Reptiles & Birds
Chapter 31
Reptiles
What is a Reptile?
• Snakes, turtles,
alligators, and
lizards are an
extremely diverse
group of animals,
yet all share certain
traits that place
them in the class
Reptilia.
Adaptations
• All reptiles have adaptations that enable them to
complete their life cycles entirely on land.
Have Scaly Skin
• Reptiles have dry skin
covered with scales.
• Scaly skin prevents
moisture loss
• Provides protection
from predators
• Can never be too far
from water or their
skin will dry out.
Some have 4-Chambered Hearts
• Some (crocodiles)
have 4-chambered
hearts that separates
the supply of blood
with oxygen from
blood without oxygen
• The separation allows
more oxygen to reach
body tissues
Skeletal changes
• This early reptile had legs that were placed more
directly under the body rather than at right angles
to the body as in early amphibians.
• This positioning of the legs provides greater body
support and makes walking and running on land
easier for most reptiles.
• Reptiles that have legs
also have claws that
help them obtain food
and protect
themselves.
Reptiles are Ectotherms
• Body temperature
depends on the
temperature of the
environment.
• Many become
dormant in cold
environments.
Reptiles Reproduce on Land
• Most lay eggs on land
• Hatchlings look like
adults
• All reptiles have
internal fertilizationeggs are laid after
fertilization
• Most lay eggs under
rocks, bark, grasses or
other surface material.
• Few dig holes or build
nest.
Reptiles Reproduce on Land
• Most provide no care
for the hatchlings
• Female crocks have
been observed
guarding their nest
from predators
• Nile Crocks have been
obsered carrying
young around in their
mouth
Reptiles reproduce on land
• Amniotic (am nee
AH tihk) egg was
the adaptation that
liberated reptiles
from a dependence
on water for
reproduction.
An Amniotic Egg
How reptiles use their sense organs
• Reptiles have a variety of
sense organs that help
them detect danger or
potential prey.
• The heads of some snakes
have heat-sensitive organs
or pits that enable them to
detect tiny variations in air
temperature brought about
by the presence of warmblooded animals
Jacobson’s organ
Tongue
An extrasensory organ in the roof of a
snake’s mouth sharpens its sense of
smell. Called Jacobson’s organ, it consists
of two hollow, highly sensitive saclike
structures. The snake’s acute odor
perception allows it to track both prey
and potential mates.
How reptiles obtain food
A. Turtles or Tortoises:
•
Too slow to be effective
predators.
•
Most are herbivores, and
those that are predators
prey on worms and
mollusks.
•
Snapping turtles are
extremely aggressive.
Attack fish & amphibians
(even ducks)
How reptiles obtain food
B. Lizards
• Eat primarily insects
• Marine Iguanas of the
Galapagos Islands is
one of the few
herbivores
• Komodo dragon:
effective predator
sometimes eats
humans
How reptiles obtain food
C. Snakes
• Snakes are also effective
predators.
• Some, like the
rattlesnake, have poison
fangs that they use to
subdue or kill their prey.
• A constrictor wraps its
body around its prey,
tightening its grip each
time the prey animal
exhales
Evolution of
Reptiles
• From studies of fossil
anatomy biologist
think that reptiles
arose from a group of
ancestral reptiles
called Cotylosaurs
(KOT’l-oe-SORZ)
• They lived about 310
MYA.
• These 4-legged
vertebrates resembled
small lizards & had
teeth suited for eating
insects.
MODERN REPTILES
Biologists have classified reptiles into
16 orders, (12 of which are extinct).
The 4 surviving orders are made up
of about 6,000 species.
1. Rhynchocephalia
(RING-koe-shu-FAY-lee-uh)
• An ancient one that
contains only 1 living
species – The Tuatara
~Called the “Living
Fossil”
• Found on 20 small islands
off the coast of New
Zealand.
• Burrows during the day &
feeds on insects, worms
and small drum at night.
