION BIOLOGY 11 DM 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 1. Asexual and 2. Sexual

Comparing Asexual and Sexual Reproduction ASEXUAL 1. One parent. SEXUAL 1. Two parents. 2. Mitosis responsible for offspring formation. 2. Meiosis makes sex cells that fuse together. 3. Offspring identical to parent and one another (clones). 3. Genes are mixed so offspring different from parents and one another. 4. No variety 4. Variety

Advantages of Asexual Reproduction 1. Offspring all exactly alike and like parents. 2. Less risky way of reproduction (simple). 3. Happens very quickly.

Disadvantages of Asexual Reproduction 1. Since all offspring the same, they will be vulnerable to all the same illness and problems. 2. Organisms cannot adapt to changes easily. 3. 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: 1. Natural (vegetative/storage organs form) 2. 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) 1. Underground stem (ginger, Irish potato) 2. Above ground stem (sugarcane) 3. Roots (carrot) 4. Underground leaves (onion) 5. Fruits 6. Seeds

UNDERGROUND STEM RHIZOME (ginger) CORM (dasheen)

UNDERGROUND 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) 1. Runners (pumpkin, strawberry) 2. Suckers (Banana, plantain) 3. Leaf buds (leaf of life)

RUNNERS

SUCKERS

LEAF BUDS

ARTIFICIAL ASEXUAL PLANT REPRODUCTION • Done by man to assist in reproduction. 1. Cutting 2. Budding / Grafting

CUTTING

BUDDING / GRAFTING