amniotes

Amniota (not taxonomic) include

Non-avian reptiles, birds, mammals

What are Amniotes eggs like?

Shell-less eggs remains tied to water

Amniotic = "Pond"

Amniotes take the pond with them.

what difference did the shelled egg make?

freed the reptilian groups to exploit land

What is the Amnion

the membrane enclosing the developing young

Secretes amniotic fluid in which embryo/fetus floats

Amniote evolution

Arose from amphibian-like tetrapods (anthracosaurs) during the Carboniferous (290-350 mya) - first see the development of the amnion

Late Carboniferous, skulls separated into groups patterns of openings (fenestra - openings in the skull) in the temporal region

fenestra

openings in the skull

Possible patterns of skulls in Amniotes

Anapsids, Diapsids, Synapsids.

lineage of everything that comes after amphibians, everything is an amniote but varies based on pattern of skull

Anapsids

0 temporal opening behind orbits turtles

Orbits are where the eyes are.

Turtles are special type of opening

Diapsids

2 temporal openings

One pair below the cheeks and another above

Diapsids gave rise to

1. Lepidosaurs: traditional "reptiles" (except turtles)

2. Archosaurs: dinosaurs (EXTINCT), living crocodilians, birds

3. Sauropterygians: extinct (e.g., plesiosaurs - Loch Ness Monster)

4. Ichthyosaurs: extinct

Synapsids

1 pair of openings low on the cheeks

"stem mammals", mammals

• Mammals are only extant, living synapsids

Openings associated with large jaw muscles

• Opens relate to muscle attachment which relates to how we feed.

Shift from suction feeding in aquatic to terrestrial feeding (chewing)

7 Adaptations of amniotes

1. Amniotic egg (gives name to the group)

2. Thicker, more waterproof skin

3. Lungs, ribs

4. Stronger Jaws

5. High-Pressure Cardiovascular system

6. Water-conserving nitrogen excretion

7. Expanded brain and sensory organs

Amniotic egg

Eliminated need for water (no gilled larvae, internal fertilization)

Larger, faster-growing embryo

Shell: used for calcium in skeleton

• Bony skeletons developed by mineral deposition. Shell allows the embryo to have calcium, phosphorus for baby to develop its own skeleton.

Amniotic egg has 4 extraembryonic membranes

4 extraembryonic membranes of the amniotic eggs

Amnion

Allantois

Chorion

Yolk sac

These layers are all present in all amnion eggs.

Amnion

Encloses embryo in fluid

Cushions the embryo

Allantois

Stores metabolic wastes

Waste products

Chorion

Surrounds all other membranes

Just beneath shell, highly vascularized (blood vessels), respiration

• Shelled egg is not solid because the animal inside of it needs to breathe, so air can get into the chorion.

layer in chicken egg that makes it hard to peel.

Yolk sac

Nutrient storage

Thicker, more waterproof skin

Amphibians' vulnerable to dehydration, physical trauma

Amniote skin: thick, tends to be more keratinized,
less permeable

Keratin

Keratin

(makes up a LOT)

protein to make scales, hair, feathers, claws (only difference is what genes get turned on)

Scales of reptile are made of

beta keratin

Beta keratin…

Protection against wear (so the scales don't break down.)

Lizards, snakes shed, crocodiles do not

Turtles have scutes (actually made out of bone)

Crocodiles, many lizards possess osteoderms (bony plate embedded within the skin)

• Bony plates located in the dermis beneath scales

scutes

actually made out of bone

osteoderms

bony plate embedded within the skin

Lungs, ribs

Lungs have more surface area

Draw air into lungs by expanding the thoracic cavity

Which animals have the best lungs?

Bird have the best lungs, very high metabolism so need lots of oxygen to support them

Stronger Jaws

Fish jaws for suction, not possible on land

Mechanical advantage from expanded muscles

Grabbing, holding, chewing is more efficient by adding more muscles

High-Pressure Cardiovascular system

Flow patterns in heart limits mixing of O2 -rich and O2 -poor blood

Mammals, birds, crocodilians have 2 separate ventricles

Why do Mammals, birds, crocodilians have 2 separate ventricles

to keep oxygen rich and poor blood separate)

Water-conserving nitrogen excretion

Birds, reptiles excrete their wastes as uric acid (concentrated)

Explain nitrogen effects

When you eat meat, you eat a lot of protein which have nitrogen. Nitrogen builds muscles and comes from eating other animals. More efficient to eat animals than plants, but produce waste products like nitrogenous waste.

Humans dilute it with water and pee it out. However, white stuff in bird feces is the nitrogenous waste which is a solid and an acid - reptiles do this too brown and white - never pee to conserve water.

Expanded brain and sensory organs

Enlargement of cerebrum, correlated with integration of sensory info, control of muscles for locomotion.

More muscular movement and coordination in a tetrapod. All of this movement is done using the brain forcing the brain to be bigger and more complex

How many species are in Class Reptilia?

8000

When was the "age of reptiles"?

165 million years, included the dinosaurs

Are dinosaurs reptiles?

No, Dinosaurs are not reptiles, they are their own group.

How do control Class Reptilia temperature?

