Chapter 26 Reptiles and Birds

Reptile skin Dry, thick, with scales Prevents water loss Provides protection

Reptile heart / lungs Use lungs for breathing Most have 3-chambered hearts Crocodilians – 4-chambered hearts Completely separates oxygen-rich blood from oxygen-poor blood Supports higher level of energy use

Skeletal changes Leg position (under body) provides better support Makes running / walking easier Easier to catch prey / avoid predators Claws used to get food / protection Jaws and teeth

Reptile reproduction Lay eggs on land No larval stage Hatchlings resemble adults, only smaller Amniotic egg nourishes embryo and provides protection Internal fertilization No care for hatchlings (except crocodiles)

Other reptile characteristics Ectotherms-body temperatures depend on temperature of environment Don’t live in cold regions Prefer warm or hot climates Become dormant during cold months

Reptile adaptations Turtles and tortoises Lizards Snakes Most hervibores Predators eat worms, mollusks, fish Lizards Eat insects Snakes Small mammals

Snake sense organs Heat-sensitive organs allow them to detect variations in air temperature (warm-blooded animals) Jacobson’s organ-used to smell

Turtle adaptations Shells protect Powerful jaws but no teeth Live in water, (tortoises on land)

Crocodiles Don’t migrate Jaws and teeth, used to drown their prey Lays eggs on land Guard nests

Lizards Found in all habitats except polar regions Jaws and teeth

Snakes No limbs Found in all regions except polar areas Kill prey in three ways Constrictors wrap around and squeeze Venomous snakes inject toxin with fangs Most swallow prey whole

Birds Class Aves Fossil evidence show evolution from thecodonts Clawed toes on feet Internal fertilization Amniotic eggs with shells

Feathers Lightweight, modified scales Provides insulation and enables flight Preening with the beak / bill keeps feathers clean and oiled for water-proofing Feathers molted usually in summer and new ones grow

Bird bodies Front limbs modified into wings Powerful flight muscles attached to sternum and upper bone of each wing (to generate lift) Requires large amounts of energy; eat large amounts of food 4-chambered heart Endotherms-control own temperature Live in all environments

Bird adaptations Feathered legs-walk in snow Wings / feet adapted for swimming Insulating fat Large eyes, acute hearing, sharp claws Shape of beak adapted for specific food

Mammals Active, large-brained, endothermic animals Complex social, feeding and reproductive behaviors Come in many different shapes and sizes

4 characteristics shared by ALL mammals Hair Mammary glands Middle ear containing 3 bones Jaw to chew food

Hair Most species are covered with it Used to retain heat by trapping a layer of air close to the skin Can be used for behavioral displays (puffing up when frightened) Can be used for camouflage Specialized hairs (whiskers) help with sensory information

Mammary glands Glands that produce milk to feed the newborn young Milk contains water, sugars, protein, fats, minerals, and antibodies Found in both sexes of all species but only produce milk in females

Middle ear 3 small bones (stapes, malleus, incus) Vibrations of the eardrum are transferred through the malleus and incus bones to the stapes Vibrations are converted into nerve impulses in the inner ear and interpreted by the brain Allows mammals to hear high-pitched sounds

Chewing Begin to break up food in the mouth (rather than starting in the digestive tract) Secondary palate separates the nasal and oral cavities so mammals can eat and breathe at the same time Complex muscles control movement of the jaw

3 groups of mammals 1. monotremes Lay eggs 3 species (platypus, 2 types of echidna) Retain some reptilian features (sprawling posture, single external opening, amniotic eggs with leathery shells) Some mammal features (hair, mammary glands)

3 groups of mammals 2. marsupials- 282 species including kangaroos, wombats, Opossum, koalas Give birth to under-developed young that must complete development inside a pouch Tiny young must attach themselves to a nipple inside the pouch for feeding during development

3 groups of mammals 3. eutherian mammals Give birth to live young that completed development internally Often called placental mammals Parental care is necessary to protect young after birth when they are most susceptible to predators