octopus chromatophores: hands on science at pasadena public library
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Hands-on Science and
Engineering at Pasadena
Public Library
Oct. 22, 2014
Many animals are born with skin that’s the same color as
their environment—an adaptation that protects them
from predators. But how is it that a frog, chameleon or
octopus can literally change the color of its skin, in
SECONDS?
Chromatophores, or
pigment sacs in their skin,
that expand and contract!
These animals have
pigment sacs of many
different colors, usually
brown and yellow but
sometimes green, red or
other colors. They sense
the color of their
environment and
instinctively choose which
pigment sacs to expand and
which ones to contract.
http://phys.org/news/2013-05-
chameleons-creatures-colour.html
Build octopus chromatophores!
“The outer layers of
octopus skin are
covered with
chromatophores, which
are tiny cells containing
brown, red, and yellow
pigments. Each
chromatophore is
controlled by a muscle
and a nerve. The
octopus’s brain sends a
signal along the nerve
to tell the muscle to
contract, and when it
does so, the
chromatophore changes
color.”p. 16, Octopuses by Melissa Gish, published by
Creative Education
“In addition to
color, the octopus
can also change its
skin texture. Tiny
knobs on the skin,
called papillae,
can lie flat or rise
up into bumps or
ridges, instantly
giving the octopus
a smooth or rough
appearance.”
p. 16-18, Octopuses by Melissa Gish, published by
Creative Education
Scientists don’t know exactly how octopuses are so adept at matching the color of their environment without being able to distinguish those colors with their eyes. They believe it’s due to a kind of cell in the outer layer of the octopus’s skin that reflects the environment and responds to light, and the nerves connected to the chromatophores respond by matching the color wavelength they “see.”
“Woods Hole Marine Biological Laboratory and University of Washington researchers found that the skin of the cuttlefish Sepia officinalis, a color-changing cousin of octopuses, contains gene sequences usually expressed only in the light-sensing retina of the eye. In other words, cephalopods—octopuses, cuttlefish, and squid—may be able to see with their skin.”
From “Inside the Mind of the Octopus” by Sy Montgomery, published in Orion Magazine in November/December 2011.
http://www.orionmagazine.org/index.php/articles/article/6474/
Challenges:
*Try making all the balloons of the same color expand with one pull, the way an octopus would send a signal to all the brown chromatophores to expand!
*Try making papillae or bumps that can rise and retract!
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