Reptiles, Birds and Mammals Our scaly, feathered and hairy friends!

3 Key Adaptations for Life on Land 1. Amniotic Egg 2. Internal Fertilization 3. Water-tight skin An amniotic egg is a waterproof egg with a shell. It is named for a particular membrane called the amnion. The amnion protects the embryo from drying out and surround a fluid filled cavity that cushions it.

Key Adaptations The other membranes formed during development of the embryo function in gas exchange, waste removal and supplying nutrients. The amniotic egg makes it possible to lay an egg on land without needing to return to the water like an amphibian.

Key Adaptations In internal fertilization, the male deposits sperm within the female’s body. The sperm then swims inside the reproductive tube towards the egg. This allows for reproduction to take place outside of water. Amniotes have a water-tight skin enriched with a waterproofing protein called keratin. The keratinized skin prevents dehydration.

Key Adaptations Reptile skin has scales which are hard, overlapping structures made of keratin. Birds have feathers made of keratin. Mammals have hair, nails and horns made of keratin.

Vocabulary Ectotherms-main source of body heat is the environment-cold-blooded Endotherms-body heat generated internally by cell metabolism, warm-blooded

History of Reptiles The oldest reptile fossils have been found in rocks dating from the Carboniferous period about 300 mya. Reptiles diversified in the Mesozoic era. At that time, dinosaurs occupied every habitat and ecological role. Some were very quick and agile indicating that they might have been endotherms. Some fossils of dinosaurs have been found with feathers. Dinosaurs became extinct 65 mya from a massive collision with a comet or asteroid.

Snakes

Lizards

Crocodilians Alligator Crocodile

Crocodilians Gavial Caiman

Tuaturas Rare, old species Different structures than lizards, vestigial third eye and slowest metabolism in reptile class Endangered Live only on islands near Australia and New Zealand

Tuatara-living fossil

Reptiles Turtles and Tortoises Hard shell Made of scutes Longest lived reptiles Lizards and snakes Can be legless or Have limbs Snakes evolved From lizards Crocodilians Alligators Crocs caimans Related to dinosaurs Tuataras Rare endangered Different physical Characteristics Than lizards

History of Birds Molecular and fossil evidence indicated birds and crocodilians are more closely related to dinosaurs than any other reptiles. Feathers-modified scales made of keratin used for flight and insulation

Birds Birds have a system of branching air sacs that function with their lungs in respiration. The air sac system helps supply the high levels of oxygen that support a high rate of metabolism. Air sacs also reduce the overall body weight of the bird. Bird bones are honeycombed and mostly hollow but are still structurally strong.

Bird’s Adaptations to Decrease Body Weight 1. Air sac system 2. Honeycombed bones 3. Absence of many internal organs 4. Absence of teeth

Birds Gizzard- muscular organ often containing small stones that grind seeds and other food Crop- sac like organ used for temporarily storing food 4 chambered heart is efficient by keeping oxygen rich blood completely separate from the oxygen poor blood.

Origin of Birds Many paleontologists agree the ancestor of birds was a small, feathered dinosaur. A famous bird fossil, Archaeopteryx lived 150 mya. It had a mixture of bird and reptilian features.

Archaeopteryx

Flying Styles Rapid altitude changes-finches, cardinals Soar and glide on air currents-falcons and albatrosses Flap or buzz quickly and can hover or go backwards- hummingbirds Flightless swimming/diving birds-penguins Flightless running birds-ostriches, emus

Beak Adaptations Made of keratin Modified to the food source Toothless and cannot chew

Foot Structure Perching-songbirds Grasping-woodpeckers, nuthatches Raptors-eagles, hawks Swimming-ducks, geese

Perching Birds

Swimming Birds

Raptors

Birds Perching Cardinals songbirds grasping woodpeckers raptors Eagles hawks swimming Duck geese

Behavioral Adaptations Complex courtship behaviors Complex song communications Caring for offspring Nest building

Origin of Mammals The oldest fossils of mammals date back about 200 mya to early Mesozoic era. Fossil evidence indicates mammals evolved from reptiles called therapsids. Early mammals coexisted with dinosaurs but were mouse- sized and ate insects. These early mammals were nocturnal and endothermic. Mammals took over all habitats and diversified once the dinosaurs went extinct. Mammal-endothermic vertebrate that possesses mammary glands and hair

All Mammals have: 1. Mammary glands 2. Hair 3. Lungs 4. Muscular diaphragm that separates lungs and heart from the rest of the body 5. 4 chambered heart 6. Reproduce sexually with internal fertilization (a few exceptions) 7. Most give live birth with few exceptions

Mammals Placentals Embryo develops In a uterus Placenta provides Nutrients to embryo Contains amnion like bird and reptile eggs 4,200 species Monotremes Lay eggs Only live in Australia and Neighboring islands Mixture of reptilian And mammalian characteristics Platypus and echidna Marsupials Have a pouch Young born before Fully developed Most live in Australia and Neighboring Islands, except opossum Kangaroos Koalas Opossums Etc..

Monotremes

Marsupials

Marsupial babies

Placental Mammals

Early Hominids Oldest evidence for bipedalism or upright walking was Australopithecus about 4 mya. Famous fossil called Lucy.