Download Asexual Reproduction

 Compare
all the different types of asexual
reproduction and determine where the
genetic information comes from in each.
 Why

must species reproduce?
For the continuation of the species
 How
does the reproduction of cells differ
from the reproduction of a specialized
multicellular species?
What do you observe about these lizards?
If you found out they can reproduce asexually,
what could you infer?
http://www.pbs.org/
wgbh/evolution/libr
ary/01/5/l_015_01.
html
 Sexual
reproduction: two organisms
produce a new unique organism
 Asexual
reproduction: one organism
produces a new nearly identical organism =
no variability!
 Your
somatic cells in your multicellular body
use:

Cellular asexual reproduction (mitosis and
cytokinesis)
 Some





other organisms use:
Binary fission
Budding
Sporulation (spore formation)
Regeneration
Vegetative Propagation
 Organisms
with eukaryotic cells use mitosis
and cytokinesis to create cells with the same
genetic information (DNA) as the parent cell.
 Equal
division of nuclear material and
cytoplasm
 Results in two organisms nearly identical to
parent
 Takes place in most unicellular organisms

for example: protists and bacteria
 Equal
nuclear division, but unequal
cytoplasmic division
 New individual produced as an “outgrowth”
of parent
 Takes place in some unicellular and some
multicellular organisms

for example: yeast and hydra
Nuclei are exactly the same.
Cytoplasmic division is unequal.
 Spores:
single, specialized cells produced by
mitosis released from a parent organism.
 Each spore contains a nucleus and a small
amount of cytoplasm surrounded by a thick,
hard outer cell wall
 Develop into new individuals under favorable
conditions

for example: bread mold and mushrooms
If you
magnify it,
it looks
like this…
 Development
of entire organism from part of
the original, because some cells are not
specialized
 Also used to replace damaged or lost parts
 Takes place in many invertebrates

for example: starfish and planaria
Starfish
 Regeneration
also applies to the replacement of
lost structures.


the starfish will also regrow the lost arm.
a lobster may regenerate a lost claw
 The
power of regeneration decreases as
organisms become more complex


A salamander can regenerate a lost tail.
Mammals can repair damaged tissue but cannot
regenerate a leg or even a toe.
 Generally,
the more undifferentiated tissue
an organism possesses, the greater its ability
for regeneration.
 As a result, invertebrates exhibit a higher
degree of regenerative ability than do
vertebrates.
•
•
Plant vegetative structure (root, stem, leaf) having
some unspecialized cells used to produce a new plant
Types:
–
–
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•
Bulb (onions, tulips)
Tubers (potatoes)
Runners (strawberries)
Cutting (Japanese Maple tree)
Grafting (orange tree)
Advantages:
–
–
–
–
–
No variation
Speed
Certainty
Seedless fruit
Combination of desired characteristics
 Asexual
reproduction involves mitotic cell
division.
 Chromosomes replicate before cell division so
that each daughter cell receives the exact same
genetic material as the parent cell.
 Asexual reproduction involves only one parent
and the offspring are exactly the same as each
other and the parent.
 There is NO VARIABILITY in asexual reproduction.