Transcript Asexual Reproduction

Asexual Reproduction
Producing Identical Offspring
Asexual Reproduction
• Unicellular
organisms, many
simple animals, and
many plants
reproduce asexually,
at least during part of
their life cycles.
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des/subjects/biologyedited/chap14/14_13.gif
http://content.answcdn.com/main/content/img/Gardeners/f0261.jpg
Asexual Reproduction
• Because asexual
reproduction takes
place only by mitotic
cell division, every
offspring has the same
exact DNA as its
parent.
http://www.phoenix5.org/glossary/graphics/mito
sis.jpg
Check for Understanding
• Would you
expect offspring
produced
asexually to
show much
variation? Why?
Asexual Reproduction
• Usually rapid and often results in
the production of large numbers of
offspring.
Methods of Asexual Reproduction
• There are several methods of asexual
reproduction, including:
1. Binary Fission
2. Budding
3. Spore Formation
4. Regeneration
5. Vegetative Reproduction
Binary Fission
• Binary fission is the
simplest form of
asexual reproduction.
• Parent organism
divides into two
equal parts.
Binary Fission
• Binary fission is the
usual method of
reproduction in one
celled organisms,
including bacteria,
protozoa, and many
algae.
http://www.biologyresources.com/images/paramecium-dividingbig.jpg
Budding
• Budding is a method of asexual
reproduction in which the parent
divides into two unequal parts.
Budding
http://images.carolina.com/images/en_US//local/pro
ducts/detail/132804_la.jpg
• The new individuals
develop as small
outgrowths, or
buds, on the outer
surface of the
parent.
Budding
• The buds may break
off to live as an
individual, or they
may remain
attached, eventually
forming a colony.
http://farm3.static.flickr.com/2217/2845170474_b24c
6a986f_o.jpg
Budding
• Budding differs from
binary fission in that
the parent and
offspring are not
the same size.
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apter%208-5.gif
Budding
• Budding takes
place in yeast
and hydra, as
well as in
sponges and
some worms.
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tbn:ANd9GcTpiYj6gZg_bDwNgF4
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Budding in Yeast and Hydra Video
Budding in
Yeast and
Hydra Video
Spore Formation
• Spores are single,
specialized cells that
are produced by
certain organisms.
• Can be formed
sexually or asexually.
http://medicineworld.org/images/blogs/moldspores214412.jpg
Spores
• Although spores can vary greatly in
appearance, they all function as
single units of reproduction.
• Often surrounded with a thick hard
outer wall.
• May sometimes have a flagella.
Spores
• Asexually formed
spores are a
common method
of reproduction in
many simple
organisms, such as
fungi, algae, and
protozoa.
http://www.sixwise.com/images/articles/2005/10/26/fung
usPIL.gif
Spores
• These spores are produced through
mitotic cell division.
• They are formed within and released
from a single cell structure that is the
remains of the original parent cell
from which they are formed.
Spore Formation in Bread Mold
• Bread mold is a
fungus, and can
sometimes be seen
growing as a dark
mass on bread or
other food.
http://www.buzzle.com/img/articleImages/375982-238734.jpg
Bread Mold
• Spores are
produced by
mitotic cell
division in spore
cases on
specialized stalks
that grow upward
from the surface.
Bread Mold
• Thousands of black spores
develop within each spore
case.
• When fully grown, the
walls break down, and the
tiny light spores are swept
away by air currents.
http://www.skidmore.edu/academics/biol
ogy/plant_bio/fungi/Rhizopus%20%20bread%20mold.jpg
Spores
• When a spore lands
in a warm, moist
environment, where
nutrients are
available, it
germinates and
grows to form a new
mass of mold.
http://www.scienceprojectlab.com/image-files/moldon-bread.jpg
Bread Mold
• Bread mold also reproduces
sexually, which we will discuss later.
Bread Mold Video
(click photo above)
Bread Mold
• In the space
provided on your
worksheet, draw
and label a
diagram showing
the main
structures of
bread mold.
Regeneration
• Regeneration is the
ability of an
organism to regrow lost body
parts.
http://www.biosulf.org/1/images/newt-regeneration.jpg
Regeneration
• Relatively simple animals can
regenerate lost body parts. For
example:
* Hydra
* Planaria
* Starfish
* Earthworm
http://www.scientificillustrator.com/art/microscopic/hydra.jpg
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/images?q=tbn:ANd9
GcToMtoKHurk2PVTNMVJnRe43EJ6pMb3J
XfgHcNffAy71KQBM&t=1
http://users.rcn.com/jkimball.ma.ul
tranet/BiologyPages/S/Starfish012.j
pg
http://campus.albio
n.edu/wjwilson/file
s/2010/12/regenlab
el.jpg
Regeneration
• The power of
regeneration decreases
in more complex
organisms.
