Transcript Open File

Asexual Reproduction
Reproduction without sex
Reproduction
• DNA is special because it is able to
make a perfect copy of itself.
• A cell doesn’t need two sets of DNA,
so after the copy is made the cell
splits in two.
• The old cell dies and two new cells
are born.
• This is called cell division.
Binary Fission
• When cell division
happens in a single-celled
organism, the result is
two new organisms.
• The old organism dies and
two new “daughters” are
born.
• This is called binary
fission.
• Binary fission is the most
common type of asexual
reproduction.
Budding
• Budding is similar to
binary fission.
• Instead of splitting in two,
the new organism begins
as a small bump or “bud”
on the side of the parent.
• The parent supplies the
bud with nutrients until it
is big enough to survive
on its own.
• Budding can happen in
single- or multi-celled
organisms.
Spores
• Spores are like seeds.
• They protect the first
cell of the new
organism, until
conditions are right for
it to start growing.
• Spores are common in
fungi and some
primitive plants.
Vegetative Reproduction
• If I cut a coconut in half
and plant the halves will
they grow into new trees?
• If I cut a potato in half
and plant the halves will
they grow into new
plants?
• In vegetative
reproduction, if part of
the plant is cut off, that
part can grow into a
whole new plant.
• Can you think of any
examples?
Vegetative Reproduction
Regeneration
Regeneration
• What happened to this
tokay?
• Is it gone for ever?
• The tokay will grow a
new tail, but will the tail
grow a new tokay?
Regeneration
• In some animals, like
starfish, if part of the
animal is cut away, both
parts can grow into a
new animal.
• This kind of
reproduction is called
regeneration.
• If I have all hens and no
roosters will my hens
still lay eggs?
• Will the eggs hatch?
• Why not?
• Some animals can lay
eggs that will hatch
even if there are no
males around to fertilize
the eggs.
• This is called
parthenogenesis—
Greek for “virgin birth”.
Parthenogenesis