Reptiles and Birds

• What are amniotes?

  Tetrapods with a terrestrially adapted egg
• What are the extant groups of amniotes?

  Reptiles, birds, and mammals
• What are the derived characteristics of amniotes?

  Amniotic egg and four extraembryonic membranes
• What are the four extraembryonic membranes of the amniotic egg?

  Amnion, chorion, yolk sac, allantois
• What is the significance of the amniotic egg?

  It allows colonization of land by vertebrates
• Which vertebrates do not have extra-embryonic membranes?

  Fish and amphibians
• What are the evolutionary reasons for the amniotic egg?

  Unclear, but it allows increased size and strength
• How does the amniotic egg provide protection?

  Through a leathery or calcified shell
• How does respiration occur in the amniotic egg?

  Through the shell and vascularized membranes
• What role does the allantois play in the amniotic egg?

  It is involved in respiration and excretion
• What is the function of albumen in the amniotic egg?

  It provides nutrition and protection
• What adaptations do amniotes have for life on land?

  Rib cage for lung ventilation
• How does rib cage ventilation compare to throat-based ventilation?

  Rib cage ventilation is more efficient
• What is the significance of less permeable skin in amniotes?

  It aids in water conservation
• When did the most recent common ancestor of living amphibians and amniotes exist?

  Approximately 370 million years ago
• What evidence suggests early amniotes could live in drier climates?

  Fossils indicate adaptations for arid environments
• What are the extant groups included in the reptile clade?

  Tuataras, lizards, snakes, turtles, crocodilians, birds
• What are the derived characters of reptiles?

  Scales made of keratin and shelled eggs
• How do most reptiles reproduce?

  Through internal fertilization before egg shell formation
• What is the energy requirement difference between reptiles and mammals?

  Reptiles require ~10% of mammal energy
• When did the oldest reptilian fossils appear?

  Late Carboniferous, around 310 million years ago
• What are parareptiles?

  Large, stocky, quadrupedal herbivores
• What are the two main lineages of diapsids?

  Lepidosaurs and archosaurs
• What are the characteristics of ornithischian dinosaurs?

  Herbivores with anti-predator defenses
• What adaptations do theropods have for predation?

  Bipedal stance and sharp claws
• How many extant species of turtles are there?

  307 species
• What is the significance of the turtle shell?

  It provides defense and protection
• How did the retraction mechanisms of turtles evolve?

  Independently in two branches
• What are the threats to turtle populations?

  Fishing nets, habitat destruction, pollution, climate change
• What adaptations do crocodilians have for their habitats?

  Upturned nostrils and aquatic adaptations
• What is the origin of birds according to cladistic analysis?

  Derived from bipedal saurischians, theropods
• What functions did feathers serve before powered flight?

  Insulation, camouflage, courtship, brooding
• What is Archaeopteryx known for?

  Being a feathered theropod with ancestral characters
• What are the derived characters of birds?

  No urinary bladder and toothless beak
• How do birds maintain their high metabolic rate?

  Through a four-chambered heart and efficient lungs
• How many extant orders of birds are there?

  32 extant orders
• What adaptations do flightless birds have?

  Similar body shapes and modified beaks
• What are the evolutionary origins and trends in the reptilian clade?

  • Evolution of the amniotic egg
  • Adaptations for terrestrial life
  • Diversification of reptiles and birds
• What is the importance of the amniotic egg?

  • Allows reproduction on land
  • Protects developing embryo
  • Provides nutrition and waste management
• What are the adaptations of birds for flight?

  • Lightweight skeleton
  • Feathers for aerodynamics
  • High metabolic rate
  • Efficient respiratory system