Reproduction Part 1 Asexual vs. Sexual Reproduction

1
Reproduction Part 1Asexual vs. Sexual
Reproduction
2
Objectives

• Compare and contrast sexual reproduction vs.
  asexual reproduction
• Understand and explain the 5 types of asexual
  reproduction

3
Asexual vs. Sexual Reproduction

• What are the main differences between sexual and
  asexual reproduction?
• List any advantages and disadvantages of each.

4
Types of Asexual Reproduction

• 1. Binary Fission
• 2. Budding
• 3. Regeneration
• 4. Sporulation (Spore Formation)
• 5. Vegetative Propagation

5
Binary Fission

• Binary Fission
• Occurs in single celled organisms such as
  bacteria, protists (amoeba, euglena, etc.),
  algae.
• The cell increases in size until it divides into
  two new cells
• No parent is left.

6
Binary Fission
7
Budding

• Budding
• Occurs in single celled and some simple
  multicellular organisms such as yeast, hydra, and
  sponges.
• A small bud or outgrowth forms on the organism
• The organism divides into two unequal parts the
  bud is smaller than the parent organism it
  sprouted from.

8

• Budding in hydra

• Budding in single celled yeast.

9
Regeneration

• Regeneration
• Occurs in simple multicellular organisms (hydra,
  starfish, sponges, earthworms)
• If cut into pieces, pieces will grow into new
  organisms.
• Simpler organisms (sponges, cnidarians,
  echinoderms) are rich in embryonic stem cells
  which can differentiate to regenerate tissue.
• More complex organisms such as humans lack these
  stem cells as adults and cannot regenerate.

10
An entire starfish can regenerate from a lost
limb (ray)!!!
11
Sporulation Spore formation

• Occurs in fungus, algae and mold
• Process in which any cell of an organism produces
  one or more reproductive cells inside its cell
  walls
• Tiny spores form inside the parent cell and are
  released
• Spores are released and carried to a favorable
  environment (by swimming, wind, etc.) where they
  can grow into an adult organism.

12
Spore formation in mold
13
Vegetative Reproduction

• Vegetative Reproduction
• Some plants can grow from roots, stems, and
  leaves.
• Bulbs and tubers are underground stem structures
  that can grow to form new plants.
• Examples include tulips, potatoes, strawberries,
  irises.

14
Vegetative Reproduction

• Tubers Enlarged portion of an underground stem
  that contains stored nutrients (starch).
• Potatoes can be cut into pieces with each piece
  having an eye which can grow into a new potato
  plant.

15
Vegetative Reproduction

• Bulbs Short underground stems surrounded by
  thick fleshy leaves that contain stored food.
• As the plant grows small new bulbs sprout from
  the old one.
• Each bulb can grow into a new plant
• Ex. Onions, tulips, garlic.

16
Vegetative Reproduction

• Runner (stolon) Stem that grows sideways along
  the surface of the ground.
• Runners have buds that can grow into new plants
  when they contact soil.
• Ex. Strawberry plants, silverweed.

17
Vegetative Reproduction

• Rhizome Stem that grows sideways underground.
• Rhizomes are thick and fleshy and contain stored
  food.
• Enlarged portions called nodes grow into buds
  which can form new plants.
• Ex. Irises, ginger.

18
Methods of Artificial Vegetative Reproduction

• Cutting Any vegetative part of a plant (stem,
  leaf, root) that is used to make a new plant.
• Layering Stem is bent over so part of it is
  covered with soil. When covered part roots, new
  plant may be cut from parent plant.
• Grafting Stem or bud is removed from one plant
  and permanently joined to the stem of another
  closely related plant. Many fruits and roses are
  propagated using grafting.

19
Grafting consists of two parts, the stock and the
scion
SCION
STOCK
20
Begonia plants growing from cuttings
21
Grafting in cactus plants