Reproduction

• Reproduction


  When organisms produce new living things. Plants and animals reproduce to make new individuals of the same species
• Asexual reproduction


  • Only one parent
  • Genetically identical to its parent
• Sexual reproduction


  • Two parents
  • Sex cells or gametes
  • Genetically quite different to their parents
• Asexual reproduction


  1. Requires only 1 parent

  2. Offspring are an exact copy of the parent---a clone

  3. Does not involve sex cells
• Organisms that reproduce asexually cannot develop much variety, because they are "copying" the original organism exactly
• Budding


  1. New individual is formed through formation of a bud which in time splits off from the parent and develops into a new individual

  2. Buds are lateral outgrowths formed when food in the environment is abundant
• Organisms that reproduce by budding

  • Yeast
  • Hydra
• Fission


  The body divides into two (binary fission) or into fragments (multiple fission) and the pieces develop into new individuals which are exact clones of the parent
• Organisms that reproduce by fission

  • Protozoans like amoeba and paramecium
  • Plasmodium (microbe causing malaria)
• Fragmentation


  1. Involves the breaking of any parts of the body or the breaking up of the entire body into several pieces

  2. The broken parts in time develop into complete new individuals
• Fragmentation


  • A new starfish can grow from one detached arm
• Regeneration


  Development of the cut body part into a complete organism
• Autotomy


  The ability to cast off a part of its body to lure and escape predators
• Spore formation


  1. Sporulation

  2. Spore – haploid cell enclosed in a thick case and held together by a structure called sporangium

  3. Spores are light and easily dispersed by wind from one place to another
• Organisms that reproduce by spore formation

  • Fungi like bread mold (Rhizopus)
  • Mosses
  • Ferns
• Parthenogenesis


  Where an egg develops into a complete individual without being fertilized
• Organisms that reproduce by parthenogenesis


  • Invertebrates such as water flees, rotifers, aphids, stick insects, some ants, wasps, and bees
  • Some vertebrate animals—such as certain reptiles, amphibians, and fish
• Vegetative propagation


  Plants reproduce asexually using their specialized organs for reproduction
• Uses of vegetative propagation

  • Mass production of plants using plant parts of mother parent
  • No seed is required to multiply varieties having desired quantitative and qualitative traits
  • Useful technique in production of plants which are difficult to propagative using seed
• Runners or stolons


  Horizontal stems at the base of a plant that develop into roots when their nodes touch the ground
• Plants that reproduce through runners or stolons

  • Strawberry
  • Bermuda grass
• Rhizomes


  Specialized stems that grow underground and naturally produce roots and shoots above the ground
• Plants that reproduce through rhizomes


  • Grasses
  • Ginger
  • Turmeric
• Bulbs


  Underground stems with fleshy leaves or scales that serve as food storage for the plants
• Plants that have bulbs for reproduction

  • Onion
  • Garlic
• Tubers


  Fleshy underground stems or roots with "eyes" or buds around them from which new plants grow
• Plants that grow from tubers

  • Potatoes
  • Sweet potatoes (kamote)
• Leaf margin growths


  Some plants give rise to young plants along their leaf margins
• Plants that reproduce through leaf margin growths

  • Kalanchoe - katakataka
• Suckers


  Side shoots that grow from the stem of a mother plant
• Plants that reproduce through suckers

  • Bananas
• Grafting


  Technique that joins two plants into one, combining characteristics of both plants
• Layering


  A shoot of a parent plant is bent until it covered by soil, with the tip remaining above ground
• Sexual reproduction


  • Requiring 2 parents
  • Male and female (egg & sperm)
  • The egg and sperm join (zygote) to form an entirely new organism
  • Involving the fusion of haploid female gamete and haploid male gamete
  • Offspring are different from the parent organism because of the combination of different genetic information
• Sperm


  Male sex cells produced in the testes
• Eggs


  Female sex cells produced in the ovaries
• Flowering plants (angiosperms)


  • Have seeds that are enclosed in a container or case - ovary
• Anthophytes


  • Plant producing flowers (distinctive features), have ovary that is part of a flower
• Parts of a flower

  • Female parts and functions
  • Male parts and functions
  • Other parts and functions
• Pollination


  1. The transfer of the pollen grains from the anther to the stigma of a flower

  2. Prerequisite to fertilization

  3. Self-pollination or cross-pollination