asexual reproduction

• Asexual reproduction is the formation of new individual from the cell of a single parent, where the offspring is identical to the parent.
• After ovulation, the estrogen level drops abruptly, and the progesterone level rises; these hormone levels correlate with male behavior.
• Asexual reproduction does not involve meiosis, for example, in some animals, plants, yeasts, bacteria & protists.
• Asexual reproduction allows for the mass production of offspring in a short period of time, saving time & energy for courtship.
• The offspring from asexual reproduction will be identical to the parent, ensuring that the offspring will always be well adapted to its environment.
• Asexual reproduction reduces genetic variation in a population, as harmful mutations are sometimes passed on to the progeny.
• Types of asexual reproduction include binary fission, budding, sporulation, fragmentation, vegetative reproduction, and parthenogenesis, which range from unicellular to the vertebrates.
• Vegetative reproduction involves a short underground stem surrounded by thick fleshy leaves that contain stored food.
• Onion, garlic, tulips, lilies are examples of vegetatively reproducing plants.
• Bulbs are an enlarged part of an underground stem that contains stored food.
• The stems of bulbs have buds which develop into new plants.
• Potato tubers are an example of vegetatively reproducing plants.
• Germinating eye buds are a type of runner (stolon) that grows sideways and has buds.
• Strawberries are an example of a vegetatively reproducing plant.
• Rhizome is a stem that grows sideways underground, usually thick and fleshy.
• Ginger, turmeric, galangal are examples of vegetatively reproducing plants with rhizomes.
• Node and bud are artificial vegetative propagation techniques.
• Farmers have developed ways to grow plants with desirable traits through artificial vegetative propagation.
• Cutting is any vegetative part of the plant used to produce a new individual, usually placed in water and allowed to grow roots.
• Stem cutting of a hibiscus is an example of a cutting.
• Leaf cutting is an example of a cutting.
• Grafting involves removing a stem or bud from one plant and permanently joining it to the stem of a closely related plant.
• Parthenogenesis is a process where females produce eggs that develop without fertilization by male, occurring when male is unavailable in the vicinity.
• Whiptail lizards have evolved from species with two sexes and still need certain sexual stimuli for maximum reproductive success.
• There is a doubling of chromosomes after meiosis to create a diploid “zygote” in parthenogenesis.
• Both lizards in the photograph are of Cnemidophorus uniparens females, with one playing the role of a male.
• The sexual behavior of Cnemidophorus uniparens is correlated with the cycle of ovulation mediated by sex hormones, as blood levels of estrogen rise, the ovaries grow, and the lizard behaves like a female.
• Binary Fission is a process where a parent organism divides into two equal cells through mitosis, with the daughter cells being genetically identical to the parent.
• In bacteria, the cell elongates and DNA is replicated before the cell wall and plasma membrane begin to divide.
• A cross-wall forms completely around divided DNA during the division process.
• The cell separates into two during the final stage of binary fission.
• Budding is a process where new organisms develop as small outgrowths or buds on the parent organism, which enlarges and develops into an individual.
• The buds may break off and live independently or remain attached forming a colony.
• Spores are single specialised cells that are asexual spores formed by the nucleus of a single-celled organisms breaking up into many nuclei.
• Many green algae produce spores asexually by mitosis, and if these spores have flagella and are motile, they are called zoospores.
• Fragmentation is a process where a parent organism breaks into fragments, and all broken parts of the organism develop into a new organism.
• Fragmentation occurs in organisms with lower organisation, such as flatworms, sponges, and spirogyra (algae).
• In some flatworms, like Planaria, the body of the parent breaks into several pieces, and each piece develops into a whole animal.
• Vegetative propagation is the development and production of independent plants from vegetative parts of the same plant, often specialised for the purpose of asexual reproduction.
• Organs of vegetative propagation include bulbs, tubers, runners, and rhizomes, and this process occurs naturally and can be produced artificially.