Amniote Orgins and Nonavian reptimes

What does the diversity of amniotes do?

break ties with water

What type of shells do amniotes have

amniotic egg; shelled membranous egg, internal membranes

Before the end of the Palezoic Era, amniotes diverged into …

1. nonavian reptiles

2. birds

3. mammals

How many species of paraphyletic Class Reptilia

around 9000

How many species of the Class Reptilia occur in the US and canada

around 320

The age of Reptiles lasted over … years and included …

1. 165 million years

2. dinosaurs

Modern reptiles represent surviving lineages of a mass extinction at the end of the … also known as the …

1. Mesozoic Era

2. Age of Reptiles

What is the sole survivor of a group that otherwise disappeared 100 million years ago

The tuatara

Amniotes arose from amphibian like tetrapods called … during the carboniferous

The anthracosaurs

By the late Carboniferous, amniotes had separated into 3 patterns of holes (fenestra) in the temporal region of the skull

1. Anapsid

2. Diapsid

3. Synapsid

Anapsid

lack arch; no temporal openings behind the orbits

Diapsid

2 arches; has two temporal openings

Synapsid

1 arch; single pair of temporal openings

Turtles have a what skull

Anapsid

What animals have a diapsid skull

1. lizards

2. snakes

3. tuatara

4. crocs

5. birds

Mammals have what type of skull

synapsid

Diapsid is the …

ancestral condition

Turtles are secondary …

anapsid

Early diapsids gave rise to 4 morphologically distinct groups

1. Lepidosaurs

2. Archosaurs

3. Sauropterygians

4. Ichthyosaurs

Lepidosaurs

the living reptiles like lizards and snakes

Archosaurs

the dinosaurs, pterosaurs, and also the living crocs and birds

Sauropterygians

the extinct aquatic groups like the long-necked plesiosaurs

Ichthyosaurs

the extinct aquatic dolphin like forms

Orgin and early evolution of amniotes jaw

1. openings attach large muscles that elevate the lower jaw

2. Changes in jaw musculature might reflect a shift from suction feeding in aquatic vetebrates to terrestrial feeding the required larger muscles

The only living synapsids are …

mammals

All amniotes have eggs with three internal membranes

1. amnion

2. allantois

3. chorion

Amnion

encloses the embryo in fluid, cushioning the embryo and providing an aqueous medium for growth

Allantois

stores metabolic waste

Chorion

surrounds the contents of the egg and is highly vascularized , Oxygen and CO2 is exchanged

The allantois and Chorion form an efficient …

respiratory organ

What is an advantage of an amniote egg

it permits development of a larger, faster growing embryo

One hypothesis suggests that a first step in the evolution of the amniotic egg was replacement of the jelly layer with a shell, what does this provide

1. provided better support

2. diffusion of oxygen

3. shell provides calcium to growing skeleton

All amniotes lack larval stage and have …

internal fertilization

Characteristics of the amniotic egg eliminated the need for …

aquatic environments

What is the difference with amniote skin compared to other species

thicker and more waterproof

Amniote skin is thick and tends to be more … and less permeable to water

keratinized

What do amniotes have

1. scales

2. hair

3. feathers

What does amniote skin do

prevents dehydration

In crocs scales remain …

throughout life

In nonavian reptiles such as lizards and snakes, new kertinized epidermis replaces the old epidermis which is …

shed

Ecdysis

shedding

Turtles have plate - like modified scales called

scutes

A penis is the most common copulatory organ and is derived from the cloacal wall and is an ….

amniote innovation

Rib ventilation of the lungs

Amniotes draw air into their lungs by expanding the thoracic cavity; vascularized sponge

Stronger jaws

1. early tetrapods had expanded jaw musculature

2. muscular tongue for mastication and swallowing

High pressure cardiovascular systems

1. partitions between atria and ventricles

2. ther is either limited or no mixing of oxygen rich and oxygen poor blood within the heart

Most reptiles have what type of heart

2 atria and 1 ventricle

Crocs have what type of heart

2 atria and 2 ventricles

Birds and mammals have what type of heart

2 atria and 2 ventricles

Many amniotes remove nitrogenous wastes mostly as …

uric acid (some with urea) which require more energy to produce but do not need to be dissolved in water

Uric acid

precipitate

In some amniotes, excess salts can be removed through other structures such as ….

