Transcript Reptiles - River Ridge

Reptiles
Which one is a reptile which one an
amphibian?
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I. Reptiles
A. What is a Reptile
1. The basic body plan of a reptile is a
well-developed skull, a backbone and
tail, two limb girdles and for limbs.
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2. Two types of reptiles have slightly
different body plans. Snakes are
limbless and turtles have hard shells
that are fused to their vertebral column.
3. A reptile is a vertebrate that has dry,
scaly skin, lungs and terrestrial eggs
with several membranes.
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4. Reptile skin is dry and often covered
with thick, protective scales. These
scales may be smooth or rough.
5. The body covering helps prevent the
loss of body water in dry environments.
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6. The skin can also be a disadvantage
to reptiles because the skin does not
grow with the animal. It must shed its
skin periodically.
7. The only places on Earth that most
reptiles cannot live in are very cold
areas.
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B. Evolution of Reptiles
1. Reptiles evolved from amphibian like
were the first vertebrates to develop
the adaptation to lay eggs on land.
2. The fossil record of reptiles date
back to 350 million years ago.
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3. By the end of the Permian period,
about 245 million years ago there was a
mammal like reptiles these were the
dinosaurs.
4. At the end of the Cretaceous Period
about 65 million years ago there was a
mass extinction of the dinosaurs.
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5. The extinction was caused by a dramatic
series of natural disasters.
6. A bunch of massive volcanic eruptions and
lava flows, dropping of sea level and a huge
asteroid or comet smashing causing forest
fires and dust clouds. These are a few of the
theories.
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C. Form and Function
1. Most reptiles have adapted to a fully
terrestrial life.
2. Well developed lungs; a double-loop
circulatory system a water conserving
excretory system, strong limbs, internal
fertilization, shelled, terrestrial eggs are the
other adaptations that have contributed to
the success of reptiles on land.
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D. Body Temperature
Control
1. Ectoderms rely on behavior to help
control body temperature.
2. To warm up they will lie in the sun,
to cool down they will go in the shade.
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E. Feeding
1. Reptiles eat a wide range of food.
2. Iguanas are herbivores and tear
plants in chunks.
3. Many other reptiles are carnivores.
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F. Respiration
1. The lungs of reptiles are spongy
providing for more gas-exchange.
2. Reptiles CANNOT breathe through
their skin.
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3. Several species of crocodiles have
flaps of skin that can separate the
mouth from the nasal passages,
allowing these crocodiles to breathe
through their nostrils while their mouth
remains open.
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G. Circulation
1. Reptiles have a double loop circulatory
system.
2. One of the loops brings blood to and from
the lungs and the other loop brings blood to
and from the rest of the body.
3. Most reptiles have a single ventricle with a
partial septum to separate bad blood from
good blood.
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H. Excretion
1. Urine is produced in the kidneys.
2. Reptiles’ urine contains either
ammonia or uric acid.
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3. Reptiles that live in the water such
as crocodiles and alligators have
ammonia as liquid waste because they
drink lots of water.
4. Reptiles that are on land eliminate
uric acid.
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I. Response
1 1. The basic pattern of a reptile’s brain is
similar to that of an amphibian.
2. Reptiles that area active during the day
have cones in their eyes to see color.
3. Many snakes have good sense of smell.
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4. Many reptiles have sensory organs in the
roof of their mouth to detect chemicals.
5. They have simple ears with an external
eardrum.
6. Snakes can also pick up vibrations in the
ground through bones in their skulls.
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7. Some snakes can even detect body
heat.
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J. Movement
1. Compared to most amphibians,
reptiles with legs tend to have larger,
stronger limbs which allows them to
walk, run, burrow, swim and climb.
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K. Reproduction
1. All reptiles reproduce by internal
fertilization.
2. Most male reptiles have a penis like organ.
3. Most reptiles are oviparous, laying eggs
that develop OUTSIDE the mother’s body.
