Transcript Asexual Reproduction

Asexual Reproduction
Living Environment
Modified From:
http://bcsd.k12.ny.us/high/EVANS/Evans%2520New%2520Website/Excel%2520Science%252010%2520PowerPoint
s/Asexual%2520Reproduction.ppt
• Mitosis animation:
• http://brodylab.eng.uci.edu/cgibin/jpbrody/animation/files/6973887139.html
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:
Cut it 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
• Bacteria
– 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
• Protozoa – Mitosis occurs.
Cytoplasm
pinches in and divides the organism in
half. Each half has a copy of the
genetic material. Diagram.
• Protozoa – Mitosis occurs.
Cytoplasm
pinches in and divides the organism
in half. Each half has a copy of the
genetic material. Diagram.
They Where 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 brake 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 cell cycle including budding:
• http://brodylab.eng.uci.edu/cgibin/jpbrody/animation/files/13977277560.html
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 re-grow parts. Crab can
re-grow a claw. Some reptiles can
re-grow a tail. Most mammals can
repair damaged tissue but can not regrow 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
undergro
und
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.
How you plant
potatoes. Great
potato famine.
• 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.
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.
Can robot teachers from the future
asexual reproduce?
(Relax that was a rhetorical question)
Websites
• Yeast cell cycle including budding:
• http://brodylab.eng.uci.edu/cgibin/jpbrody/animation/files/13977277560.html
• Mitosis animation:
• http://brodylab.eng.uci.edu/cgibin/jpbrody/animation/files/6973887139.html