Those Scaly Reptiles Mrs. Redinger Plant & Animal Bio Best Class Ever!!!!!

Classification Kingdom: Animalia Phylum: Chordata Class: Reptilia Subphylum : Vertebrates Class: Reptilia

4 Orders 1) Chelonia – 250 species of turtles & tortoises 2) Crocodilia – 21 species of crocs & gators 3) Squamata – 5,500 species of snakes & lizards 4) Rhynchocephalia – 2 species of tuaturas

Evolutionary History Evolved ~ 300 mya - from amphibians - had sharp teeth, claws, & strong jaws for hunting insects 300 different genuses of dinosaurs adapted to wide range of environmental conditions 65 mya = EXTINCT = MASS EXTINCTION # 1 hypothesis = ASTEROID Only the 4 modern Orders of reptiles SURVIVED

Reptilian Traits

Reptilian Traits 1) Dry, scaly, waterproof skin

Reptilian Traits 2) Amniotic egg = shell & yolk

Reptilian Traits 3) Lungs

Reptilian Traits 4) Ecto/Exotherms

Reptilian Traits 5) Molt/Shed their skin

Amniotic Egg ~ this is strong evidence that 3 groups (Reptiles, Birds, & Some Mammals) come from the same ancestor Purpose: nutrients, protection, support, prevents H2O loss,takes in O2 / rids CO2

Amniotic Egg Amnion: thin membrane which encloses embryo & contains floating liquid Amnion

Amniotic Egg Yolk sac: nutrients & fats

Amniotic Egg Allantois: store N2 waste & exchanges O2 & CO2

Amniotic Egg Chorion: protects embryo & its vital parts

Amniotic Egg Albumen: white – stores protein & H2O for the embryo

Amniotic Egg Egg Shell: protection, prevents H2O loss, & is tough & leathery

Amniotic Egg Air Sac/Space: breathe when hatching

Water Tight Skin Purpose:- decreases H2O loss - protection against wear,tear, & infections Made up of: keratin – thick protein with lipids to help repel H2O - same as hair & nails

Respiration Purpose: exchange O2 & CO2 with animal & environment Made up of: - Lungs ~ increased surface area -Alveoli ~ air sacs that make up lungs for increased surface area

Respiration Mechanics: Diaphragm - rib cage expands when inhale & contracts when exhale

Respiration Variation in snakes: larger right lung (½ length of body) ~ small, non-functioning left lung

Excretory Purpose: to remove nitrogenous waste Nitrogenous waste: - reptile’s urine is very concentrated with ammonia

Digestive Purpose: Break down food into useable molecules 1-way system composed of: - mouth & anus

Circulatory ~ more advanced & efficient than amphibians 2 loop system: Systemic loop: - heart to body to heart Pulmonary loop: - heart to lungs to heart

Number of heart chambers: Lizards, snakes, turtles: 3 2 A 1 V Crocs, gators: 4 2 V partial or full septum

Nervous Sight: larger eyes better sight Hearing: all reptiles except *SNAKES!* - tympanic membrane (inner ear) Variation in snakes: use lower jaw to detect vibrations

Smell: Jacobson’s organ: ~ located on roof of mouth - brings in scents by using tongue Pits: small openings under eyes that detect heat given off by prey ~ brain = same size as amphibians brain but larger cerebrum & optic lobe ~ all have nares except crocs & gators

Nervous System

Thermoregulation: Two Types: Ecto/exotherms: cold blooded – use sun to regulate body temperature Examples: reptiles & amphibians

Thermoregulation: Advantages Require less energy 1/10 food

Thermoregulation: Limitations Can’t live in cold environment unless they hibernate Not very active

Endotherms - warm blooded - regulate own body temp. thru metabolism Examples: mammals & birds

Endotherms Advantages Can live anywhere Lots of energy Very mobile

Endotherms Limitations Need large quantities of food

Reproduction 3 patterns of reproduction: Oviparity: most reptiles, all birds, & 3 species of mammals ~ shell formed in reproductive tract ~ laid outside the body

Reproduction Ovoviviparity: some reptiles ~ shell is retained in female ~ young hatch while inside cloaca

Reproduction Viviparity: most mammals ~ female releases egg, internal fertilization ~ mom houses, protects, & feeds young via placenta

4 orders and they all share the following traits: Modern Reptiles: 4 orders and they all share the following traits: 1. Dry, scaly, water tight skin 2. Ecto/exothermic ~ low metabolisms 3. Amniotic egg with internal fertilization 4. Respire through lungs

Order Chelonia: Traits of the order: 1. Beak *NO TEETH* 2. Oviparity: lay eggs in sand/soil 3. Body covered with 2 shells, pieces called SCUTES

Order Chelonia: Carapace: - top, dome-like shell - vertebrae of turtle is fused into shell - ribs form off vertebrae Plastron: - lower, ventral shell - protect internal organs

Turtle Skeleton

4. Body Shapes & Adaptions Aquatic turtles: ~ flat disc-like shaped shell: easier to move in H2O ~ webbed feet for swimming

4. Body Shapes & Adaptions Terrestrial turtles: ~ dome-shaped shell ~ feet are scaled & clawed

More on Turtles…

Order Crocodililia: Traits of order: 1. Large, heavy armored 2. Carnivorous 3. Oviparity - lay eggs in nest - mom cares for young for 1-3 yrs.

Order Squamata: Traits of order: Lizards: 1. Carnivorous (insects & small mammals) 2. Lower jaw attached loosely to skull 3. Agility, speed, & camo to elude predators 4. Actually detach & regrow tail in order to escape

Snakes: 1. No legs 2. Very long backbone with a pair of ribs off each vertebrae 3. 100-400 vertebrae 4. Can pop lower jaw in or out to eat prey whole 5. 1000’s of muscles for movement

Snakes: Constriction: ~ coil around prey ~ each time prey breathes, snake increases its tension ~ suffocates to death Injection of venom: 2 Types: hemotoxins = affects blood neurotoxins = affects nerves

Snakes: Fangs: ~ back of throat Elapids: ~ 2 small fixed fangs in front of mouth Vipers: ~ 2 retractable fangs on roof of mouth Ex: copperheads & rattle snakes

Order Rhynchocephalia: Order traits: 1. New Zealand 2. Third eye - sun detector - on crest of head ~ burrow during the day ~ hunt insects at night