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 fertilization-eggs 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 EggAn 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 warm-blooded 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 foodB. 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 foodC. 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

The 4 surviving orders are made up of about 6,000 species.

Biologists have classified reptiles into 16 orders, (12 of which are extinct).

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

Baby Paint Turtle

Official Alabama Reptile

Alabama Red-bellied Turtle

TortoiseSpend 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 clawsFemales having smaller ones

3. Crocodilia• Consist of 23 different

species of large lizard-shaped reptiles

• Consist of crocodiles, alligators, caimans and gavials

• All are carnivores & hunt by stealth (waiting for prey to come near & then attacking aggressively

Characteristics: Their eyes are on top of their Head & nostrils on top of snout (for seeing & breathing in water)

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.

• 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.

Chameleon

Horned Toad

Lizards

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=XAo09yYOpCU

Only 2 species of lizards that are venomous:

Gila Monster: southwest U.S.

Beaded Lizard: western Mexico

Lizards OF ALABAMA Glass Lizard (legless)

Gecko

Spiny Lizard

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 SnakeGartner Snake

Milk Snake

Snakes OF ALABAMA Venomous

CopperheadCottonmouth

EasternDiamond-Back Rattlesnake

Pigmy Rattlesnake

Timber (canebrake) 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

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

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

1. Constriction: used by squeezing prey as it inhales

2 methods of killing Ex: boas, pythons & anaconda

2. Injection of Venom:

a. Rear-fanged snake:

(bite prey & use grooved back teeth to guide venom into the puncture

Snakes obtaining prey2 methods of killing Ex: Boom slang Snake & Twig

Snake of Africa

2. Injection of Venom:

b. Elapids: inject poisons through 2 small front fangs that act like hypodermic needles

Snakes obtaining prey2 methods of killing Ex:Cobras & Kraits

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

Snakes obtaining preyEx: Rattlesnake, Water Moccasin& Copperheads (Vipers)

2 methods of killing

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 Camouflagefor defense

Rattlesnake shakes it’s tail to warnpredators of its presences

Endangered Snake SpeciesFour endangered snakes found in our area

1. Gulf Salt Marsh Snake 2. Eastern Indigo Snake

3. Black Pine 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. Loggerhead

2. Kemp’s Ridley

3. Green

4. Leatherback

5. Hawksbill

6. Black

7. Flat back

8. Olive Ridley

1. Loggerhead

2. Kemp’s Ridley

3. Leatherback

4. Hawksbill

5. Green Sea Turtle

5 Common to the Atlantic Ocean & Gulf of Mexico

Loggerhead

• Medium to large turtle - adults are reddish-brown in color Medium to large turtle - adults are reddish-brown in color • Not as esteemed for eating as with other sea turtlesNot as esteemed for eating as with other sea turtles• Come shore at night to nest and lay clutches of 80-125 eggsCome shore at night to nest and lay clutches of 80-125 eggs• Gathering loggerhead eggs for use in bakeries was once Gathering loggerhead eggs for use in bakeries was once a thriving industry in St. Augustine, Florida. a thriving industry in St. Augustine, Florida. • The major factors leading to the decline of the loggerhead The major factors leading to the decline of the loggerhead

loss of eggs (due to humans and predators) loss of eggs (due to humans and predators) Mortality due to fisheries operations Mortality due to fisheries operations (primarily shrimp trawling).(primarily shrimp trawling).

• Considered "threatened".Considered "threatened".

Kemp’s Ridley

•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

Leatherback

• 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.

Hawksbill

• 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

Green Sea Turtle

•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

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.

Crawl – tracks easy to see

nesting

Young follow the moon light backto the ocean

group of eggs laid by one mother at one time is referred to as a "clutch".

Reproduction

Habitat & Destruction

• Only nest in tropical & subtropical beaches

• Beaches used as countless generation nesting

• Beaches altered by humans (lights)

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.swf?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?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 feathersBirds 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.

• 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 molt in new feathers at least once a year.

Birds have wingsBirds have wings

• A second adaptation for flight in birds is the modification of the front limbs into wings.

Birds are endothermsBirds 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 birdsReproduction 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.

• Bird eggs are distinctive, and often the species of bird can be identified just by the color, size, and shape of an egg.

Reproduction in birdsReproduction in birds

Diversity of BirdsDiversity 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.