Ectothermic (rely on outside temperature)

How many pairs of limbs do Class Reptilia have?

two pairs of limbs, usually 5 toes.

Orders of Class Reptilia

Order Sphenodontia, Order Testudines, Order Squamata, and Order Crocodillia

Order Sphenodontia

Tuatara

Order Testudines

Turtles

Order Squamata

lizards, snakes

Order Crocodillia

Crocodiles, Alligators

Are Order Sphenodontia lizards?

NO, they are Tuataras

Which reptile is a very ancestral way of being a reptile?

Order Sphenodontia

How many species of Order Sphenodontia?

2

Where is Order Sphenodontia located?

New Zealand, restricted to small islands

Are Order Sphenodontia slow or fast growing?

Slow growing (up to 77 years)

Order Sphenodontia Skull nearly identical to skulls of 200 million years ago

diapsid

Order Sphenodontia have a _ ____ buried beneath their skin

median parietal eye

What is the functino of Order Sphenodontia's median parietal eye?

Sensing light and dark, photoperiod.

• In the video, animal only hunted when the crab moved. If it doesn't move, they can't see it.

How many species are in Order Testudines?

300

What are the two parts of the Order Testudines shell?

dorsal carapace, ventral plastron

What is the dorsal carapace Order Testudines shell?

the back part of the shell that's pointed upward when a turtle is walking

What is the ventral plastron Order Testudines shell?

belly side that's pointed down when a turtle is walking.

Order Testudines outer layer is _, inner layer is ___

keratin, bone

keratin is a _ color

brown

Order Testudines bone layer is a fusion of , , and

ribs, vertebrae, and ossified elements

Order Testudines have ___, instead of teeth, for gripping food.

tough plates

Do Order Testudines chew?

No, they just bite and swallow

Do Order Testudines use chest expansion for breathing?

No, they do not use chest expansion since their ribcage is fused.

What is a "diaphragm" of Order Testudines?

abdominal and pectoral muscles

helps Order Testudines breathe.

walking.

• Revive turtle by moving limbs in and out

Order Testudines reproduction is .

oviparous

What is parental care in Order Testudines like?

Bury eggs, no parental care besides choice of where to place the eggs.

In some Order Testudines, nest __ determines sex of hatchlings

Temperature

True or False: Order Testudines have chromosomal or gene determination of sex like mammals

FALSE.

Low temperatures in Order Testudines =

males

High temperatures in Order Testudines =

females

What percent is Order Squamata out of living reptiles?

95%

How many species are in Order Squamata?

7500 species

What are the two suborders of Order Squamata

Two suborders are lizards (Sauria) and snakes (Serpentes).

• Lizards are just snakes with legs or snakes are just limbless lizards

How do Order Squamata catch prey?

Can seize, manipulate prey, close jaw with force

order squamata __ (snakes) major factor in diversification - can swallow prey that's much larger than opening of mouth.

skull mobility

How do order squamata reproduce?

viviparity (live offspring - no egg)

Viviparity in reptiles is limited to _

squamates

order squamata reproduction is associated with _

cold climates

• Increasing the length of time eggs are kept in oviduct

Order Squamata are mostly

carnivores

Order Squamata, Suborder Sauria include:

Lizards, Geckos, Iguanids, Chameleons, and Gila Monsters

Lizards

Suborder Sauria

Geckos

Suborder Sauria

Small, agile, nocturnal

Adhesive toe pads

Iguanids

Suborder Sauria

many New World lizards, marine iguana of the Galápagos

Chameleons

Suborder Sauria

Arboreal lizards of Africa and Madagascar

Many have an extendible tongue

Gila monster

Suborder Sauria

Venomous bite

Order Squamata, Suborder Serpentes include:

snakes

What is the body of Suborder Serpentes look like?

Limbless, lost pectoral, pelvic girdles (except in pythons - vestigial)

What is the roe of the kinetic skull in Suborder Serpentes?

Allow snakes to eat prey several times their own diameter

What is a Kinetic Skull physically in Suborder Serpentes?

Two halves of lower jaw are loosely joined

How do kinetic skulls influence breathing for Suborder Serpentes?

the tracheal opening is extended during swallowing (No chewing - air passage is also moveable)

Do Suborder Serpentes have external ears?

No external ears

If Suborder Serpentes lack external ears, then how do they perceive noise?

feel low frequency vibrations (walking towards a snake, they hear you through the vibration as you walk)

Types of Locomotion in Suborder Serpentes?

Lateral

Concertina

Rectilinear

Sidewinding

What is in Lateral movement Suborder Serpentes?

S-shaped movement, pushes against rough ground

What is in Concertina movement Suborder Serpentes?

Extension of S-shaped loops to strike, climb trees

Accordion squeezes back and forth.

What is in Rectilinear movement Suborder Serpentes?

Straight movement using lifting of ribs

What is in Sidewinding movement Suborder Serpentes?

Looping by desert vipers

How do most Suborder Serpentes reproduce?

Most are oviparous

What is the parental care of Suborder Serpentes?

guard their eggs

Suborder Serpentes Pit vipers are _

ovoviviparous

A few Suborder Serpentes can be _

Viviparous

• have a primitive placenta

Suborder Serpentes have a special feature called the ____ ___

Jacobson's organs