Transcript Adaptation - cayugascience

Adaptation
Adaptation
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Any trait that enhances an organisms fitness or
increases it’s chance of survival and probability of
successful reproduction is called an adaptation.
Adaptations arise from natural selection.
Over a period of time, individual organisms become
adapted to their immediate environment.
Only those organisms that possess characteristics
that enable them to survive are able to pass on these
favorable adaptations to their offspring.
Evolution of Complex Adaptations
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Adaptations do not arise all at once. They evolve
over time as a result of a series of small adaptive
changes.
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An example of a complex adaptation is the evolution
of the human eye from the eyes of lesser organisms.
This complex form of the eye is a result of many
years of developing in stages from a more simple
eye.
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As the structural changes giving rise to more
complex organs benefit organisms, these changes are
then passed on to offspring
Evolution of the Human Eye
Changing Function of Adaptations
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Sometimes an adaptation which evolved for one
function can have another use. This is called
exaptation.
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Example Evolution of limbs and digits of terrestrial
vertebrates.
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Used by aquatic organisms to move around in their
environment. These limbs were used to crawl, run, etc as
the organisms moved onto land to live
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Thus, what evolved as an adaptation for an aquatic
existence eventually became useful for living on land.
Limb Evolution Illustrated
Types of Adaptations
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Three types of adaptations:
1.
Structural
2.
Physiological
3.
Behavioral
Structural Adaptations
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Adaptations that affect the appearance, shape, or
arrangement of particular physical features. Includes
adaptations such as mimicry and cryptic coloration.
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Mimicry allows one species to resemble another species or
part of another species.
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Ex: Syrphid Fly will often mimic a more harmful yellow-jacket wasp.
Cryptic colouration (camouflage) allows prey to blend in
with their environment. This is accomplished when an
organism camouflages itself by shape or color.
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Ex: A sea dragon resembling seaweed.
Mimicry and Cryptic Colouration
Physiological Adaptations
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Adaptations which are associated with
particular functions in organisms.
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Examples:
1.
2.
3.
4.
Enzymes needed for blood clotting.
Proteins used for spider silk.
Chemical defenses of plants.
The ability of certain bacteria to withstand
extreme heat or cold.
Behavioural Adaptations
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Adaptations which are associated with how
organisms respond to their environment.
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Examples:
1.
2.
3.
4.
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Migration patterns.
Courtship patterns.
Foraging behaviors.
Plant responses to light and gravity.
These types of adaptation do not exist in isolation,
they depend on one another.
Is Evolution Perfection??
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Although many people think that adaptation
and natural selection tend to make an
organism perfect, this is not the case.
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Adaptation and natural selection simply
change an organ or organism in a way that
improves the organisms chance of survival in
its environment.
Why Evolution Is Not Perfect
1.
2.
3.
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Natural selection only edits variations that already exist in a
population. Evolution has to make do with what is created;
the new designs, although better than the old ones, are less
than perfect.
Adaptations are often compromises of what an organism is
ideally aiming to achieve.
Not all evolution is adaptive. Sometimes chance events can
change the composition of a populations gene pool. Those
organisms which survive a chance events do so randomly, not
because they were better than other organisms.
The individuals that do survive are able to reproduce and
pass on their genes to their offspring. Over time the
population will change, hopefully for the better.
The following slides give
examples of adaptations in
animals.
Elephants
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Elephant's bodies are well adapted for
survival in the rugged conditions of Africa.
These special adaptations include:
Elephants
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The Trunk
The elephant's trunk does so much more than
smell. This "hose nose" is also used for
drinking (actually blowing water into the
mouth), communication, feeding, chemocommunication, offense/defense, touching,
lifting, greeting, caressing, throwing dust, and
just about any other activity an elephant is
involved in.
Elephants
Elephants
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Ears
In the hot African climate, keeping cool is a constant
challenge. Believe it or not, an elephant's enormous
ears (weighing up to 110 pounds each), while
exceptionally good at picking up sound, are also
used as an air conditioner of sorts. When the
temperature rises, elephants flap their ears. This
cools blood flowing through vessels in the ears,
which then flows back to the body, cooling it in turn.
Giraffe
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Giraffes have many obvious physical
adaptations to help them survive in the
African savannas.
Giraffe
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Camouflaged coat - Patches of different sizes
and colors help hide the giraffe in the African
savanna.
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Fringed tail - A fringe at the end of the tail
keeps flies and other pests away.
Giraffe
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Long neck - It is used to reach leaves in tall
acacia trees.
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Long front legs - Unlike many animals, the
giraffe's front legs are longer than the hind
legs. These long front legs make it easier to
reach tall leaves.
Echidna
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An Echidna is a mammal and is also known
as the Spiny Anteater. An Echidna's body is
covered with long sharp spines set in short
fur. These spines are the Echidnas defense
mechanism. When attacked, it rolls itself in a
tight ball and burrows out of reach.
Echidna
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Echidnas have no teeth, but uses a long sticky
tongue to penetrate ant and termite nests,
which they have gauged open with their
strong ripping claws.
Echidna
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Shelter is where ever the echidna finds it and
this could be in logs, under bushes or in
caves. They are 35 - 45 cms long and can
weigh 2-7 kg. The Echidna has a spur on its
ankle but it is not poisonous.
Gecko
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At 28 cm long, The Round Island Day Gecko
is the largest of 27 species of day geckos. The
smallest day gecko is only about 8 cm long.
Most day geckos are bright green in color.
