Transcript Asexual Reproduction - Mrs. Primatesta

Asexual
Reproduction
Are you two twins?
• Asexual Reproduction:
 Used by many unicellular organisms, plants, and lower
animals.
 Involves only mitotic cell division = each offspring has
exactly the same heredity as its parent.
 Usually rapid compared to sexual reproduction.
 Types of Asexual Reproduction Include:
 Binary fission
 Budding
 Spore formation
 Regeneration
 Vegetative Reproduction
Cut it in half!
• Binary Fission =
•
simplest form of
asexual
reproduction. Parent
organism divides
into two
Approximately equal
parts. Each
daughter cell
becomes a new
individual.
Binary Fission
Bacteria
(prokaryotic single cell organism)
 No organized nucleus.
 Genetic material in the form a single
circular chromosome.
 Before division starts chromosome is
replicated then each daughter cell gets
one copy of the chromosome.
 Can occur every 20-min.
Protozoan
(eukaryotic single cell organism)
• Mitosis occurs.
• Cytoplasm pinches in and divides the
organism in half.
• Each half has a copy of the genetic
material.
They were best buds…
• Budding = Parent organism divides
into two unequal parts.
• The new organism is created as a
smaller out growth or bud on the
outside of the parent.
• Buds will break off and live
independently or remain attached
and form a colony.
Budding
• Yeast – Once the yeast cell reaches a
certain size it undergoes mitosis.
• Once the genetic material is replicated
budding begins.
• Hydra – Cells on the outside of the
parent hydra begin to undergo
mitotic division creating a small
group of cells. Those cells continue
to divide until in a completely new
hydra is formed. Can also reproduce
sexually.
• Yeast budding:
• http://https://www.youtube.com/watch?v
=iOvrq6ssy2Y
Can I have some spore?
• Spore Formation – spores = small
specialized cells that contain a
nucleus and cytoplasm surrounded
by a thick outside wall which
protects the spore.
• Under the right conditions the spore
can rise to a new organism. Found in
bacteria, molds, yeast, mushrooms,
mosses, ferns and some protozoans.
Spore formation
Don’t try this at home
• Regeneration = The ability to re-grow
lost or damaged body parts. Hydra,
planaria, starfish, and earthworm
• More complex animals less able to regrow parts.
• Crab can re-grow a claw. Some
reptiles can re-grow a tail.
• Most mammals can repair damaged
tissue but can not re-grow missing
parts.
Regeneration
Vegetative Reproduction
• Bulb = Short
underground
stem surrounded
by thick leaves.
Contain stored
food. As the
plant grows it
produces new
bulbs which will
grow into new
plants. Tulips,
onions, and
lilies.
• Corms =
Similar to
bulbs but
do not
contain
leaves, just
underground
stems.
Water
chestnuts.
• Tuber =
enlarged part of
an underground
stem that
contains stored
food. Potatoes
are tubers.
“Eyes” = tiny
buds that can
form a new
potato plant.
• Runner or stolen =
horizontal stem
above the ground
with buds. If a bud
touches the ground
it will form roots
and stems and
start a new plant.
Strawberries.
• Rhizome =
horizontal stem
that grows
underground.
Thick and
contains stored
food. Upper
portion form
nodes which will
form buds which
will form new
plants. Lower
portion forms
roots. Ferns,
cattails, and
water lilies.
Artificial Vegetative
Reproduction
Watch out for those old ladies.
• Cutting = use a
portion of a
developed plant
to make a new
plant. Roses, ivy,
and grapevines
are reproduced in
this way.
• Layering = a stem
is bent so that it is
covered with soil.
Once the branch
forms roots it is
disconnected from
the original plant.
Raspberries and
roses.
• Grafting = Bud
or stem of one
plant is
permanently
attached to the
stem or trunk of
a very similar
plant. The
cambium layers
grow together
and form a
single plant.
Apple trees.
That’s a
strange cacti!
Why Bother??
• Advantages to artificial vegetative
propagation:
1. Plants that grow from seed are not
always exactly the same as their parents.
2. Takes less time to artificially propagate.
3. Can create seedless fruits.
4. Grafting can be used to generate higher
levels of fruit and nut production.