Flashcards in Lecture 14 Deck (73)
Optical communication relies on?
Specializations of the sender
• Body structures modified to generate or reflect light for the purpose of communication
• Specializations of the receiver
• Visual system is designed to pick up electromagnetic radiation
• Adaptation to the channel • Properties of the signal are selected to maximize the likelihood of
For a reflecting surface to appear colored it must selectively...?
reflect certain wavelengths of light more than others
• Reflecting all wavelengths equally = white
• Absorbing all wavelengths equally = black
Curves with _____ peak over a _______ wavelength range are highly saturated.
broader curves are less saturated
Area under the curve is a measure of what?
_______ animals generally perceive a wider range of colors.
Color is produced through 3 different mechanisms:
• Thin-layer interference
What are pigments?
chemical compounds whose molecules absorb certain
wavelengths of light and transmit the remaining wavelengths
Long-pass filters allow only _______ wavelengths to pass
How is the color red produced? Yellow?
Red is produced by allowing all wavelengths above 600 nm to pass
• Yellow is produced by allowing all wavelengths above 500 nm to pass
_______ ______ filters allow only short wavelengths to pass.
_________ only allow wavelengths below 450 nm to pass.
What does color combination result in? Give an example.
additive color mixing
• Purple is not a spectral color but results form filters that block mid-range wavelengths (green) and allow red (long) and blue (short) wavelengths to pass
What are the 3 types of pigments?
Carotenoids – produced by plants and acquired by eating plants or by eating
something that has eaten plants
• Typically produce red, orange, yellow
• Porphyrins – modified amino acids all fluoresce under ultraviolet light
• Typically produce pink, browns, reds, and greens
• Melanin – tiny granules of color found in feathers and skin; provide
structural support as well as coloring
• Typically produce darkest black, reddish browns, pale yellow
What are conjugated double bonds?
Pigments are organic compounds that contain long chains of conjugated double bonds. They are carbon atoms joined by alternating single and double bonds.
What is carotene?
18-carbon chain that absorbs longer wavelength and transmits green, yellow,
and red to appear yellow or orange
Carotenoids bound to proteins absorb green but
transmit violet and red – appear purple
What are Pterins?
nitrogenous rings that
produce white, yellow and red
colors often found in butterfly
What is a Quinone?
Represent a class of organic compounds that are formally "derived from aromatic compounds
What is a Verdins?
color often found in bird’s eggs
What are porphyrins?
verdin molecule with
the ends connected into a ring around
a central metal ion; color is
dependent on the type of metal
Most animals place _____ in the center.
Hemoglobin: red (chicken comb)
Plants place _________ in the center.
Turacos place _______ in the center
dark-colored pigments found in a wide
variety of vertebrates, invertebrates, and
• Large protein molecule that absorbs most
or all visible wavelengths to produce
brown or black
forms microcrystalline deposits (platelets) that reflect
• Dense packing of guanine crystals causes specular reflectance
• Silvery appearance of fish scales
What must pigments be coupled with?
Where are pigments located.
outer epidermal or derman llayers of skin.
What are chromatosomes?
small granules or packets that contain
pigments; found in chromatophores
What are chromatophores?
pigment-containing and light-reflecting cells, or groups of cells, found in a wide range of animals including amphibians
What happens to light when it travels through pigment?
undergoes the first round of absorption/reflection
• Light waves that are reflected back out will undergo a second
round of absorption/reflection through the pigments