•Has an unusual feature –a third eye on top of it’s
head called “Parietal Eye” (thermostat)
Named for its spine that runs
down it’s back.
2. Chelonian
• Consist of 265 species
of turtles or tortoises
• Changed little in the
last 200 mill years.
• Body covered by a
shell-some species is
made of hard plates,
others –tough leathery
skin
The shell consist of 2 parts
Carapace – top or dorsal
Plastron – ventral or belly
Turtles
Official Alabama
Reptile
Alabama Red-bellied Turtle
Baby Paint Turtle
Tortoise
Spend time on land
Galapagos Tortoise
"Is my Turtle a Boy or a Girl?"
Males have a longer,
thicker tail, with the
cloaca located closer
to the tip of the tail
Females with have a
smaller, thinner tail
with the vent closer
to the main part of
the body.
Males plastron is
concave or dented in
Males have long fore claws
Females having smaller ones
Characteristics:
Their eyes are on top of their
3. Crocodilia Head & nostrils on top of
• Consist of 23 different snout (for seeing & breathing
species of large lizard- in water)
shaped reptiles
• Consist of crocodiles,
alligators, caimans and
gavials
• All are carnivores &
hunt by stealth
(waiting for prey to
come near & then
attacking aggressively
Crocodiles
• Live in or near water
in tropical/subtropical
regions (Africa, Asia,
& the Americas,
including Florida)
Alligators
• Live in China and the
Southern U.S.
Caimans
• Resembles the
alligator
• Native to Central
America, but are
becoming established
in Florida
Gavials
• Group of fish-eating
crocodiles with a long,
slender snout adapted
for snaring & eating
fish.
• Live only in India &
Bermuda
4. Squamata
• Consist of 5,640
species of lizards &
snakes
• Upper jaw is loosely
jointed to the skull
• Presence of paired
reproductive organs in
the males.
Chameleon
Lizards
• Lizards include iguanas,
horned toads, chameleons,
skinks & geckos
• Lizards distinguished
from snakes by presence
of limbs.
• They live on every content
except Antarctica
• Most prey on insects/other
small animals
• Some blend with their
background by changing
colors.
Horned Toad
Basilisk Lizard
“Jesus Christ Lizard”
•Central and South American
rainforests.
•Size - 2 & 1/2 feet long
including the tail.
•Diet - Insects, small
invertebrates, flowers, and small
vertebrates (like snakes, birds,
and fish).
•Enemies - Large birds of prey,
snakes, fish, other large reptiles,
and mammals.
•This animal is not endangered.
•They have the
nickname "Jesus
Christ Lizard" because
when fleeing from a
predator, they are very
fast and can even run
on top of the water.
Basilisk Lizard
“Jesus Christ Lizard”
http://www.youtube.com/watch?v=45yabrnryXk
Frilled Lizard
• http://www.youtube.com/watch?v=XAo09y
YOpCU
Only 2 species of lizards that are
venomous:
Gila Monster:
Beaded Lizard:
southwest U.S.
western Mexico
Lizards OF ALABAMA
Glass Lizard (legless)
Spiny Lizard
Gecko
5 lined Skinks
Monitor Lizards
• The largest is the
Komodo Dragon of
Indonesia.
• Reaches 3 meters in
length
• Thought to be related
to the snake
• Consume prey whole
• Uses tail & bacterial
salvia as defense,
speeds of 40 mph.
Komodo dragon can swallow
an 80 pound deer in one
meal.
Snakes
• Biologists suggest
snake’s probably
evolved from lizards
during the Cretaceous
Period.
