SEXUAL AND ASEXUAL REPRODUCTION

• Sexual reproduction is the process involving union of gametes from the male and female parent
• the female gamete in both animals and palnts is called an ovum or egg
• the male gamete in animals is called sperm
• the male gamete in plants is called pollen
• meiosis is the type of cell division that happens in sex cells
• spermatogenesis is the meiosis in sperm cells, which take place in the testes
• oogenesis is the meiosis in ova, which takes place in the ovaries
• fertilization (animals) and pollination (plants) is the union of male and female gametes, producing a fertilized egg called zygote
• reproduction is the process of creating new organisms from existing individuals
• reproduction is the basis of heredity
• asexual reproduction is a process that does not involve union of gametes
• offspring produced asexually become clones of/genetically similar to the parent
• asexual reproduction is used mostly by unicellular organisms and soem invertebrates
• binary fission is the simplest form of asexual reproduction
• in binary fission, the genetic material of the parent cell is replicated, then divided into two genetically similar daughter cells
• bud formation/budding is when a new organism develops a bud, then casts off of its parent to become a new individual, then finds a substrate
• a bud is a mass of tissue containing actively dividing cells
• fragmentation is the development of new organisms from fragments of the parent organism
• autotomy is the ability of animals to cut themselves to escape predators
• regeneration is the ability to replace any lost part/s of the body
• regeneration takes place in simple organisms; the more complex an organism is, the harder it is to regenerate
• an organism may autotomize its parts, then regenerate these missing body parts
• the planaria is the only animal able to regenerate its head
• spore formation or sporulation involves formation of many pores in a sporangium
• in sporulation, the spores are capable of germinating into new individuals when landed in suitable areas
• a spore is a special microscopic cell enclosed within a case which can easily be carried from one place to another
• parthenogenesis is when an egg cell can develop into an embryo without fertilization by a sperm
• the term parthenogenesis comes from the words "parthenos" meaning virgin, and "genesis" meaning origin
• vegetative propagation is asexual reproduction exclusive to plants only; wherein new plants grow from an existing plant's part(s)
• the natural forms of vegetative propagation are bulbs, stolons/runners, suckers, tuber, corms, rhizomes, and notches.
• the artificial forms of vegetative propagation are cutting, grafting, and layering
• Bulbs - short, underground stems with fleshy leaves called scales that stores food
• Runners/Stolons - stem that grows below the ground, forming adventitious roots at the nodes and forming a new plant from the buds
• Suckers - a new stem grow from the root base of existing plant which give rise to new plants
• Tubers - swollen part of an underground stem. It bears several nodes or “eyes” each eye bears one or more buds which develop into new plants.
• Corms - short, vertical underground horizontal stem with nodes and internodes where buds grow and develop into new plants
• Rhizomes - is an underground horizontal stems with nodes and internodes where each node give rise to a new plant.
• Notches - structure found at the margins of some leaves where new tiny buds emerge.
• Cutting - method when a piece of the stem is cut from a plant. When place in a moist soil can develop new roots, which will grow in a new similar plant.
• Grafting - method where two different plants are joined together to grow into a new plant.