Ecology in Further Detail ❮ 227systems. Burglars notice the red light and may think twice about attempting to steal that
car because of the potential for encountering an alarm system.
InBatesian mimicry,an animal that is harmless copies the appearance of an animal
that is dangerous to trick predators. An example of this is a beetle whose colors closely
resemble those of bees. Predators may fear that the beetle is a bee and avoid confrontation.
Incryptic coloration,those being hunted adopt a coloring scheme that allows them
to blend in to the colors of the environment. It is like camouflage worn by army soldiers
moving through the jungle. The more you look like the terrain, the harder you are to see.
Some animals have patterns called deceptive markings,which can cause a predator to
think twice before attacking. For example, some insects may have colored designs on their
wings that resemble large eyes, causing individuals to look more imposing than they truly are.
InMüllerian mimicry,two species that are aposematically colored as an indicator of
their chemical defense mechanisms mimic each other’s color scheme in an effort to increase
the speed with which their predators learn to avoid them. The more often predators see
dangerous prey with this coloration, the faster the negative association is made.
Looking at Figure 18.5, we can see how the predator–prey dance plays out. When the
prey population starts to decrease because of predation, there is a reactionary reduction in
the predator population. Why does this happen? Because the predators run low on a valu-
able resource necessary to their survival—their prey. Notice in the figure that as the preda-
tor population declines, an increase in the population of the prey begins to appear because
more of those prey animals are able to survive and reproduce. As the prey population den-
sity rises, the predators again have enough food available to sustain a higher population, and
their population density returns to a higher level again. Unless disturbed by a dramatic
environmental change, this cyclical pattern continues.= Predator= PreyPopulation
densityTime
Figure 18.5 Predator–prey population curves.Coevolutionis mutual evolution between two species and is often seen in predator –prey
relationships. For example, imagine that the hunted prey adapts a new character trait that
allows it to better elude the predator. In order to survive, the predator must evolve so that
it can catch its victim and eat.http://www.ebook3000.com