• For example: While a
crab can re-grow a lost
claw, it cannot
regenerate an entire
animal from pieces.
http://newsliteimgs.s3.amazonaws.com/100429_cra
b1.jpg
Sea star regeneration
video
(click photo above)
Vegetative Reproduction
• Although most
plants reproduce
sexually by means
of seeds, asexual
reproduction
involving roots,
stems, and leaves
also occurs.
http://www.localdelicious.com/wpcontent/uploads/2010/09/strawberry-runners.jpg
Vegetative Reproduction
• Roots, stems, and
leaves are called
vegetative structures.
• They normally play a
role in the nutrition
and growth of plants.
http://extension.oregonstate.edu/mg/botany/images/fig1.gif
Vegetative Reproduction
• When these structures
give rise to new plants,
the process is known
as vegetative
reproduction, or
vegetative
propogation.
Check for Understanding
• Give three examples of vegetative
structures.
• Roots, stems, leaves
• When these structures give rise to new
plants, the process is known as what?
• Vegetative Reproduction
(propogation).
Vegetative Propagation
• In vegetative
reproduction, cells divide
mitotically, then
differentiate to produce
another plant.
• The new plant has the
same hereditary
characteristics as the
parent plant.
http://plantphys.info/plants_human/veg
prop/root.gif
Vegetative Propagation
• Vegetative propagation occurs naturally
and can be produced artificially.
http://leavingbio.net/VEGETATIVEPROPAGATION_
files/image004.gif
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hapter%201_files/Chapter%201-18.png
Natural Vegetative Propagation
• A bulb is a short
underground stem
surrounded by thick
fleshy leaves that
contain stored food.
Bulbs
• As the plant grows,
small new bulbs
sprout from the old
one.
• Each of the new bulbs
can give rise to
another plant.
http://blogs.phillynews.com/inquirer/hortis
exual/tulip%20single%20purple.jpg
Bulbs
• Examples of plants that reproduce
with bulbs are:
* Tulips
* Onions
* Lillies
http://runningraw.com/
blog/wpcontent/uploads/2010/
12/onion1.jpg
http://www.mdidea.c
om/products/proper/li
ly_bulb10.jpg
Tubers
• A tuber is an
enlarged part of an
underground stem
that contains
stored food.
http://content.answcdn.com/main/content/img/Gard
eners/f0261.jpg
Tubers
• White potatoes are
tubers.
• Along the surface of
the tuber are
indentations called
“eyes”.
http://food.evilwalrus.net/wpcontent/uploads/2008/07/potatoes-white.jpg
Tubers
• The eyes are tiny buds
that grows into a
shoot.
• The young shoot uses
food stored in the
tuber until it can carry
on photosynthesis.
Runners
• A runner or stolen, is
a stem that grows
sideways and has
buds.
• Usually grows along
the surface of the
ground.
Runners
• Where buds from the
runner touch the
ground, new plants
develop.
• These new plants will
send out runners that
will repeat the process.
http://forum.sensiseeds.com/uploads/19197/
wildstrawberryrunners.jpg
Runners
http://living-country-life.com/wpcontent/uploads/2009/05/strawberry-plant2.jpg
http://i.ehow.com/images/a06/20/81/
plant-grass-runners-200X200.jpg
• Strawberry plants
and many grasses
that reproduce
quickly use
runners.
Rhizome
• A rhizome is a stem
that grows sideways
underground.
• Usually thick and
fleshy and contains
stored food.
http://www.rhizomesystems.com/images/rhizom
e_example.png
Rhizome
• Along the rhizome are
enlarged portions
called nodes.
• Buds along the upper
surface of the rhizome
give rise to leaf-bearing
branches.
http://www.turfgrass.ncsu.edu/images/Plants/bermu
dagrass/Web/rhizome.jpg
Artificial Vegetative Propagation
• Farmers and gardeners have
developed ways to grow plants with
desirable traits.
• They do this through artificial
vegetative propagation.
Cuttings
• A cutting is any
vegetative part of
the plant used to
produce a new
individual.
http://www.instructables.com/image/F520ALBP7REP2
7QGYD/Rooting-plant-cuttings.jpg
Cuttings
• Cuttings are usually
placed in water and
allowed to grow roots.
• Once roots develop,
the cutting is planted
in soil and grows as a
new plant.
http://www.happynews.com/living/living
images/cuttings-plants-trees.jpg
Grafting
• In grafting, a stem or
bud is removed from
one plant and
permanently joined
to the stem of a
closely related plant.
http://www.bodwennursery.co.uk/Resources/ag3964.gif
Grafting
The added piece is
called the scion
Part of the combination
providing the roots is
known as the stock
Grafting
• In the space
provided on
your
worksheet,
draw and label
a typical
grafting set up.
Advantages of Artificial Vegetative
Propagation
• Plants grown from seeds do not
always show the same
characteristics as the parent plant.
• Vegetative propagation produces
plants identical to the parent.
Advantages of Artificial Vegetative
Propagation
• Example 1:
Seedless fruit can only be
grown through
vegetative propagation.
• Example 2:
Scions of a desirable plant
can be grafted onto
plants with a disease
resistant root system.
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