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4. Some reptiles leave the eggs
unguarded some reptiles like alligators
will provide some care after hatching.
5. Some snakes and lizards are
ovoviviparous and the young are born
alive.
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6. Unlike an amphibian egg, the shell
and membranes of a reptilian egg
create a protected environment in
which the embryo can develop without
drying out.
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7. This type of egg is called an
amniotic egg, named after the amnion,
one of the four membranes that
surrounds the developing embryo.
8. The other three membranes are the
yolk case, the chorion, and the
allantois.
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9. The amnion is a fluid filled sac that
surrounds and cushions the developing
embryo. It produces a presoaked, watery
environment.
10. Chorion regulates the transport of
oxygen from the surface of the egg to the
embryo and transport of carbon dioxide.
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11. Yolk sac is a baglike structure contains a
yolk that serves as a nutrient rich food supply
for the embryo.
12. Allantois stores the wastes produced by
the embryo. It later fuses with the chorion
and serves as a repository organ.
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L. Groups Of Reptiles
1. The four surviving groups of reptiles
are lizards, snakes, crocodilians, turtles
and tortoises and tuatara.
2. Modern lizards and snakes belong to
the order Squamata or scaly reptiles.
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Squamata
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3. Most lizards have
legs, clawed toes,
external ears and
movable eyelids.
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4. Some lizards have evolved into
highly specialized forms. Some live in
trees and bushes, eating insects.
5. The world’s largest lizard the
monitors are the only reptiles alive
today that provide some idea of what
small dinosaurs may have been like.
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6. Many eat birds and mammals. The
largest is the Komodo dragon with the
length of 3 meters and the mass of
75kilograms.
7. Komodo dragons can kill and eat
their animals as large as a water
buffalo.
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8. Snakes have lost both pairs of legs
during the course of evolution.
9. Snakes like sharks have a bad
reputation. More people die from bee
stings than from snakebites.
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10. Alligators, crocodiles, caimans and
gavials all belong to the order
Crocodilian.
11. Crocodiles are carnivores, they are
protective of their young.
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12. In 200 million years since then
alligators a crocodiles have changed
little.
13. Crocodilians are the largest living
reptiles. Some can live in fresh water
or salty water
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Alligator
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Crocodile
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14. Turtles and tortoises are members
of the order Testudines.
15. Turtles and tortoises have a shell
built into the skeleton.
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16. The shell
consists of two
parts: a dorsal part
or carapace and a
ventral part or
plastron.
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17. Lack teeth but have jaws powerful
enough to deliver a bite.
18. Turtles and tortoises members of the
order Chelonia also evolved a successful way
of life during the Triassic Period and have
changed little over the last 200 million years.
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19. Turtle usually refers to members
that live in water.
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20. Tortoises are
those that live on
land
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21. Tuatara is the only surviving
species of the order Sphenodonta.
They look like lizards.
22. They also have a “third eye,” This
eye can sense the level of sunlight but
its function is unknown.
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M. Ecology of Reptiles
1. Many reptiles are in danger because
their habitats have been destroyed.
2. Humans hunt reptiles for food, to sell
as pets and for their skins.
3. Laws protect some species like the
sea turtle.
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N. The evolution of
Temperature control
1. Control of body temperature is
important for animals, particularly in
habitats where temperature varies
widely with time of day and with
seasons.
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2. Ectotherms are animals that cannot
maintain a constant body temperature.
They get their heat from the
environment sunbathing. Examples,
turtles, snakes and other modern
reptiles.
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3. Ectothermic animals are often
incorrectly thought of as cold-blooded.
Cold-blooded animals may have a body
temperature higher than their
surroundings.
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4. Animals that are endotherms are
able to keep a constant body
temperature. Birds and mammals are
examples
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5. Endothermic animals are often
incorrectly thought as warm-blooded
animals. Many times they have lower
body temperatures than their
environment.
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THE END
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