Herp exam 2

Amniotes

early reptiles

most numerous and largest radiation of reptiles

Mesozoic

Lepidosauromorphs evolution

2nd major diapsid lineage

1st lizards

hylanomus

When did snakes start evolving more rapidly

Jurassic period

ruling reptiles of mesozoic

Archosauromorphs

Amniotic egg anatomy

4 membranes

• Yolk sac - nutrients (connected to embryo, below)

• Amnion - cushion from impact (around embryo)

• Chorion - gas exchange (outer layer)

• Allantois - storage waste (connected to embryo, above)

Stratum corneum

thick outer layer of dead epidermal cells

Stratum germinativum

cell derivatives produced by living cells of deep epidermal layer

Scales or scutes (turtles) are

folded areas of epidermis, made up of keratins process called embryogenesis

Osteoderms

bony pates or deposits within the skin

Lenticular sense organ (scale organs)

small circular sense organs ; mechanoreceptors

Columella

single sound transmitting bone in inner ear, Assists in detection of vibrations

Copulatory organs of Squamata

Hemipenes - everted during copulation

Acrodont teeth

attached to crest of jawbone

Pleurodont

attached inner sides of jaw bone

polyphyodont

continuously replace teeth ; most are poly

Panthenogenesis

• ability to reproduce without offspring

  • Many have temperature dependent sex determination

Caudal autotomy

ail breaks off

• Anti-predation

• Can be intravertebral or intervertebral

Intravertebral autotomy

Fracture planes in tissue and vertebrae for ease of break

Intervertebral autotomy

Involuntary, tail will not regenerate

Venom

synthesized proteins

Snakes vs other reptiles

• Protective Cover: Snakes have a spectacle (transparent scale); lizards do not.

• Focus & Structure: Lizards use ciliary muscles to shape the lens and almost all have scleral ossicles (bony supports).

• Light Filtering:

  • Lizards: Use colored macrolipid droplets and always have clear lenses.

  • Snakes: Use colorless microlipids; diurnal species have amber lenses to filter blue light.

• Processing: Both use retinal motility to adjust light, but their brains process images differently: lizards use the tectum, while snakes use the thalamus.

 pit organs

Snakes have pit organs that detect infrared radiation

Aglyph

homodont dentition - aka no fangs

Opisthoglyph

rear fangs

Proteroglyph

hollow fangs on anterior end

Solenoglyph

Vitellogenesis

accumulation of nutrients, nutrients will later become the yolk

Cleiodoic egg

shelled egg

Parthenogenesis

females reproduce without males or sperm

Genotypic sex determination

Males XY, females ZW. can be heterogametic

TSD (temp sex determination) pattern la

males produce at cooler temps, females higher (turtles, squamates)

TSD (temp sex determination) pattern lb

females produced at cooler temps, males warmer (tuatara, squamates, crocs lizards)

TSD (temp sex determination) pattern ll

females produced at both cool and warm temps, and males at intermediate temps

Pre depositional parental care

finding and building nest

Post depositional parental care

guarding her eggs

vivipary

live birth

Ovovivipary

eggs retain longer inside then live birth

characteristics of a species produce single clutch

• Delayed maturity (>1 year after hatching)

• Require more time to grow

• Typically produce large numbers of small eggs or small number of large eggs

• Longer lived

Species produce multiple clutches

• Early maturity

• Rapid growth

• Lay eggs consistently

• High reproduction offset by high mortality

•  Shorter lifespans

Gas exchange - aspiration pumping

lungs using negative pressure

Expiration

 raise pressure in lungs and force air out

Inhalation

lower pressure in lungs and draw air in

Relaxation

small gap of time before reptiles expirate again

Lizards use same muscles to shift air between lungs when

moving, running. They don't breathe when running

how many lungs do snakes have

2, one is 98-99% smaller - increase surface area, limit blood supply, buoyancy

Crocodylians have _____ of air in lungs (similar to birds)

unidirectional flow

Turtles air flow

Shell prevents normal expansion of rib cage. visceral cavity expands and contracts for air flow in lungs

Systemic blood flow

vessels into capillaries = high pressure - oxygenated blood to parts of the body

Pulmonary blood flow

some capillaries = low pressure - deoxygenated blood deposits waste

Crocodiles have a/an __ chambered heart

4

Frogs hearts

spiral valve, very minimal mixing of blood

Turtles and squamates hearts

 near full separation of blood, 3 chambered heart

ATP synthesis

energy gained from aerobic respiration

oxidative respiration

aerobic metabolism

glycolytic respiration

anaerobic metabolism

VO2 rest

you are motionless

VO2

rises when the animal starts to walk, rises as locomotion rises

VO2 max

highest speed that can be sustained by oxidative metabolism

Optimal foraging theory

no animal will expend more energy than the meal itself gives

Aestivation

long term dormancy

Hibernation

dormancy during periods of cold and food scarcity

Inertial suction

Snake necked Turtles - Creates inward flow of water

Projectile Feeding

High-speed extension of the tongue or jaw to capture prey at a distance.

Akinetic Feeding

Feeding with a rigid, non-moving skull (common in turtles/crocs).

Kinetic Feeding

Feeding involving moving joints within the skull to increase gape or bite force (common in snakes/lizards).

Reaction force

equal and opposite force on surface when a limb is pressing on ground

Vertical component

up and down pressure from locomotion

Propulsive component

forward and backward movement

footfall pattern

pattern on how left and right hind and forefeet fall

Lizards (locomotion)

Uses lateral bending of trunk to enhance stride length = faster movement

Crocodylians (locomotion)

Gallop in semierect position; limb movement nearly parasagittal; still sprawl like lizards

Turtles (locomotion)

Ribs and vertebrae fused to shell (low flexibility); limb girdles enclosed in shell; lateral footfall pattern with wide support

Snakes (propulsion)

Use friction as propulsion force

Lateral undulation

Most common snake locomotion method

Concertina locomotion

Snake locomotion used on low-friction surfaces and in confined spaces

Sidewinding

Snake locomotion used on low-friction or shifting surfaces

Rectilinear locomotion

Snake locomotion with no alternating contraction of lateral muscles; both sides contract synchronously

Aquatic locomotion

Water is dense and viscous (good for propulsion) but heavy (limits depth) and offers greater resistance

Undulatory swimmers

Use axial waves to propel; increase lateral surface area; rotate ribs to compress body; marine snakes flatten tail

Oscillatory swimmers

Use limbs like humans; perform frog kick

Climbing – Grasping

Grip with fingers and toes; use prehensile tails; maintain straight vertebral column

Climbing – Adhesion

Modifications of feet, toes, or tails for sticking to surfaces

Geckos (climbing)

Use adhesion via specialized foot/toe modifications

Falling

Free fall where drag equals resistance

Parachuting

Drag is greater than lift; occurs at ~45° angle

Gliding

Lift is greater than drag; occurs at ~45° angle

Cervical

Nuchal

Peripheral

Pleural

Suprapygal

Costal

Vertebral

Marginal