Reptiles and Birds Adaptations for Living on Dry Land Amniotic egg Leathery shell Amniotic membrane Retains fluid in egg Lung breathing young Internal fertilization Water proof skin Kidneys can reabsorb water Amniotic Egg Amniotes Lung Breathing Young Reptile Skin Kidney Structure Scales Fish dentin (bone-like) Reptile keratin Evolved Feathers - birds Hair - mammals Feather Structure Made of keratin Same protein found in nails, hair and skin Modified scales Bone Structure Reduce weight Pneumatized filled with air Marrow some marrow still present Blood cell production Forelimb Structure Pectoral Muscles Wing Aerodynamics Flight Feathers Reduction in weight Pneumatized bones air filled bones One functional oviduct and ovary Large breast muscles Enlarged sternum with keel Bird Breathing One way system No diaphragm air sacs act like bellows to pump air into lungs No alveoli exchange occurs in thin tubes More efficient than mammalian breathing Allows birds to breath in low oxygen conditions Bird Breathing Dodo Bird Flightless Bird Ovary One functional ovary and oviduct (left) Fertilization occurs in upper oviduct Albumin added Shell gland produces hard shell Complete fertilized egg exits through cloaca Parental Care of Young Nest preparation Egg incubation Feeding Protection Mating Systems Monogamy Mate for life Swans, pigeons, geese Seasonal monogamy Most songbirds Polygamy Male with many females Turkey, grouse Newly Hatched Young Precocial Covered with down Can see Mobile (walk, run, swim) Forage for food Altricial Naked Blind Remain in nest Fed by parent or parents Altricial Both parents often needed for feeding Insects, fruit, rodents, birds Pigeons Pigeon milk Produced in crop Nest Parasites Lay eggs in smaller birds nest Parasitic bird usually hatches first Parasitic bird is larger and pushes out other young and eggs Cowbird, cuckoo Host birds are often smaller songbirds Wrens, blackbirds, sparrows Cowbird