Transcript Reptiles and Birds

Reptiles and Birds
Life Science
Reptiles
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Reptiles are vertebrates that have lungs, scaly
skin, and a special type of egg.
Reptiles are also ectotherms, or cold-blooded.
Reptiles include: snakes, turtles, crocodiles,
iguanas, and the now extinct dinosaurs and
pterodactyls.
History of Reptiles
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Reptiles first appeared hundreds of millions of
years ago shortly after the first amphibians
evolved.
The first reptiles looked like a cross between a
lizard and a toad.
However, reptiles had several adaptations that
made them land animals.
Characteristics of
Reptiles: Water
Loss
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Reptiles have skin that is covered
with a tough, dry layer of scales.
The scales are made of dead cells and
provided them with waterproof skin
which keeps them from losing water.
Reptiles also have special kidneys
that help them to loses as little water
as possible when wastes are
eliminated.
Characteristics of Reptiles: Anatomy
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Reptiles have a double-looped circulatory
system.
In some reptiles there oxygen rich blood and
oxygen poor blood never mix.
Reptiles are dependent upon their lungs for
oxygen, they can’t breathe through their skin
because of their scales.
Reptiles have a slightly more developed brain
than amphibians and better sense organs.
Characteristics of Reptiles: Eggs
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The reptile egg is surrounded by a protective
shell that prevents the insides from drying out.
Most reptile eggs are tough and flexible with a
leather-like covering.
There are tiny holes in the shell that allow gas
exchange, but prevent water from leaving the
egg.
Importance of the Egg
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The reptile egg is important because it meant
that reptiles were no longer dependent on water
to reproduce.
Secondly, it shows that both birds and mammals
evolved from reptiles.
Bird eggs are very similar to reptile eggs and the
tissues that protect a mammal embryo are the
same as the ones that protect a reptile embryo.
Reptile Reproduction
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Reptiles have internal fertilization.
Internal fertilization is important because after
the egg if fertilized, then the female’s body
builds the protective shell around it.
Most reptiles lay their eggs right after the shell is
formed, but some carry them around until the
eggs are ready to hatch.
Lizards
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Lizards are reptiles that typically have slender
bodies, movable eyelids, long tails, four legs, and
clawed toes.
They range from 3 cm long geckos to 4.5 m
long monitor lizards.
Lizards are primarily sedentary insect eaters.
Some lizards have evolved adaptations such as:
The chameleons' tongue and ability to change color
 The Gila monster’s poisonous bite
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Snakes
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Snakes are basically lizards that have lost their legs,
eyelids, and ears about 80 million years ago.
Snakes move by wriggling its long, thin, muscular body
and using their scales to get traction.
Snakes typically feed on small animals like mice.
Snakes are deaf and have poor eyesight, however they
have the ability to smell using their tongues and detect
heat through special pits in their heads.
Some snakes have also evolved poison glands that they
use for hunting and protection.
Turtles
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Turtles are reptiles whose bodies are enclosed in
a shell.
The shell is made of plates of bone covered by a
scale like substance.
Turtles do not have teeth, they have beaks
similar to birds.
Turtles can eat both plants
and animals.
Alligators and Crocodiles
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Alligators and crocodiles are large meateating lizard-like reptiles.
They have long snouts, powerful tails, and
thick, armored skin.
Alligators and crocodiles spend much of
their time submerged in water.
They are nocturnal and hunt
everything from insects to hoofed
mammals to Jr. High kids.
They also build nest to lay their
eggs in.
Birds
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Birds are warm blooded egg-laying vertebrates
that have feathers.
Feathers are the most important characteristic of
birds.
Feathers are made of dead cells that contain the
same material that is found in your fingernails.
Feathers
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Feathers come in all shapes, sizes, and colors.
Feathers on the wings and the bird’s body
are called contour feathers.
Down is short, fluffy feathers that act as
insulation.
Feathers are used for flight, camouflage and
to attract mates or communicate.
Bird
Nutrition
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Birds must expend energy to maintain their body,
therefore they eat large amounts of energy.
Flying also demand a lot of energy.
Birds eat many foods including bacteria, fruits, seeds,
insects, other birds, small mammals and dead material.
A bird’s beak is adapted to the type of food it eats.
Bird
Flight
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Birds bones are hollow which makes them
lighter for flight.
The internal organs are also adapted for flight.
The lungs are adapted with special air sacs
which allow them to have a constantly moving
supply of fresh air.
Birds have a double-loop circulatory system
that is completely separate to insure oxygen is
delivered.
Bird Anatomy
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Birds have two long, oval kidneys that produced
concentrated waste products.
Birds have well developed brains and some have very
good eyesight.
Birds have small compact reproductive systems that
are only functional during breeding season.
Bird eggs have the same basic structure as reptile eggs,
only they have a hard shell.
Bird Communication
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Birds sing for a variety of reasons including:
To attract a mate
 To warn other birds
 To establish their territory
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Birds also communicate with their
feathers.
Bird Nests
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Most birds build nests to protect their eggs and
their young to develop.
The nest can vary from a hollow trench to
elaborate materials such as spider silk.
Migration
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Many birds migrate to new environments during
different seasons of the year.
Some travel over 25,000 km.
Birds migrate for many reasons including:
Seasonal food supplies
 Nesting habitats
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Types of Birds
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There are around 8700 living species of birds.
They are divided into the groups:
Song birds like cardinals, robins &
nightingales
 Hunting birds like hawks, eagles &
owls
 Waterfowl like ducks, geese & swans
 Flightless birds like penguins, ostrich
& emus.
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