Ch.34 Pt.2 Tetrapods: Amphibians,Amniotes: Reptiles (not birds)

How do land amniotes concentrate nitrogenous waste?

-convert NH3 to less toxic urea or nitric acid (takes energy) -kidneys concentrate urine by conserving water

Archosaurs: Crocodilians include

-crocodiles, alligators and kin

Amniote fertilization

must be internal (before shell is made) -shell produced in female reproductive tract

3 groups of amphibia

salamanders, frogs, caecillians

Endothermic animals..... What animals do this?

-high metabolic rate warms the body -requires insulation (feathers, fur, fat) -characteristic of birds and mammals

Aquatic reptiles return to land to ........

-lay eggs -can be buried: moist, warm and safe

Amniotes waterproof skin is made of? This means there is?

-layers of dead cells w/ keratin and lipids -no gas exchange across the skin

Unusual features of tuataras

-light sensitive pineal gland on top of head (3rd eye) -unique dentition (teeth) -no external ears -prefers cooler temps (75 degrees)

Lepidosaurs: Squamates includes.....

-lizards and snakes

Acanthostega fossil was a ____________

fish like tetrapod with limbs (8 digits), not fins

Amniotic egg: Chorion

gas exchange

Tiktaalik fish and tetrapod characteristics

Fish: scales, fins, gills and lungs Tetrapod: neck, ribs, fin skeleton, flat skull, eyes on top of skull

Amphibia heart

-3-chambered for better oxygen supply -dual circulation = higher blood pressure (blood is oxygenated then pumped again)

Salamander characteristics

-4 legs and tail as adults -live in a moist terrestrial environment

Frog characteristics

-4 legs but no tail as adult -moist terrestrial or fresh water environment -breed in ponds or puddles

Tetrapod Characteristics (5)

-4 limbs with wrist and digits -pelvic girdle fused to backbone -head moves independently of the body -lung breathing as adults -no scales on skins

Snake characteristics

-all predators -descended from lizards - no eyelid -no external ear -broad ventral scales (lizard has small scales across its body)

Aquatic animals including most body fish rid nitrogenous wast as

-ammonia -highly toxic and lost thru gills or skin

Amniote characteristics (6)

-amniotic egg -waterproof skin -water conserving excretion of nitrogenous waste -negative pressure breathing -improved dual blood circulation -control of body temp

Amphibia larval stage characteristics

-aquatic with gills (eats algae, aquatic larvae, worms) -metamorphosis into carnivorous adult (eats insect, worms)

What are turtles teeth replaced by?

-beak or keratin

During the mid-to-late Paleozoic the tetrapods had ______

-become large and diverse -remained close to fresh water (all living tetrapods have five digits)

Explain negative pressure breathing

-bring in air by expanding the rib cage -more efficient than gulping air by fish and amphibians (positive pressure breathing) -expand rib cage --> increase volume --> lower pressure--> "sucks" in air -increase volume, less pressure

How do amniotes rid waste?

-conserve water by concentrating and riding nitrogenous waste

Archosaurs include

-crocodilians -birds

What are turtles shells made of? Shape?

-flat -keratinous shell plates

gizzard function

-food grinding organ in the digestive tract

Reproduction in amphibia is tied to _________ Add. characteristics of reproduction?

-fresh water -diverse mating behaviors -frogs and toads have external fertilization (female lays eggs, male squirts sperm) -oviparous: fish like eggs

How do amphibia breath?

-gas exchange across moist skin and lungs -gulps air like fish to fill lungs -expanding mouth cavity "sucks" air into the mouth, but mouth must push air into lungs (positive pressure breathing) -can not eat and breath at the same time

Who were the ancestors of tetrapods?

-lobe-finned fish, lung breathing -had many tetrapod features ex. Tiktaalik- had tetrapod features (could shuffle in water and maybe on land)

Toads characteristics

-more terrestrial - thicker skin w/ bumps

Lizard characteristics

-most are terrestrial predators (iguana- vegetation eater) -external ear openings -eyelids that close

Amphibia characteristics

-most basal extant tetrapod group -thin, moist skin that loses H2O easily -gas exchange: skin and lungs -3-chambered heart -reproduction tied to water

Amniotic egg: Yolk sac

-nutrients reservoir -delivers nutrients

Turtle reproduction

-oviparous - lay eggs, buried on land

What caused improved dual blood circulation in amphibians?

-partly or completely divided ventricles

Function of the egg shell in the amniotic egg? Made of?

-porous, reduces water loss but allows O2/CO2 exchange -rigidity varies with amount of CaCO3 (ex. bird eggs-highly calcified)

Amniotic egg: Amnion function

-protects embryo within a watery amniotic sac -cushions embryo

Lepidosaurs: Tuataras

-remnant ancient lizard like reptile -in lizard/snake clade but with unusual features

The amniotic egg allowed for

-reproduction freed from water

Characteristics shared by non-bird reptiles

-scaly skin w/o feathers or fur -low profile, sprawling stance -low metabolic rates -ectothermic -eggs w/ leathery, less calcified egg shells (compared to birds)

Crocodilian characteristics

-semi aquatic predators -extant from the Triassic dinosaur age -both dinosaur and bird like features -gizzard -4 chambered heart -oviparous (some nesting care)

Caecillian characteristics

-snake-like -no legs as adult -mostly terrestrial, burrow (evolutionary convergence with snakes)

Snakes and lizard diverse birth types

-some parthenogenesis -most oviparous -some ovoviviparous -few viviparous

Amniotic egg: Ambumen

-stores water (produced by the mother)

Distinctive characteristics of turtles

-upper and lower bony shells fused to ribs and vertebrae -teeth absent -adapted to land, freshwater, and marine environment -diverse foods -oviparous

Mammals, most amphibians, sharks, and some bony fish rid nitrogenous waste as ....

-urea -concentrated by the kidneys

Many reptiles (incl. birds) rid nitrogenous waste as.....

-uric acid -least toxic but most costly -saves the most water

Birds combine what two things when riding waste?

-uric acid (white) and feces -one hole

Exothermic animals....... What animals do this?

-use the environment to warm their body (use behavioral thermoregulation) -low metabolic rates generate little heat -basking behavior -all non-bird reptiles

Do mammals have an amniotic egg?

-yes, but the egg shell is absent -the membranes still function

Food sources of turtles

diverse - vegetation and animals

Other extraembryotic membranes function to

sustain the embryo with little water loss

Amniotic egg: Allantois

water disposal and gas exchange