Flashcards in Lecture 14 Deck (73)
Some birds have learnt to successfully mimic the alarm calls of multiple species. What is the benefit of this?
These alarm calls are given to
convince a potential predator
that a larger predator is near
(a threat to both species)
All organisms can generate visual images passively. How?
Light reflects off their bodies.
How can organisms increase their visibility?
between themselves and their background, moving, or generating
one’s own light signal
__________ _______ from the visible range of the spectrum of EM radiation.
What are some sources of light?
Light travels in ________.
Light obeys the inverse square law. What is that?
(intensity decreases with distance from a point source as the inverse function of the distance squared)
• Decreases in intensity equal the square of the distance from the source to the perceiver
Light travels best in a _________.
– light waves bend
and spread out as they travel
through a narrow aperture
When would diffraction effects be pronounced?
propagating wavelength is
similar in size to the
direction of a wave due to a
change in its speed, most
commonly observed when a
wave passes fro one medium
the change in direction of a wavefront at an interface between two different media so that the wavefront returns into the medium from which it originated.
optical energy is
lost (absorbed) as it travels
through the medium
refers to a signal’s overall intensity
Function of both the range of wavelengths reflected and the surface
structure of the object or signaling organism
_______ surface will produce higher intensity signal
Brightness of self generated signals depends on the...?
amount of energy used to produce the signal.
Define spectral composition?
color of a light signal
Hue (dominant wavelength)
• Chroma (saturation or purity of
Reflected and self-generated
light signals may be
characterized by their _______.
Describe spatial characteristics?
Visual acuity of the receiver
impact the details and
localizability of the sender
Define temporal variability?
timing changes in intensity, color, and
• Used to generate a wide variety of signals
What are some typical components of visual displays?
Complex patterns of changes
in size, shape, color, flashing,
and limb movements
__________ between an object
of interest and the object’s
background determines the
conspicuousness of the object
How can contrast be achieved?
Contrast can be achieved with
any one or more of these light
What is camouflage?
color or shape of an animal is similar to the background.
What is mimesis?
mimics another plant or animal for camouflage.
What is an aposematic signal?
warning signals associated with the
unpalatability of a prey animal to potential predators
What is batesian mimicry?
one species has evolved to mimic the warning
signals of another species directed at a common predator; mimic
is palatable while model is poisonous or noxious
• E.g., Moarch and Viceroy butterflies
What is mullerian mimicry?
convergence between two or more species
to warn predators of their unpalatability; both species are
poisonous or noxious
• E.g., cuckoo bee and yellow jacket
What is an example of batesian mimicry?
The filefish mimics the coloring of the unpalatable puffer fish