1. sweat glands/pores

2. nose

3. eyes

4. tongue

Reptiles and birds excrete …

uric acid

Mammals excrete …

urea

The adaptation of the amniote brain

expanded, and sensory organs

Both the … and … are larger in amniotes

1. cerebrum

2. cerebellum

Many amniotes have excellent senses of …

1. hearing

2. vision

3. olfaction

These are known as tactile

Fossils of the order testudines( turtles) appear in the upper triassic …

220 million years ago

In turtles the shell has an outer horny layer of keratin and an inner layer of bone

1. dorsal carapace

2. ventral plastron

Tomium

in turtles instead of teeth, bony plates over jaws for gripping food

How do turtles solve their breathing problem

using abdominal and pectoral muscles as a diaphragm

What are characteristics of the turtles nervous system and senses

1. brain is small

2. have a middle and inner ear but sound perception is poor

Reproduction and development of turtles

1. oviparous; fertilization is internal and all turtles buy their eggs in the ground

2. once the female lays her eggs in a nest, she deserts them

Squamates

Lizards, amphisbaenians and snakes

Squamates are the most …

recent and diverse of the diapsid

Squamates comprise over what percentage of living reptiles

90%

Diapsid skulls have lost dermal bone ventral and posterior to the lower temporal opening, this allowed evoloution in lizards of a mobile skull with movable joints called a …

kinetic skull

Live bearing in reptiles is limited to

squamates (lizards and snakes)

Lizards conserve water by producing semisolid urinary waste with a high content of crystalline …

uric acid

Some lizards can store fat in their tails to provide energy and metabolic water during …

drought

The Gila monster and beaded lizard are the only lizards capable of a …

venomous bite

Lizards keep their body temperature relatively constant by … although they are ectothermic

behavioral thermoregulation

The … or worm lizards are lizards highly specialized for a fossorial (burrowing life)

amphisbaenians

Morphological and molecular data show that amphisbaenians are …

highly modified lizards

Amphisbaenians characteristics (4)

1. lack limbs

2. eyes hidden

3. no external ear openings

4. skull is conical/ spade shaped

Where are amphisbaenians found

south america, tropical africa, one species in flordia

Sepentes

snakes

Snakes are limbless and lost the … and … girdles

pectoral and pelvic

For serpentes to keep breathing during swallowing the tracheal opening is …

extended forewards

… rather than vision or hearing are the main senses snakes use to hunt prey

chemical senses

… such as rattle snakes have pits with nerve endings sensitive to heat emitted by potential prey or predators

pit vipers

Viper fangs and … and … to inject venom when the snake strikes

hollow and hinged

Includes new world and old world vipers with and without pits

family viperidae

includes cobras, mambas, coral snakes, and kraits

family elapidae

includes specialized sea snakes

family hydrophiidae

Most members of this family are non-venomous; several including the African boomslang and African twig snake are rear fanged and their bite can be dangerous for humans.

family colubridae

Saliva of harmless snakes contains limited …; this provided a basis for natural selection of venom

toxins

Act on the nervous system, causing blindness or stopping repiration

neurotoxins

Break down blood vessels; blood is leaked into tissue spaces

hemotoxic venoms

What two snakes have the most deadly venom per unit

1. sea snakes

2. australian tiger snake

How many snake bites in india per year and why

1. 200,000

2. poor footwear

How many snake bites per year in the US and how many deaths

1. 7,000

2. 5

Total deaths of snake bites per year and mostly occuring where

1. 50,000-60,000

2. India, burma, pakistan, myanmar

Less than what percent of all snakes are venomous

20%

What is the ratio of venomous speciea to nonvenomous species in australia

4-1

Many snakes are … and lay shelled eggs under logs or rocks or in holes in the ground

oviparous

Snakes including pit vipers are …

ovoviviparous

A few snakes are … having primitive placenta to exchange nutrients with the young

viviparous

Only one species in new zealand area represent this ancient lineage

order sphenodontia : the tuatara

The tuatara once widespread across new zealand, the species is now restricted to …

small islands