Transcript Presentation

Asexual Reproduction
• The formation of a new individual that has
identical genetic information to its parent.
• Occurs in all five kingdoms
– Monera (bacteria)
– Protists (amoeba)
– Fungi (mushrooms)
– Plants (spider plant)
– Animalia (planaria)
Binary fission – bacteria do not have nuclei but do have DNA. A bacteria cell
undergoes a simplified version of mitosis resulting in 2 new cells having
identical DNA as the original cell.
Protists – These organisms have a true nucleus. When these single celled
organisms undergo mitotic cell division they form two new single celled
organisms. An example of this is the paramecium.
Fungi – contain many cells
• Fragmentation – a small piece ( of the organism simply breaks off
and grows into a new fungus.
• Budding requires the nucleus to replicate itself. Then a bud forms
on the side containing the replicated nucleus. The bud breaks off to
form a new individual. Yeast reproduces this way.
• Spores – Moulds commonly form a reproductive cell called a spore
that is created by mitosis. Moulds produce millions of these cells
that when mature form masses of blue, green, or yellow coatings on
organic substances.
Animals without backbones
• Invertebrates commonly reproduce
asexually by:
– Regeneration – regrowing cut off parts
– Budding – part of the organism forms a clump
of cells that breaks off and forms a new
organism.
Plants
• Plants continue to grow throughout their whole life (unlike animals).
• They have special growing areas called meristems.
• As cells from these areas grow, they specialize into roots, leaves or
stems.
• If meristematic tissue is placed under certain conditions, it will form a
new plant.
• The new cells formed in this tissue do so by mitosis.
Types of Asexual Reproduction in
Plants
• Cloning - Cuttings taken from a plant will create a new
plant with the identical DNA as the original.
• New shoots from the roots - Each new shoot is
essentially a new plant identical to the original.
• New plants from stems – Some plants produce stems
called runners. When these specialized stems contact
the ground new roots and leaves form creating a new
plant. (strawberries)
• Grafting – by taking a bud from a tree and attaching it to
the stem of a new tree, the bud will grow into a stem.
New fruit trees are created in this manner.
• Tissue cultures – meristematic cells are placed in a
growing media that causes each cell to grow into a new
plant. This method is used to create 100’s of new plants.