Transcript Reproduction

Asexual Reproduction
The production of a new organism without the fusion of two nuclei. The
new organism develops FROM the cells of a single parent and has
identical characteristics as the parent. This is very rapid and many
offspring are produced.
Cell division consists of two processes:
1. Nuclear Division
• This is called Mitosis or mitotic cell division
• There is an exact duplication of a set of chromosomes creating
two identical sets.
2. Cytoplasmic Division
• This occurs during or after mitosis resulting in the formation of
two daughter cells, each containing an identical set of
chromosomes.
What is a chromosome? A thick threadlike structure that
contains genetic information in the form of DNA.
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A Chromosome is a double strand of chromatid
joined in the center by a centromere.
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Mitosis
In Animals
•Prophase
•Metaphase
•Anaphase
•Telophase
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Interphase
•Not really a part of Mitosis (it
happens before)
•Lasts from the end of one cell
division to the beginning of the
next.
•Known as the “resting period”
Prophase
•Single stranded chromosome replicates into
a double-stranded chromosome
•Double stranded chromosomes are joined
by centromeres.
•Centrioles migrate to opposite ends (poles)
of the cell forming spindle fibers.
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Metaphase
•The double stranded chromosomes line up in the
middle of each cell
Anaphase (think apart)
•The double stranded chromosomes break at
the centromere and divide into singlestranded daughter chromosomes
•The daughter chromosomes then move
apart to opposite poles with the aid of spindle
fibers.
Telophase
•Last stage of mitosis
•Begins when chromosomes reach the poles
•A nuclear membrane forms around each daughter cell
•Cytokinesis divides the cell into two cells and the
cytoplasm pinches in and identical two cells are made.
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Mitosis in plants
Plant cell division and
animal cell division differ
in two ways:
1. Plants do not have centrioles
2. Plants have a rigid cell wall
which prevents the cell
membrane from pinching in.
Instead, a cell plate forms
which divides the plant cell in
half.
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Label the phases of Mitosis
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Types of Asexual Reproduction
•Binary Fission
•Budding
•Spore Formation
•Regeneration
•Vegetative Propagation
Binary Fission
•Parent divides into two
equal parts.
•The two daughter cells are
equal in size and grow to
normal size.
•Examples are Amoeba
and Paramecium
(Binary Fission of Amoeba)
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Budding
•The Parent cell divides into two unequal parts.
•Yeast (unicellular)
Two daughter cells are produced and one is larger than the other.
•Hydra (multicellular)
The daughter is a multicellular outgrowth of the parent, which bud
separates from the parent.
(Yeast budding)
(Hydra budding)
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Sporulation
•Many single celled reproductive cells are
released into to environment
•Under the right temperatures and
moisture conditions these can develop
into new individuals.
•Examples are bread mold and
mushrooms.
(blueberry)
Regeneration
•This is the development of a new organism from
part of the original.
•It can also mean the replacement of a body part.
•A new starfish can develop from part of the parent.
•A lobster can grow a new claw if one it torn off.
•An earthworm can re-grow if one tip is cut off.
•A salamander can also re-grow limbs
(salamander)
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Vegetative Propagation
•The growing of new plants form parts of other plants.
•Examples include:
Propagation
Organism
cuttings (stem, leaf, root)
geranium
bulbs
onion, tulip
tubers
potato
runners
strawberry
grafting (joining of two parts)
seedless orange or watermelon
(any different version of a fruit)
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