• To escape predators,
some may have
burrowed underground
Snakes OF ALABAMA
Eastern Worm Snake
Southern Black Racer
Gray Rat Snake
Southern Hognose Snake -PROTECTED
Snakes OF ALABAMA
Eastern King Snake
Coach whip Snake
Milk Snake
Gartner Snake
Snakes OF ALABAMA
Venomous
Eastern
DiamondBack
Rattlesnake
Cottonmouth
Copperhead
Timber (canebrake) Rattlesnake
Pigmy Rattlesnake
Other Snakes:
http://www.giffbeaton.com/snakes.htm
Snake movement
• A snake has a
backbone of 100 – 400
vertebrae which
provides framework
for thousands of
muscles
Snakes move in 1 of 3 ways
Lateral Undulation:
-most snakes move this
way
-snake moves its head to
one side, which initiates a
wave of muscular
contraction
-body moves in an S-shape
path
Snakes move in 1 of 3 ways
2. Rectilinear Movement
-snake applies muscular
force on its belly, not
sides
-inches along like a
caterpillar
Snakes move in 1 of 3 ways
3. Side-Winding
-some desert-dwelling
snakes move this way
-moves sideways
(usually because of the
hot sand)
Snakes obtaining prey
2 methods of killing
1. Constriction: used by
squeezing prey as it
inhales
Ex: boas, pythons & anaconda
Snakes obtaining prey
2 methods of killing
2. Injection of Venom:
a. Rear-fanged snake:
(bite prey & use
grooved back teeth to
guide venom into the
puncture
Ex: Boom slang Snake & Twig
Snake of Africa
Snakes obtaining prey
2 methods of killing
2. Injection of Venom:
b. Elapids: inject
poisons through 2
small front fangs that
act like hypodermic
needles
Ex:Cobras & Kraits
Snakes obtaining prey
2 methods of killing
2. Injection of Venom:
c. Front-Fanged
Snakes: hinged fangs
swing forward from
the roof of the mouth
& inject venom more
deeply than the fangs
of the elapids
Ex: Rattlesnake, Water Moccasin
& Copperheads (Vipers)
Defense
• Camouflage: beneficial to seeking prey &
escaping predators
• Making presence known: changing their body
shape or making sounds
Such mouth
bleeding
occurs in some
specimens of
the grass
snake as a
defense
mechanism.
Defense
Green Mamba uses Camouflage
for defense
Rattlesnake shakes it’s tail to warn
predators of its presences
Endangered Snake Species
Four endangered snakes found in our area
1. Gulf Salt Marsh Snake
3. Black Pine Snake
2. Eastern Indigo Snake
4. Florida Pine Snake
Sea Turtles
Governmental Protection
• Protected in our country by the Endangered
Species Act
• Protected Internationally by the Convention of
International Trade in Endangered Species
(CITES)
8 Species of Sea Turtles
1.
2.
3.
4.
5.
6.
7.
8.
5 Common to the Atlantic Ocean &
Loggerhead
Gulf of Mexico
Kemp’s Ridley
Green
1. Loggerhead
Leatherback
2. Kemp’s Ridley
Hawksbill
3. Leatherback
Black
4. Hawksbill
Flat back
5. Green Sea Turtle
Olive Ridley
Medium to large turtle - adults are reddish-brown in color
• Not as esteemed for eating as with other sea turtles
• Come shore at night to nest and lay clutches of 80-125 eggs
• Gathering loggerhead eggs for use in bakeries was once
a thriving industry in St. Augustine, Florida.
• The major factors leading to the decline of the loggerhead
loss of eggs (due to humans and predators)
Mortality due to fisheries operations
(primarily shrimp trawling).
• Considered "threatened".
•
Loggerhead
•Most endangered specie of sea turtle
•Smallest of the 5 sea turtles found in the Gulf of Mexico
•Only sea turtle with an almost circular upper shell
•Diet consists mostly of crabs
•Nests contain 80-120 eggs with an average of around 100
Kemp’s
Ridley
• They do not have shells as other sea turtles do.
Instead, their backs are covered by a slate black to
bluish-black leathery skin
• They are the largest turtles in the world
• Their diet consists almost entirely of jellyfish;
many die from feeding on discarded plastic bags
mistaken for jellyfish.
Leatherback
•
•
•
•
•
One of the smaller sea turtles of the Gulf of Mexico
Hawksbills have a hawk-like beak (named)
Hawksbills are found worldwide in tropical and subtropical seas.