The Round Island Day Gecko is probably the
dullest looking one of all. It lives on palm
trees and is perfectly camouflaged against the
brown bark of the main stem of the tree.
Gecko
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Geckos have special feet to help them climb
up smooth surfaces. The flattened toes have
elongated scales. A microscopic view would
show thousands of tiny, hooked bristles that
can hold on to any surface. This means they
can easily climb up palm trees, as well as hide
on the underside of leaves.
Gecko
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They also have sharp teeth to penetrate the
exo-skeleton of an insect. If attacked, Round
Island Day Geckos have a unique way of
defending themselves.
Gecko
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The tail just drops off and lies moving around
on the ground. Hopefully the enemy will pay
attention to the tail while the gecko escapes.
The stump quickly heals, and they will
eventually grow a new tail.
Kangaroo
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These animals are mostly found in the dry
inland Australia, including desert,
grassland, mallee, and mulga country. It is
able to go with out drinking as long as green
grass is available and it adapts well to
drought.
Kangaroo
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Despite its name, the Red Kangaroo is
sometimes a blue-grey color, particularly the
female. Even though these animals look
cuddly, they are to be approached with
caution. They have evolved with a large
claw attached to its hind leg.
Kangaroo
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Red Kangaroos can hop as fast as 40 mph
(64 km). They use this as their first line of
defense. Kangaroos have a tendon in the leg
which acts like a rubber band, conserving
energy as the animal moves lands. Red
Kangaroos actually expand less energy in
locomotion as they move faster, up to very
fast speeds.
Shark
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A shark is a fish. It breathes through its gills,
has a backbone and lives in water. However,
unlike all other fish, its skeleton is made from
cartilage, not bone and they do not have
scales but denticles. Also, they have five to
seven gill slits rather than one each side as in
bony fish.
Shark
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Sharks can detect one part of blood per ten
billion parts of water – that means they could
detect one drop of blood in an area the size of
an Olympic swimming pool! The nose of a
shark is only used for smell, unlike in humans
where we also use our noses for breathing.
African Wild Dog
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Location: South Africa and east of Sahara
African Wild Dog
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Wild dogs have a canine body shape like a
wolf's, but they have larger, bat like ears and
white tipped tails. They have splotches of
black, yellow, white, and dark brown, with no
two dogs marked exactly the same.
African Wild Dog
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Wild dogs have a highly developed social
structure. They live in packs that vary from
10 to 15 animals, including males, females,
and young. Their packs are nomadic, and
they roam across a range of 1 to 30 miles a
day. Members of the pack cooperate when
hunting and raising their young.
African Wild Dog
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Wild dogs have developed incredible speed
and endurance for attacking prey. They have
been clocked at running 37 miles per hour for
distances over 3 miles. They also have
specialized, large, bat like ears that allow for
excellent auditory ability used for hunting and
ritual ceremonies
Lion
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A lion's roar can be heard up to 5 miles away.
Roaring is believed to have a territorial
function and to help animals locate each
other.
Lion
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Territories are scented marked with urine,
feces, and head rubbing. Lions mark with
their claws on trees and other signposts. The
mane of the male provides protection from
the claws and teeth of other males.
Lion
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They eat anything they can catch and kill, and
groups have even been observed killing
rhinoceros. A lion can eat up to 35 grams of
meat at a sitting. They drink freely when
water is available, but they can survive only
on the water they get from their prey for long
periods of time.
Lion
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Lions can run at speeds over 30 mph, but only over
short distances. This speed is insufficient for
catching a large antelope, so group stalking is an
important hunting strategy. Lions appear to assess
how much effort will be required for taking down a
particular target, and if the prey is small enough to
be taken by a single female, the other members of
the hunting group will let her catch it alone.
Polar Bear
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Polar bears have thick white fur. Their fur and
layers of fat beneath their skin protect them
from the Arctic cold. Their fur also provides
camouflage when they are hunting. Polar
bears have a keen sense of smell. They can
smell food as much as 10 miles away. On land
polar bears can run for short bursts at speeds
of up to 35 miles per hour.
Polar Bear
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They hunt seals such as the ringed seal and
other animals for food.
Skunk
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Sometimes the skunk will dig its own den, but it
may also move into another mammals den.
Skunks also live under old buildings.
The skunk drags dried leaves and grass into its
burrow to make a mat. In the winter, it might
form a ball of grass and push this into the door of
the den to keep out the cold wind.
Skunk
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The skunk is the size of a house cat. Its eyes ane
ears are small. It can not see too well, but its sense
of hearing is good.
During the day, a skunk sleeps. It hunts at night,
walking slowly along, catching insects and
looking for small fruit. It also eats meadow mice,
gophers, moles, and chipmunks.
Skunk
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The skunk has musk glands and can shoot a
liquid that has a terrible odor.
First, it gives a warning when something
approaches it. With its legs stiff, the skunk
stamps the ground with its feet, snaps its teeth,
and its hairs stand up.
Then,if necessary, the skunk swings its rear end
round , lifts its tail up out of the way and shoots
its musk. The liquid can shoot out as far as four
meters. If it hits the enemy in the eyes, the enemy
cannot see for a few moments.
Zebra
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Each zebra has its own stripe pattern. The
zebras recognize each other by their stripe
pattern and by their smell. Some species have
narrow close set stripes, while others have
broader stripes.
Zebras like to help groom each other.
Zebra
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Zebras are black with white stripes. If you
shaved a zebra, you would see that its skin is
black
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