Transcript Variation and Adaptation, pg 338

Variation and Adaptation, pg 338
Mimicry and camouflage
Mimicry
• When one animal copies the appearance,
actions, or sounds of another animal, the first
animal is called a mimic. You can think of
it as a copycat!
Usually, an animal will mimic another to avoid
predators. If it can trick its enemy into thinking
it is something less tasty or more dangerous, it
will survive.
Three forms of mimicry
• Mimicry refers to the similarities
between animal species.
• There are three forms of mimicry utilized
by both predator and prey:
• Batesian mimicry,
• Muellerian mimicry, and
• self-mimicry.
Monarch butterfly on the left, viceroy butterfly
on the right. Both taste bad to predators
• Batesian mimicry
refers to two or more
species that are
similar in appearance,
but only one of which
is armed with spines,
stingers, or toxic
chemistry, while its
apparent double lacks
these traits.
Batesian mimicry
• The second species has no defense other than
resembling the bad tasting species. This is an
advantage since it gets protection from certain
predators since it resembles the bad tasting
species, which the predator associates with a
certain appearance and a bad experience.
Deadly coral snake
"Red next to yellow,
kill a fellow"
Every other band is
yellow and yellow
touches both black
and red, but black
and red never touch.
harmless king snake
“Red against black:
friend to Jack."
Yellow does not touch
red and every other
band is not yellow.
Black and red always
touch.
Can you guess which one is a sea slug and which
is the flatworm mimic?
• The sea slug gives off
poisonous, smelly chemicals
to discourage its predators. It
exude very noxious and toxic
chemicals from their skin and
appear to be avoided by most
fish. They are often the only
sea slugs which blatantly
crawl out in the open during
the day. Why would the
flatworm want to look like the
sea slug?
Bumblebees and Robber Flies
• Two of these are
Bumblebees (with
stingers) and two
are Robber Flies
(which also make a
sound similar to a
bee).
If you were a
predator, could you
"bee" sure of the
difference?
Yellow Banded Poison Frog
• Muellerian mimicry
• This form of mimicry
refers to two
unpalatable species
that are mimics of
each other with
conspicuous warning
coloration.
Green and black poison dart frog
• Thus all mimics
share the
benefits of the
coloration since
the predator will
recognize the
coloration of an
unpalatable
group after a few
bad experiences.
Blue poison dart frog
• Since several species
have the same
appearance to the
predator, the loss of
life will be spread
out over several
species, reducing
the impact on each
individual species.
Self mimicry
• Self-mimicry is a misleading term for
animals that have one body part that
mimics another to increase survival
during an attack or helps predators
appear harmless.
Owl butterfly
• For example,
countless moth,
butterfly, and
freshwater fish
species have "eyespots"? Large dark
markings that when
flashed may
momentarily startle a
predator and allow
the prey extra
seconds to escape.
"Eye-spots" also help prey
escape predators by giving
predators a false target. A
butterfly has a better chance of
surviving an attack to the outer
part of its wing than an attack
to the head.
This jumping spider uses color and shape to mimic
the ants that it hunts.
• Some animals, like the octopus,
can even change their color to
match their environment. The
octopus can also change the
texture of its skin to look
bumpy like the rocks where it is
hiding. The walking stick and
the skeleton shrimp also copy
both the shapes and colors of
the plants. You have to look
closely to tell which are the
branches and which are the
animals.
Self mimicry
• One of the most interesting
examples of self-mimicry is
the so-called "two-headed"
snake of Central Africa which
has a tail that resembles a
head and a head that
resembles a tail. The snake
even moves its tail in the way
most snakes move their
heads. This adaptation
functions to trick prey into
believing the attack is
originating from where it is
not.
Another example, several turtle
species and the Frogmouth Catfish
(Chaca sp.) of Southeast Asia have
tongue extensions that are used…
… as a sort of lure to attract prey to a
position where they become an easy
catch.
camouflage
• An animal uses camouflage to blend in with
its environment. Camouflage is the use of
color, pattern, and shape to look like the
things around you.
• Predators, or hunters, will use camouflage to
help them catch food. Prey, or the ones being
hunted, will use camouflage to keep from
being caught. Many animals use color to help
them hide.
Its yellow color helps this crab spider to hide
while it hunts.
• The polar bear's white fur
keeps him hidden in the
snow. Grasshoppers and
lynx spiders use their
green color to hide among
the leaves and stems of
plants. Crab spiders use
color when they are
hunting. See how the crab
spider in the photo uses
its yellow color to blend in
while it waits for an insect
to land.
Katydid, a group of grasshopper like
insects
• Katydids have evolved to
the point where their
body coloring and shape
matches leaves.
Including half-eaten
leaves, dying leaves, and
leaves with bird
droppings and also
camouflage sticks, twigs,
and tree bark.
• Katydids are
nocturnal insects
which use their
cryptic coloration to
remain unnoticed
during the day when
they are inactive.
They remain
perfectly still, often
in a position that
makes them blend in
even better.
http://www.myinsectarium.com/
Walking stick insect
Philly insect museum
The gecko lizard is hard to see when
he’s climbing a tree!
Leaf moth
Ruins moth
Brookesia superciliaris
Playing dead
In leaf litter
Leopard sleeping in a tree
• Other forest
species,
especially
mammals, have
spots or stripes
to help break up
the animal's
outline.
jaguar
• In the shade created
by the canopy, large
mammals like
leopards, jaguars,
ocelots, and okapi
are surprisingly
difficult to see with
their disruptive
coloration.
ocelot
Okapi, rare cousin of the giraffe
• The Okapi is a primitive giraffe,
about the size of a horse, found in
a small region of rainforest in the
Congo. It has striped legs like a
zebra to help it blend into the
shadows of the forest and a long
neck to reach leaves above the
floor. The Okapi is solitary or lives
in pairs and feeds on foliage that
is shunned by other forest
creatures.
The Okapi was only discovered by
Western science in 1899 and less
than 10,000 individuals exist
today.