Inhabit shallow coastal areas, lagoons, and coral reefs.
"tortoise shell" - beautiful carapaces [used in]
(jewelry, combs, eyeglass frames, and tabletops)
• Reasons for decline b/c killed for their shells
• Hawksbills feed primarily on sponges
Hawksbill
•Color is not actually green, but molten brown
•Name comes from the greenish fat of the body
•Considered medium to large in size
•Feeds on sea grasses and algae.
•Main reason for the decline of the green turtle is its culinary
Green Sea
Turtle
Under the Endangered Species Act the green sea turtle is considered "endangered“
for the breeding populations in Florida and the east Pacific and "threatened“
everywhere else.
Reproduction
group of eggs laid by one mother at one time
is referred to as a "clutch".
Crawl – tracks easy to see
nesting
Young follow the moon light back
to the ocean
• Only nest in tropical &
subtropical beaches
• Beaches used as
countless generation
nesting
• Beaches altered by
humans (lights)
Habitat &
Destruction
TED Turtle Excluder Device
• Is a grid of bars with
an opening at the top
or bottom
• Fits into the neck of a
shrimp trawl
• Created to let large
animals escape the net.
(turtles & shark)
Monitor Movement
• Migration is difficult
to monitor
• Flipper tagging
• Satellite tracking used
• Adopt – A – Sea turtle
http://www.cccturtle.org/satfljuv_jennifer.htm
Problems for Extinction
Sea Turtles get entangled in fishing
nets and fishing line
Finding Nemo-Sea Turtle
http://www.jibjab.com/player/main.s
wf?jid=144023
Birds
What is a Bird?
• Birds inhabit
a variety of
environments around
the world, including
Antarctica, deserts,
and tropical rain
forests.
What is a bird?
• Like reptiles, birds have clawed toes and protein
scales on their feet.
• Fertilization is internal and shelled amniotic eggs are
produced in both groups.
• Although some birds are flightless, all birds have
feathers and wings.
Emu
Birds have feathers
• A feather is a
lightweight, modified
protein scale that
provides insulation and
enables flight.
• Preening, keeps the
feathers in good
condition for flight.
This is especially
important for water
birds as a way to
waterproof the feathers
• During preening, a bird also uses its bill or beak to rub
oil from a gland near the tail onto the feathers.
Birds molt in new feathers at
least once a year.
• The shedding of old feathers and the growth of new
ones is called molting.
• Most birds molt in late summer. However, most do
not lose their feathers all at once and are able to fly
while they are molting.
Birds have wings
• A second adaptation for flight in birds is the
modification of the front limbs into wings.
Birds are endotherms
• Birds are able to maintain
the high energy levels
needed for flight because
they are endotherms.
• Feathers reduce heat loss
in cold temperatures. The
feathers fluff up and trap a
layer of air that limits the
amount of heat lost.
• Responses to high temperatures include flattening the
feathers and holding the wings away from the body.
• Birds also pant to increase respiratory heat loss.
Birds live in all types of
environments
• Birds can live in all environments, from the hot
tropics to the frigid Antarctic.
Reproduction in birds
• Birds reproduce by internal fertilization and lay
amniotic eggs usually inside a nest.
• Birds do not leave the eggs to hatch on their own.
Instead, birds incubate or sit on their eggs to keep
them warm.
• The eggs are turned periodically so that they develop
properly.
• In some species of birds, both
parents take turns incubating
eggs; in others, only one parent
does so.
Reproduction in birds
• Bird eggs are
distinctive, and
often the species
of bird can be
identified just by
the color, size, and
shape of an egg.
Diversity of Birds
• The shape of a bird’s beak or bill gives clues to the
kind of food the bird eats.
• Hawks have curved beaks
that are adapted for
tearing apart their prey.
• Pelicans have huge bills
with pouches that they
use as nets for capturing
fish.
• The short, stout beak of a
cardinal is adapted to
cracking seeds.