Transcript 1.3 Regeneration

Regeneration
Is
the ability to regrow a
tissue, an organ or a part
of the body
Humans can regenerate:
blood, bone, skin
Animals that Regenerate
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What animals can
regenerate?
Many animals can
grow new parts of
their bodies to
replace those that
have been damaged
LIZARDS--> tail
Animals that Regenerate
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Planarians-->if cut into pieces, each
piece will grow into a new worm (p.186)
Sea Cucumbers--> body is three feet
long. If cut, can grow new sea cucumber
Sharks-->continually replace lost teeth
Spiders--> regrow missing legs or parts
of legs
Sponges--> can be divided, and will
regrow to be exactly as before.
Animals that Regenerate
Starfish--> that
lose arms can
grow new ones
 Sometimes an
entire animal can
regrow from a
lost arm

Fragmentation
A
form of asexual reproduction
where a new organism is
formed from a part that breaks
off from the parent
 ie. Sponge, planarian
Cell Specialization
The nucleus of every cell contains a
complete code for your characteristics.
 (Every cell contains identical DNA)
 Why can skin cells regenerate when
nerve cells can’t?
 Because each cell uses only a specific
part of their DNA.
 Ie. The muscle producing part of DNA is
turned off in nerve cells

Cell Specialization cont’d
Animals with little cell specialization are
capable of regeneration
 The cells of these organisms are very
similar
 Complex animals (like dogs, elephants
etc.) have more cell specialization
(where specific parts of the DNA are
turned off)

Producing Plants without
Seeds
What happens to a potato when it has
been left for a while?
 It grows eyes (tiny buds)
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see p.190
Potatoes
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So, when farmers grow potato crops,
they make sure a section of the potato
containing an eye is planted

Using a potato eye to grow a new
potato is a type of asexual reproduction
What are some other examples of
growing a new plant from another
plant?
 ie. Spider plant

Fact
When a new plant that has been grown
from an already existing plant, is the
new plant is genetically identical to the
parent?
 Yes!

Dolly
Dolly