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CHAPTER 4 LESSON 2
ASEXUAL REPRODUCTION
Key Concepts
• What is asexual reproduction, and why is it
beneficial?
• How do the types of asexual reproduction differ?
What Is Asexual Reproduction?
• In asexual reproduction, one parent organism
produces offspring without meiosis and fertilization.
• Parent and offspring are genetically identical to each
other.
o Reason: Offspring inherit all of their DNA from
one parent.
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6 Types of Asexual Reproduction
1. Fission
Recall: Prokaryotes are unicellular organisms. Their cells
have a simpler cell structure than eukaryotes.
o The DNA is not in a nucleus.
Cell division in prokaryotes that forms two identical cells
is called fission.
 A prokaryote’s DNA molecule is copied and each copy
attaches to the cell membrane.
 The cell grows longer, pulling the two copies of DNA
apart while the cell membrane begins to pinch inward
along the middle of the cell.
 Then the cell splits and forms two new identical
offspring.
 The original cell no longer exists.
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Fission of E. coli bacterium:
2. Mitotic Cell Division
 One organism forms two genetically identical
offspring through mitosis and cell division.
 Many unicellular eukaryotes reproduce in this way.
 Example - amoeba
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3. Budding – p. 131
 In budding, a new organism grows by mitosis and
cell division on the body of its parent.
 The bud is the offspring. It is genetically identical to
the parent.
 When the bud is large enough, it breaks off from the
parent to live on its own.
 Example – The hydra. It is multicellular.
4. Animal Regeneration – p. 132
 This occurs when an offspring grows from a piece of
its parent.
 Examples of animals that can undergo regeneration:
Some sea stars, sea urchins, sea cucumbers,
sponges, planarians
 Regeneration can produce new parts for
salamanders, tadpoles, crabs, hydra
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 The human liver can regenerate to a degree.
5. Vegetative Reproduction – p. 133
• This is a form of asexual reproduction in which
offspring grow from a part of a parent plant.
• It usually involves structures such as the roots,
the stems, and the leaves of plants.
• Examples – spider plants, strawberry plants, mint
plants, new potato plants from the eye of a
potato
6. Cloning
• Cloning is a type of asexual reproduction performed
in a laboratory that produces identical individuals
from a cell or from a cluster of cells taken from a
multicellular organism.
• Some plants can be cloned using a method called
tissue culture.
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• Animal cloning has been done. Example: Dolly
the sheep.
• Dolly developed arthritis and old age problems
while still young. Dolly had to be “put down.”
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Advantages of Asexual Reproduction
• Organisms get to reproduce without a mate, saving
time and energy.
• Some organisms to produce large numbers of
offspring in a short period of time.
Disadvantages of Asexual Reproduction
• The results offer little genetic variation within the
population.
• Asexual reproduction can also be responsible for
harmful genetic mutations.