Zoology Exam 4 (Part 2- Amniotes and Reptiles)

Anamniotes

vertebrates without an amniotic egg

examples of anamniotes

Fish and Amphibians

Amniotes

Vertebrates with an amniotic egg

examples of Amniotes

Retiles, Birds, and Mammals

Amnion membrane

encloses the embryo in fluid

Allantois membrane

forms a sac to store metabolic wastes

Chorion membrane

surrounds the entire contents of the egg

The chorion and allantois form a

respiratory organ for removing CO₂ and acquiring O₂

What are the two functions of the egg shell?

• The shell gives mechanical support

• Allows passage of gases but limits water loss

Which amniotes do not have shelled eggs?

many lizards and snakes, and most mammals

What are the Advantages of an amniotic egg?

1) Can be laid in places too dry for anamniotic eggs

2) With its structural support and oxygen movement it allows for a larger, faster-growing embryo

3) The calcium deposited in the shell can be consumed by the growing embryo and provides the raw materials needed for skeleton construction

The lungs of amniotes have a _____ surface area than amphibian lungs

much greater

positive-pressure breathers

fill lungs by forcing air into them (frogs)

negative pressure breathers

draw air into their lungs by expanding the thoracic cavity using rib muscles (amniotes)

Are reptiles ectothermic or endothermic ?

ectothermic

occipital condyle

bony bump that connects to the first vertebra

How many occipital condyle (s) do reptiles have?

one

homodont teeth

all similar in function and shape

What kind of teeth do reptiles have?

homodont with a single point

how many pairs of cranial nerves do reptiles have?

12 pairs

a reptiles’ brain is …

moderately well developed with expanded cerebrum

In reptiles, Metanephric kidneys and ureters open into …

a cloaca

what is usually a reptiles main nitrogenous waste

uric acid

a reptiles heart has

two atria and a ventricle which is partially, but incompletely divided

which reptile has two atria and two ventricles

Crocodilians

Many reptiles can bypass the lungs when

pulmonary respiration is not occurring

Which kind of keratin is in reptile scales?

beta-keratin proteins

osteoderms

bony plates located in the dermis, beneath the keratinized scales of some reptiles

Order Testudines

Turtles

a turtle’s shell consists of

a dorsal carapace and a ventral plastron

What are the two layers of a turtle’s shell

1) the outer layer made of keratin

2) the inner layer made of bone which is a fusion of ribs, vertebrae, and many dermally ossifying elements

Unlike other vertebrates, turtle limbs are located

inside the ribs

In most amniotes, rib growth is directed

ventrally, leaving the scapula outside

In turtles, rib growth is directed

laterally, ultimately enclosing the scapula

What type of reproduction do turtles have

oviparous

Low temperature produces

males

High temperatures produces

females

Reptiles with temperature- dependent sex determination lack

sex chromosomes

what is the largest turtle?

the leatherback turtles

How large can a leatherback turtle get

2 meters

how long can a Galapagos turtle live?

more than 170 years

which types of turtles have reduced shells?

common snapping turtles and alligator snapping turtles

Order Sphenodonta

Tuataras

how many living species are there of Tuataras?

two, both found in New Zealand

the skulls of tuataras are similar to …

fossil species found in the Mesozoic layers

Parietal eyes, which also occur in frogs and lizards, play a role in

regulating daily and seasonal rhythms of behavior

What is a unique characteristic of Order Sphenodonta ?

they bear a well-developed median parietal eye

The parietal eye of order Sphenodonta has what characteristics?

a cornea, lens and retina but can only register changes in light intensity because it is located under opaque skin

Order Squamata

Lizards and Snakes

Which order of reptile makes up 95% of all known retile species?

Order Squamata

snake and lizards skin is made of …

keratinized epidermal scales or plates which are shed

Kinetic (movable) skulls

significant movement of skull bones relative to each other

the skulls of ____ are even more kinetic than that of ______

snakes, lizards

a kinetic skull allows the jaws to be depressed _____ to each other to increase effective closing force.

parallel

most lizards have ____eyelids

moveable

Are lizards endotherm or ectotherm?

ectotherm and behavioral hemeotherms

What dose it mean that lizards are behavioral hemeotherms?

Although physiologically they are ectotherms, their actual body temperature exhibit little relationship to the ambient temperature

if the ambient temperature is lower than preferred, the lizard can …

spread its ribs, flatten its body, and orient itself so that its body is at right angles to the sun to gain the maximum amount of heat

if ambient tempurature is too high, lizards can …

pull its ribs together and orient its body parallel to the sun, decreasing the surface exposed

Geckos

Small, agile nocturnal lizards with adhesive toe pads

Skinks

Elongate with tight-fitting osteoderms

Chameleons

Arboreal lizards with long, sticky tipped tongues

Gila monsters

Secrete venom from glands in their lower jaws

Glass Lizards

legless lizards with extremely ling fragile tails

Worm lizards

legless lizards with uniform cylindrical bodies

What is different about snake vertebrate and lizard vertebrate?

in snakes vertebrate are more numerous, shorter and wider than that of lizards

movement of snakes bodies is called…

lateral undulations

Neural Spine

A dorsal projection of a vertebra that functions as a muscle attachment site

Elongation of the neural spine in snakes …

gives numerous muscles more leverage

What is different about snake ears from lizard ears?

Lizard ears are external while snakes lack external ears

the _____ lung in snakes is reduced or absent

left

In snakes, the eyelids are _____ and form a _______ transparent cap over the eyes

fused, transparent

What allows snake jaws to spread apart?

The two halves of the lower jaw (mandibles) are joined only by muscles

In snakes, many skull bones freely articulate….

but they do not become unhinged

Glottis

A tracheal opening that is thrusted forward between the two mandibles to allow the snake to keep breathing when swallowing large prey

Jacobson’s organs

A pair of pit-like organs in the roof of the mouth that are lined with chemosensory cells

Pythons, boas and pit vipers have pit organs on their …

heads, located between their nostrils and eyes

snakes can distinguish differences in temperature of …

0.003 Cº

pit organs respond to …

long-wave infrared radiant energy

What % of snakes are venomous?

20%

How many snakes are venomous in Australia?

4 out of 5

Neurotoxic snake venom

Acts on the nervous system, especially the optic nerve and phrenic nerve of the diaphragm

What are the two type of snake venoms?

Neurotoxic and Hemorrhagin

Hemorrhagin snake venom

destroys red blood cells and blood vessels

example of a Hemorrhagin venomous snake?

eastern diamondback rattlesnake

example of a neurotoxic venomous snake

eastern coral snake

most venomous snakes have what kind of venom?

a combination of both neurotoxic and hemorrhagin

most snakes are

oviparous (but some are viviparous or ovoviparous)

Order Crocodilia

Crocodiles, Alligators, Caimans and Gharials

order crocodilia has a _____ skull

non-kinetic (immovable)

What is present in the skulls of order crocodilia that is also found in mammals?

a secondary plate

Thecodont teeth

Teeth that are set in sockets

Order crocodilia have ______ teeth

thecodont

What is the structure of order crocodilia hearts?

four-chambered with completely divided atria and ventricles

Crocodilians are _____

oviparous

What is the only order of reptiles that have well-developed parental care?

Order Crocodilia

Where do Caimans occur

Central and South America

Where do Alligators occur?

southeastern U.S. and China

What is the difference between Alligators and crocodiles?

Alligators have a broader snout than crocodiles and their fourth lower jaw tooth is hidden when the mouth is closed while is visible in crocodiles

Where are crocodiles found?

extreme south of Florida, Asia, Africa and Australia