Asexual vs Sexual

• Sexual reproduction


  A type of reproduction in which the genetic materials from two different cells combine, producing an offspring
• Sex cells


  • Female - egg
  • Male - sperm
• Fertilization


  1. An egg cell and a sperm cell join together

  2. A new cell is formed and is called a zygote
• Advantages of sexual reproduction

  • Diverse offspring: genetic variation among offspring
  • Half of the DNA comes from mom
  • Half of the DNA comes from dad
  • Slight differences within a population
  • Allows plants to resist diseases
  • Allows traits to develop to resist harsh environments
• Advantages of sexual reproduction

  • Selective breeding: used to develop many types of plants and animals that have desirable traits
  • Agriculture/Farming: better plants, larger animals
  • Desirable pets
• Disadvantages of sexual reproduction

  • Time and energy: organisms have to grow and develop until they are old enough to produce sex cells
  • Searching for a mate can expose individuals to predators, diseases, or harsh environmental conditions
  • Fertilization cannot take place during pregnancy
• Asexual reproduction


  One parent: organism produces offspring without fertilization
• Advantages of asexual reproduction

  • Enables organisms to reproduce without a mate
  • No wasted time and energy
  • Enables some organisms to rapidly reproduce a large number of uniform offspring
• Disadvantages of asexual reproduction

  • No genetic variation that can give an organism a better chance for survival
  • If a weed killer can kill the parent, it will also kill the offspring
  • A whole species can be wiped out from a disease
  • Dangerous mutations in DNA - if the parent has the mutation, the offspring will have it too
• Fission


  1. Cell division in prokaryotes that forms two genetically identical cells

  2. DNA is copied

  3. The cell begins to grow longer, pulling the two copies apart

  4. The cell membrane pinches inward in the middle of the cell

  5. Cell splits to form two new uniform, identical offspring
• Fission

  
  

  • Examples: Bacteria, E.coli, pond critters
• Budding


  1. A new organism grows by mitosis and cell division on the body of its parent

  2. The bud, or offspring is identical to the parent

  3. The bud, when large enough, can break off of the parent and live on its own

  4. Offspring may remain attached and form a colony
• Budding


  • Yeast, Hydra, cactus
• Regeneration


  1. Occurs when an offspring grows from a piece of its parent

  2. Producing new organisms: Sea Stars, Sea urchins, sea cucumber, sponges, and planarians

  3. Producing new body parts: Gecko, Newts, tadpoles, crabs, hydra, and zebra fish
• Vegetative Propagation


  1. Uniform offspring grow from a part of a parent plant

  2. Parent plants sends out runners

  3. Where the runner touches the ground, roots can grow

  4. A new plant is produced even if the runner is broken apart

  5. Each new plant is uniform and identical to the parent
• Vegetative Propagation


  • Strawberries, potatoes, ivy, crabgrass